SUMMARY: Injection is defined as the grouting of fluidized materials into voids of the ground or spaces between the ground and adjacent structure, generally through bore holes and under pressure. For many engineers, injection is still considered an art rather than a science. Therefore, its successful application requires a great deal of experience, thorough knowledge of geological conditions, and an awareness of equipment capabilities and limitations. This paper describes a new approach to modeling injecting domain based on a non darcian flow and theory of consolidation. The proposed model utilizes the variation of the coefficient of permeability with respect to distance to bore hole axis to achieve a non-Darcian flow characteristics below certain hydraulic gradients. The potential of the proposed model is evaluated in prediction the extension of grouting for a single injection bore hole. The general comparison indicates that this approach is capable of solving injection boundary value problems and predict the extension of each grouting bore hole. A simple rule based on the percentage of overlapping two domains affected by two side by side injections bores is led to carry out the effective thickness of insolated cut-off wall. Accordingly, the priority of first injection bore hole and the provided impermibility of corresponding domain and the interaction of the second domain with the previous have been considered. This simple rule can lead the solution to carry out an average effective thickness of insolated wall upon the proposed model. INTRODUCTION Generally, grouting is terminated either when a defined grouting pressure is obtained, or when the capacity of the available pump does not allow an additional increase. However, it can be assumed that the thin sections in porous media display homogeneous cement stone with dewatering canals, which are filled with the solid particles floated in grouting materials.

ABSTRACT: The paper refers to a field study performed to investigate the effectiveness of static preloading in improving soil conditions against excessive settlement and liquefaction. Resulted settlements were recorded and analysed. Soil conditions before and after preloading were compared through sample taking and performance of penetration tests. Test results were averaged over borings and over depth. These tests showed significant improvement of soil conditions and reduction of the liquefaction potential. Based on the results a preloading time before construction of permanent structures was recommended. INTRODUCTION The study described herein was carried out in the context of an engineering design study for a highway, the New Egnatia Road . Purpose of the study was to establish conclusions and draw quantitative results for (a) the degree of soil improvement and (b) the time required for this improvement to be used as guide for treating the problem of ground subsidence under the load of the permanent road embankment. The selection of the method (static preloading) was made on the basis of previous experience and its relatively low cost. SITE AND PRELOADING STRUCTURES DESCRIPTION The sites selected for the tests ( Site 1 and Site 2 ) were located on the axis of the designed New Egnatia Road near the town of Lagadas, northeast of Thessaloniki, with almost 0o ground inclination and very near to openflow canals. Water table levels were, on average during the period of the tests, 3.50 m, 4.70 m below ground in the two sites respectively. It should be noted however that these levels are not the highest ones since they were taken in the beginning of winter season. The area is subjected to significant seismic activity. The study involved the construction of two experimental embankments at two different sites in order to monitor the settlement behavior of the ground.

ABSTRACT: This paper investigates the mechanism of slope displacement using the results of long-term monitoring of the unstable behavior and failure of a large excavated rock slope with an elevation difference about 300 m. The study also evaluates the influence of joint sets on slope behavior through numerical analysis. Then fundamental points regarding the stability of large excavated rock slopes are introduced as follows. The stability of a large excavated rock slope is greatly influenced by the joints and weak layers in the rock, and the relationship between their positions and the positions of the excavated surface. It is important not to fail to notice signs of instability caused by the influences of them early through long-term monitoring started in the early stages of excavation. Based on such monitoring, the need of actions should be determined such as additional investigations, stability analysis, and design modifications and changes. INTRODUCTION This paper focuses on a case of failure of a large excavated rock slope with a height (an elevation difference) about 300 m. First, the behavior of each part of the slope is analyzed based on the displacement measurements obtained during a period of about 10 years before the failure. Next, each cross section of the slope is modeled by elasto-plastic equivalent continuum analysis to illustrate that the measurements are explainable. And how the unstable behavior of the slope occurred according to the topographical and geological conditions of the respective cross sections is examined. SLOPE DEFORMATION BEHAVIOR BASED ON LONG-TERM MEASUREMENT Geological structure The slope involved in this case study consists of late Paleozoic to early Mesozoic olistostrome: limestone, shale, tuff, and sandstone. The alterations of shale and tuff include lenses of sandstone, and these layers are overlain by olistoliths of limestone.

ABSTRACT: When a foundation located on or next to slope is loaded to failure, the zone of plastic flow in the soil on the sides of the slope is smaller than those of a similar foundation on level ground and consequently, the ultimate bearing capacity is reduced. Due to reduction in bearing capacity, it became necessary to strengthen the foundation soil. Since geojutes are abundant and cheaply available in tropical counties like India, it may be used for providing the reinforcement to the foundation soil. In this research, the effects of depth and number of layers of reinforcement (geojute) on the bearing capacity of a square footing on slopes have been studied. The experimental results encourages the use of geojutes in soil reinforcement. INTRODUCTION In hilly regions, it is a common practice to place buildings on or next to a slope due to non-availability of plain ground. When such a foundation is loaded to failure, the zone of plastic flow in the soil on the sides of the slope is smaller than those of a similar foundation on level ground and consequently, the ultimate bearing capacity is reduced (Sud, 1984; Srikant, 1996). Due to reduction in bearing capacity, it becomes necessary to strengthen the foundation soil. With the growing awareness about protection of the environment, scientists have developed geojutes. Since geojutes are abundant and cheaply available in tropical countries like India, it was decided to use them for providing the reinforcement. LITERATURE REVIEW Binquet & Lee (1975) conducted model tests on reinforced soil using metal strips placed in horizontal layers. It is observed that there is an optimum depth of reinforcement to have maximum benefit in terms of bearing capacity. Soni (1994) has developed an analytical method to assess the bearing capacity of a geojute reinforced sand bed.

ABSTRACT: Geotextiles have been extensively used in hydraulic structures as revetment filters subjected to wave loads. The alternating flow through the geotextile creates a flow regime very different from the unidirectional flow condition that has been extensively studied. The stability of the revetment system depends on many factors, such as the hydraulic properties of geotextile, the initial placement condition, particle size distribution of the subsoil, and the intensity of the wave loads. A new laboratory apparatus has been developed to investigate the influence of the hydraulic conditions on the behavior of soil-geotextile interaction and the stability of the revetment system. This apparatus is capable of simulating cyclic flow conditions normal to the soil-geotextile interface. Two series of tests have been conducted using this apparatus and preliminary test results are presented and discussed in this paper. INTRODUCTION The main role of the geotextile as a filter in hydraulic structures such as revetments is to prevent the erosion of the subsoil, while allowing the free drainage of water across the revetments. Hence, the pore size of geotextile should be small enough to retain the soil particles, while large enough for free passage of water. Preferably, the performance of these geotextiles under active wave action has to be evaluated instead of unidirectional flow conditions. Conventional filtration criteria for geotextiles, established for steady flow conditions, state that for a uniformly graded soil, geotextile opening size must be smaller than a characteristic diameter of base soil, say D85 (some times this criterion also involves relative density of subsoil, coefficient of uniformity, etc.). In unsteady flow conditions, the stability of the revetment system depends on many factors, such as the hydraulic properties of geotextile, the grain size distribution and the initial condition of the subsoil, as well as the intensity of the wave loads.

ABSTRACT: To plan any kind of prevention work in an active landslide, it is necessary to obtain enough information about the condition of ground water in moving masses and bedrock. Measurement of temperature of spring-water and wells in landslide area show that the variation of temperature of ground water in winter and summer is negligible and it is comparatively stable. However, the temperature of ground surface at one-meter depth is not stable. This variation can be due to the non-uniform distribution of ground water. Based on this fact, it is possible to detect the vein-stream of ground water in displaced masses by measuring one-meter depth temperature (Takeuchi, 1980). In this method of investigation, the temperature of one-meter depth on a net work of landslide area is measured; then, the map of isothermal contour lines of one-meter depth temperature will be prepared. This map can be used to interpret the position of ground water and vein-streams in landslide masses This method was used in a large-scale reactivated landslide in Akha area located in Alborz Range, northern Tehran, Iran. The basics of the method and its application in a real landslide are reported in this paper. INTRODUCTION It is well recognized that the topography of the surface of underground water does not follow the topography of ground surface. Measurement of temperature of spring-water and wells in landslide area shows that the variation of temperature of ground water in winter and summer is negligible and it is comparatively stable, however, it is found that the annual variation of temperature at one-meter depth is appreciable in landslide masses. This variation could be due to the non-uniform distribution of ground water. Based on this fact, it is possible to detect the vein-streams of ground water in displaced masses by measuring one-meter depth temperature (Takeuchi, 1980).

ABSTRACT: In this paper an attempt has been made to simplify the complex interface pullout mechanism using nonlinear elastic formulations. Formulations of interface pullout tests are expressed in non-dimensional terms for general applicability. Concepts of relative stiffness and displacement parameters are defined to explain the non-linear pullout response. Comparative parametric studies were carried out for a range of relative stiffness and bond resistance. Normalised load - displacement relations and the variations of pullout force and displacements with distance, are expressed in finite difference equations and solutions presented graphically. The predictions based upon a hyperbolic relation for shear mobilisation are compared with those from the elasto-plastic model. It was observed that the formulations might be used for small to large strain problems i.e., for inextensible to extensible reinforcements. Evaluated results of laboratory and field pullout experiments for steel straps, geotextiles, polymers and nylon geosynthetics are summarised. INTRODUCTION Earth reinforcements are increasingly used in offshore/harbour structures, retaining walls, embankments, landfills, liners, foundations, in-situ slopes, excavations and road construction. New developments in the innovative use of geosynthetics have offered engineered solutions for reinforcement, drainage, separation and stabilisation. This has resulted in the applications of the theory to practice of numerous earth structures, such as slopes and embankments, retaining walls, foundations and dams. There have been many hypotheses postulated about the load transfer and interaction mechanisms but none fully explain the phenomena. Major applications of reinforced soil are retaining walls and steep slopes where the reinforcement provides short term as well as long term stability over the design life of the reinforced soil structures. Figure 1 illustrates typical examples of reinforced soils. FORMULATIONS REVIEWS To understand the behaviour of reinforced earth various laboratory tests such as triaxial, direct shear, pull-out and physical model tests were investigated and used by many researchers.

ABSTRACT: In-situ measurement of subsurface temperature (temperature prospecting) has been developed as a method of groundwater-vein surveying. However, the usual method is labour intensive and the temporal resolution is poor, so we could never obtain sequential data of the temperature distribution. Continuous observation of the temperature distribution (i.e. distribution of the preferential flow-path) using fibre-optic temperature sensor is reported in this paper. High temperature regions indicate the groundwater pathway. The intensity of its signature was found to show slight fluctuations. In addition to that, it was found that these high temperature regions also have relatively large vertical temperature gradients. These signatures may be associated with the fluctuations of the preferential flow-path of groundwater, indicate the dynamic state of groundwater flow, and provide new parameters for the temperature prospecting method. INTRODUCTION The existence of preferential flow-paths for groundwater is an important factor which influences form of groundwater flow. It could be not only an ideal place for the water resource, but also a cause of disaster such as road and river bank failure. Therefore, having an accurate grasp of the preferential flow-path, such as distribution, scale and dynamics of preferential flow-path is important to prevent natural hazards and to develop water resources. In-situ measurement of subsurface temperature (temperature prospecting) has already been used in groundwater surveying (e.g., Cartwright, 1968a; Krcmar and Masin, 1970; Takeuchi and Akibayashi, 1977). This method is based on the concept that the subsurface temperature is affected by flux and temperature of the groundwater flowing through the measurement point. This method has been established both empirically (e.g., Cartwright, 1968b; Yamamoto et aI., 1994; Yasuda and Takeuchi, 1998) and theoretically. However, the conventional method is labour intensive, and has poor temporal resolution. Thus, until now, the method only indicates the static distribution (i.e. a snap-shot) of the preferential flow-path.

ABSTRACT: For the Changi East Reclamation Projects in Singapore, about 140 million metres of prefabricated vertical drain (PVD) are being installed. Due to the requirement of large quantity of materials, several types of prefabricated vertical drains are being used. Quality control system was established to check on the quality of vertical drains. The methods and procedure of quality control tests of both hydraulic and mechanical parameters of prefabricated vertical drain are described in this paper. The tests results and the factors affecting the resultant parameters of PVD are discussed. INTRODUCTION The Changi land reclamation projects in Singapore cover more than 2000 hectares area and are being carried out in four phases over 7 years. Several types and more than 140 million metres of PVD are being used for soil improvement works. These include Colbond CX 1000, Mebra MD7007 produced in Holland, Korea and Malaysia and Flexi FD767 drains. As different types and huge quantity of drains are being used, quality control of the drain materials and installation procedures become an important task. To serve this purpose, requirements for the specific properties of vertical drains are specified and a quality control system has been established to check the properties of the drains and to supervise the construction process. For vertical drains, both the hydraulic and mechanical properties were checked before installation. Laboratory vertical drain testing devices were developed to measure the discharge capacity of the drains, the permeability of the filter, the apparent opening size (AOS) of the filter, and the tensile strength of both the drain and the filter. The hydraulic properties affect the performance of PVD whereas the tensile strengths of both the drain and the filter are required to ensure the integrity of the drain after installation.

INTRODUCTION: Unstable slopes often show time dependent movements which may be highly variable. In general these variations are often explained with changing water levels behind and in the slope resulting from rainfall. In engineering practice this dependency is commonly accepted. But experience shows, that in low permeable soils heavy rainfall will more likely run off at the surface rather than penetrating into the subsoil at a substantial rate. Thus the influence of rainfall on the piezometric line in low permeable soil should be expected to be minor and delayed in time. Because variations in pore water pressure control effective shear stress (Terzaghi and Peck, 1948) this accepted soil mechanical principle has been enhanced by including time dependent effects of external pressure variation and its influence on the soil below the piezometric line. So far accepted external pressure variation may originate in changes of water level (e. g. tidal effects in estuaries, water level draw down effects in reservoirs or waterways). In this paper it is proposed, that variations of barometric pressure acting on a slope may also influence pore water pressure conditions. Under certain conditions this effect may be decisive in triggering landslides. Extensive field measurements have been performed in unstable clay slopes. In this paper recent results will be presented of these measurements in progress as well as results of back calculations. INSTRUMENTATION OF SLOPES AT LÜHNDE For a navigable canal (Stichkanal Hildesheim -SKH-) a cut has been constructed in Lias clay close to Lühnde (Germany) in the 1920s. After major failures in the beginning due to extremely steep slopes (1: 1.5) the slopes still remain unstable at slope inclinations presently ranging at about 1: 2.5 to 1: 3.5. In 1996 inclinometer casings have been installed and periodically read.

ABSTRACT: The presence of shells is very frequent in the resulting deposits of the geological processes of transgression and regression of the sea. They happen close to the coastline, especially in Metropolitan Area of Recife, Brazil, where load constructions are being built. The geotechnical properties of this marine deposits are not very well-known for foundations, so this work presents the first results obtained in the field and laboratory tests accomplished in deposits of shell samples. INTRODUCTION Along the Brazilian coast, we find deposits reworked by the different agents prevailing in the geological processes of transgression and regression of the sea. The presence of shell of marine origin is frequently one of these deposits found in the underground of Recife, whose characteristics are very variable. Concentrated, they appear in the profile below the marine terraces, originated in the Quaternary by the flotation of the level of the sea and they form very defined layers. Sometimes they are mixed with the other coarse sediments, besides coral fragments, in bigger or smaller proportion. Many big engineering structures have been built on lands carrying these deposits. Some buildings show settlements so high that their serviceability are becoming questionable. Thus it is important to know their characteristics and geotechnical properties. This paper describes the experience in terms of field data and laboratory tests on shell deposits of the Metropolitan Area of Recife DEPOSITS OF CORAL AND SHELL In many parts of the world, the calcareous materials are present, especially those of organic origin as coral and shell, chose to the line of continental coast and the hottest oceans. The corals are secretions of the zoophytes, that are animals seeming plants, and are remarkable for their capacity to build massive structures of skeletons of calcium carbonate, in environment of shallow, warm and clean water.

ABSTRACT: Any mechanistic analysis of pavements requires the knowledge of resilient moduli (M R) of all their components. The specimens used in the laboratory for resilient modulus determination are usually compacted and tested at the optimum water content and maximum dry density, but the pavement subgrade, although compacted close to these conditions, will support moisture variations as a result of seasonal and environment fluctuations. This paper presents results from an experimental study in which one typical lateritic soil encountered in roadbed in Brazil was tested under triaxial cyclic loading and evaluate the relationship between MR variations and water content and suction level variations. It was found that the lower moisture content results in the greater resilient modulus, and this decreases as the moisture content is increased, for any level of deviator stress. The filter paper showed good performance to assess even high suction levels and the soil characteristic curve illustrates that as the soil gets more wetted, the suction decreases. The cyclic loading triaxial test does not modify the soil suction and the resilient modulus increases so that the soil suction is increased. A good relationship was obtained between resilient modulus, deviator stress and suction level. INTRODUCTION The specimens used in the laboratory for resilient modulus determination are usually compacted and tested at the optimum water content and maximum dry density, but the pavement subgrade, although compacted close to these conditions, will support moisture variations as a result of seasonal and environment fluctuations. Fine-grained soils, principally, exhibit a decrease in modulus as the water content is increased, leading to increased deflections in the pavement subgrade and most pavement failures occur as a result of wet and dry moisture content cycles of subgrade layers (Mohammad et al. 1995, Drumm et al. 1997).

ABSTRACT: This paper presents some preliminary results from a comprehensive study on the application of the finite element method for reliability analysis in geotechnics. Some remarks on the stochastic nature of soil properties are given together with typical values for their stochastic modelling. The numerical procedure adopted (a point estimate method) is briefly described. A finite-element code is used to process the input variables and determine the input parameters for the performance function. The practicability of the suggested procedure is shown by solving an idealized tunnel excavation problem. INTRODUCTION In the past two decades the importance of reliability analyses and the stochastic nature of soil properties has been recognized in practical geotechnical engineering. Although the advantages of probabilistic tools are now generally accepted, there is still only a limited number of applications to practical problems documented in the literature. The reason being that closed form solutions are not available for most practical cases and numerical methods involve high computational efforts. However recent achievements in numerical analysis and the fast development of hardware have significantly reduced run times and pre- and post processing efforts so that a probabilistic approach on the based on deterministic finite element results seems to be a feasible way for the future and thus worthwhile to investigate. STOCHASTIC NATURE OF SOILS In general three major sources of uncertainties in soil profile modelling can be distinguished (Vanmarcke 1977). In this paper the natural heterogeneity or inherent uncertainty is dealt with only. In practice most geotechnical problems are still solved using a deterministic approach employing soil parameters which are Òon the safe sideÓ. In order to assess the behaviour of a geotechnical structure or the change of the deterministic factor of safety with respect to variable parameters such as e.g. shear strength sensitivity analyses are usually carried out.

ABSTRACT: This paper describes a new technique for computing lower bound limit loads in anisotropic media under conditions of plane strain. Although limit analysis has been applied extensively to homogenous and isotropic soils, as well as soils with a variation of cohesion with direction, it is well recognised that natural soil deposits also exhibit a variation of friction angle with direction. A finite element formulation or the lower round theorem is presented which allows for the variation of soil strength with direction. In order to achieve this, the conventional Mohr-Coulomb yield criterion used. An example is given to illustrate the capability of the proposed numerical procedure. INTRODUCTION In their natural state most soils are somewhat anisotropic. Due to the mode of deposition and subsequent loading of soil masses, measurements have shown that the particles tend to adopt a preferred orientation. It is this preferred particle orientation which results in a variation of soil properties as the angle of the major principal stresses varies during shear deformation. While the measurement of this inherent anisotropy is difficult, its effects have been shown via laboratory tests on samples cut at different angles. While existing data would seem to suggest that the variation of cohesion (undrained shear strength) with orientation due to soil anisotropy is more significant than the effects of friction angle, the effect of friction angle variation should not be ignored. Arthur and Menzies (1972) and Arthur and Phillips (1975) measured inherent anisotropy in prepared sand samples using a consolidated-drained shear test. They noted that a slightly higher friction angle (typically ill the order of 2–3 degrees) occurs when the direction of the major principle stress coincides with the direction of sand deposition as compared to when the major principal stress is perpendicular to the direction of deposition.

ABSTRACT: A penetrometric test under taken in a well-known granular medium (particle size distribution and water content) is directly linked with the dry density of the material. Hence it is possible to establish a relationship between dry density and cone resistance for a material at given water content. Due to extreme sensitivity of cone resistance, the penetrogram is a signature of dry density variation and nature of the soil. This method gives an efficient method of quality control in trenches up to 8 meters deep. It is proposed to use cone resistance qd to verify the in situ dry density and the whole penetrogram (qd in function of depth) to detect layers and their thickness in a compacted trench or backfill. INTRODUCTION The mechanical behaviour of a granular medium can be approached by two different ways. Either the granular medium is considered as a continuous medium with its constitutive laws, or the granular medium is described as a discontinuous medium. In the first approach, the mechanical behaviour is characterised with a set of mechanical parameters. In the second approach, the soil behaviour is well predicted by using grain parameters (mineralogy, shape texture) and assembly parameters (distribution of contacts, density and water content). Soil classification and a dynamic penetrometer test are used for quality control of compaction. The French GTR soil classification is used in this paper, but the method could be applied with any other accurate classification. A database is build, which contains physical and mechanical parameters and the penetrogram for all backfill material, at varying density and water contents. The quality control of compaction consists also of detecting verifying the layer thickness of a compacted soil structure. This paper proposes an algorithm based on the statistical properties of the penetrogram to detect layer thickness.

ABSTRACT: This paper describes the results of a study of the seismic micro-zonation of Delhi. It presents a summary of the study with respect to geological characteristics, geotechnical investigation, earthquake climate, analysis of site response, and assessment of liquefaction potential. The various site response analyses results characteristics are plotted in the form of contours over the Delhi map in order to show the local effects of soil on earthquake response. The analysis shows that the region is seismically active and that the SE area of Delhi is vulnerable to severe ground motion when the area is subjected to an earthquake of magnitude 7.0. The belt along the Yamuna river in the Eastern part of Delhi is liquefiable during earthquakes. The paper presents the major findings of the study and highlights the further scope of the study. INTRODUCTION Earthquakes occasionally shake Delhi, the capital of India, and the surrounding regions. Being densely populated with high rise structures, the damage during any anticipated earthquake of, say, Magnitude 7.0 would be expected to be very heavy. This study attempts to identify the areas of Delhi at risk during these devastating earthquakes. The approach outlined in Poulos (1993) and in ISSMFE (1993) has been adopted here for the Delhi microzonation study. Since the accuracy of the results depends upon the data used in the analysis, considerable efforts were made to collect appropriate geological, geotechnical and seismicity data from various institutions and organizations in India, as well as from other countries. For this study the area has been divided into square cells, each measuring 3km × 3km (Figure 1). The following sections present a summary of the study with respect to geological characteristics, geotechnical investigations, earthquake study, analysis of site response and assessment of liquefaction potential for each cell in the Delhi region.

ABSTRACT: Granular particles always played a major role in the domain of construction, buildings, hydraulic, they constitute the principal produce used in body of pavements. It is through granular particles that are transmitted the statistical constraints and dynamic brought by the traffic, of its quality, its homogeneity and its permanence (in the time) depends in part, the durability of the road. In Algeria most quarrys produce the sedimentary rock granulates, among which one has carbonated rocks that constitute the most important fraction and that are used essentially in the road domains. The choice of granulates destined to a given project is conditioned by, the intrinsic features - the coefficient Los Angeles, the coefficient Micro Deval in presence of water - features of manufacture (shape, the property of sands, the coefficient of aplatissement, superficial properties) as well as the mineralogical features (matrixes, nature of elements, porosity, etc). The mineralogical study and tests of laboratory have been made on samples of secondary age carbonated rocks (Jurassic, cretace), every samples made the object of a Petrography analysis and tests of laboratory to determine the nature and the percentage of the different elements as well as the cracks and discontinuities that can exist in the rock. For the physic—mecanical characteristic we determined the coefficient Los Angeles, the coefficient Micro Deval in presence of water. Results of the mineralogical study and physic—mecanical tests are represented under shape of graphs and analyses figures. Our work has for objective the stake evident relation that unites the physic mechanical characteristic and the mineralogy of carbonated rocks. INTRODUCTION Granulates always played a major role in the domain of construction, building, road, etc. In Algeria most careers produce granulates of sedimentary rock, among which one has carbonate rocks that constitute the most important fraction.

ABSTRACT: Modeling of liquefaction in saturated sand has been the aim of many researchers to predict the mechanical behavior of soil under such conditions. The means by which pore water pressure accumulate due to cyclic loading has been studied using different usual tests and effective stress analysis has been proposed to simulate damages to structures due to liquefaction of surrounding soils. Although for the purposes of actual construction design the permanent deformation caused by an earthquake is a very crucial factor there is no verification study describing the permanent deformation caused by an earthquake. In this study, an integrated planes elastic-plastic model for predicting the behavior of liquefiable sand under cyclic loading on the basis of sliding mechanisms and elastic behavior of particles has been presented. This model is implemented in a finite element program to solve any boundary value problem. The capability of the model to predict the behavior of soil under undrained condition in the case of seeing the rotation of the principal stress axes, induced anisotropy due to plasticity has been examined. It is found that the proposed model can describe the behavior of sand under various cyclic stress paths conditions, and this model will be useful for actual liquefaction analysis. However, this model, based on effective stress analysis, is able to estimate pore water pressure accumulation, full liquefaction and final elastic-plastic deformation as failure sliding shear bands and settlements. INTRODUCTION Multilaminate model is capable of predicting the behavior of granular material on the basis of sliding mechanisms and elastic behavior of particles. This simulation is demonstrated in Figure 1. The task of representing overall stress tensor in terms of micro level stresses and the condition, number and magnitude of contact forces has been long the aim of numerous researchers [1], [2], and [3].

ABSTRACT: This paper describes the development of coefficient of lateral earth pressure at rest, K0 in soft kaolinbentonite mixtures. The presence of montmorillonite in bentonite increases the consistency limits and consequently enhances the activity of the soil mixture. Ko values of a series of reconstituted kaolinbentonite mixtures were observed continuously during one - dimensional consolidation during loading as well as unloading cycles. The samples were consolidated under a constant hydraulic gradient of 0.2 kPa/mm in a purposely built consolidometer and measurements from flush diaphragm transducers gave the total vertical stress and total lateral stress on the sample. The equipment used has previously been described in Ting, Sills and Wijeyesekera (1994). Experimental observations confirm that K0 increase linearly with decreasing void ratio as reported by Ting et al (1994) for soft kaolin soils. The increasing montmorillonite content results in a lowering of the angle of friction, which in turn increases the value of K0. The value of K 0 was observed to initially decrease with time during secondary consolidation. These observations provide an answer to a query raised by Schmertman (1983) which had remained unanswered to date. During unloading, K0 values were observed to increase with increasing over consolidation ratio (OCR). INTRODUCTION The coefficient of earth pressure at rest, K0, is an essential design parameter in soil mechanics and its evaluation is important for problems related with foundations, excavations, retaining walls, friction piles and numerical modelling. Therefore the estimation of an incorrect value of Ko can seriously affect the soil deformation parameters (Wijeyesekera, 1994). Donath (1891) defined k0 as the ratio of the total horizontal stress to the total vertical stress ( sh/sv) when under a condition of zero lateral strain. KAOLIN - BENTONITE MIXTURES The kaolin used was Speswhite China Clay, marketed by English China Clays Ltd.

ABSTRACT: The behaviour of cohesive soils under triaxial test has attracted the attention of large number of investigators because of its practical importance. The behaviour of saturated clays during shear in particular has important practical implications. The study of the effect of overconsolidation is also of great value as in nature many deposits of clay have been overconsolidated in their geological history. In order to have a thorough appreciation of stability and deformation problems, it is extremely important to understand the inter relationship between the strength, pore water pressure and volume change characteristics of the material concerned. A series of tests both drained and undrained and drained/undrained conditions alternatively on the same sample on remoulded specimen of clay (KAOLIN) to study the stress strain characteristics, response to pore pressure development and volume change during shearing were conducted and results are presented herein. INTRODUCTION The results of triaxial tests on saturated soils are of immense value so far as the practical view points is concerned. In field, saturation of foundation soil can occur from loading. Saturation by percolation of water during the performance of a structure is a common condition requiring analysis for steady state and draw down conditions. The shear-strength parameters of cohesive soils are much influenced by its stress history. The volume changes and pore-pressure variations of normally consolidated clays are similar to those of loose sends while overconsolidated clays behave like dense sands. Factors that affect the shear-strength parameters of cohesive soil include its structure, clay content, drainage conditions, strain rate and water content (Khan, 1998). A series of tests were carried out on remoulded samples of Kaolin to study its response towards pore pressure development, volume change, failure behaviour during shearing. The results have been presented through a number of figures.