A constitutive equation is proposed for describing changes of states of granular materials which are sufficiently characterized by the void ratio and the stress tensor. It may be considered as an extension of the Critical State concept. It is based on recently published hypoplastic equations and covers a wide range of densities, pressures and deformations. A factorial decomposition allows a rather easy separation and determination of material parameters. Two factors depend on a relative void ratio so that it remains within lower and upper bounds. The bounding void ratios decrease monotonously from maximal values to zero with increasing pressure. The same reduction of the void ratio is proposed for an isotropic compression starting from a suspension. Thus a granulate hardness is defined, and a stiffness factor can be determined. Four material parameters can be estimated from classification tests and determined from the asymptotic behaviour in element tests. Four further parameters are determined by calibration; they are rather constant for wide groups of materials. Strength and stiffness values can be derived and used for the analysis of deformations, stability, and flow. The viscous behaviour is modelled by a rate dependent factor with one further parameter. Limitations and possible extensions of this comprehensive approach are also outlined.

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Based on the concept of hypoplasticity, a comprehensive constitutive equation describing the three-dimensional nonlinear stress-strain behaviour of granular materials was presented by Gudehus (1996). This companion paper focuses more on experimental and numerical investigations for the calibration of this constitutive model. The representations of the functions chosen are discussed in detail. The consideration of special state paths permits an easy assignment of the constitutive parameters to the experimental data from standard and element tests. Numerical simulations of various element tests indicate that the model is able to reproduce the salient features of granular materials in a wide range of pressures, deformations and densities.

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A numerical model incorporating a three-parameter dilatant nonlinear incrementally elastic soil model was used to analyze three well-controlled full-scale geosynthetic-reinforced soil (GRS) retaining wall tests. The three tests were conducted to examine the effects of facing rigidity and reinforcement length on the performance of GRS retaining walls subject to central loading (far from the facing panel). It is shown that the numerical model is capable of accurately simulating the behavior of the three tests under service loads, in particular, their sensitivity to facing rigidity and reinforcement length. The validated numerical model was then used to conduct a comparative analysis on four GRS retaining walls subject to front loading (adjacent to the facing panel). The GRS retaining walls comprised four different types of facings having different degrees of rigidity. The results of the comparative analysis are considered useful as a guide for selecting the proper facing rigidity of GRS retaining walls subject to front loading.

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This study presents a simplified method for estimating earthquake-induced settlements of saturated sand deposits based on previously available studies and undrained cyclic loading tests followed by drained reconsolidation under non-zero or zero lateral strains for various sands. It has been shown that : (1) the volume change of different sands over a wide density range can be uniquely related to "relative compression" as defined by Δe/(e_i-e_min); (2) the total volumetric strain of saturated sand is not obviously influenced by a swelling history following undrained cyclic loading; and (3) the volumetric strain after undrained cyclic loading is not significantly affected by the boundary constraint of non-zero or zero lateral strains. It has been found that the relationship between the logarithm of the relative compression after complete or incomplete liquefaction and the logarithm of the maximum shear strain induced during preceding undrained cyclic loading is approximately linear over a range of maximum shear strain from 0.01% to 10% and of relative densities from 20% to 90% for five sands under non-zero or zero lateral strain conditions. The results predicted by the proposed method compare favorably with experimental observations of shaking table tests on saturated sand in a laminar container. The proposed method may therefore be used as a first approximation for estimating earthquake-induced settlements of saturated sand deposits.

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Calcium carbonate may precipitate with an almost constant rate on the seabed. Therefore, it can be concluded that the calcium carbonate content of the sediments is governed by the accumulation rate of solids other than carbonate. The ultimate objective of this study was to consider the sedimentary environment for the calcium carbonate content in terms of the accumulation of solids and submarine topography. In order to ensure that the present sedimentary environment was related to the calcium carbonate content of the bottom sediments, a correlation between calcium carbonate content and bottom topography is discussed. In addition, the accumulation rate of sediments is discussed in terms of calcium carbonate content. In Osaka Bay, the sedimentary characteristics seem to be simple. The greater the water depth and the larger the distance from the shoreline, the calcium carbonate content becomes higher. Assuming a constant precipitation rate of calcium carbonate, the result obtained shows that the accumulation rate of sediments is higher near shorelines. The reason for this is that more sediments accumulate near and around river mouths and shorelines. In Sagami Bay and Suruga Bay, the sedimentation characteristics depend on the complex topography. The erosion of the continental slope may cause the transportation of sediments from the original location of deposition to another. This results in a tongue-shaped distribution of the lower carbonate content in the Sagami Trough. In the western part of Suruga Bay, it was found that from the distribution of calcium carbonate content, Senoumi banks play an important role as a barrier for sediments and suspended solids from being transmitted.

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A conventional type of earthquake response analysis of ground gave a maximum acceleration for soft deposits that is lower than that for stiffer soil conditions. Since this was contradictory against the knowledge that soft deposits are more hazardous, an improvement of the analysis was attempted. A series of geophysical surveys was carried out to investigate the variation of shear wave velocity in the vertical direction and it was suggested that the velocity and shear modulus vary more continuously with depth even though the soil type changes from cohesive to cohesionless. The idea of continuity in soil property was further supported by the variation of fines content with depth. With these in mind, a wave propagation equation was developed and then solved analytically by taking into account the continuity of modulus. The calculated amplification of seismic motion indicated that more wave energy can reach the ground surface with this new analysis than in the more conventional way of calculation.

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This paper identifies bifurcation phenomena as a major source of uncertainty in soil shearing behavior. On the basis of the bifurcation mechanism, this source is classified into three independent categories : (1) the size effect, (2) the mode change (switching), and (3) the stochasticity of initial imperfections. The size effect is explained considering both fracture and bifurcation, based on tests on rock and soil, and the analysis of a beam on a nonlinear foundation. The mechanism of the mode change, which denotes the variation of the buckling mode due to initial imperfections, for the harmonic and localized bifurcation modes is explained based on the bifurcation behavior of a shell, an atomic chain, and soil. As an essential part of this paper, the theory of the stochasticity of initial imperfections is used to explain the probabilistic variation of the behavior of 32 sets of data for triaxial compression tests on sand specimens. The study of those sources of uncertainty permits a global view of bifurcation, which is vital to the proper understanding of soil behavior.

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In coastal region throughout arctic oceans the seabed is frequently scoured or gouged by moving bodies of ice such as icebergs and sea ice keels associated with pressure ridges. Ice scouring may present a severe environmental hazard posed to marine pipelines and other seabed structures. To investigate the ice scour events, both centrifuge model tests and numerical simulations were conducted. Attention was focused on the subscour soil deformation. The centrifuge model tests yielded extensive data which allowed to clarify the scour mechanism and to verify the numerical analysis technique. A finite element model, based on large displacement and plastic formulation, was adopted to analyze the ice scour events. The results from finite element analyses were examined and compared with the experimental data from the geotechnical centrifuge tests.

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This paper presents the effect of abundantly available fly ash, on the index properties namely liquid and plastic limits, and free swell of natural deposits of Indian black cotton soil. The effects of lime when added have also been studied. Considerable changes in these properties were observed which are explained based on grain size distribution, free lime content and pozzolanic reactivity of fly ash. Addition of fly ash improved the workability of the soil considerably. The increase in free swell in the presence of fly ash is not due to increase in the swelling potential of the soil. Over all, the effect of the addition of fly ash is to significantly improve the physical properties of the black cotton soil.

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Using the Connected Lattice Automaton (CL-CA) model, which has been specially developed for the analysis of granular materials, some pattern formations in vibrating granular media are demonstrated. In the CL-CA model, polygon particles are set on triangular lattice and the mechanical properties are less important. The dynamics of the motion of a particle is described by some simple automaton rules. Heaping, size segregation and convective motion can be seen in the simulation. Such pattern formations have been found in physical experiments. Therefore, geometrical properties of each particle and its combined geometry are key factors in the understanding such complex nonlinear phenomena for granular media.

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Solutions for settlement of subsoil improved with sand compaction piles and the vertical stresses acting on the sand compaction pile and the subsoil clay are presented. These solutions were obtained using a simplified method of analysis based on the unit cell concept and assuming that the composite subsoil deforms under one-dimensional confined compression. The solutions were shown to be identical to those of the equilibrium method by Aboshi et al. (1979) with the stress concentration ratio given by the ratio of the constrained modulus of the sand compaction pile to the constrained modulus of the clay. The accuracy of the simplified method was verified by the rigorous theoretical approach reported by Balaam and Booker (1981).

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