To see the other types of publications on this topic, follow the link: Tunnel problem.
Journal articles on the topic 'Tunnel problem'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Tunnel problem.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Sui, Chuan Yi, Xu Dong Zhou, and Lin Hui Wang. "The Comparison of Tunnel Engineering Construction Methods for Renhechang Tunnel Crossing Underneath Existing Tunnel on Lanzhou-Chongqing Railway." Applied Mechanics and Materials 405-408 (September 2013): 1330–33. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.1330.
Full textAbstract:
Problems often exist in construction of transportation tunnels, such as the effect of new tunnels constructed close to existing structures. Solving this magnificent problem by carefully choosing tunnel construction methods will be beneficial to minimize effects on existing structures while ensuring the newly constructed tunnel is both time-consuming and economical. Three representative engineering methods-the benching tunneling method, the Center Diaphragm method and the Cross Diaphragm method-are compared in controlling the settlement of new tunnel vault and the deformation of the existing tunnel. Finally checking the simulation results by comparing with field measurement data.
2
Yanli, Qi, Wen Shaoquan, Bai Mingzhou, Shi Hai, Li Pengxiang, Zhou Hao, and He Bohu. "Evaluation and Deformation Control Study on the Bias Pressure of Layered Rock Tunnels." Mathematical Problems in Engineering 2021 (August 5, 2021): 1–20. http://dx.doi.org/10.1155/2021/9937678.
Full textAbstract:
In the process of tunnel construction, the bias of layered rock mass tunnels has always been a prominent problem that troubles the construction and safe operation of tunnels. In this paper, a comprehensive method that combines monitoring technology and discrete element (3DEC) numerical simulation is proposed to analyze the deformation characteristics of the surrounding rock in the layered rock tunnel and the deformation law of the bias tunnel. The results indicate that the tunnel surrounding rock deformation in the study area showed the characteristics of bias. Based on the bias mechanism, the surrounding rock deformation law, the construction deformation control, and the optimization measures of layered rock mass in the bias tunnel were studied by means of combining monitoring technology with discrete element (3DEC) numerical simulation. Based on the research results, appropriate methods for controlling the deformation of the surrounding rock of the tunnel with comprehensive consideration of the anchor rod length, anchor rod angle, and anchor rod layout spacing were proposed. The method proposed in this paper could visually reveal the deformation characteristics of the surrounding rock of layered rock tunnels and the deformation law of bias tunnels. It could also better solve the problem of deformation control in the tunnel construction process. This approach provides a novel idea for special layered rock mass tunnel bias evaluation and deformation control parameter optimization and serves as a valuable reference for analogous engineering cases through engineering case analysis.
3
Krasyuk, Aleksander, Ivan Lugin, and Elena Alferova. "STUDY OF AIR DISTRIBUTION AT ELONGATED TRANSPORT TUNNELS OF BAIKAL-AMUR MAINLINE." Interexpo GEO-Siberia 2, no. 4 (2019): 114–21. http://dx.doi.org/10.33764/2618-981x-2019-2-4-114-121.
Full textAbstract:
At the paper results of study of air distribution at elongated railway tunnels from piston effect of trains are represented. Simulation was carried out on the example of movement of freight train with length of 1 km at tunnels with length 3 and 6 km by numerical experiment in ANSYS Fluent software pack. As a result of the study, dependences of air pressure to front and rear surfaces of train on its position in the tunnel and on value of aerodynamic resistance of the gap between train and wall of the tunnel are obtained. The results have been used for development of quasi-dynamic model of piston effect of trains for solution of static air distribution problems on network models. Comparison of air discharge at various tunnel cross-sections obtained using ANSYS Fluent pack and network model shows satisfied repeatability. In that case, time of problem solution for a tunnel with length 3km on network model in 4·105 lower than on volume model. It has important practical meaning for multivariant calculations during designing of ventilation systems at railway tunnels.
4
Knewtson, Sharon J. B., Rhonda Janke, M. B. Kirkham, Kimberly A. Williams, and Edward E. Carey. "Trends in Soil Quality Under High Tunnels." HortScience 45, no. 10 (October 2010): 1534–38. http://dx.doi.org/10.21273/hortsci.45.10.1534.
Full textAbstract:
Growers have indicated that changes in soil quality under production in high tunnels is an important problem, but these have not yet been quantified or critically assessed in the central Great Plains of the United States. We conducted surveys of grower perceptions of soil quality in their tunnels (n = 81) and compared selected soil quality indicators (salinity and particulate organic matter carbon) under high tunnels of varying ages with those of adjacent fields at sites in Kansas, Missouri, Nebraska, and Iowa in the United States. Fourteen percent of growers surveyed considered soil quality to be a problem in their high tunnels, and there were significant correlations between grower perceptions of soil quality problems and reported observations of clod formation and surface crusting and to a lesser extent surface mineral deposition. Grower perception of soil quality and grower observation of soil characteristics were not related to high tunnel age. Soil surface salinity was elevated in some high tunnels compared with adjacent fields but was not related to time under the high tunnel. In the soil upper 5 cm, salinity in fields did not exceed 2 dS·m−1 and was less than 2 dS·m−1 under 74% of high tunnels and less than 4 dS·m−1 in 97% of high tunnels. The particulate organic matter carbon fraction was higher in high tunnels than adjacent fields at 73% of locations sampled. Particulate organic matter carbon measured 0.11 to 0.67 g particulate organic matter per g of the total carbon under high tunnels sampled. Particulate organic matter carbon in the soil was also not correlated to age of high tunnel. Soil quality as measured in this study was not negatively impacted by use of high tunnel structures over time.
5
Kim, Jaeyoung, and Sehong Min. "Study on Securing Safety Based on Emergency Power Dualization inside Road Tunnel." Journal of the Korean Society of Hazard Mitigation 20, no. 1 (February 29, 2020): 217–21. http://dx.doi.org/10.9798/kosham.2020.20.1.217.
Full textAbstract:
With continued economic development, movement and logistics to various parts of the country are increasing. Consequently, long tunnels in the mountains and the large city underground road tunnels under construction have become increasingly important. Further, the escalating number of road tunnels has resulted in the deepening of tunnels and an increase in the number of long tunnels. Because it is highly possible fora traffic accident inside a tunnel to cause further accidents, various safety improvement measures should be prepared. To resolve the problem, dualizing the emergency power of CCTVs (which perform the major functions of tunnel safety) is proposed for application in a plan to improve safety. This plan improves safety control inside the tunnel and contributes to its maintenance. This study was prompted by the expressway tunnel accidents that occurred in the Central Region Expressway in October 2015 and February 2016. The safety security system based on the dualization of the emergency power inside the road tunnel is being monitored, with its application in some tunnels as the pilot project of an actual lab concept. Moreover, measures on safety control inside the road tunnel can be prepared through the monitoring.
6
Timchenko, R. A., D. A. Krishko, and S. О. Macyshin. "CONSTRUCTIVE SOLUTION OF A TUNNEL UNDER THE EXISTING HIGHWAY." ACADEMIC JOURNAL Series: Industrial Machine Building, Civil Engineering 2, no. 49 (October 17, 2017): 214–20. http://dx.doi.org/10.26906/znp.2017.49.845.
Full textAbstract:
Urban underground structures (shallow tunnels), which are usually built in conditions of urban area with heavy traffic, are considered. It was clarified that the reinforced concrete lining are performed of concrete, reinforced concrete, natural and artificial stones in most cases. The types of tunnels road cutting are given. The geometrical dimensions and characteristics of using materials in the construction of tunnels are given. It was established that the existing methods of tunnel construction do not allow to solve the problem in cramped conditions and intense traffic. The new constructive solution of the transverse tunnel under the existing highway was proposed. It is found that the proposed design of the transverse tunnel may be performed in cramped urban environments with the use of modern technological equipment and the proposed method of tunnel meets the requirements of strength, reliability, durability.
7
Pan, Fei, and Sheng Guo Cheng. "Analysis of Deformation Mechanism and Control Technology of Soft Rock Tunnel with High Geostress." Applied Mechanics and Materials 638-640 (September 2014): 794–97. http://dx.doi.org/10.4028/www.scientific.net/amm.638-640.794.
Full textAbstract:
With the development of transportation construction, soft rock tunnel with high geostress construction has become a key problem to overcome of traffic engineering construction. In order to explore the deformation mechanism and control technology of soft rock tunnel with high geostress, Xiakou tunnel engineering as an example, the geological characteristics and deformation characteristics of the tunnel were analyzed, to obtain the deformation mechanism of soft rock tunnels with high geostress, and to develop deformation control technology, the results provide a basis and reference for the domestic and foreign the similar engineering construction.
8
Li, Pan, and Xiaobo Qu. "Optimal Allocation of Tunnel Safety Provisions Based on a Quantitative Risk Assessment Model." Scientific Programming 2016 (2016): 1–5. http://dx.doi.org/10.1155/2016/9628095.
Full textAbstract:
This paper addresses the issue of optimally selecting the tunnel safety provisions. Tunnel safety provisions are the assets of urban road tunnels which are installed and implemented to reduce the tunnel risks, which are basically selected by expert judgment in practice. An optimization model is proposed to obtain the optimal solution for the selection of tunnel safety provisions. The objective function is to minimize the life cycle costs of tunnel safety provisions, which is subject to the requirements for tunnel safety provisions and the safety targets. Finally, by taking advantage of the special structure of the optimization model, a Bi-Section Search and Bound Algorithm (BSSBA) is designed to efficiently solve the problem.
9
Shi, Zhenyue, Qingbiao Wang, Chuming Pang, Yueming Yuan, Fuqiang Wang, Hongxu Song, Jichang Liu, Zijie Zhang, Rongbo Sun, and Yan Liu. "Establishment and Application of the Spatial Decomposition Method (SDM) for Tunnels Passing Through Large Karst Caves." Applied Sciences 10, no. 20 (October 15, 2020): 7204. http://dx.doi.org/10.3390/app10207204.
Full textAbstract:
Karst tunnels commonly pass through large karst caves during their construction and operation. Although treatment technologies are relatively mature, a systematic treatment method to guide the selection of treatment technologies is lacking. To solve this problem, a spatial decomposition method (SDM) of large karst caves is proposed that is based on analyzing the spatial relationship between tunnels and karst caves and summarizing the relevant treatment techniques. In this method, the space between the tunnel and the cavern is divided into eight parts using a space dividing line (SDL), which makes the spatial position relationship between the tunnel and cavern more intuitive. A geometric model of the SDM is established, and the numerical values of each geometric parameter are determined by field surveys and drawings. Constructing a three-dimensional spatial diagram by applying relevant parameters to the geometric model provides a reference for selecting a treatment technology. The SDM of the arch top, arch bottom, and two wings matching the treatment technology is proposed. Seven principles of technical selection—namely, safety, convenience, scientificity, sustainability, economy, feasibility, and openness—are mentioned in order to overcome the difficulty of technology selection due to such factors as technological diversity, materials, equipment, and environment. Finally, the SDM is used to solve the problem of the Shangyuan tunnel passing through a large karst cave. The implementation of the SDM in tunnel construction would represent a significant breakthrough and has important engineering value in solving the problem of tunnel passes through large karst caves.
10
Kiyanitsa, Lavrentiy A., and Ivan V. Lugin. "JUSTIFICATION OF THE PARAMETERS OF CHILLING ZONE OF LINING OF NEAR-ENTRANCE SITE OF LONG RAILWAY TUNNELS IN COLD SEASON." Interexpo GEO-Siberia 2 (July 8, 2020): 57–63. http://dx.doi.org/10.33764/2618-981x-2020-2-57-63.
Full textAbstract:
When operating long railway tunnels in harsh climatic conditions of Siberia and the Far East, there is a problem of tunnel lining freezing on near-entrance sites in the cold season. Due to the cyclical effects of negative outside temperatures, the surface layer of tunnel lining is constantly freezing and thawing, which causes rapid frost deterioration. This effect is especially pronounced for tunnels with closing near-entrance gates and one-way train traffic on the exit site. This is explained by the fact that at each train passage through the exit site, a significant amount of cold atmospheric air enters the tunnel. The length of chilling zone and the temperature of tunnel lining in the “outside air - tunnel lining” contact zone from the exit site deep into the tunnel, depending on the technological and climatic parameters of the tunnel are justified by analyzing the results of computational experiment. The correctness of obtained regularities is justified by the convergence of experimental results and analytical calculations based on the displacement method.
11
Zhao, Jing, and Ren Xian Li. "A Study of Aerodynamic Effects of High-Speed Trains through Tunnels." Applied Mechanics and Materials 94-96 (September 2011): 1663–67. http://dx.doi.org/10.4028/www.scientific.net/amm.94-96.1663.
Full textAbstract:
In this paper, the aerodynamic effects of high-speed train passing in tunnels are investigated in numerical calculation method of hydromechanics. According to the actual situation of flow filed when the train through the tunnel, the flow geometry model is set up. The flow problem is described by Navier-Stokes equations of unsteady viscous compressible fluid and k-e two equations turbulent model. Thereby the aerodynamic effects of the train through the tunnel are analyzed comprehensively. The changes of the air pressure in tunnel caused by high-speed train entering into the tunnel are mainly analyzed. In addition, the mechanical characteristics of carriages when two train in the tunnel passing through each other are analyzed.
12
Li, Wen Hua, Da Jun Zhao, and Shi Sheng Zhou. "Numerical Simulation Analysis and Engineering Applications on the Double-Side-Wall Heading Step Bench Excavation of Large-Cross Section and Shallow Tunnel." Advanced Materials Research 594-597 (November 2012): 1182–87. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.1182.
Full textAbstract:
With the pace accelerating of development of urban rail traffic in large and medium-sized cities, urban subway and railway lines need to construct shallow and large-cross section tunnels and especially large-cross section tunnels. Large-cross section tunnel constructions make big influence on the surrounding buildings, roads and environment. How to build underground tunnel fast and safe in the downtown has become an problem which needs to be solved urgently. This article is for the technology of city large-cross section and shallow buried-tunnel, relying on the phase 1 of rail transit no.2 in Changsha, which combined with construction characteristics of the excavation method, double-side-wall method and step method, numerical simulation analysis on influence of the large-cross section tunnel disturbance in the surrounding rock, and provides the necessary technical support.
13
Xu, Hua, Tian Bin Li, and Long Qi Li. "Research on Dynamic Response of Underground Circular Lining Tunnel under the Action of P Waves." Applied Mechanics and Materials 99-100 (September 2011): 181–89. http://dx.doi.org/10.4028/www.scientific.net/amm.99-100.181.
Full textAbstract:
Dynamic stress concentration of tunnels and underground engineers under the action of earthquake waves is a fundamental problem. Selecting circular lining tunnel in semi-infinite space under the action of P waves as prototype, based on the assumption of large circular arc, a set of dynamic stress series solution in semi-infinite space and lining is deduced by wave function expansion method. With specific examples, the influences on shallow-buried depth rock tunnels of different factors which include incident frequency, incident angle, buried depth, rock conditions and lining rigidity are studied. The results show that low-frequency P waves are more dangerous to tunnel lining than high-frequency P waves; When P waves is incident from the bottom of the vertical tunnel or small angle (θα = 0° ~ 30°), the damage of tunnel lining is more seriously; Under the hard rock conditions, when the tunnel buried depth reaches more than 100m, the thickness of overlying rock is not a major factor effecting the dynamic stress and earthquake damages of tunnel structure lining; Under the soft surrounding rock condition, the value of dynamic stress concentration coefficient of lining is still up to 6.5 when the buried depth of tunnels is more than 100m, and what’s more the tunnel lining may still be caused seriously earthquake damage; With the increasing of lining stiffness, the dynamic stress concentration of lining is more uneven, and the value span is greater; so under the premise of meeting bearing capacity and deformation of lining, soft lining is recommended to adapt in the tunnel structure to decrease earthquake damage of tunnels.
14
Fei, Hong Lu, Xing Zhu Zhang, and Zhi Guang Yang. "The Prediction and Control Research on the Attenuation Law of Blasting Vibration Peak Velocity in Daiyuling Tunnel." Advanced Materials Research 838-841 (November 2013): 1429–34. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.1429.
Full textAbstract:
In combination with field blasting vibration tests in Daiyuling 2# Tunnel, abundant field monitoring datum have been obtained, in order to predict the strength of blasting vibration and research the control problem about stability of surrounding rock. Through the evaluation on blasting affects of the first excavated tunnel when the last excavated tunnel in the initial stage is into tunnel hole, establish the relationship of blasting vibration disturbing degree both neighborhood tunnels to improve the accuracy. Acoustic testing technology has been adapted to test rock acoustic velocity with blasting from beginning to end. The experimental results show that: (1) rock has a larger effect on attenuation effect in the spread of seismic wave, and blasting is really damage the surrounding rock; (2) regression analysis with the formula reflecting correctly the real situation on the blasting stress wave attenuation; (3) compared with blasting vibration attenuation coefficient both the left tunnel and right tunnel, the blasting vibration damage in soft rock is more than in hard rock; (4) the most dangerous location caused by tunnel blasting excavation is the adjacent tunnel blasting face, and its velocity is 5.8845 cm/s, it is practical and feasible that the clear distance of neighborhood tunnels should keep in 21m.
15
Gong, Wenping, Hongwei Huang, C. Hsein Juang, Sez Atamturktur, and Andrew Brownlow. "Improved shield tunnel design methodology incorporating design robustness." Canadian Geotechnical Journal 52, no. 10 (October 2015): 1575–91. http://dx.doi.org/10.1139/cgj-2014-0458.
Full textAbstract:
This paper presents an improved design methodology for shield tunnels. Here, a new framework for three-dimensional analysis of shield tunnel “performance” (defined herein as the structural safety and serviceability of each tunnel ring) is developed, which considers the effect of the longitudinal variation of input parameters on the tunnel performance. Within this framework, random fields are used to simulate the longitudinal variation of input parameters, and the three-dimensional problem of shield tunnel performance is solved through a two-stage solution involving a one-dimensional model (for tunnel longitudinal behavior) and a two-dimensional model (for performance of segment rings). Furthermore, the robust design concept is integrated into the design of shield tunnels to guard against the longitudinal variation of tunnel performance caused by the longitudinal variation of input parameters. In the context of robust design, a new measure is developed for determining the robustness of the tunnel performance against the longitudinal variation of noise factors. A multi-objective optimization is then performed to optimize the design with respect to the design robustness and the cost efficiency, while satisfying the safety and serviceability requirements. Through an illustrative example, the effectiveness and significance of the improved shield tunnel design methodology is demonstrated.
16
Yi, Cheng, Dening Lu, Qian Xie, Jinxuan Xu, and Jun Wang. "Tunnel Deformation Inspection via Global Spatial Axis Extraction from 3D Raw Point Cloud." Sensors 20, no. 23 (November 28, 2020): 6815. http://dx.doi.org/10.3390/s20236815.
Full textAbstract:
Global inspection of large-scale tunnels is a fundamental yet challenging task to ensure the structural stability of tunnels and driving safety. Advanced LiDAR scanners, which sample tunnels into 3D point clouds, are making their debut in the Tunnel Deformation Inspection (TDI). However, the acquired raw point clouds inevitably possess noticeable occlusions, missing areas, and noise/outliers. Considering the tunnel as a geometrical sweeping feature, we propose an effective tunnel deformation inspection algorithm by extracting the global spatial axis from the poor-quality raw point cloud. Essentially, we convert tunnel axis extraction into an iterative fitting optimization problem. Specifically, given the scanned raw point cloud of a tunnel, the initial design axis is sampled to generate a series of normal planes within the corresponding Frenet frame, followed by intersecting those planes with the tunnel point cloud to yield a sequence of cross sections. By fitting cross sections with circles, the fitted circle centers are approximated with a B-Spline curve, which is considered as an updated axis. The procedure of “circle fitting and B-SPline approximation” repeats iteratively until convergency, that is, the distance of each fitted circle center to the current axis is smaller than a given threshold. By this means, the spatial axis of the tunnel can be accurately obtained. Subsequently, according to the practical mechanism of tunnel deformation, we design a segmentation approach to partition cross sections into meaningful pieces, based on which various inspection parameters can be automatically computed regarding to tunnel deformation. A variety of practical experiments have demonstrated the feasibility and effectiveness of our inspection method.
17
Liu, Zhiqiang, Haifeng Jiang, and Minmin Yuan. "Study on Application of TiO2 Photocatalytic Materials in Purification of Highway Tunnel Tail Gas." E3S Web of Conferences 233 (2021): 01073. http://dx.doi.org/10.1051/e3sconf/202123301073.
Full textAbstract:
In recent years, with the continuous expansion of the scale of highway tunnels in China, the problem of tail gas pollution in highway tunnels has become increasingly prominent. The tunnel is a long and narrow space, which makes air pollutants easy to accumulate and difficult to diffuse. In this paper, the present situation and application scenarios of TiO2 photocatalytic materials in the purification technology of highway tunnel exhaust gas are studied and analyzed, and the nano TiO2 photocatalytic materials which can be applied to highway tunnels, corresponding highway stations and their affiliated facilities are put forward, so as to greatly degrade automobile exhaust gas, atmospheric chemical pollution and environmental biological pollution.
18
Su, Zhong Ming, Xiao Feng Wang, and Rui Liu. "Type Selection of Arches in Primary Support of Loess Tunnel with Small Interval under Shallow Buried & Unsymmetrical Pressure." Applied Mechanics and Materials 170-173 (May 2012): 1656–59. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.1656.
Full textAbstract:
The problem of arches selection in primary support of loess tunnel is one of the problems that are now focused on. Based on the two type support of gird and shaped steel, the plastic zone and internal forces are mainly analyzed, by means of numerical simulation, in the loess tunnels with small interval under shallow buried & unsymmetrical pressure. Analysis results indicate that the internal forces in the gird support is slightly smaller than that of the shaped steel support, and the plastic zones are almost the same in the two type support; so it is suggested that the grid support should be adopted in the design of such tunnel from the comprehensive analysis.
19
Lesbarrères, David, Thierry Lodé, and Juha Merilä. "What type of amphibian tunnel could reduce road kills?" Oryx 38, no. 2 (April 2004): 220–23. http://dx.doi.org/10.1017/s0030605304000389.
Full textAbstract:
Increased traffic volumes worldwide are contributing to amphibian declines, and measures to reduce the occurrence of road kills are needed. One possible measure is the construction of underpasses through which animals can pass under roads, but little is known about whether amphibians will choose tunnels if given a choice or about their preferences for different tunnel types. We tested the preferences of three anuran species for two kinds of concrete amphibian tunnels currently used in France. One was a tunnel lined with soil, the other a bare concrete pipe. The animals could use the tunnels or bypass them over a grassy area. Water frogs Rana esculenta and common toads Bufo bufo showed a preference for the tunnels, whereas agile frogs Rana dalmatina avoided them. Among the individuals that chose either of the tunnels, all species showed a significant preference for the tunnel lined with soil. These results indicate that species differ in their preferences and in their likelihood of using underpasses when given a choice. This highlights the fact that there is no unique solution to the problem, and underpasses are only one of the possible mitigation measures that need to be assessed.
20
Chapman, Michael A., Cao Min, and Deijin Zhang. "CONTINUOUS MAPPING OF TUNNEL WALLS IN A GNSS-DENIED ENVIRONMENT." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B3 (June 9, 2016): 481–85. http://dx.doi.org/10.5194/isprsarchives-xli-b3-481-2016.
Full textAbstract:
The need for reliable systems for capturing precise detail in tunnels has increased as the number of tunnels (e.g., for cars and trucks, trains, subways, mining and other infrastructure) has increased and the age of these structures and, subsequent, deterioration has introduced structural degradations and eventual failures. Due to the hostile environments encountered in tunnels, mobile mapping systems are plagued with various problems such as loss of GNSS signals, drift of inertial measurements systems, low lighting conditions, dust and poor surface textures for feature identification and extraction. A tunnel mapping system using alternate sensors and algorithms that can deliver precise coordinates and feature attributes from surfaces along the entire tunnel path is presented. This system employs image bridging or visual odometry to estimate precise sensor positions and orientations. The fundamental concept is the use of image sequences to geometrically extend the control information in the absence of absolute positioning data sources. This is a non-trivial problem due to changes in scale, perceived resolution, image contrast and lack of salient features. The sensors employed include forward-looking high resolution digital frame cameras coupled with auxiliary light sources. In addition, a high frequency lidar system and a thermal imager are included to offer three dimensional point clouds of the tunnel walls along with thermal images for moisture detection. The mobile mapping system is equipped with an array of 16 cameras and light sources to capture the tunnel walls. Continuous images are produced using a semi-automated mosaicking process. Results of preliminary experimentation are presented to demonstrate the effectiveness of the system for the generation of seamless precise tunnel maps.
21
Chapman, Michael A., Cao Min, and Deijin Zhang. "CONTINUOUS MAPPING OF TUNNEL WALLS IN A GNSS-DENIED ENVIRONMENT." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B3 (June 9, 2016): 481–85. http://dx.doi.org/10.5194/isprs-archives-xli-b3-481-2016.
Full textAbstract:
The need for reliable systems for capturing precise detail in tunnels has increased as the number of tunnels (e.g., for cars and trucks, trains, subways, mining and other infrastructure) has increased and the age of these structures and, subsequent, deterioration has introduced structural degradations and eventual failures. Due to the hostile environments encountered in tunnels, mobile mapping systems are plagued with various problems such as loss of GNSS signals, drift of inertial measurements systems, low lighting conditions, dust and poor surface textures for feature identification and extraction. A tunnel mapping system using alternate sensors and algorithms that can deliver precise coordinates and feature attributes from surfaces along the entire tunnel path is presented. This system employs image bridging or visual odometry to estimate precise sensor positions and orientations. The fundamental concept is the use of image sequences to geometrically extend the control information in the absence of absolute positioning data sources. This is a non-trivial problem due to changes in scale, perceived resolution, image contrast and lack of salient features. The sensors employed include forward-looking high resolution digital frame cameras coupled with auxiliary light sources. In addition, a high frequency lidar system and a thermal imager are included to offer three dimensional point clouds of the tunnel walls along with thermal images for moisture detection. The mobile mapping system is equipped with an array of 16 cameras and light sources to capture the tunnel walls. Continuous images are produced using a semi-automated mosaicking process. Results of preliminary experimentation are presented to demonstrate the effectiveness of the system for the generation of seamless precise tunnel maps.
22
Kang, Xiao Bing, Xie Wen Hu, and Huai Qian Xie. "Numerical Simulation on the Influence of the Groundwater Flow Field during Tunnelling." Advanced Materials Research 594-597 (November 2012): 1230–33. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.1230.
Full textAbstract:
With the vigorous development of China's economic construction, especially since the western development, needs of traffic tunnel construction are increasing, a large number of tunnels will be built in the mountainous with deeply buried and high water pressure, it is an urgent problem about research on the groundwater environment and the ecological environment in the tunnel site area causes of tunnel construction. The Songpan County Mounigou tunnel located in the high altitude alpine region, regional and environmental geological conditions are complicated, the strata in the tunnel site area is aquifer, and developed faults fractures and fissures, tunnelling will lead to groundwater dewatering and cause the deterioration of the groundwater environment, Then great collapse, burst mud and water gushing will occur during the tunnel construction due to the enrichment of groundwater in tunnel site. Take a research on numerical simulation of groundwater flow in the tunnel site area, the tunnel excavation will form a larger catchment corridor, the impact is bound to the tunnel site hydrogeological conditions in the sphere of influence may appear to lower the groundwater level, seisensui drawdown or part of the dry, provide the basis for tunnel construction.
23
Kang, Xiao Bing. "A Study on Forming Mechanism of Gas Tunnel in Non-Coal Strata." Advanced Materials Research 243-249 (May 2011): 3296–99. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.3296.
Full textAbstract:
In addition to the gas tunnel in coal strata, there are a large number of gas tunnel in non-coal strata, these tunnels itself do not through the coal strata, but all encountered the gas problem in the construction process. Because of not a full understanding and preparation on gas of tunnel in non-coal strata zones, and the gas emission is random, uneven distribution of the characteristics, so the gas disaster hazard is larger in such gas tunnel, study on its formation mechanism is great significance. Based on the study of a lot of the gas tunnel has been constructed, summed up three genetic types of the non-coal strata gas tunnel: one type is structural connectivity, according to the different structure types, can be divided into fracture connectivity type, fault type and fold connected connectivity type; Second is surrounding rock metamorphic type; third is compound effects type.
24
Chen, Yan, Xiao Chun Zhang, Hua Rong Wang, and Nan Tong Zhang. "Influence of Soft Rock Factor and Time Dependence in Deep Tunnel." Applied Mechanics and Materials 353-356 (August 2013): 1625–29. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.1625.
Full textAbstract:
With the development of highway tunnel engineering, the stability of the tunnel become the chief problem in designing and constructing. Tunnel surrounding rock under high stress based on the actual engineering background, model test process of excavation in soft rock tunnels under the distribution factors was finished in triaxial test mechine. Through sensor test, the whole process of tunnel became instable was reflected, and the different conditions of the change rule of surrounding rock stress was budgeted and analysed. the numerical simulation method was used to study dependency of deep tunnel with soft rock in it and the lining deformation time. in which nonlinear Drucker-Prager plastic coupling and creep constitutive model were used to describe the nonlinear viscous-elastic-plastic properties of high stress soft rock. The characteristies of tunnel lining deformation and internal force variation were studied with the above model. Soft rock thickness, soft rock tunnel location effect on inner force and deformation of the structure were discussed. The results have reference value in evaluation of long-term stability of deep tunnel.
25
Lu, Ying, Jin Wang, Xiaojun Bai, and Hehan Wang. "Design and implementation of LED lighting intelligent control system for expressway tunnel entrance based on Internet of things and fuzzy control." International Journal of Distributed Sensor Networks 16, no. 5 (May 2020): 155014772092574. http://dx.doi.org/10.1177/1550147720925742.
Full textAbstract:
Due to the special characteristics of highway tunnels and vehicles, the interior of the tunnel is required to provide appropriate lighting to ensure the safety of driving vehicles, especially at the entrance section of the tunnel. At present, most of the tunnel entrance lighting control system only considers one single factor, the brightness outside the tunnel. However, in practice, the required lighting brightness in the tunnel is also related to traffic flow, speed, and other factors. Comprehensively utilizing these factors to improve the control strategy is urgently needed. To deal with this problem, this article has designed a multi-source information acquisition system for tunnel lighting based on the Internet of things technology, which combined with fuzzy control theory in order to develop an intelligent control system for LED lighting at the entrance section of the tunnel. The designed system was implemented and long-term tested in a real highway tunnel. The experimental results have shown that the system designed in this article can automatically control the brightness of the lighting inside the tunnel according to the real-time measurements of the brightness outside the tunnel, traffic flow, speed, and so on. Furthermore, the utilizations of the system can minimize the human and power consumption of tunnel lighting while ensuring the safety of tunnel traffic.
26
Azit, Romziah, Mohd Ashraf Mohamad Ismail, Sharifah Farah Fariza Syed Zainal, and Norzani Mahmood. "Rock Overstressing in Deep Tunnel Excavation of Pahang-Selangor Raw Water Transfer Project." Applied Mechanics and Materials 802 (October 2015): 16–21. http://dx.doi.org/10.4028/www.scientific.net/amm.802.16.
Full textAbstract:
Tunneling under high overburden and in-situ stress may cause tunnel instability because of rock overstressing. Evaluating overstressing in deep hard rocks is crucial to minimize excavation risks. The excavation of the Pahang-Selangor Raw Water Transfer Tunnel is evaluated in this study. A potential overstressing problem is expected at a tunnel depth more than 500 m. Therefore, the possibility of rock overstressing is assessed based on the evaluations of in-situ stress measurement, rock strength, and actual observations during the tunnel excavation. An analytical method is used to analyze the behavior of the tunnel under high overburden stress based on rock strength and tangential stress factors. The empirical assessment approach to the observation of actual overstressing appeared to be valid for the prediction of overstressing. These approaches facilitate the reasonable prediction of tunnel behavior under different rock conditions, support systems, and overburden stresses, which serve as useful tools in the observational design and construction method of long and deep tunnels.
27
Meguid, M. A., and R. K. Rowe. "Stability of D-shaped tunnels in a MohrCoulomb material under anisotropic stress conditions." Canadian Geotechnical Journal 43, no. 3 (March 1, 2006): 273–81. http://dx.doi.org/10.1139/t06-004.
Full textAbstract:
The near-face stability of D-shaped tunnels excavated in a MohrCoulomb material subjected to anisotropic in situ stress conditions is investigated in the present study. The construction of the intake tunnel of the Darlington Nuclear Generating Station is analyzed using three-dimensional elasto-plastic finite element analysis. The induced displacement and stresses around the tunnel opening as the face advances are compared to the field measurements recorded during the tunnel excavation. The effect of rock mass strength reduction on the tunnel deformation, face stability, and distribution of stresses at the tunnel circumference is investigated for different in situ stress conditions. When the ratio of rock mass strength to overburden pressure falls below 0.5, excessive deformation occurrs and squeezing of the rock mass becomes a problem that can cause instability of both the tunnel circumference and the face.Key words: weak rock, tunnelling, horizontal stresses, three-dimensional, finite element, excavation, face stability.
28
Sun, Lan Ning, and Zhong Hu Zhao. "The Study on Movement of Underground Water and its Effect on the Stability of Surrounding Rocks." Advanced Materials Research 838-841 (November 2013): 726–32. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.726.
Full textAbstract:
Because of the special geological structure, folds are the main place where underground water gathers and moves. When we build roads or tunnels in folds of the western mountain areas, we should consider the effect of underground water on surrounding rocks and on stability of lining of a tunnel. The author explains in system the movement of underground water in anticlines, limbs and synclines, analyzes the physical, chemical and mechanic effects on rocks during its movement, then puts forward the reasonable advices in choosing the location where a tunnel should be built and specifies the stability of a tunnel. Also, in order to solve the water-gushing problem which may occur during the construction, the author brings forward some control measures for reference when selecting tunnel line and constructing.
29
Wu, Bo, and Wei Huang. "Optimization of sequential excavation method for large-section urban subway tunnel: A case study." Advances in Mechanical Engineering 12, no. 9 (September 2020): 168781402095718. http://dx.doi.org/10.1177/1687814020957185.
Full textAbstract:
In response to the requirement for population increase, the cross-section area of the urban subway is enlarged, resulting in that one-time excavation technology cannot be directly applied to the excavation of large-section tunnels. Consequently, how to partition the cross-section of the large-section tunnels and optimize the corresponding construction parameters is of great significance. In this paper, we establish a unified planar partition optimization model based on the four parameters of the number of horizontal layers, the number of transverse partitions, the height of the step, and the width of sections. Moreover, using the dynamic programming principle, we can further obtain the optimal excavation sequence and the construction parameters of the large-section tunnels by solving the planar partition optimization model. Combined with the case of an extra-large cross-section tunnel excavation of Chongqing Metro Central Park East Station, the paper optimizes the excavation method of the tunnel with the aim of the maximum construction efficiency and tunnel stability to obtain the optimal excavation sequence, the optimal construction parameters, and the optimal comprehensive evaluation index. The practice has proved that the optimization model based on the dynamic programming principle can effectively solve the problem of large-section tunnel construction. The case analysis can provide an effective reference for similar large-section tunnel projects.
30
Hui, Wang, and Wang Qing-biao. "Dynamic Optimization Research on the Section Morphology of Large-span Tunnels in Shallow Rock Mass." Open Construction and Building Technology Journal 9, no. 1 (September 10, 2015): 210–13. http://dx.doi.org/10.2174/1874836801509010210.
Full textAbstract:
The optimization design of the section morphology of large-span tunnels plays an important role for saving cost and improving the engineering stability. The flat ratio of tunnel which is as an important control index, its rationality is the key problem in the design of tunnels. Program with Python to set up the dynamic calculation model of a large-span tunnel planned to be constructed which can be run and analyzed in ABAQUS. The MATLAB language is used to compile the optimization analysis program based on genetic algorithm, and then the dynamic calculation model is embedded into it. Using excavation area, plastic zone, ground surface settlement, vault subsidence, etc. as optimal objective to make dynamic analysis for the model and put forward the reasonable flat ratio of the supported project. The result of this paper provides reference for the section optimization design of similar tunnel engineering.
31
Lin, Trains Qinhua, and Victor V. Krylov. "Effect of Tunnel Diameter on Ground Vibrations Generated by Underground." Journal of Low Frequency Noise, Vibration and Active Control 19, no. 1 (March 2000): 17–25. http://dx.doi.org/10.1260/0263092001492769.
Full textAbstract:
A theoretical model has been developed of generating ground vibrations by underground trains travelling in idealised circular tunnels of finite diameter. By means of the reciprocity principle, the displacement field radiated by a point force applied to the bottom of the tunnel, i.e., the Green's function of the problem, has been derived in zero and first approximations versus tunnel diameter. This more precise Green's function has been applied to carry out calculations of railway-generated ground vibrations using earlier developed methods. The results show that the velocities of generated low-frequency ground vibrations increase with the increase in tunnel diameter. It is also shown that zero approximation is accurate only at very low frequencies.
32
Król, Aleksander, and Małgorzata Król. "Some Tips on Numerical Modeling of Airflow and Fires in Road Tunnels." Energies 14, no. 9 (April 22, 2021): 2366. http://dx.doi.org/10.3390/en14092366.
Full textAbstract:
The efficiency of tunnels systems is often evaluated using numerical simulations. This concerns both to normal and emergency mode of tunnel systems operation. Therefore the safety level of tunnel users may depend on the quality of numerical models being built. The most often studied areas cover the researches on natural and forced airflows in the normal mode and on fire development and smoke spreading in the emergency mode as well as modeling of fan operation. Thus, many software packages implementing Computational Fluid Dynamics (CFD) are applied here. Despite the available software is recognized as reliable, the problem arises because the built numerical models should be validated at least partially with experimental data. There is a shortage of experimental data from real tunnels due to high costs and many organizational or formal difficulties. Some researchers use data from scaled experiments, but this leads to problems connected with scaling. The paper presents the application of two widely used software packages—Fire Dynamics Simulator (FDS) and ANSYS Fluent to reproduce some scenarios of the operation of a tunnel ventilation system for normal and emergency mode. Most of results were compared with data obtained by own full scale measurements or data available in literature. Some practical issues concerning the application of FDS and ANSYS Fluent were discussed as well.
33
Liu, Jia Xiang, Xue Fu Zhang, Guo Hui Li, Xiao Cheng Ma, and Guo Ying Fu. "Study on the Effects of Air Temperature Distribution by Flow State inside Cold Region Tunnel." Applied Mechanics and Materials 170-173 (May 2012): 1455–62. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.1455.
Full textAbstract:
Utilizing the basic theory of heat transfer and computational fluid dynamics and considering the coupling influence of air in the channel and tunnel surrounding rock, the paper deduced control equation of hydrokinetics, calculated the formulas and made secondary development program applying UDF language on ANSYS FLUENT as a basis. Based on materials of Fenghuo Mountain tunnel, the paper analysis for coupled problem of heat transfer of surrounding rock and heat convection between air in cold region tunnel and surrounding rock, and comparative analysis of the annual average temperature between the calculation result and the actual observation records in 2004. The results demonstrated: in the laminar flow condition, the annual average temperature of the cross-section of tunnel entrance and exit is the same as or higher than the tunnel inside. In the turbulence fluid condition, the annual average temperature diminishes from entrance to exit, and there exists mutation between the cross-section of entrance and exit and other cross-section. When air flow state is assumed to be laminar inside Fenghuo Mountain tunnel, the calculation result and the actual observation records are the same. Assumed to be turbulent, both of result are different. Therefore, the calculation depend on the actual corresponding air flow state in tunnels in cold regions designs. The paper results will be providing the theory base and reference of design, construction and study of tunnels in cold regions.
34
Liu, Ning, Ranqiao Zhang, Zhong Su, Guodong Fu, and Jingang He. "Research on Wavelet Threshold Denoising Method for UWB Tunnel Personnel Motion Location." Mathematical Problems in Engineering 2020 (February 28, 2020): 1–14. http://dx.doi.org/10.1155/2020/9039648.
Full textAbstract:
In the process of tunnel construction, the problems of strong sealing, inconvenient communication, and harsh environment pose a serious threat to the personal safety of construction workers. Therefore, personnel positioning technology has important application value in tunnel safety construction. A special environment for tunnel personnel positioning and the ultrawideband (UWB) positioning system are affected by personnel movement, which leads to the problem of lowering positioning accuracy. A wavelet threshold denoising method for motion positioning of people in tunnels is proposed. The positioning algorithm of the method adopts a three-sided positioning algorithm based on symmetric double-sided two-way ranging. The wavelet analysis is used to decompose the motion signal of the personnel in the tunnel, and the low frequency coefficient and high frequency coefficient of the signal are decomposed to determine the influence of the motion noise of the personnel on the UWB positioning. The soft threshold function and the hard threshold function are, respectively, selected to perform wavelet threshold denoising on the motion positioning result in the tunnel. According to the denoising effect, the db5 wavelet 5-layer decomposition, under the heuristic threshold estimation criterion, the soft threshold function denoising is the best denoising method. The verification by the positioning experiment shows that the method is suitable for tunnel personnel positioning. The wavelet threshold denoising method can weaken the influence of outliers in the motion positioning of UWB personnel and improve the positioning accuracy.
35
Wang, Ang, Chenghua Shi, Chenyang Zhao, E. Deng, Weichao Yang, and Hong He. "Response Characteristics of Cross Tunnel Lining under Dynamic Train Load." Applied Sciences 10, no. 12 (June 26, 2020): 4406. http://dx.doi.org/10.3390/app10124406.
Full textAbstract:
The crossing area is a vulnerable component of the interchange high-speed railway tunnel because of the high-static stress level and the long-term dynamic train load in the operation period. Although attention has been paid to this problem, the response characteristics of high-speed railway tunnel lining at the cross position under the dynamic train load may still need further research as very little investigation is available on this issue at present. In this paper, the initial stress state and dynamic response characteristics of tunnel lining were studied using the three-dimensional finite element method. Furthermore, the damage evolutionary characteristics of the tunnel inverted arch under dynamic and initial static loads were researched using a set of self-developed indoor fatigue test devices. The size of the test box is 400 × 300 × 250 mm (length × width × height). Numerical simulation results indicate that the displacement and stress levels of tunnel lining are very high at the cross position. The stress increment of tunnel lining due to the dynamic train load is more likely to induce a break in the tunnel lining at this position. The indoor fatigue tests reveal that the change of structural strain increment amplitude and strain ratio is obvious when the dynamic load stress level is higher. It is better for dynamic stress levels not to exceed 0.6 times of structural tensile strength to avoid the tunnel lining being damaged in the long-time service period. The initial static load has an influence on the tunnel inverted arch, and the static stress level should be lower than 0.65 times of structural tensile strength to ensure the tunnel has long-time serviceability. This paper provides a reference for the future design of new cross tunnels and the operation safety evaluation and disease regulation of existing high-speed railway tunnels.
36
Chen, Lei, Chao Fu, Xinji Xu, and Lichao Nie. "Imaging the Geology Ahead of a Tunnel Using Seismics and Adaptive Polarization Analysis." Journal of Environmental and Engineering Geophysics 25, no. 2 (June 2020): 189–98. http://dx.doi.org/10.2113/jeeg19-063.
Full textAbstract:
The seismic method is one of the main geophysical methods that are widely used to image the geology ahead of tunnels during tunnel construction. However, owing to the complex environment and limited observation aperture in a tunnel, symmetric false results (that appear in imaging results but not in the actual environment) frequently occur in imaging results. In a symmetric false reflection, false and true reflection points are axisymmetric around the tunnel axis. Such false results frequently cause errors in the interpretation of the geological conditions ahead of a tunnel face. To overcome this problem, a seismic method that uses adaptive polarization analysis was adopted to better image geological conditions. Based on an adaptive time window, the polarization characteristics of seismic signals were analyzed to calculate the main polarization direction. The symmetric false results in imaging results were suppressed by adopting a weighting coefficient based on the angle between the main polarization direction and ray direction. Numerical simulations revealed the superiority of the method when applied to synthetic data processing. Moreover, the method was applied to a diversion tunnel. The method successfully identified the fracture zones ahead of the tunnel face, thus significantly enhancing the safety of tunnel construction.
37
Guo, Feng, Feng Gao, Hong Gang Ma, and Shuai Guo. "Study on Trackless Tyred Vehicle Intelligent Scheduling System Base on Time Response." Applied Mechanics and Materials 373-375 (August 2013): 1525–28. http://dx.doi.org/10.4028/www.scientific.net/amm.373-375.1525.
Full textAbstract:
According to traffic jam problem in the tunnel, we study and design an analysis method of roadway transportation line which is suited of trackless tyred vehicle system underground coal mine, Through detailed analysis for traffic jam problem by trackless tyred vehicle in the tunnel, we designed automatic control algorithm for trackless tyred vehicle haulage system underground coal mine and designed the intelligent scheduling system, and solved the trackless tyred vehicles traffic problems.
38
Zheng, Xueyu, Luchen Zhang, Shiqiang Wu, and Kai Song. "Study on the Shape of the Aerator of High-Head Discharge Tunnel with Mild Bottom Slope." Water 13, no. 15 (August 2, 2021): 2128. http://dx.doi.org/10.3390/w13152128.
Full textAbstract:
Due to the high flow velocity and easy cavitation of high-head drainage tunnels, it is usually necessary to set up aeration facilities. In particular, when the bottom slope of the tunnel is mild, the aeration facilities often have problems such as difficulty with air intake, short cavity, and serious water accumulation, which aggravate the risk of cavitation damage. In this paper, based on the Rumei hydropower station and the Gushui hydropower station, a method combining theoretical analysis and model testing is used to solve the connection problem between the aeration facility and the 3% mild bottom slope of a tunnel body, and the aeration facility shape of “lifting ridge + flat (mild) slope + steep slope” is put forward. The research shows that the steep slope section can smoothly connect the water flow over the cantilever, reduce the jet impact angle, prevent the water from backtracking, and produce a long and stable cavity in the flat (mild) slope section. The aeration concentration along the bottom of the tunnel is higher than 3% at 140 m over the top of the dam. The aeration effect of this type is better, and it can provide effective long-distance protection for a drainage tunnel with high head and a mild bottom slope.
39
Tao, Xiang-Ling, Yun-He Su, Qi-Yin Zhu, and Wen-Long Wang. "Pasternak Model-Based Tunnel Segment Uplift Model of Subway Shield Tunnel during Construction." Advances in Civil Engineering 2021 (September 9, 2021): 1–10. http://dx.doi.org/10.1155/2021/8587602.
Full textAbstract:
Segment uplift is a frequent problem during the construction of shield tunnels. The phenomenon of segment uplift in Xuzhou Metro Line 1 is investigated. The segment uplift magnitude in the shale layer is quite smaller than that in the clay layer. A tunnel segment uplift calculation model based on the Pasternak foundation beam model is proposed, which considers the hardening process of the grouted body with time. The finite difference method is adopted to calculate the magnitude of segment uplift during different tunnel construction stages, and a numerical solution of segment uplift on the longitudinal direction is obtained. The applicability of the numerical solution is studied by comparing with the field test results and parametric analyses are also performed to investigate the effects of different factors on segment uplifting. The results show that the coefficient of subgrade modulus, shear stiffness of the shear layer, and grout pressure all influence the segment uplifting of the tunnel. The influence of the coefficient of subgrade modulus and grout pressure on segment uplift is more significant.
40
Ng, C. W. W., Jiangwei Shi, David Mašín, Huasheng Sun, and G. H. Lei. "Influence of sand density and retaining wall stiffness on three-dimensional responses of tunnel to basement excavation." Canadian Geotechnical Journal 52, no. 11 (November 2015): 1811–29. http://dx.doi.org/10.1139/cgj-2014-0150.
Full textAbstract:
Basement excavation inevitably causes stress changes in the ground, leading to soil movements that may affect the serviceability and safety of adjacent tunnels. Despite paying much attention to the basement–tunnel interaction, previous research has mainly focused on the influence of tunnel location in relation to the basement, tunnel stiffness, and excavation geometry. The effects of sand density and basement wall stiffness on nearby tunnels due to excavation, however, have so far been neglected. A series of three-dimensional centrifuge tests were thus carried out in this study to investigate these effects on the complex basement–tunnel interaction. Moreover, three-dimensional numerical analyses and a parametric study by adopting a hypoplastic sand model were conducted to improve the fundamental understanding of this complex problem, and calculation charts were developed as a design tool. When the basement was constructed directly above the existing tunnel, excavation-induced heave and strain were more sensitive to a change in soil density in the transverse direction than that in the longitudinal direction of the tunnel. Because a looser sand possesses smaller soil stiffness around the tunnel, the maximum tunnel elongation and transverse tensile strain increased by more than 20% as the relative sand density decreased by 25%. Moreover, the tensile strain induced along the longitudinal direction was insensitive to the stiffness of the retaining wall, but the tensile strain induced along the transverse direction was significantly reduced by a stiff wall. When the basement was constructed at the side of the existing tunnel, the use of a diaphragm wall reduced the maximum settlements and tensile strains induced in the tunnel by up to 22% and 58%, respectively, compared with the use of a sheet pile wall. Under the same soil density and wall stiffness, excavation-induced maximum movement and tensile strains in the tunnel located at a side of the basement were about 30% of the measured values in the tunnel located directly beneath the basement centre.
41
Tabatabaei, Narges, Ramis Örlü, Ricardo Vinuesa, and Philipp Schlatter. "Aerodynamic Free-Flight Conditions in Wind Tunnel Modelling through Reduced-Order Wall Inserts." Fluids 6, no. 8 (July 27, 2021): 265. http://dx.doi.org/10.3390/fluids6080265.
Full textAbstract:
Parallel sidewalls are the standard bounding walls in wind tunnels when making a wind tunnel model for free-flight condition. The consequence of confinement in wind tunnel tests, known as wall-interference, is one of the main sources of uncertainty in experimental aerodynamics, limiting the realizability of free-flight conditions. Although this has been an issue when designing transonic wind tunnels and/or in cases with large blockage ratios, even subsonic wind tunnels at low-blockage-ratios might require wall corrections if a good representation of free-flight conditions is intended. In order to avoid the cumbersome streamlining methods especially for subsonic wind tunnels, a sensitivity analysis is conducted in order to investigate the effect of inclined sidewalls as a reduced-order wall insert in the airfoil plane. This problem is investigated via Reynolds-averaged Navier–Stokes (RANS) simulations, and a NACA4412 wing at the angles of attack between 0 and 11 degrees at a moderate Reynolds number (400 k) is considered. The simulations are validated with well-resolved large-eddy simulation (LES) results and experimental wind tunnel data. Firstly, the wall-interference contribution in aerodynamic forces, as well as the local pressure coefficients, are assessed. Furthermore, the isolated effect of confinement is analyzed independent of the boundary-layer growth. Secondly, wall-alignment is modified as a calibration parameter in order to reduce wall-interference based on the aforementioned assessment. In the outlined method, we propose the use of linear inserts to account for the effect of wind tunnel walls, which are experimentally simple to realize. The use of these inserts in subsonic wind tunnels with moderate blockage ratio leads to very good agreement between free-flight and wind tunnel data, while this approach benefits from simple manufacturing and experimental realization.
42
Belostotsky, Alexander, Pavel Akimov, and Irina Afanasyeva. "ABOUT “LEGITIMIZATION” OF NUMERICAL MODELLING OF WIND IMPACTS ON BUILDINGS AND STRUCTURES IN DESIGN CODES." International Journal for Computational Civil and Structural Engineering 15, no. 4 (December 29, 2019): 14–24. http://dx.doi.org/10.22337/2587-9618-2019-15-4-14-24.
Full textAbstract:
The distinctive paper is detoded to problem of “legitimization” of numerical modelling of wind loads and impacts on buildings and structures. General information about computational fluid dynamics (CFD) and its development prospects is presented. The main advantages and disadvantages of numerical simulation compared with tests in wind tunnels (wind tunnel tests) are considered. Besides, information about the second modification of corresponding Russian design codes (SP 20.13330.2016 “SNiP 2.01.07-85* Loads and effects”) is provided. Prospects for the further development of numerical modelling and its applications for solution of problems of construction aerodynamics are given.
43
Huang, Ming Li, Xiao Wei Meng, and Zhong Sheng Tan. "Research on the Blasting Shock Absorption Technology of Shallow-Buried Tunnel Under-Traversing the Dense Houses." Advanced Materials Research 243-249 (May 2011): 3546–50. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.3546.
Full textAbstract:
How to deal with a conflict between blasting vibration damage of tunnels construction with complex shallow and the efficiency has been always a difficult technical problem. Relying on the Chang Hong Ling tunnel which under-traverses the Jiangchi Town, using of field monitoring method to comparative study on the blasting vibration under different blasting scheme construction, research shows that: the up-step of non-blasting excavation + lower-bench of controlled blasting technique, successfully controls the surface blasting vibration speed within 1.5 cm/s.Then the tunnel can be constructed safely and rapidly, which provides a reference for the blasting excavation engineering in urban.
44
Su, Zhongming, Jianxun Chen, and Yanbin Luo. "Mechanical Characteristic and Length Optimization of System Anchor in Loess Tunnel Based on Field Measurement and Analytical Solution." Mathematical Problems in Engineering 2021 (August 2, 2021): 1–11. http://dx.doi.org/10.1155/2021/5582041.
Full textAbstract:
In this paper, field measurement is used to obtain the force of system anchor in its actual working condition and stress situation of system anchors in different parts of loess tunnel is analyzed based on field test results, indicating the reasons why values of measured axial force of system anchor are different in different parts of loess tunnel. Based on the displacement solution of Mindlin problem, this paper deduces the analytical solution to stress distribution of system anchors in the sidewall of loess tunnel under the pull-out force, analyzes the distribution forms and influencing factors of shear stress and axial force. At the same time, analytical solutions to system anchor stress and surrounding rock plastic zone radius are tentatively applied to the analysis of stress characteristics and length optimization of system anchor in loess tunnel. The research results are of great significance to understand the mechanical characteristics of anchors in loess tunnel and to optimize the design of anchors in the primary support system of loess tunnel, which leads to accelerated construction progress and low economically cost, especially in loess tunnels with large cross section and long span.
45
Sun, Zhenyu, Dingli Zhang, and Qian Fang. "Determination Method of Reasonable Reinforcement Parameters for Subsea Tunnels Considering Ground Reinforcement and Seepage Effect." Applied Sciences 9, no. 17 (September 2, 2019): 3607. http://dx.doi.org/10.3390/app9173607.
Full textAbstract:
The key issue for construction of subsea tunnels through unfavorable geological conditions is to determine a reasonable reinforcement scheme, while the core problem for the reinforcement design is to accurately evaluate the mechanical behavior of surrounding rock with ground reinforcement. Considering that advanced curtain grouting and full-face grouting are widely used in subsea tunnels, a mechanical model for the subsea tunnel surrounding rock accounting for both ground reinforcement and seepage effect was established. According to the distribution and extent of the plastic zone(s), six potential configurations were appropriately analyzed, which were validated by numerical simulations and analytical solutions for simplified settings from the literature. The sensitivities of the reinforcement parameters were examined, and by taking into account the tunnel radial displacement and the seepage quantity as the main objectives, the multi-objective optimization of the reinforcement parameters was put forward via the stratified sequencing method. Finally, application of the proposed method to the Qingdao Jiaozhou bay subsea tunnel project in China was explained. Research results could provide insightful ideas for the quantitative design of the ground reinforcement of subsea tunnels and may have reference value for their construction safety through unfavorable geological conditions.
46
Kositsyn, Sergei, and Vladimir Akulich. "Numerical methodology for determining the soil mass surface slump, caused by the tunnel construction with the geodetic monitoring results comparison." E3S Web of Conferences 281 (2021): 01042. http://dx.doi.org/10.1051/e3sconf/202128101042.
Full textAbstract:
The work is aimed at determining the construction effect of a running tunnel on the stress-strain state change of the surrounding soil massif, in particular, on the development of a sediment basin on the Earth’s surface. The soil massif is defined by an elastoplastic material according to the Drucker - Prager model. The paper proposes two numerical methods for solving the problem: with and without the use of contact elements for modeling the construction gap between the tunnel shell and the soil mass caused by the tunnel boring mechanized complex operation. The proposed methods were applied in the construction of Kalininsko-Solntsevskaya line tunnels of the Moscow subway. A comparative analysis of the results obtained with geodetic monitoring of the Earth’s surface slump in the construction influence zone has been carried out.
47
Ponte, Maurizio, Filippo Catanzariti, and Gloria Campilongo. "Application of the Finite Element Method (FEM) through GFAS Software to the study of a tunnel." Green World Journal 4, no. 2 (May 1, 2021): 001. http://dx.doi.org/10.53313/gwj42006.
Full textAbstract:
Computational simulation is widely used in companies to perform analysis and improve the quality of products and projects. Most of these analyses are carried out using software that uses the Finite Element Method, which allows to obtain answers to numerous engineering problems. In this study, two examples of application to the study of tunnels of the Finite Element Method using the Geostru Software "GFAS - Geotechnical F.E.M. Analysis System" are proposed. The case of a tunnel excavated inside a granite rock massif was analyzed, first determining the state of stresses in the cavity contour through a theoretical method and comparing these results with those obtained in the software. Then, by means of finite element modeling, the settlements induced by the excavation were determined. Finally, the problem of tunnel excavation in a viscoplastic rock mass is presented and the authors propose a comparison of the analytical and numerical method.
48
Wang, Lin, Kaihang Han, Tingwei Xie, and Jianjun Luo. "Calculation of Limit Support Pressure for EPB Shield Tunnel Face in Water-Rich Sand." Symmetry 11, no. 9 (September 2, 2019): 1102. http://dx.doi.org/10.3390/sym11091102.
Full textAbstract:
With the rapid development of the tunnels constructed under the rivers and seas, the research on face stability of shield tunnel in water-rich sand has important theoretical value and engineering application significance. In addition to the loads exerted by overlaying strata, the tunnels constructed in water-rich strata are usually subjected to high hydrostatic pressure or seepage forces, which are apt to cause the ground collapse of the shield tunnel face. The distribution of hydraulic head field around the tunnel face is critical to assess the impacts of the seepage forces on the tunnel face stability. This paper investigates the axisymmetric problem of the face stability of the shield tunnel under a seepage condition within the framework of limit equilibrium analysis. First, numerical simulations are carried out in this paper to analyze the distribution rules of total hydraulic head and pore water pressure near the tunnel face of the shield tunnel under the condition of stable seepage with different cover depths. Then, based on the distribution rules of total hydraulic head, new formulas for predicting the total hydraulic head along the horizontal and vertical directions are proposed and compared with the numerical simulations in this paper and existing approximate analytical solutions. Second, the classical axisymmetric limit equilibrium model is revised by incorporating the new approximate analytical solutions of hydraulic head field to determine the failure modes and the limit support pressures with a numerical optimization procedure. Lastly, the comparisons of the results obtained from the theoretical analysis model in this paper and the existing approaches are conducted, which shows that the failure mechanism proposed in this paper could provide relatively satisfactory results for the limit support pressures applied to the tunnel face.
49
Fattah, M. Y. "Boundary Element Analysis of a Lined Tunnel Problem." International Journal of Engineering 25, no. 2 (B) (May 2012): 89–97. http://dx.doi.org/10.5829/idosi.ije.2012.25.02b.02.
Full text
50
Ingram-Rice, Barbara. "Carpal tunnel syndrome: more than a wrist problem." Journal of Bodywork and Movement Therapies 1, no. 3 (April 1997): 155–62. http://dx.doi.org/10.1016/s1360-8592(97)80035-6.
Full text