Academic literature on the topic 'Muck pile'

<p><strong>Abstract.</strong> In open pit mining it is essential for processing and production scheduling to receive fast and accurate information about the fragmentation of a muck pile after a blast. In this work, we propose a novel machine-learning method that characterizes the muck pile directly from UAV images. In contrast to state-of-the-art approaches, that require heavy user interaction, expert knowledge and careful threshold settings, our method works fully automatically. We compute segmentation masks, bounding boxes and confidence values for each individual fragment in the muck pile on multiple scales to generate a globally consistent segmentation. Additionally, we recorded lab and real-world images to generate our own dataset for training the network. Our method shows very promising quantitative and qualitative results in all our experiments. Further, the results clearly indicate that our method generalizes to previously unseen data.</p>

The North Carolina Department of Transportation is currently conducting a predesign foundation load test for a new bridge over the Northeast Cape Fear River near Wilmington, North Carolina. The primary purpose of the load test program is to determine whether concrete piles can penetrate a very dense and cemented sand layer and what side friction and tip bearing capacities should be used for the design of the drilled piers. Significant cost savings could be realized if pile foundations instead of drilled piers could support the approach spans of the bridge. For this determination, three concrete piles will be installed 30 m into the ground. Significant cost savings could also be realized by making a more accurate determination of the drilled pier capacities. For this determination, the side friction and tip bearing capacities of the dense Peedee sands and the underlying hard marine clays will be determined with Osterberg cell tests on two 2130-mm-diameter drilled piers. The different subsurface layers (muck, alluvial sands, and Peedee sands) will also be tested laterally with both static and statnamic testing to assist in the foundation design. The load test program incorporates an NCHRP research program on pile groups. The program includes testing a reusable instrumented steel pile group and frame at various sites in various soil conditions around the United States. The load test program results to date, the effect of the results on the foundation design, and the construction, testing, and instrumentation of the drilled piers are described.

Explosive specific charge is the key to the high level of casting blast. In order to study how the explosive specific charge affects the high bench cast blasting, theoretical analysis and experimental study were used in the Hei Dai-gou open pit cast blasting. Experimental study shows that: under the same engineering geological conditions and blasting parameters, the throw distance increases as the average explosives specific charge increases, and this trend slows down gradually. Settlement muck-pile height increases as explosives specific charge increases, and then gently muck-pile shape tends to be more conducive to the work platform dragline flat-field and inverted reactor efficiency. Whenq> 0.65 kg/m3, the cast percentage can reach more than 30%, as 0.67 kg/m3<q<0.70 kg/m3, the cast percentage increases with a significant effect as the explosives specific charge increases; whenq> 0.74 kg/m3, the increasing rate of the cast percentage with the increase of explosive specific charge decreases.

The current techniques used for monitoring the blasting process in open pit mines are manual, intermittent and inefficient and can expose technical manpower to hazardous conditions. This study presents the application of unmanned aerial vehicle (UAV) systems for monitoring and improving the blasting process in open pit mines. Field experiments were conducted in different open pit mines to assess rock fragmentation, blast-induced damage on final pit walls, blast dynamics and the accuracy of blastholes including production and pre-split holes. The UAV-based monitoring was done in three different stages, including pre-blasting, blasting and post-blasting. In the pre-blasting stage, pit walls were mapped to collect structural data to predict in situ block size distribution and to develop as-built pit wall digital elevation models (DEM) to assess blast-induced damage. This was followed by mapping the production blasthole patterns implemented in the mine to investigate drillhole alignment. To monitor the blasting process, a high-speed camera was mounted on the UAV to investigate blast initiation, sequencing, misfired holes and stemming ejection. In the post-blast stage, the blasted rock pile (muck pile) was monitored to estimate fragmentation and assess muck pile configuration, heave and throw. The collected aerial data provide detailed information and high spatial and temporal resolution on the quality of the blasting process and significant opportunities for process improvement. The current challenges with regards to the application of UAVs for blasting process monitoring are discussed, and recommendations for obtaining the most value out of an UAV application are provided.

In order to make a scientific and accurate evaluation of blast casting results, according to the characteristics of blast casting-dragline stripping system, effective casting rate, looseness coefficient, limit vibration velocity, powder factor, fragmentation distribution, muck pile shape, boulder generation, damage degree of coal seam step, and dust pollution are selected as the evaluation indicators of blast casting results, and a classification standard is established. The unascertained measure theory was adopted to determine the membership degree of influencing factor indicator, which expanded the expression method of fuzzy information of evaluation indicators. The Analytic Hierarchy Process was used to determine the subjective weight of indicators, the entropy weight method was used to determine the objective weight of indicators, and the intuitionistic fuzzy set was used to express the range of the comprehensive weights of indicators. An evaluation model of blast casting results was constructed based on unascertained measurement and intuitionistic fuzzy set. The measured and processed data of blast casting in Heidaigou Open-Pit Coal Mine were calculated by the evaluation model. Besides, the sensitivity of indicator weights to the evaluation result of blast casting results was also analyzed. The results show that the blast casting results are level III (well). The effective casting rate ranks first in terms of the influence on the evaluation result, followed by damage degree of coal seam step, muck pile shape, looseness coefficient, powder factor, dust pollution, limit vibration velocity, and boulder generation/fragmentation distribution, and it was proved that the weight fluctuation of the evaluation indicator has no obvious correlation with weight.

When the loading sustained by the foundation is large, employing piled raft foundation is one of the best solutions. In the elasto-plastic design of piled raft, piles could improve the differential settlement and reduce raft thickness. As the raft sustains high earth and water pressures, by reducing the span length of raft and excavation depth, one can get economic design. Using elasto-plastic property of the pile is a better method to avoid increasing the pile length and pile diameter and making full capacity of the piled raft foundation in design compared to normal piled raft. With adoption of few small diameter piles, the raft thickness could be reduced significantly. This makes it much better than raft foundation.

Piled foundations are often subjected to cyclic axial loads. This is particularly true for the piles of offshore structures, which are subjected to rocking motions caused by wind or wave actions, and for those of transport structures, which are subjected to traffic loads. As a result of these cyclic loads, excessive differential or absolute settlements may be induced during the piles’ service life. In the research presented here, centrifuge modelling of single piles and pile groups was conducted to investigate the influence of cyclic axial loads on the performance of piled foundations. The influence of installation method was investigated and it was found that the cyclic response of a pile whose jacked installation was modelled correctly is much stiffer than that of a bored pile. During displacement-controlled axial load cycling, the pile head stiffness reduces with an increasing number of cycles, but at a decreasing rate; during force-controlled axial load cycling, more permanent settlement is accumulated for a bored pile than for a jacked pile. The performance of individual piles in a pile group subjected to cyclic axial loads is similar to that of a single pile, without any evident group effect. Finally, a numerical analysis of axially loaded piles was validated by centrifuge test results. Cyclic stiffness of soil at the base of pre-jacked piles increases dramatically, while at base of jacked piles it remains almost constant.

Comparative analyzing pre-cutting seam in size between 0.5 m and 0.8 m in the top of bridge arch, and vice-arch column blasting range between 1.6 m and 0.8 m , numerical simulations on typical highway double curved arch bridge structure blasting demolition process are carried out adopting common node separate reinforced concrete model. Simulation result indicates that, common node separate model can reflect mechanical properties difference of concrete and reinforcement through analysis on their loading process. Adopting 0.5 m in size of pre-cutting seam is sufficient to ensure the superposition and complete collapse of the bridge. The vice-arch blasting range by 1.6 m can make the bridge more complete disintegration, and it can also decrease the whole collapse time and the height of muck pile.

Die erreichte Zerkleinerung und die Form des Haufwerks sind die beiden wichtigsten Ergebnisse einer Tagebausprengung. Schnelle Informationen über die Eigenschaften des gesprengten Haufwerks ermöglichen eine zielgerichtete und effiziente Produktionsplanung und Kenntnisse über die erreichte Zerkleinerung ermöglichen außerdem Anpassungen in der weiteren Zerkleinerungskette. Durch den Einsatz von UAVs (unmanned aerial vehicles) gemeinsam mit modernen Algorithmen aus dem Bereich Computer Vision und des maschinellen Lernens soll eine schnelle Erfassung und Interpretation der Daten bei gleichzeitiger Integration in die herkömmlichen betrieblichen Abläufe ermöglicht werden, und außerdem können Schwächen bodengebundener Systeme hinsichtlich Vollständigkeit und Repräsentativität umgangen werden. Im vorliegenden Beitrag wird einerseits auf den relevanten Stand des Wissens und der Technik eingegangen und andererseits wird die verfolgte Stoßrichtung bei der Systementwicklung dargelegt sowie erste Arbeiten präsentiert
The fragmentation and the shape of the muck pile are the two major outcomes of open pit mine and quarry blasts. Fast information about the muck pile properties will help to improve the production scheduling and furthermore this information could be used to optimize the blasting patterns of future production blasts. The combined use of unmanned aerial vehicles (UAVs) and modern machine learning and computer vision systems offers a new way of acquiring spatial data to determine on-site fragment size distribution, while at the same time enabling integration into common work flows and mitigating the weaknesses of ground-based systems with special regard to completeness and representativeness. In the present paper, we will discuss the relevant related work, present the planned path for system development and give examples of first work

Se han desarrollado y optimizado dos nanoemulsiones que contienen Nistatina (N1 y N2) para su aplicación en piel y mucosa oral, respectivamente. Estas formulaciones tuvieron un tamaño de gota nanométrico y resultaron ser estables a lo largo del tiempo. Adicionalmente se determinó el comportamiento reológico de ambos sistemas resultando ser fluidos newtonianos. Se evaluó la actividad antifúngica in vitro, observado que la potencia de la nistatina aumentó al ser introducida en las nanoemulsiones, cuando se comparaba con la nistatina libre. El mecanismo de liberación de la nistatina de las nanoemulsiones siguió una cinética de orden uno para ambas formulaciones. Trás el ensayo de permeación ex vivo en piel humana con la nanoemulsion N1 se observó que la cantidad de fármaco permeada fue muy baja, pudiendo descartarse la posible aparición de efectos adversos a nivel sistémico. De la misma manera se realizó el ensayo de permeación ex vivo en mucosa oral porcina para la formulación N2 llegando a la misma conclusión que en el caso de la permeación en piel. En ambos casos la cantidad de fármaco retenido en el tejido (tanto en piel o mucosa) es suficiente para observar un efecto fungistático, fungicida y un prolongado efecto post-antifungico (PAFE). Con el fin de determinar el efecto de la nanoemulsion N2 sobre la mucosa oral se visualizó la ultra-estructura del tejido y no observándose variaciones significativas cuando se comparaban con el control (mucosa no tratada con la nanoemulsion). Las nanoemulsiones N1 y N2 son formulaciones prometedoras para el potencial tratamiento clínico de candidiasis muco-cutáneas.
Muco-cutaneous candidosis is a common opportunistic infection must be treated to prevent other tissue invasion. Nystatin is one of the most prescribed drugs to treat this pathology, but due to its physicochemical properties its pharmaceutical-technological requirements make it a challenge. The purpose of this work was the development and characterization of an optimal nystatin delivery system for the potential treatment of oral candidosis avoiding undesirable side effects and toxicity of potential systemic absorption. Two nanoemulsion (N1 and N2) was developed, evaluated and characterized. It has been formulated successfully as a stable nanoemulsion with a droplet size of 75 and 138 nm, respectively. First order release parameters were estimated using different mathematical approaches and ex vivo permeation of nystatin through human skin and porcine buccal mucosa were found no systemic effects would happen. Microbiologic studies performed revealed an enhanced antifungal effect of the nystatin loaded nanoemulsion. Also the evaluation of buccal mucosa ultrastructure by transmission electron microscopy methodology showing a harmless effect in the mucosa microstructure. We can infer that the selected nystatin nanoemulsion could be potentially used on candidosis infection under mucositis conditions.

Dans le tractus gastro-intestinal, l'adhésion des bactéries commensales à l’épithélium permet leur maintien, ce qui aide à contrôler l’implantation de germes indésirables par des mécanismes de concurrence (effets nutritionnels, sites spécifiques d'adhésion ...). Bien que le rôle de la couche du mucus (principalement composée de glycoprotéines à haut poids moléculaire, appelées mucines) recouvrant la muqueuse soit connu et décrit depuis de nombreuses années, notamment pour sa fonction de barrière protectrice, l'intérêt pour décrypter les mécanismes précis d’interaction(s) avec le microbiote (bactéries commensales, pathogènes ou probiotiques) n’a que récemment émergé. Dans ce cadre, l'objectif de cette thèse, menée en collaboration entre le Laboratoire d’Ingénierie des Systèmes Biologiques et des Procédés de Toulouse et le Laboratoire d’Analyse et d’Architecture des Systèmes de Toulouse, est de caractériser in vitro le comportement muco-adhésif de Lactococcus lactis, le modèle des bactéries lactiques, en utilisant des approches de quantification multi-échelles (du niveau moléculaire à l’échelle multicellulaire) sur un large panel de souches naturelles et recombinantes. Une attention particulière est accordée au rôle des mucines, en utilisant le modèle PGM (mucine gastrique de porc ou « Pig Gastric Mucin »).La première partie du travail a porté sur la quantification à l'échelle de la cellule unique des interactions entre L. lactis et une surface abiotique (polystyrène) recouverte de PGM, en utilisant la microscopie à force atomique (AFM). La faisabilité de la méthode a tout d'abord été démontrée sur la souche modèle L. lactis ssp. cremoris MG1820. La couche de PGM a été caractérisée en utilisant des méthodes analytiques complémentaires (AFM, XPS - spectroscopie de photoélectrons induits par rayons X, QCM-D - Microbalance à Quartz à mesure de Dissipation...). En parallèle, les bactéries L. lactis ont été immobilisées sur la pointe AFM et utilisées comme « sonde de force », en considérant la souche naturelle IBB477 (L. lactis ssp. cremoris), d’origine laitière et présentant une forte persistance dans le tractus digestif du rat lors d’essais réalisés in vivo (collaboration avec l’Institut de Biochimie et de Biophysique de Varsovie, Pologne). Comparé aux conditions contrôle (i.e., surface de polystyrène sans PGM), les niveaux de force d'adhésion enregistrés entre L. lactis et PGM sont inférieurs, ceci en raison des répulsions électrostatiques, hydrophiles et stériques s’établissant entre la couche de PGM et la paroi cellulaire. La forme des courbes représentant l’évolution de la force au retrait en fonction de la distance est également différente. Une analyse détaillée souligne la contribution, conjointe et différente selon les souches testées, d’événements (i) non adhésifs, (ii) adhésifs non spécifiques (interactions électrostatiques, hydrophobes, de van der Waals) et (iii) adhésifs spécifiques (liaison de type ligand/récepteur). La contribution spécifique a ensuite été explorée plus finement en termes de constantes cinétiques d’association et de dissociation. Nous avons, par ailleurs, poursuivi notre exploitation de la biodiversité naturelle chez les lactocoques en étudiant la souche TIL448 (L. lactis ssp. lactis) d’origine végétale, en collaboration avec l’Institut MICALIS de Jouy-en-Josas. Nous avons ainsi démontré, pour la première fois chez L. lactis, le rôle combiné des protéines à domaine(s) MUB (« Mucus-Binding ») et des pili, à travers l'analyse approfondie des données AFM (force d'adhésion, répartition des événements adhésifs spécifiques/non spécifiques, distances d'interaction...). Le rôle des pili a été confirmé sur des souches recombinantes piliées (L. lactis ssp. lactis IL1403), toujours en partenariat avec l’Institut MICALIS de Jouy-en-Josas. En parallèle, en collaboration avec l’Unité de Glycobiologie Structurale et Fonctionnelle de Villeneuve d'Ascq, nous avons cherché à identifier les O-glycannes de PGM (fractions neutre et acide), impliqués dans le processus d'interaction avec la surface bactérienne. Pour confirmer l’ensemble des résultats obtenus à l'échelle de la cellule unique et en mode statique par AFM (effet anti-adhésif de PGM, comportement muco-adhésif différent selon les souches de L. lactis), la deuxième partie du travail a été consacrée à des expérimentations à l’échelle de l’ensemble de la population bactérienne, en conditions dynamiques (QCM-D, chambre à écoulement cisaillé). Nous avons évalué par QCM-D chez les souches IBB477 et MG1820 les propriétés viscoélastiques des dépôts bactériens, en relation avec le comportement bio-adhésif vis-à-vis de la couche de PGM. Les données obtenues par AFM et chambre à écoulement cisaillé sur ces mêmes souches ont été confrontées pour accéder plus finement au mode d’interaction avec PGM (densité de liaisons sur la surface bactérienne). Enfin, nous avons évalué chez IL1403 l’effet des pili sur la dynamique de détachement et d’orientation sous cisaillement contrôlé.En conclusion, la combinaison des échelles d'observation et d’analyse, aussi bien au niveau de la cellule unique qu’à celui de l’ensemble de la population bactérienne, nous permet désormais de disposer de nouvelles connaissances sur les mécanismes diversifiés d'interaction entre L. lactis et PGM, visant à une meilleure compréhension des fonctionnalités de cette bactérie au niveau du tractus gastro-intestinal
In the gastrointestinal tract, adhesion of commensal bacteria to epithelial cells allows their retention, which helps to control the implementation of unwanted germs through mechanisms of competition (nutritional effects, specific sites of adhesion ...). Indeed, bacterial adhesion to the intestinal epithelium seems to be important for the balance of intestinal microbiota. Although the role of the mucus layer lining the mucosa, which is mainly composed of large glycoproteins termed mucins, is known and described for many years, particularly for its protective barrier function, the interest for unraveling precise mechanisms of interaction with bacteria (commensal, pathogens or probiotics) has just recently emerged. In this framework, the aim of the PhD thesis was to characterize in vitro muco-adhesive behavior of Lactococcus lactis, the model of Lactic Acid Bacteria, using multi-scale approaches (from molecular to multicellular levels) on a large set of natural and recombinant strains. A particular attention was paid to the role of mucins, using the PGM model (Pig Gastric Mucin).The first part of the work was focused on the quantification at nanoscale of interactions between L. lactis and adsorbed PGM, using AFM. The feasibility of the method was first demonstrated on the reference strain MG1820. PGM coating was characterized using a complementary set of analytical methods (AFM, XPS, quartz crystal microbalance with dissipation monitoring…). In parallel, L. lactis cells were immobilized onto the AFM tip and used as a living force probe, considering the natural strain IBB477 (L. lactis subsp. cremoris), isolated from Polish artisanal dairy products and previously shown to display in vivo retention in the rat gut (collaboration with the Institute of Biochemistry and Biophysics of Warsaw, Poland). Compared to control conditions (i.e., no PGM coating), adhesion force levels recorded for PGM were lower, due to the interplay of electrostatic, hydrophilic and steric repulsions. The shape of retraction force-distance curves for L. lactis/PGM interactions was also different. The detailed analysis of curve shape highlighted the contribution of non-adhesive, non-specific (electrostatic, hydrophobic, van der Waals interactions) and specific adhesive events (ligand/receptor bonding), depending on the strain under study. Specific forces were analyzed in terms of dissociation/association kinetic constants.We then explored the natural biodiversity among lactococci by studying the natural strain of L. lactis (subsp. lactis) TIL448 from plant origin, in collaboration with MICALIS (Jouy-en-Josas). We demonstrated, for the first time for L. lactis, the combined role played by “MUB-like” domain-containing protein and pili, through the thorough analysis of AFM data (adhesion force, repartition of specific/non-specific adhesive events and distances of interaction…). The role of pili was also confirmed with recombinant piliated strains (L. lactis subsp. lactis IL1403), in partnership with MICALIS (Jouy-en-Josas). In parallel, in collaboration with the “Unité de Glycobiologie Structurale et Fonctionnelle de Villeneuve d'Ascq”, a first attempt was done to identify the O-glycans of PGM (neutral and acid fractions), involved in interactions with the bacterial surface.To confirm these results achieved at single-cell scale and under static mode by AFM (anti-adhesive of PGM, different muco-adhesive properties among several strains of L. lactis), the second part of the work was devoted to experiments at multicellular scale under dynamic conditions (quartz crystal microbalance with dissipation monitoring – QCM-D, shear stress flow chamber). We evaluated by QCM-D, for MG1820 and IBB477 strains, the viscoelastic properties of the cell layers, in relation with the bio-adhesive behavior towards PGM. The data obtained by AFM and shear stress flow chamber were combined to access more precisely to the interaction mode with PGM (density of bonds over the cell surface). Finally, using the recombinant piliated strain (IL1403), we focused on the effect of pili on detachment and re-orientation dynamics under shear flow

The Hawaiian Islands are the most isolated inhabited archipelago in the world. Initially colonized around A.D. 1000, the environmental gradients of rainfall and island-age have influenced subsequent cultural variation and differentiation in the islands. Settlements are typically dispersed hamlets and integrated within agricultural facilities such as irrigated pondfields and dryland field systems. Populations were politically organized in idealized pie-shaped units or ahupua`a that typically encompass a cross-section of island resources. Material culture , including fishhooks, stone tools, and religious temples, is broadly similar within these units, but there is also much evidence for elite control of specialized production in some areas. The Hawaiian Islands are the archetypal chiefdom society, although based on changes in demography, monumental architecture (heiau) and royal centers, intensive agriculture, and divine kingship, the population had likely crossed the threshold of sociopolitical complexity to that of an archaic state prior to the arrival of Europeans in 1778.

AbstractThe next approach to research on water was to measure the small amount of water actually moving within a plant. The best method is to utilize radioisotope (RI)-labeled water and measure the radiation from outside of the plant. However, it is rather difficult to label water, since there are only limited kinds of RI for tracing water.When utilizing 18F to trace water movement, another fundamental question to consider was the features that characterize drought-tolerant and drought-sensitive plants. It is natural to suppose that drought-tolerant plants have strong water absorption; therefore, by analyzing the water absorption mechanism of tolerant plants and by introducing this function to sensitive plants, it might be possible to make the sensitive plants more tolerant.However, when water uptake was studied in naturally developed drought-tolerant and drought-sensitive cowpea, selected from 2000 cowpea plants grown in the field of Africa, the result was unexpected. Under normal conditions, the amount of water absorbed by the drought-tolerant strain was much lower than that absorbed by the sensitive strain, as if showing the low capability of water absorption. When a drought condition was introduced, the tolerant strain began to absorb much more water than usual, whereas the sensitive strain could not absorb as much water as before. This result provided us with an important lesson. Analyzing the mechanism of drought tolerance only by comparing the water absorption of tolerant and sensitive plants might not readily reveal the reason for drought tolerance. The features of the naturally produced plants showed us different mechanisms that might not match our expectations developed in the laboratory.Next, we performed water measurements using 15O-labeled water, which has an extremely short half-life of 2 minutes. Here, we found another astonishing result, which was “water circulation” in the plant internode. A tremendous amount of water was always leaking from xylem cells, which had been regarded as a mere pipe to transfer water from the root to the aboveground parts. In another subsequent study, it was shown that the water flowing out from the xylem was pushing out the water already present in the stem and then returning to the xylem again to move upward. The water velocity in the internode was kept constant, and through simulation, it took less than 20 minutes to exchange the water already present in the stem with newly absorbed water.

Welcome to Pine Point is a 2011 interactive web documentary about a Canadian town that was physically demolished when the mine closed and residents dispersed. As folklorists, we tend to seek continuation, preservation, sustainability and we see in stories like Pine Point the demise of a folk group in the face of class struggle. “Pine Point” the web video, however, suggests a story and a folk group may be more important in their absence than in their continuation. Putting Welcome to Pine Point into discussion with Jacque Derrida's "hauntology," this chapter explores the preservationism inherent in not only folklore but much of the arts and humanities.

Near a month went by without much doing. The same night of our marriage Galoshes called round, and made himself mighty civil, and got into a habit of dropping in about dark and smoking his pipe with the family. He could talk to Uma,...

Monopiles installed by impact driving are the preferred system for the foundation of offshore wind turbines in water depths up to 40 m. The vibration technique as alternative installation method has big advantages regarding piling noise and installation time. Much experience exists for the design and installation of impact driven piles. Within the research project ZykLaMP, the lack of experience concerning vibrated monopiles shall be faced by means of large-scaled model investigations regarding the lateral load-bearing behavior. Therefore, open ended steel pipe piles (L = 2.4 m, Dpile = 0.6 m) are installed into dense sand by means of impact and vibratory pile driving and then subjected to cyclic lateral loading. This paper focusses on pile driving predictions and measurements during the installation process. Pile driving post-predictions were carried out based on a simple force equilibrium approach. Model piles were installed using two different vibro hammers with different eccentric moments and one impact hammer. Measurements of strains and accelerations were carried out to investigate dynamic movements during pile driving. Earth pressure transducers were used to investigate the development of soil stresses due to the installation process. Measurements show that even at high acceleration amplitudes a refusal to vibratory driving may occur at a certain penetration depth. Soil stresses in the vicinity of the pile decrease to about 50 % due to vibratory driving which is one reason for the friction fatigue phenomenon. Drivability studies using the force equilibrium model give rough predictions about whether or not a pile can be driven to a certain penetration depth but are quite sensitive to input parameters. For the model tests, post-predictions gave reasonable results.

With the rapid development of offshore wind energy in Europe, a large number of piled structures are being installed. In areas with sandy seabed conditions, erosion of sediment by the actions of wave and current can negatively influence foundation capacity. An accurate prediction model of scour around the piles is therefore required. Well-accepted scour prediction methods exist; both for the equilibrium scour depth and the time scale of scour [1] around single piles. These standard formulas have been combined with metocean data and a hindcasting model to calculate the expected scour depth around piles of wind turbine tripod foundations. Other causes of scour, such as pile-pile interaction, effect of proximity of structural members to the seabed, and seabed mobility were also assessed in order to determine the amount of global scour to be considered. The scour predictions were compared to measurements taken at an offshore wind turbine foundation at Park Alpha Ventus (PAV) in the German North Sea [2]. The data showed very good agreement with the measured scour around the piles. Both the equilibrium scour depth and time scale of scour were well predicted using the hindcasting model. The measured scour below the central column of the tripod structure exceeded expectations; this is believed to be due to a pumping effect during storm episodes. Finally, the effect of scour on the vertical effective stress around the tripod piles was assessed with a finite element model. Local scour had an important effect while scour below the centre of the structure had a much more limited effect. Considering the combined effects of multiple pile interaction, scour below the central column, and making an allowance for seabed mobility, an equivalent global scour depth for pile capacity calculations was established.

For the foundation of an industrial complex, auger-cast-in-place piles (ACIP-Piles) have been installed on behalf of the recommendation of a local geotechnical consultant. With respect to the poorly graded sand deposits and the high ground water table, the installation was critically reviewed with respect to the European Code DIN EN 1536. In the course of the installation process of a couple of working piles, extensive soil was drilled by the auger, which led to a loss of soil mass in the vicinity of the pile shafts. A detailed engineering analysis came to the conclusion, that the reasons of the damage can be attributed to a concurrence of the subsurface soil conditions, the chosen drilling technique, the choice of the contractor as well as the workmanship. However, a distinct soil loosening could also be measured by a plenty of cone penetration tests in the vicinity of those working piles, which have apparently been installed properly. Surprisingly, the compact sand layers were much more affected by the installation process than the loose deposits. These findings lead to the conclusion, that the installation process of ACIP piles has to be critically evaluated during the construction process and may become a decisive design influence in the case of a pile design by empirical pile capacity magnitudes.

With the increasing demand of petroleum exploitation as well as the construction of bridges and ports, the size of pile driving barges becomes much greater with longer piles. Considering of the economy, many old pile driving barges face to the reconstruction through the strengthening and heightening. In determining the reconstruction scheme, the traditional method for loads estimation is the combination of static load with dynamic coefficient, but it is perhaps not reasonable. The reconstruction design of a pile driving barge is described in this paper. Various of loads were considered including the normal working load, the wind load, the wave load as well as the added dynamic loads especially the transient load during hoisting and pile sliding. The loads transfer between the main hook and the auxiliary hook were simulated experimentally. The FE method was adopted to obtain the stress contribution and find the position with maximum stress. A reconstruction scheme was then put forward to strengthen the weak position of the frame. The upper platform and the main stanchion need strengthened by increasing the outer diameter and the wall’s thickness locally. The connection structure of the upper platform and the main stanchion should be strengthened through the structural optimization. The stress distribution and the maximum stress were then calculated and the safety was verified according to the allowable stress value of the materials. The transient movement of the pile was investigated. The pile driving barge was then reconstructed based on the reasonable reconstruction scheme from the load simulation and structural optimization.

The increasing use of flexible pipes in subsea with high pressure/high temperature brings about much more challenges, for example flexible riser fatigue, bird-caging and armour wire disorganization, development of flexible pipes with smooth bore and ones with anti-H2S layer, which demand operators to adopt an effective integrity management program including every phase of flexible pipe industry to avoid reduction of production. To date, much research work has been carried out on this topic. In this paper, the applicable inspection and monitoring measures are presented as proposals to develop the integrity management of flexible pipes. Meanwhile, this paper takes a practical project as an example to show the whole process of integrity management study clearly. The process can be used as reference for the other similar integrity management projects.

At present, flexible pipes are used worldwide to conduct several fluids within the offshore oil production industry. These flexible pipes are complex composite structures made up of several plastic and steel layers. They are intended to work for a long period of time, something around 20 years. Although the flexible pipes behavior is satisfactory in most applications, they are susceptible to simple damages, for example on the external sheath, which much reduces their service life. The offshore inspection activities are extremely expensive and, given that, these activities need to be very well oriented in order to be effective. This paper describes the Risk Based Inspection Methodology, which is a helpful applicable tool in the integrity management of several flexible pipe systems, allowing to concentrate the efforts where they are really needed. This methodology may be used by the oil companies to reduce overall costs and enhance safety and integrity of the production systems.

Pipe-in-pipe is a flowline concept that shows an increasing popularity when certain flow assurance aspects are to be dealt with. U-values in the order of 1W/m2K are achievable, ensuring that the well fluid temperature can be kept high for longer time after shut-down and over longer distances. This two layer steel construction also has some mechanical properties that can be beneficial for the design such as a stronger, more robust cross section, better protection against 3rd party interference and increased stability as a few examples. Disadvantages such as high weight causing higher bending moments during installation or in free spans should also be mentioned. The global response of a pipe-in-pipe will be very much similar to a conventional single pipeline. It will expand due to pressure and temperature loads, longitudinally or in combination with lateral motion (global buckling), always in the direction of the lowest resistance. However, there are also some important differences compared with conventional pipelines. Interaction between the inner and outer pipeline is secured using rigid bulk heads at each end. Along the pipeline the separation of the two pipes can be ensured by e.g. rollers, plates, spacers, insulation and additional intermittent bulk heads. In the most extreme case the spacing between intermittent buck heads is down to every pipe joint. At present there is no public pipeline code that in detail addresses pipe-in-pipe. One reason is of course that there is not only one pipe-in-pipe concept but a large number of variants. This paper’s focus is on mechanical behaviour of a pipe-in-pipe in relation to expansion and global buckling. Both the friction between to two pipes and soil friction influence on the global buckling pattern is discussed. An introduction is given to where pressure and temperature loads are acting and how these loads raises forces in the pipeline (load effects).