Academic literature on the topic 'Numerical classification of soil profile'

The study classified the coastal plain sands of south-eastern Nigeria at the series level and modeled the classification using digital terrain attributes. The study utilized 72 secondary and 12 primary profile pits data generated from 24 and 4 locations (at 3 per location) for classification/modelling and validation respectively. The three profile pits per location represents the three topographic positions of upper, middle and lower slopes. Digital elevation model was also utilized for the generation of terrain attributes. Soil morphological characteristics were coded for suitability in statistical analysis. Hierarchical clustering was utilized in the grouping of the soil into 17 homogeneous groups referred to as soil series. Regression kriging was used to model the predicted soil series within the area covered by coastal plain sands in Akwa Ibom State. The variables that could be used in the modelling of the different classified soil series include Sand Content, aspect, flow accumulation, compound topographic index (CTI), elevation, hill shade, slope, curvature, flow direction, stream power index (SPI), profile curvature, tangential curvature (R2 = 0.21).Out of the 17 soil series classified, 14 was successfully mapped using digital technique. It was observed that 66.7% of the classified soil series were accurately predicted using digital mapping technique. The classifications carried out numerically made use of morphological discrete variables whereas digital used empirically determined continuous variables which could be more accurate. Therefore it could be inferred that the digitally produced soil classification is more accurate and 14 soil series could be identified and mapped in the study area. Key words: pedogenesis, digital soil mapping, soil series, hierarchical clusters, regression kriging

The utility of the Factual Key and Soil Taxonomy was tested by using comprehensive soil survey data from the lower Macquarie Valley, N.S.W. The aim was to assess whether the two classification schemes partitioned soil variation efficiently and to establish their usefulness for predicting variables not used during profile allocation. A numerical taxonomic method was used to generate a local classification which served as a benchmark to assess the two national systems. The effectiveness of the three classifications was determined by comparing the proportion of variation accounted for in a range of soil properties of direct relevance to irrigated and dryland agriculture. The Factual Key and Soil Taxonomy were found to be equally poor for predicting relevant soil properties. Both systems arbitrarily subdivided important local modalities. The variation accounted for by the numerical classification was 20-30% greater. The result demonstrates the practical advantages of a local classification and the reality of Butler's taxonomic hiatus.

The average shear wave velocity over the top 30 m of a soil profile ( VS,30) represents an usual parameter for soil classification in a modern building code for seismic design. In this work the ground response of about 100 soil profiles in Tuscany and Molise (Italy) is studied through 1-D numerical simulations in order to evaluate the reliability of European and Italian soil classifications based on the VS,30 criterion. The amplification factor, Fa, defined here as the ratio of the pseudo-velocity response spectrum intensity (Housner 1952) at the surface, S Is, to the pseudo-velocity response spectrum intensity at the rock outcrop, S Ir, is related to some soil parameters, such as VS,30, the fundamental frequency of vibration of the soil column, F0, and seismic impedance contrast, Iw. Analyzing the standard deviation of the residual obtained from regression analyses of Fa versus VS,30, F0, and Iw shows that F0 is the most helpful parameter for the prediction of Fa. Hence F0 appears to be more appropriate than VS,30 and Iw for the characterization of the seismic response of a site and, therefore, should not be disregarded in building code soil classifications.

Analysis and numerical classification of Lanoraie Delta soils were performed as part of an ecological study. After stratification, using detailed soil maps, 84 forest sites were randomly sampled. Eighteen soil descriptors, mainly morphologic, were retained for numerical analysis. Gower's similarity coefficient between profiles was used for the principal coordinate analysis (PCA) which brought out the most probable factors governing soil distribution. The first two axes of the PCA represented 15.5 and 6.2% of the total variance. Soil distribution was along two gradients: soil water regime (Xeric-Hydric) and genetic development (Gleysolic-Podzolic). Cluster analysis by complete linkage created five soil groups which were composed of 23, 9, 17, 25 and 10 soil individuals, respectively. The interpretation of these soil groups utilized the superposition of clusters onto the first two axes of the PCA. Each group was classified into a taxonomic subgroup (Canadian System of Soil Classification) and defined by a typical humus form. Key words: Lanoraie Delta, multivariate analysis, soil classification

Considering that information from soil reflectance spectra is underutilized in soil classification, this paper aimed to evaluate the relationship of soil physical, chemical properties and their spectra, to identify spectral patterns for soil classes, evaluate the use of numerical classification of profiles combined with spectral data for soil classification. We studied 20 soil profiles from the municipality of Piracicaba, State of São Paulo, Brazil, which were morphologically described and classified up to the 3rd category level of the Brazilian Soil Classification System (SiBCS). Subsequently, soil samples were collected from pedogenetic horizons and subjected to soil particle size and chemical analyses. Their Vis-NIR spectra were measured, followed by principal component analysis. Pearson's linear correlation coefficients were determined among the four principal components and the following soil properties: pH, organic matter, P, K, Ca, Mg, Al, CEC, base saturation, and Al saturation. We also carried out interpretation of the first three principal components and their relationships with soil classes defined by SiBCS. In addition, numerical classification of the profiles based on the OSACA algorithm was performed using spectral data as a basis. We determined the Normalized Mutual Information (NMI) and Uncertainty Coefficient (U). These coefficients represent the similarity between the numerical classification and the soil classes from SiBCS. Pearson's correlation coefficients were significant for the principal components when compared to sand, clay, Al content and soil color. Visual analysis of the principal component scores showed differences in the spectral behavior of the soil classes, mainly among Argissolos and the others soils. The NMI and U similarity coefficients showed values of 0.74 and 0.64, respectively, suggesting good similarity between the numerical and SiBCS classes. For example, numerical classification correctly distinguished Argissolos from Latossolos and Nitossolos. However, this mathematical technique was not able to distinguish Latossolos from Nitossolos Vermelho férricos, but the Cambissolos were well differentiated from other soil classes. The numerical technique proved to be effective and applicable to the soil classification process.

The architectural heritage is subjected to various risk factors like the lack of maintenance, the material decay and the external solicitations. Nowadays, due to the ever-increasing demand for urban space, a relevant cause of structural damage that the historical buildings experience is the ground settlement due to excavation works. In the city of Amsterdam, for example, the construction of the new North-South metro line will involve an area characterized by the presence of many ancient masonry buildings. A fundamental phase of the design of this kind of projects is the assessment of the risk of subsidence which can affect the existing structures. The actual method to perform this assessment provides for a preliminary screening of the buildings located in the area surrounding the excavation, in order to evaluate which structures are at risk of settlement induced damage. It is based on the simplification of the building as a linear elastic beam and the assumption of the absence of interaction between the soil and the structure. An improved classification system should take into account the main parameters which influence the structural response, like the nonlinear behaviour of the building and the role played by the foundation in the soil-structure interaction. In this paper, the effect on the damage mechanism of the excavation advance and the location of the tunnel with respect to the building is evaluated. Numerical analyses are performed in order to understand the effect of different settlement profiles of the ground. A coupled model of the structure and the soil is evaluated, taking into account a damage model for the masonry building and the nonlinear behaviour of the soil-structure interaction. This paper demonstrates the importance of 3D modelling; neglecting the tunnel advance can lead to an underestimation of the damage.

A identificação e mapeamento dos solos servem como subsidio para planejamentos agrícolas, levantamentos do uso da terra, estudos de terras para irrigação, estudos de preservação, análise e recuperação ambientais, predição de desastres naturais como o monitoramento de processos erosivos, dentre outros. Nesse sentido, os levantamentos e avaliações de solo, para fins agrícolas ou não, ganham importância, pois através deles é possível conhecer as propriedades desse recurso natural, permitindo sua utilização de forma consciente e adequada. O uso de sistemas de informações geográficas tem introduzido novos métodos para o levantamento e mapeamento de solos, por meio de modelagens, a partir da utilização de mapas temáticos básicos e modelos numéricos de terreno ou modelos digitais de elevação, que possibilitam, principalmente, a compreensão das relações entre a paisagem e as classes de solo. Assim, o objetivo deste trabalho foi a realização do levantamento e mapeamento dos solos do município de Inconfidentes - MG, utilizando técnicas de geoprocessamento, e a classificação pedológica até o quarto nível categórico através da generalização, a partir da descrição morfológica e determinações analíticas de perfis de solos representativos. Foi realizada a caracterização da área de estudos, a aquisição e tratamento de dados cartográficos. A descrição morfológica dos perfis foi realizada em pontos previamente definidos, representativos das distintas classes de solo do município. As análises físico-químicas foram realizadas em todas as amostras dos horizontes dos perfis de solos coletados em campo. A generalização do levantamento de solos foi elaborada através do processamento dos dados cartográficos e obtidos em campo, com a utilização do software ArGIS 9.3. O mapeamento pedológico do município foi então o resultado da integração e correlação dos dados altimétricos, da declividade, da rede de drenagem, do canal fluvial, do relevo e da litologia, associados com a caracterização feita em campo e as determinações analíticas. Como resultado, foi possível mapear as áreas de ocorrência de Latossolos, Gleissolos e Cambissolos, as três ordens de solos mais representativos do município, classificando-os até o quarto nível categórico. O uso das ferramentas de geotecnologia se mostrou muito útil para a caracterização das classes pedológicas e posterior generalização, uma vez que através delas foi possível inferir as condições ambientais de formação dos solos e integrá-los com dados de campo e análises laboratoriais. ABSTRACT The identification and mapping of soils serve as subsidy for agricultural planning, land use surveys, land studies for irrigation, preservation studies, environmental analysis and recovery, prediction of natural disasters such as monitoring erosion, among others. In this sense, soil surveys and assessments, for agricultural purposes or not, become important because through them you can know the properties of this natural resource, allowing its use consciously and appropriately. The use of geographic information systems has introduced new methods to survey and soil mapping, through modeling, from the use of basic thematic maps and numerical terrain models and digital elevation models, which enable, especially, understanding the relationship between the landscape and the soil classes. The objective of this work was the completion of the survey and mapping of soils of city of Inconfidentes - MG, using geoprocessing techniques, and the pedological classification until the fourth categorical level by generalising from the morphological description and analytical profiles determinations representative soil. It was carried out to characterize their field of study, the acquisition and processing of cartographic data. The morphological description of the profiles was held in fixed locations, representative of the different soil classes of the municipality. The physicochemical analyzes were performed on all samples from the horizons of soil profiles collected in the field. Widespread soil survey was prepared by processing the cartographic data obtained in the field and, with the use of ArGIS 9.3 software. The pedological mapping of the municipality was then the result of the integration and correlation of altimetry data, the slope, the drainage network, the river channel, relief and lithology associated with the characterization made in the field and the analytical determinations. As a result, it was possible to map the areas of occurrence of Ferrasols, Cambisols and Gleysols, the three most representative soils of the municipality orders, sorting them until the fourth categorical level. The use of geotechnology tools proved very useful for the characterization of soil classes and subsequent generalization, since through them it was possible to infer the environmental conditions of soil formation and integrate them with field data and laboratory analysis. Keywords: Cambisols, Gleysols, Ferrasols, classification, hillslope.

O conhecimento dos atributos do solo e de sua variabilidade espacial são essenciais para a aplicação de um manejo racional, promovendo altas produtividades e baixo impacto ambiental. Dentre as informações mais utilizadas para o planejamento e tomadas de decisão na atividade agrícola, observa-se o mapa pedológico. Este indica de maneira simplificada uma série de atributos, tais como a textura, as condições químicas e a morfologia. Em contrapartida, estes mapas são escassos, desatualizados ou mesmo apresentam-se em escala inadequada, resultando em um entrave no desenvolvimento agrícola sustentável. Desta forma, surge a necessidade de ferramentas que auxiliem no processo de levantamento e mapeamento de solos, reduzindo custos e tempo de execução. Duas técnicas capazes de atenuar tal problemática são a espectroscopia de reflectância e o mapeamento digital de solos. Diversos trabalhos indicam o potencial das curvas espectrais para determinar atributos como teor de argila e carbono, no entanto, há carência de estudos avaliando relações entre classes taxonômicas e o comportamento espectral. Da mesma forma, não se encontra na literatura pesquisas que conciliaram o mapeamento digital de solos e o espectro eletromagnético. Sendo assim, este trabalho foi desenvolvido visando responder os seguintes questionamentos: (a) Existe correlação entre atributos do solo e o comportamento espectral para as amostras estudadas?; (b) Teriam as curvas espectrais padrões específicos para diferentes classes taxonômicas? (c) Seria possível distinguir diferentes classes de solo utilizando técnica de classificação numérica de perfis e dados de reflectância? (d) Seria possível estabelecer limites de solo em topossequências utilizando somente curvas espectrais e métodos estatísticos? (e) O processo de mapeamento digital de solos é capaz de produzir mapas semelhantes aos obtidos por metodologia convencional?
The knowledge of the spatial distribution of soils is important for crop management, providing a high productivity and less environmental impact. The soil map is one of the most important information used for planning or to make a decision in agriculture. It is a simply way to acquire information about soil attributes, such as texture, morphology and chemical conditions. However, the existent soil maps are outdated or present an inadequate scale. This issue is an obstacle to sustainable agricultural development. Due to this, arises the need for tools to help the process of surveying and mapping of soils, reducing costs and time. Two techniques that could help to mitigate such problems are reflectance spectroscopy and digital soil mapping. Several studies indicate the potential of spectral curves to determine attributes such as clay and carbon, however there are few studies evaluating the relationships between taxonomic classes and soil spectral behavior. Also, there is not many works evaluating the use of soil spectra in digital soil mapping. Thus, this study attempts to answer the following questions: (a) Is there any correlation between soil properties and spectral behavior of the studied samples? (B) Would the spectral curves have specific features for different taxonomic classes? (C) Is It possible to distinguish different soils using a profile numerical classification technique and reflectance data? (D) Is it possible to establish boundaries on soil toposequences using only spectral curves and statistical methods? (E) Is digital soil mapping able to produce similar maps to those obtained by conventional methods?

Tagungsband des Ohde-Kolloquiums 2014. Die Fachtagung fand am 26.03.2014 an der TU Dresden statt.:Experimentelle Untersuchung der Kapillarität bei Sand unter monotoner und zyklischer Belastung, Marius Milatz Mehrphasen-Modell zur Simulation von Suffosion, Heike Pfletschinger-Pfaff, Jan Kayser, Holger Steeb Experimentelle Ermittlung intergranularer Kräfte unter Nutzung von 2D-DIC, Max Wiebicke, Edward Andò, Denis Caillerie, Gioacchino Viggiani Systeme paralleler Scherbänder - Experimentelle und analytische Untersuchungen, Lars Röchter Rechnerischer Stabilitätsnachweis für verflüssigungsgefährdete Standorte, Nándor Tamáskovics Untersuchung des Einflusses von Gaseinschlüssen unterhalb des Grundwasserspiegels auf Druckausbreitung und Bodenverformungen mittels gekoppelter FE-Berechnungen, Hector Montenegro, Oliver Stelzer Zeitabhängige Setzungen von Sand und FE-Simulationen einer Tagebaukippe, Stefan Vogt, Emanuel Birle, Gero Vinzelberg Über die Berücksichtigung großer Bodendeformationen in numerischen Modellen, Daniel Aubram Die Gefrierkernmethode - Weiterentwicklung des Erkundungsverfahrens zur geohydraulischen Charakterisierung von Sohlsedimenten, Daniel Straßer, Hermann-Josef Lensing, Dominik Richter, Simon Frank, Nico Goldscheider Nutzung von Verfahren der Bildanalyse zur Baugrundbeurteilung, Markus Wacker, Thomas Neumann, Jens Engel, Gunter Gräfe Anwendung von Elektroosmose zur Reduzierung des Herausziehwiderstandes von Spundwänden: Großmaßstäbliche Modellversuche in Ton, Christos Vrettos, Kai Merz Zementfiltration bei der Herstellung von Verpressankern in nichtbindigen Böden, Xenia Stodieck, Thomas Benz Modell- und Elementversuche zur Bodenverflüssigung, Erik Schwiteilo, Ivo Herle Dynamische Probebelastung einer Mikropfahlgründung - Feldversuch und dynamische 3D-FE-Simulation mittels Hypoplastizität, Thomas Meier, Jens Jähnig, Sina Meybodi Numerische und analytische Berechnungen zur Erdbebenbemessung von Böschungen, Hassan AlKayyal

Nas obras de infraestruturas hidráulicas sistemas de abastecimento de água, sistemas de drenagem de águas residuais e pluviais e sistemas de rega - os processos de escavação das valas são fundamentais para a garantia do bom assentamento e desempenho das tubagens. O dimensionamento do equipamento para a escavação de valas baseia-se no estudo geotécnico do terreno apresentado em projeto de modo a garantir a boa execução da obra. Neste trabalho é apresentada e comparada a análise económica de duas formas de execução das valas: escavação de valas executadas pelo perfil-tipo do projeto, recorrendo ao uso de entivações, e escavação de valas com taludes inclinados e livres e abdicando do uso dos painéis de entivação, mantendo as condições de segurança da obra. As conclusões deste trabalho salvaguardam a importância do cumprimento dos prazos da obra, a produção, os custos e a segurança; Abstract: HYDRAULIC INFRASTRUCTURES TRENCHES EXCAVATION, EQUIPMENTS AND ECONOMICAL ANALYSIS In hydraulic infrastructures jobs such as water consumption and irrigation supply and wastewater and rainwater drainage, the processes used in the excavation and backfilling of trenches are key to ensure good performance and settlement of the pipes. The size and type of equipment for excavation and backfilling trenches is done by careful analyzing the project geological data. Thus, only after knowing the terrain features we can choose the work equipment and the appropriate processes to the proper performance of this activity. In this study is done the economical analysis based on two trench excavation methods. Firstly, we present the study of the costs of trench excavation performed by standard project profile, resorting to the use of shoring panels. Then the economical analysis of trenching creating security slopes on the walls of the trenches abdicating the use of shoring panels but keeping all the conditions of security for all workers. Finally draw some conclusions about the study, safeguarding the importance of meeting deadlines without disregarding the production and safety of its players.

Das Bodenverhalten unter dynamischer Beanspruchung ist sehr komplex, wird jedoch in der Praxis häufig mit Hilfe von vereinfachten Modellen abgebildet. Die Gültigkeit solcher Modelle ist jedoch aufgrund des spannungs- und dehnungsabhängigen Bodenverhaltens sehr begrenzt. Alternativ dazu bieten sich dynamische numerische Berechnungen mit fortgeschrittenen Stofmodellen, die das Bodenverhalten in einem großen Dehnungs- und Spannungsbereich realitätsnah repräsentieren können. In dieser Arbeit wurde untersucht, inwieweit sich das komplexe Bodenverhalten unter dynamischen Einwirkungen mit Hilfe der Hypoplastizität abbilden lässt. Dabei wurde die entscheidende Rolle der Parameterermittlung veranschaulicht und zusätzlich ein angemessener Vorgang zur Bodenparameterbestimmung beschrieben. Zunächst wurde das Verhalten einer trockenen Sandschicht infolge von Erdbebenbeanspruchungen numerisch untersucht. Die Ergebnisse der Berechnungen zeigen, dass die Beschleunigungsamplifikation in der Nähe zur Bodenoberfläche von der Frequenz und der Amplitude der Grundbeschleunigung abhängt. Weiterhin nimmt die berechnete Eigenfrequenz und die entsprechende Amplifikation mit zunehmender Beschleunigungsamplitude ab. Des Weiteren wurde ein Zentrifugenversuch an einem im Sand eingebeteten Tunnel unter Erdbebeneinwirkungen nachgerechnet. Die berechneten Ergebnisse zeigen eine ausreichende Übereinstimmung mit dem Experiment. Mit der numerischen Nachrechnung wurde auch eine Abhängigkeit zwischen den Änderungen der Biegemomente in der Tunnelschale und der Oberflächensetzung im umliegenden Boden festgestellt. Die Standsicherheit von Böschungen unter Erdbebenbeanspruchungen stellt wegen des komplexen Bodenverhaltens eine weitere Herausforderung für die Berechnungen dar. Zunächst wurde überprüft, inwieweit sich das Böschungsverhalten mit der in der Praxis häufig eingesetzten pseudo-statischen Methode abbilden lässt. Hierfür wurde für eine in der Zentrifuge untersuchte Modellböschung die pseudostatische Analyse durchgeführt. Die im Zentrifugenversuch aufgetretenen oberflächennahen Gleitfläche lässt sich durch die pseudo-statische Methode nicht prognostizieren. Für eine oberflächennahe Gleitfläche wurde hingegen ein sehr hoher Standsicherheitsfaktor ermittelt. Mit einer numerischen Nachrechnung mit einem hypoplastischen Stoffmodell mit Betrachtung der intergranularen Dehnungen konnte das Verhalten der Modellböschung qualitativ und quantitativ sehr gut abgebildet werden. Somit wurden sowohl die oberflächennahe Gleitfläche als auch die Vertikal- und Horizontalverschiebungen realitätsnah wiedergegeben. In dieser Arbeit wurde des Weiteren ein Vorgang als Kombination zwischen den dynamischen numerischen Berechnungen und der pseudo-statischen Methode zur Bewertung der Standsicherheit von Böschungen unter dynamischer Einwirkung vorgeschlagen. Damit ließ sich ebenso ein realitätsnäher Stansicherheitsfaktor ermitteln. Da die Anwendung der pseudo-statischen Methode bei den Böschungen aus wassergesättigten kohäsionslosen Böden problematisch ist, lassen sich solche Böschungen entweder mit Zentrifugenmodellen oder numerisch mit fortgeschrittenen Stoffmodellen untersuchen. In dieser Arbeit wurden Nachrechnungen von Zentrifugenversuchen durchgeführt. Es handelt sich um einen Erddamm aus einem wassergesättigten, dicht gelagerten Nevada Sand unter Erdbebeneinwirkung. Mit der numerischen Berechnung wurde das Dammverhalten qualitativ und quantitativ sehr gut abgebildet. Sowohl die Dammverschiebungen als auch der Aufbau des Porenwasserdrucks zeigen eine sehr gute Übereinstimmung mit den Messungen. Weiterhin wurden mit den gleichen Bodenparametern zwei weitere Zentrifugenversuche unter Erdbebeneinwirkung nachgerechnet. Beide Modellversuche wurden mit einem locker gelagerten, wassergesättigten Nevada Sand durchgeführt. Bei einem Versuch wurde ein Erddamm und bei dem anderen eine Sandschicht untersucht. In den numerischen Nachrechnungen ließen sich sowohl die Verschiebungen als auch die Porenwasserdrücke in beiden Randwertproblemen realistisch abbilden. Weiterhin wurde die Wirkung von Schottersäulen zur Verhinderung der Bodenverflüssigung numerisch untersucht. Zunächst wurden die Dränage- und die Aussteifungswirkung der Schottersäulen unabhängig voneinander betrachtet. Die Dränagewirkung ist vernachlässigbar, da sich während eines Erdbebens der Porenwasserdruck sehr schnell aufbaut. Wegen der hohen Steifigkeit der Schottersäulen wird zwar weniger Porenwasserdruck in den Boden aufgebaut. Die effektive Spannung nimmt jedoch trotzdem unverhindert ab. Dies lässt sich damit begründen, dass die hohe Säulensteifigkeit zu einer Spannungsumlagerung in Richtung Säulen führt und ein Siloeffekt entsteht. Somit wird der Boden zum Teil von den Säulen getragen und die totale Spannung im Boden nimmt ab. In der 3D-Berechnungen ist dieser Siloeffekt deutlich geringer als in den 2D-Berechnungen. Nichtsdestotrotz zeigen sowohl die 2D- als auch die 3D-Berechnungen, dass die Säulensteifigkeit eine nur mäßige Wirkung zur Verhinderung der Bodenverflüssigung aufweist. In weiteren 3D-Berechnungen wurde der Einfluss der Säulenherstellung untersucht. Hierfür wurden Berechnungen mit erhöhter Bodendichte und Seitenspannung durchgeführt. Sowohl die Verdichtung als auch die Erhöhung der Seitenspannung verlangsamen den Porenwasserdruckaufbau bzw. die Abnahme der effektiven Spannung. Der Einfluss der Bodenverdichtung ist jedoch wesentlich höher. Weiterhin weist die Wirkung der Schottersäulen eine Abhängigkeit von der dynamischen Belastung auf. Die Bodenverflüssigung infolge eines kleinen Erdbebens wird verhindert, während sich die Verflüssigung infolge eines stärkeren Erdbebens nur um wenige Sekunden verzögert
The soil behavior under dynamic loading is very complex. However, in daily use it is often illustrated by means of simplified models. The validity of these models is very limited due to the stress and strain-dependent soil behavior. Alternatively, dynamic numerical calculations can be performed with advanced constitutive models which can represent soil behavior in a wide range of strain and stress. In this work it was investigated, to which extent the complex soil behavior can be reproduced using hypoplasticity.Furthermore,the important role of parameter determination was illustrated. In addition, an appropriate procedure for determining soil parameters was described. First, the behavior of a dry sand layer under earthquake load was investigated numerically. The results of the calculations show that the acceleration amplification near the ground surface depends on the frequency and the amplitude of the basic acceleration. Furthermore, the calculated natural frequency and the corresponding amplification decrease with increasing acceleration amplitude. In addition, a centrifuge test on a tunnel embedded in sand under earthquake effects was numerically calculated. The calculated results show a satisfactory agreement with the experiment. The numerical calculation also revealed a dependency between the changes in the bending moments in the tunnel lining and the surface settlement of the surrounding soil. Due to the complex soil behavior, the stability of slopes under earthquake loads poses a further challenge for the calculations. Firstly, it was examined, to which extent slope behavior can be represented with the frequently used pseudo-static method. For this purpose the pseudo-static analysis was carried out for a model earth dam examined in the centrifuge. The pseudo-static method predicts a deep seated sliding surface in contrast to the shallow sliding surface in the centrifuge test. However, for a shallow sliding surface, a very high stability safety factor was determined. With a numerical calculation using a hypoplastic material model considering the intergranular strains, the behavior of the earth dam could be reproduced qualitatively and quantitatively very well. Thus, the shallow sliding surface as well as the vertical and horizontal displacements were reproduced realistically. In this thesis, a combination of the dynamic numerical calculation and the pseudo-static method for assessing the stability of slopes under dynamic influence was proposed. So, a realistic stability safety factor can be determined. The application of the pseudo-static method is problematic in case of slopes in saturated non-cohesive soil. These slopes can either be investigated with centrifuge models or numerically with advanced material models. In this work, numerical recalculations of centrifuge tests were carried out. It is an earth dam from a saturated Nevada sand under an earthquake effect. With the numerical calculation the dam behavior was reproduced qualitatively and quantitatively in a satisfactory manner. Both the dam displacements as well as the build-up of pore water pressure show a very good agreement with the measurements. Two further centrifuge tests were also carried out using the same soil parameters. Both model tests were conducted with a loose saturated Nevada sand. One test was carried out on an earth dam and the other on a sand layer. With the numerical calculations, both displacements and pore water pressures were reproduced realistically in both boundary value problems. In addition the effect of stone columns to prevent soil liquefaction was studied numerically. First, the drainage and stiffening effects of stone columns were examined separately. The drainage effect has no significant influence because of the very rapid build-up of pore water pressure during the earthquake. Due to the high stiffness of the stone columns, less pore water pressure builds up in the soil. However, the effective stress continues to decrease unhindered. The high stiffness of the columns leads to a stress redistribution in the direction of the columns and a silo effect arises. In 3D calculations, the silo effect is significantly lower than in 2D calculations. The 2D and 3D calculations show that the column stiffness has a moderate effect to prevent soil liquefaction. In further 3D calculations, the influence of column installation was investigated. Calculations with increased soil density and lateral stress were carried out for this purpose. Both the compaction and the increase of the lateral stress slow down the build-up of pore water pressure and the decrease in effective stress. However, the impact of soil compaction is much higher. Furthermore, the effect of stone columns depends on the dynamic load. The soil liquefaction due to a small earthquake is prevented, while liquefaction due to a stronger earthquake is delayed only by a few seconds

Liquefaction is the phenomena when there is loss of strength in saturated and cohesion-less soils because of increased pore water pressures and hence reduced effective stresses due to dynamic loading. It is a phenomenon in which the strength and stiffness of a soil is reduced by earthquake shaking or other rapid loading. In this study, after the short review of liquefaction definition, the models of prediction and estimation of liquefaction were considered. Application of numerical modelling with two major software (FLAC & PLAXIS) for the Wildlife site liquefaction, under superstition earthquake in 1987 were compared and analysed. Third step was started with introduction of Fuzzy logic and neural network as two common intelligent mathematical methods. These two patterns for prediction of soil liquefaction were combined. The “Neural network- Fuzzy logic-Liquefaction- Prediction” (NFLP) was applied for liquefaction prediction in Wildlife site. The results show the powerful prediction of liquefaction happening with high degree of accuracy in this case.

Recently observed cumulation of unexpected collapses of slope-distant waste dumps in lignite mining areas of eastern germany re-initiated research of soil liquefaction. Especially it turned the question of internal initials that correspond to water rise. Parallel to laboritory tests and field experiments a micromechanical model should be developed, which can reproduce processes in the soil during saturation. In first approximation a partly saturated soil consists of two phases: the soil particles and the pore fluid. For micromechanical modeling a coupling of discontinuum particles) and continuum (fluid) is required. The soil particles can be simulated with the Discrete-Element-Method (DEM). For the pore fluid, which is assumed to be a mixture of liquid and gaseous fractions, Pore scale model with Finite Volumes (PFV) is used. At low water content liquid bridges (meniscii) arise between the particles that cause an apparent cohesion. The effect of the meniscii is considered by a correspondingly contact law in the DEM model. During the saturation of a soil both, cohesive effect and fluid bulk modulus, are reduced. In addition buoyancy acts on the particles during the process. The micromechanical modeling approach has the advantage, that just a few model parameters are needed. The numerical model shows pore fluid pressures during saturation process, that leads to a reduction of effective stress. It is investigated how much the reduction is regarding porosity, degree of saturation, stress conditions and grain shape. Furthermore the influence of model parameters as well as hydromechanics is investigated. The investigations are completed with another series of experiments under special conditions like integration of macropores, horizontal fixed model boundaries and abrupt saturation.:Einleitung Literaturauswertung Numerische Modellierung Modellstudien Ergebnisauswertung Zusammenfassung Extended summary

The South African Taxonomic soil classification system (SAT) is well established and utilised in South Africa. However, it is not internationally well known and therefore the need arose to provide a tool by which South African soil taxonomists can convert South African soil classifications and profile descriptions to the international classifications of the World Reference Base (WRB) for soil resources. The diagnostics and tacit knowledge presented in this publication are therefore based on the SAT and the WRB. When necessary, further substantiation was derived from the Land Type Survey of South Africa. The adopted procedure is effective in providing a reasonable classification based on the South African soil forms and families, while excluding certain WRB soil groups and qualifiers, because these are irrelevant to South African taxonomy. Lastly, this publication also highlights some peculiarities, omissions and inconsistencies observed between the SAT and WRB.

Soil is the superficial layer of the land area of the Earth and contains weathered inorganic materials, organic matter, air, and water. The branch of soil science that studies the formation and classification of soils is termed pedology. For both scientific and technical purposes, soils around the world are organized into various categories on the basis of their differences and similarities. There are two types of soil classification schemes: (i) the scientific or pedological classification schemes which group soils on the basis of morphological, physical, chemical, and mineralogical properties as well as stage of weathering; and (ii) the technical or practical classification schemes which group soils based on selected properties for specific applications in agriculture and urban development, such as making a quick appraisal of soil fertility capability of farmlands or determining the suitability of septic tank installations of a housing development site. Soils are formed from the weathering of rocks and rock debris that have been eroded and transported by water, wind, ice, or gravity to other sites within the landscape. The soil, together with any underlying weathered debris and/or weathered bedrock, is termed regolith. The formation of soils from rock and minerals may take a long period of time, that is, thousands or millions of years. The pathways of soil formation are shown in fig. 7-1. The development of distinct characteristics of a soil profile or pedon involves physical, chemical, and biological weathering processes. The weathering process that involves the breakdown of rock and minerals by the action of water, pressure, heat, and freeze, into increasingly smaller fragments or particles is called physical weathering. The processes that involve hydrolysis, dissolution, and the formation of secondary minerals, such as clay-sized layer silicates and Fe and Al oxides, are called chemical weathering. The two important and interrelated chemical processes of tropical weathering are desilication and laterization. Desilication involves the dissolution of silicate minerals, and the subsequent leaching of dissolved silica from the soil profile by rain. The loss of silica from the soil eventually leads to the formation and accumulation of Fe and Al oxides in the soil, a weathering process known as laterization.

This chapter addresses one-dimensional infiltration and vertical flow problems. Traditionally, infiltration has received more attention than other unsaturated flow procedures, both for empirical formulations and for applications of Richards’ equation. Rarely is infiltration the only process of interest, and from an overall point of view it is only one example of soil water dynamics. Here, we will first emphasize systems for which analytical (or quasi-analytical) solutions can be found. These include the Green and Ampt solution (1911), which adds gravity to the simplified analysis discussed in chapter 4. Then a linearized form of Richards’ equation will be examined, followed by the perturbation of the horizontal problem of Philip leading to his famous series solution. Although the closed-form and quasi-analytical solutions are convenient for calculations and discussing the physical principles, generally, the nonlinearity of Richards’ equation precludes such convenient forms. However, numerical approximations can be used. The conventional numerical methods applied in water and solute transport are based on finite differences and finite elements. Because of its greater simplicity, we will emphasize finite differences and build on the methodology from the saturated-flow example in chapter 3. Richards’ equation is a parabolic partial differential equation reducing to an elliptical form for steady-state cases. The analyses and methods parallel developments for techniques developed primarily for the linear diffusion equation. Many texts exist for numerical methods; one to which we refer is by Smith (1985). Ideally, numerical methods give solutions that are as accurate as the input warrants or as necessary for application. In some cases, results may be easier or more accurate than the evaluation of a complex analytical expression. Clearly, infiltration is of limited duration, with drainage and redistribution occurring over much longer time frames. We will visit briefly some steady-state examples, including layered profile and upward flow from a shallow water table. Other examples include modeling plant water uptake from the profile and drainage of initially wet profiles. The rapid increase in computational power and availability of computers make solutions feasible and routine for problems that were very tedious or time consuming only a few years ago. This is particularly true of the one-dimensional numerical solutions.

Because of water scarcity, reduction of annual rainfall and the use of wastewater in agriculture, there is a need for research to evaluate the potential impacts of using such sources on hydraulic soil properties and groundwater quality. Nitrate loss from the area under cultivation and regular use of fertilizer and wastewater is a major reason for non-point source contamination on agricultural lands. Numerical model, Hydrus-1D used to simulate soil nitrate in soil cultivated with tomato-crop during the growing period, in North-East Iran. A randomized completely blocked design with five irrigation treatments with different sources of nitrogen was applied. Comparison between simulated and measured soil moisture content shows that the model can follow the temporal variation of soil water content. However, some over estimation of the measured data was observed during the simulation period. To evaluate the Hydrus model performance with respect to nitrogen transport and transformations, the simulated nitrogen concentrations (NH4-N and NO3-N) are compared for different treatments at different depths of soil profile, (7.5, 22.5, 37.5, 52.5 and 120 cm from soil surface). It takes about 4 days to convert 90% of urea into ammonium and it takes about 70 days to convert 90% of ammonium into nitrate. However, urea concentrations decreased with time between irrigations as a result of hydrolysis. As expected, at 3.73 days, the urea was concentrated near the surface, immediately after fertigation. Ammonium remained concentrated in the immediate in the top soil at all times for all treatments. There was only slight movement, because of soil adsorption and subsequent fast nitrification and/or root uptake. In contrast to ammonium, nitrate moved continuously downwards during the 28-day simulation period, as nitrate is not adsorbed, whereas denitrification was assumed negligible. Leaching percentages were smaller for nitrate wastewater compared to nitrate- fertilizer, and manure. Base on simulation results treated municipal wastewater by an aerated lagoon can be used as a valuable source of irrigation without causing contamination of groundwater.

Several pedological soil classification schemes have been developed to classify soils worldwide based on morphological features, stage of weathering, and to some extent their chemical and physical properties. Three soil classification systems are commonly used as research and teaching tools in the tropics, namely, the USDA Soil Taxonomy classification, the FAO/UNESCO World Soil Legends, and the French soil classification system. Brazil, the country with the largest land area in the tropics, has its own national soil classification system. However, soil survey, classification, and interpretation are costly and time-consuming, and few countries in the tropics have completed soil maps that are at a scale detailed enough to be useful to farmers and land users. In the absence of soil information at state, county or farm level, the authors propose a simple descriptive grouping of major soils in the tropics based on clay mineralogy to facilitate discussion on soil management and plant production in the subsequent chapters of this book. Reference to the Soil Taxonomy classification will be made when such information is available. It should be pointed out that the main purpose of this technical grouping is to provide field workers, especially those who are less familiar with the various soil classification systems, with a simple framework for planning soil management strategies. It by no means replaces the national and international soil taxonomy and classification systems that are designed for communication among soil scientists and for more detailed interpretation of soil survey data and land-use planning. This technical scheme classifies major arable soils in the tropics into four groupings according to their dominant clay mineralogy. They are • kaolinitic soils • oxidic soils • allophanic soils • smectitic soils Kaolinitic soils are deeply weathered soils with a sand, loamy sand, or sandy loam texture in the surface horizon and a clayey B horizon (20-60%). Silt content is low (< 20%) throughout the profile. Kaolinite (> 90%) is the dominant mineral in the clay fraction. These soils have an effective CEC of less than 12 cmol/kg of clay in the lower B horizon. Kaolinitic soils have a relatively high bulk density, especially in the clayey subsoil horizons (> 1.40 Mg/m3). The structure of the subsoil horizons is usually massive or blocky.

Soils are porous media created at the land surface through weathering processes mediated by biological, geological, and hydrological phenomena. From the point of view of chemistry, soils are open biogeochemical systems containing reactive solids, liquids, and gases. That they are open systems means they exchange both matter and energy with the surrounding atmosphere, biosphere, and hydrosphere. That they are biogeochemical systems means their development over time is a result of chemical transformations of earth materials linked to the life cycles of the soil biota and plant roots. Soils are the central feature of the life-supporting Critical Zone, which extends from the top of the vegetation canopy to the bottom of the groundwater aquifer in a terrestrial ecosystem. The Critical Zone provides essential ecosystem services (outputs of food, fiber, fuel, and water, including their quality) that sustain the biosphere. Other earth materials than soil may occur in the Critical Zone (for example, weathered rock [saprolite]), but soils are unique in showing a distinctive vertical stratification, the soil profile (Fig. 1.1), created by percolating water under the combined influence of parent material, topography, climate, living organisms, and pedogenic time—the five factors of soil formation. Analogous to biomes, which classify terrestrial ecosystems according to similar climate and vegetative cover, orders classify soils according to similar climate, parent material, or pedogenic time. With respect to climate, for example, Oxisols reflect tropical conditions, whereas Mollisols reflect temperate conditions. Spodosols and Gelisols reflect mainly boreal conditions (Table 1.1). Andisols, Histosols, and Vertisols, on the other hand, are not defined by climatic region, but instead by parent material (volcanic ash, organic litter, or swelling clay, respectively), whereas Entisols and Inceptisols reflect pedogenic time being insufficiently long for significant A or B horizon development, respectively. Biomes are basic classification units of the aboveground biosphere useful for characterizing its ecosystem services, whereas orders are basic classification units of the pedosphere useful for the same purpose. The natural capitalof soils is the set of assets that allows them to function beneficially as providers of ecosystem services.

The allowable load for slender end-bearing piles in soft soils driven or drilled to compact till or rock frequently depends on the structural capacity of the pile. Pile groups consisting of such slender preceast concrete or steel piles often include inclined piles, since such small-diameter piles have a limited horizontal bearing capacity. Inclined piles placed in settling soil are subjected to a lateral force, which reduces the pile structural capacity. The simplified beam-spring design methods normally used to predict the impact on the structural capacity of inclined piles in settling soil are currently very crude because of the simplified description of the real pile and soil. On the other hand, the possibility to accurately calculate settlements in soft soil is highly developed, and it is possible to include creep effects in routine settlement calculations. There is currently no direct link between the advanced settlement analysis and the crude beam-spring idealization of inclined piles in settling soil. A full numerical model containing both the pile soilstructure interaction and the settlement process is very time-consuming to run and associated with mesh convergence and contact formulation problems. Herein a suitable modelling idealization of the settling soil is discussed, in which a settlement distribution from an advanced FEM-analysis is adapted to a simplified FEM or beam spring analysis suitable for practical design. The calculation method is compared to field measurements, and is shown to compare well with the field case. A strategy to adapt the settlement profile to model calculation of inclined piles is discussed.

Spudcan foundation, penetrating into stratified soils is studied using H-adaptive finite element method (FE) together with Remeshing and Interpolation Technique with Small Strain model (RITSS). This is to investigate the potential hazard of punch-through failure in layered soil profiles. There are two series of analysis conducted. Firstly, for a pre-embedded spudcan foundation, a series of parametric studies has been undertaken in order to find the critical distance between the spudcan and the layer boundary, within which a punch-through failure is likely to occur. Soil profile is a uniform stiff clay layer overlaying a uniform soft clay layer with soil strength ratio (upper layer soil strength to lower layer strength) varying from 1 to 10. Secondly, continuous analysis has been undertaken for 2 cases with shear strength ratio of 2 and 3 and thickness of the upper stiff layer of one spudcan diameter. It is found that, in small strain analysis, the critical distance to the layer boundary is increasing with increasing the strength ratio. It reaches at a limit of 1.0 ∼ 1.25 D (D is the spudcan diameter) when the strength ratio is 5 or larger. In large deformation analysis, the critical distance is much lower than the one from small strain analysis. This is due to the trapped top layer soil underneath the spudcan, which cannot be simulated in small strain analysis.

The present paper presents the results of the numerical study designed to investigate the soil-structure flexibility effects on modal parameters (i.e. fundamental frequencies) and time-history analysis response (represented by the top relative displacements) of a 46.8 m high steel lattice tower subjected to a number of ground motions including also one mining tremor. In addition to the fixed-base condition, three different soil types (i.e. dense soil, stiff soil, and soft soil) were considered in this investigation. Site conditions were characterized by their average effective profile velocities, Poisson’s ratios, and finally mass densities. Soil-foundation flexibility was introduced using the spring-based approach, utilizing foundation springs and dashpots. The first step was to investigate the influence of different base conditions on modal parameters of the steel lattice tower. In the final part of the current study time-history analysis was performed using different two-component ground motion records (in two horizontal, mutually perpendicular directions). The results obtained indicate that modal parameters and dynamic response of the structure may be considerably affected by the soil-structure interaction effects. Therefore, the present paper confirms the necessity of utilizing soil-flexibility into numerical research.

This paper presents results from large displacement finite element analysis for spudcan foundation penetrating into and extracting from normally consolidated (NC) clay. The soil was idealized as an elastic-perfectly plastic material obeying a Mohr-Coulomb yield criterion and the large displacement analysis was carried out using Remeshing and Interpolating Technique with Small Strain (RITSS) model to simulate the full installation and extraction process. The numerical results were compared with centrifuge model test data and existing analytical solutions. A full parametric study was undertaken to quantify the influence on spudcan extraction process from soil strength profile, foundation interface roughness and penetration depth. The extraction results showed that the normalized uplift resistance after spudcan installation was much lower than that from small strain analysis, and it was also lower than that of pre-embedded case. Thus it is necessary to apply RITSS method in spudcan extraction simulation after installation.

A general overview of design aspects related to metal catenary risers is first given. Response characteristics of these types of riser configurations are considered. It is subsequently focused on models for soil-pipe interaction, which have a strong influence on computed riser stresses in the touch-down region. The so-called CARISIMA models for riser-soil interaction in relation to horizontal and vertical motion (i.e.horizontal resistance and suction) are presented. Inherent limitations of the models are summarised. Basic input parameters are described, considerations relevant for establishment of initial trench profile are given, and examples of riser response analysis are presented. Typical behaviour of the numerical models which is observed in the example analyses is also reported.

Previously published finite element analysis of drag anchors only involved the pullout capacity of the anchor. There are no finite element (FE) simulations of the installation of drag anchors probably because of two restrictions. First, during the anchor installation, the installation line is needed, which is difficult to be simulated in the FE analysis. Second, the anchor installation that involves large deformation of surrounding soils can not be solved using the classical FE method. In the present work, the installation line is constructed by connecting cylindrical units with each other using connector elements. Then it is introduced into the installation of drag anchors, which is simulated by a large deformation finite element analysis using the coupled Eulerian-Lagrangian (CEL) technique. By comparing with theoretical solutions, including the tension and profile of the installation line embedded in soils, and the movement direction, drag force, drag angle and trajectory of the anchor, the FE simulation of the drag anchor installation is well verified. The present study also demonstrates that the CEL technique is effective for simulating the anchor-line-soil interactional problems.

The aim of present study is to establish the numerical model for the solidification or melting of water saturated soil and to clarify the effect of thermal and physical parameters on the artificial soil freezing by comparing between the numerical and experimental results. First, the numerical model has been modified to adapt for freezing of soil. By comparing between obtained numerical solutions and experimental data, the validity of the model has been checked and certified. Next, the effect of physical property of soil, initial and boundary conditions of soil and freezing pipes, the velocity of groundwater, and the arrangement of freezing pipes on soil freezing have been examined. As the results, it was found that the water content of soil and ground water affect the volume of solid, besides the groundwater also especially changes the profile of solid/liquid interface. The rate of the interface growth would gradually stop provided that the flow speed exceeds certain limits. The knowledge obtained from our study will be useful to predict solid volume, decrease in thermal energy consumption and minimize the influence to ambience on artificial ground freezing precisely.

Mobile jack-up rigs are frequently cantilevered over production jacket platforms to drill new wells or rework existing well for the offshore oil and gas at shallow and middle water depths. The proximity of the rig to the existing fixed platform will affect the performance of pile foundations of the platform and may cause some distress to the adjacent pile foundation by spudcan penetration. With the increasing accidents with respect to the spudcan penetration and spudcanpile interaction caused severe economic losses in offshore engineering of China, solving these problems is an urgent and significance assignment at present. Since the spudcan-pile interaction is a typical offshore geotechnical large strain large deformation problem, a numerical approach based on the large strain technique is a valid solution tool for evaluating spudcanpile interaction. The paper addresses additional responses of the adjacent pile induced by spudcan penetration in single clay profile and clay overlying sand profile using two different large strain large deformation numerical approaches. One is called two-stage approach. Firstly, ALE (Arbitrary Lagrangian Eulerian) approach is used to the displacement field of soil is calculated at the free field without adjacent piles, and then bending moments of piles investigate through conventional beam-column model. Another is CEL (Coupled Eulerian Lagrangian) approach to analyze the adjacent pile responses induced by spudcan penetration through three dimensional numerical model including spudcan, soil profile and adjacent pile. The feasibility of two approaches was verified through comparison between numerically predicted and experimentally measured results. Variations of pile bending moment induced by spudcan penetration are demonstrated with different pile length, spudcan-pile clearance and soil profiles. Comparisons of the numerically predicted pile bending moment and the experimentally measured values show that the both are close agreement for the different spudcan-pile clearance at the spudcan penetration depth of less than 15m in NC soil profiles. However, an apparent discrepancy lays on that the second positive peak bending moment from the numerical calculation by the beam-column model moves up to a higher depth than the measurement for the 40m pile length.