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Showing papers in "Journal of Geotechnical and Geoenvironmental Engineering in 1981"


Journal ArticleDOI
TL;DR: In this paper, a test program was undertaken to define the nature of the cementation and its effect on behavior of the soils, and a total of 137 laboratory compression and tension load tests were performed on undisturbed samples of naturally and artificially prepared cemented sands.
Abstract: Cemented sands are found in many areas of the world; one of their distinguishing characteristics is their ability to stand in steep natural slopes. Large deposits are located along the California coast, and in a number of areas intense urban development has occurred near the crest of high, steep slopes. Because of the hazards posed by slope failures in the cemented sands, a test program was undertaken to define the nature of the cementation and its effect on behavior of the soils. A total of 137 laboratory compression and tension load tests were performed on undisturbed samples of naturally cemented sands and artificially prepared cemented sands. The materials exhibited friction angles similar to uncemented sands, but had a cementation strength intercept and a tensile strength. The primary cementing agents of the sands tested were silicates and iron oxides. The strength of the cemented sands were found to be a function of density, amount of cementing agent, grain shape and grain arrangement.

441 citations


Journal ArticleDOI
TL;DR: The steady state of deformation for any mass of particles is that state in which the mass is continuously deforming at constant volume, constant normal effective stress, constant shear stress, and constant velocity as mentioned in this paper.
Abstract: The steady state of deformation for any mass of particles is that state in which the mass is continuously deforming at constant volume, constant normal effective stress, constant shear stress, and constant velocity. The steady state of deformation is achieved only after all particle orientation has reached a statistically steady-state condition and after all particle breakage, if any, is complete, so that the shear stress needed to continue deformation and the velocity of deformation remain constant. The similarities and differences between steady-state deformation and the current use of the term critical state are described. A special undrained triaxial test on a sand is presented to demonstrate clearly that a special flow structure exists during steady-state deformation, which is quite different from the initial structure, and which is credited to a nonrandom, i.e., statistically oriented, arrangement of the sand grains.

361 citations


Journal ArticleDOI
TL;DR: In this paper, the authors explored the mechanism of geotextile reinforcement of roadways and developed a method which enables the engineer to calculate the required thickness of aggregate layer and make a proper selection of the geote-xtile to be used.
Abstract: By providing reinforcement, geotextiles improve the performance of unpaved roads, and for a given traffic, the thickness of the aggregate layer can be reduced. This paper explores the mechanism of geotextile reinforcement of roadways, and a method is developed which enables the engineer to calculate the required thickness of aggregate layer and make a proper selection of the geotextile to be used. Charts are presented to assist in the design of geotextile-reinforced unpaved roads and to evaluate the reduction of aggregate thickness resulting from the use of a geotextile. Practical examples and comparisons with full scale tests are presented.

306 citations


Journal ArticleDOI
TL;DR: In this paper, a simplified method is presented for the prediction of wall and soil movements for braced excavations in soft to medium clay deposits by combining the results of field data performance and finite element analyses.
Abstract: A simplified method is presented for the prediction of wall and soil movements for braced excavations in soft to medium clay deposits. The method is developed by combining the results of field data performance and finite element analyses. A careful review of 130 published and unpublished case histories was carried out to select well-documented projects with similar support systems and free of unusual construction effects. The finite element analyses were directed toward the evaluation of effects of variation of soil shear strength, soil stiffness, support stiffness and system geometry. Both the field data and the finite element results show that a strong correlation exists between system movements and the factor of safety against basal heave. Based on the established behavior trends, nondimensional plots are developed for predicting maximum magnitudes and distributions of wall deflections and ground settlements as a function of the factor of safety against basal heave and the other important parameters of the soil and structural system.

249 citations


Journal ArticleDOI
TL;DR: In this article, a theoretical procedure is developed to generate t-z curves for predicting pile movements under axial load, using an approximate one-dimensional, elastic continuum approach to define the tz response up to the maximum t response.
Abstract: Most procedures to compute the t-z (stress-displacement) response for axial pile loading are empirical, based mostly on data for pile diameters less than 18 in. (0.15 m) and pile penetrations less than 100 ft (30 m). These procedures may not be appropriate for pile and soil conditions that differ from those on which the procedures were developed. Therefore, a theoretical procedure is developed to generate t-z curves for predicting pile movements under axial load. The procedure uses an approximate one-dimensional, elastic continuum approach to define the t-z response up to the maximum t response and laboratory simulation to define the post-peak response. The procedure was used with several case studies. Predicted response of the pile under axial loading was in good agreement with the measured response.

245 citations


Journal ArticleDOI
TL;DR: In this article, the authors used a 4 in. (100 mm) square footing on sand reinforced with strips of a rope fiber material, and each layer of reinforcement was arranged in horizontal square grids.
Abstract: Results are presented of laboratory-scale bearing capacity tests using a 4 in. (100 mm.) square footing on sand reinforced with strips of a rope fiber material. Each layer of reinforcement was arranged in horizontal square grids. The addition of reinforcements increased the bearing capacity of the footing on the unreinforced soil by a factor which depended on the following: the horizontal spacings between strips on each layer, the vertical spacings between layers of reinforcement, the depths above the first layer of the footing, and the number of layers. Depending on the strip arrangement, the ultimate bearing capacity improvement could be up to three times that of the unreinforced earth.

188 citations


Journal ArticleDOI
TL;DR: In this article, the authors compared two-dimensional finite element analysis with one-dimensional stochastic solutions for total and differential settlement, and found that the differences were mainly due to the randomness in the stress field which cannot be included in onedimensional models, and mechanistic correlations by common dependence on the realizations of particular random variables.
Abstract: Stochastic finite element analysis is used to predict uncertainties in total and differential settlement under a large flexible footing. The results are compared with one-dimensional stochastic solutions already in the literature. Differences between the one- and two-dimensional analyses, particularly for differential settlement, are distinct. These differences seem primarily attributable to randomness in the stress field which cannot be included in one-dimensional models, and to mechanistic correlations by common dependence on the realizations of particular random variables. In principle, second-moment techniques can be extended to a broad range of analyses now performed using finite element and finite difference techniques.

179 citations


Journal ArticleDOI
TL;DR: In this paper, the generation and propagation of vibrations due to construction are discussed and the relative intensity of the vibration produced by many construction sources is identified, and a brief summary of the development of suitable vibration-measuring instruments is related.
Abstract: The generation and propagation of vibrations due to construction are discussed. The relative intensity of the vibration produced by many construction sources is identified. A brief summary of the development of suitable vibration-measuring instruments is related. Differences in current damage criteria are revealed. Future research is needed on the effects of both transient and steady-state vibrations on structures, uncured concrete, soils and underground utilities; additional research is needed on fatigue of building materials. Human response evaluation of transient vibrations also requires further research.

171 citations


Journal ArticleDOI
TL;DR: In this paper, a critical review of the literature clearly shows that existing theories which are used to determine the bearing capacity of piles driven in sand are not satisfactory Careful examination of the results of experimental studies indicates that existing theory fail to consider all significant parameters.
Abstract: A critical review of the literature clearly shows that existing theories which are used to determine the bearing capacity of piles driven in sand are not satisfactory Careful examination of the results of experimental studies indicates that existing theories fail to consider all significant parameters Field load test data are used to determine which of the pile geometry and soil property parameters are significant Special attention is given to the problem of residual stresses Bearing capacity factors are calculated from measured unit point and side resistances The bearing capacity factors are correlated with relative depth (depth of penetration to diameter ratio) and friction angle or relative density of sand New design correlations are developed for use in predicting the bearing capacity of axially loaded piles in sand

124 citations


Journal ArticleDOI
TL;DR: The existing types of collapsible soils and theories developed to explain collapse phenomenon are reviewed in this article, as well as the methods of recognizing collapsible soil in the field and laboratory.
Abstract: Metastable or collapsible soils are defined as any unsaturated soil that goes through a radical rearrangement of particles and great loss of volume upon wetting, with or without additional loading. The existing types of collapsible soils and theories developed to explain collapse phenomenon are reviewed, as are the methods of recognizing collapsible soils in the field and laboratory. Prediction techniques for the magnitude of collapse are presented and summarized; current foundation design methods on collapsible soils are explored. Finally, present methods for the stabilization of collapsible soils and possible future methods of treatment are reviewed.

119 citations


Journal ArticleDOI
TL;DR: In this paper, the peak drained friction angle π(prime) is found to be closely related to that of rock joints, and the value of (prime) depends on the porosity following compaction, and on the degree of particle roundedness and surface smoothness.
Abstract: A practical method for estimating the shear strength of rockfill is developed. The peak drained friction angle π(prime) is found to be closely related to that of rock joints. In both cases the values of π(prime) are dependent on sample size, stress level, surface roughness, and on the uniaxial compression strength of the rock. Friction angles are therefore higher for smaller samples, and very high where stresses are low, as at the toe or near the face of a rockfill dam. Test data reviewed shows that the value of π(prime) for rockfill can be quantified by a equivalent roughness (R), and an equivalent particle strength (S). The value of (R) depends on the porosity following compaction, and on the degree of particle roundedness and surface smoothness. A practical method is proposed for physically measuring the full-scale shear strength of in-place compacted rockfill.

Journal ArticleDOI
TL;DR: In this article, the water pressure required to cause hydraulic fracturing was found to depend on soil density, water content, confining stress and test duration, and it was hypothesized that hydraulic fracturing will occur in the least resistant soil subjected to increased water pressure.
Abstract: Laboratory tests on Teton Dam soil were performed by increasing the water pressure in model bore holes and in simulated rock joints. The water pressure required to cause hydraulic fracturing was found to depend on soil density, water content, confining stress and test duration. On the basis of the test results it was hypothesized that: (1)Hydraulic fracturing is a weak link phenomenon, in that fracturing will occur in the least resistant soil subjected to increased water pressure; and (2)hydraulic fracturing can probably occur only in the presence of a discontinuity, within which the water pressure can act to create a wedging mechanism, thus creating tensile stresses in the soil.

Journal ArticleDOI
TL;DR: In this paper, the causes and patterns of ground movement associated with braced excavations are examined, and practices are recommended for promoting a stiff bracing system, excavating beneath the lowest braces, and using berms to restrain ground movement.
Abstract: The causes and patterns of ground movement associated with braced excavations are examined. Field measurements of displacements for braced cuts in sand and soft to medium clay show a relationship between the deflection of the excavation wall and the ratio of horizontal to vertical movement adjoining the cut. A review of various case histories indicates that soil displacement depends strongly on the construction process. Practices are recommended for promoting a stiff bracing system, excavating beneath the lowest braces, and using berms to restrain ground movement.

Journal ArticleDOI
TL;DR: In this paper, an intrinsic effective stress is attributed to chemical bonds, which can influence the shear strength behavior of soils subjected to repeated wetting and drying in the laboratory, which results in greater shears strength and in a stiffer stress-strain response.
Abstract: Climatic changes, such as repeated wetting and drying over geological ages, lead to the degeneration of the parent rock to form soil. Simultaneously these actions can also cause some aggregation of soil particles and the production of bonds, called desiccation bonds, which impart an intrinsic effective stress to the soil. This intrinsic effective stress can influence the shear strength behavior of soils subjected to such climatic actions. When a soil is subjected to repeated wetting and drying in the laboratory, an intrinsic effective stress is imparted to it which results in greater shear strength and in a stiffer stress-strain response. This intrinsic effective stress may be attributed to chemical bonds.

Journal ArticleDOI
TL;DR: In this paper, analytical solutions for the torsional response of piles embedded in elastic soil that is either homogeneous or where the stiffness is proportional to depth are presented for different variations of soil stiffness with depth.
Abstract: Analytical solutions are presented for the torsional response of piles embedded in elastic soil that is either homogeneous or where the stiffness is proportional to depth. The solutions are extended to more general variations of soil stiffness with depth and to cover behavior after peak shaft adhesion between pile and soil. Full scale torsion load tests are studied, and an analogy is suggested between the behavior of piles subjected to torsion loading and that of long compressible piles subjected to axial loading.

Journal ArticleDOI
TL;DR: In this paper, the authors provide a guideline for estimating a reasonable strength parameter applicable to such complex soils, using plane strain tests on uniform-anisotropic, uniform-pseudoisotropic, layered anisotropic and layered pseudoisotropic samples.
Abstract: Natural soil deposits are generally anisotropic as well as heterogeneous. In order to provide a guideline for estimating a reasonable strength parameter applicable to such complex soils, plane strain tests on uniform-anisotropic, uniform-pseudoisotropic, layered-anisotropic, and layered-pseudoisotropic samples have been performed. Anisotropic strength response, caused by the anisotropic distribution of contact normals, should be expected even in a uniform mass of spheres. It is always necessary to assume that sand is generally anisotropic. Tests on samples prepared by the plunging-tapping method are advisable for obtaining a reasonable estimate of the mean strength for anisotropic sands.

Journal ArticleDOI
TL;DR: In this paper, the permanent deformation of soils as the result of cyclic loads is an important consideration in the design of offshore structures, and the permanent strains are influenced by the porosity, the intitial shear and effective normal stresses, as well as by the number of cycles of loading.
Abstract: The permanent deformation of soils as the result of cyclic loads is an important consideration in the design of offshore structures. Experimental studies show that the permanent strains are influenced by the porosity, the intitial shear and effective normal stresses, and the amplitude of the cyclic shear stress, as well as by the number of cycles of loading. These effects are combined into a logarithmic relation. The resulting equations have been incorporated into a finite element program that calculates permanent displacement without changes in net boundary loads or stresses. The analyses are applied to a proposed offshore barrier to show the importance of the ways in which cyclic loads combine with monotonic loads due to tides to give permanent displacements.

Journal ArticleDOI
TL;DR: In this article, the role of differential settlement is emphasized and the current practices and concepts for establishing the tolerable settlement of buildings are reviewed and compared with field observations of settlement and damage, and the allowable settlement is smallest for cases in which the settlement curve is concave downward.
Abstract: Current practices and concepts for establishing the tolerable settlement of buildings are reviewed. The role of differential settlement is emphasized. Most current tolerance limits are shown to be based on the works of Skempton, MacDonald, Polshin, and Tokar. These criteria are compared with field observations of settlement and damage. A simple beam analogy, which was proposed by Burland and Wroth, is used to illustrate factors that influence tolerable settlement. The effects of the critical tensile strain of the structural materials, the L/H ratio of the building, the relative stiffness of the structure in shear and bending, the longitudinal stiffness of the foundation, and the shape of the settlement pattern are demonstrated. Different criteria are required for different types of structures. The allowable settlement is smallest for cases in which the settlement curve is concave downward.

Journal ArticleDOI
TL;DR: In this paper, the effect of pile length on the development of shaft friction on piles in clay is examined in terms of the relative pile-soil stiffness and lateral pile movements during installation.
Abstract: Several studies on axial pile capacity in clays have shown that the average frictional resistance, expressed as a fraction of the average undrained shear strength or average effective overburden pressure, decreases with increasing pile penetration. Procedures to compute shaft friction are reviewed, and the effect of pile length on the development of shaft friction on piles in clay is examined in terms of the relative pile-soil stiffness and lateral pile movements during installation. Correlations are developed to relate shaft friction coefficients α,β,λ, to pile length, relative pile-soil stiffness, and soil stress history. Procedures are recommended to compute the friction capacity of piles in clay.

Journal ArticleDOI
TL;DR: The results of an experimental program directed toward evaluating K\d0 (the coefficient of lateral earth pressure under conditions of no lateral formation) and its dependence on stress history and other parameters of peat soils were presented in this paper.
Abstract: The results are presented of an experimental program directed toward evaluating K\d0 (the coefficient of lateral earth pressure under conditions of no lateral formation) and its dependence on stress history and other parameters of peat soils. Three peats with different fiber contents were consolidated in a custom-built K\d0-test tube. During loading and rebound, the axial deformations, pore pressure, and both axial and radial stresses were measured. A sand and clay sample compared well with previously reported values and empirical predictions. The values of K\d0 for the peat sample were found to remain essentially constant during the loading phase, but their values (which increased gradually during unloading) never exceeded unity. Several indirect approaches were tried to compute the K\d0 of the peats from effective shear strength parameters. Peat type appeared to exert a significant influence on the measured values of K\d0 during loading.

Journal ArticleDOI
TL;DR: In this paper, a technique is presented which modifies the basal heave analysis procedures for braced excavations to account for the strength anisotropy exhibited by most natural, soft to medium clays.
Abstract: A technique is presented which modifies the basal heave analysis procedures for braced excavations to account for the strength anisotropy exhibited by most natural, soft to medium clays. In the case of a braced wall, the clay on the passive side of the wall can develop a much lower strength than the clay on the active side, if the clay is strongly anisotropic. Since the existence of a lower strength zone is not considered by conventional basal heave analysis procedures, these techniques theoretically lead to an overestimate of basal stability. Finite element analyses are used to demonstrate the effects of anisotropy on the behavior of braced excavations. Analysis results show that if the soil is presumed to be isotropic when it is truly anisotropic the following trends develop: (1) The basal heave safety factor may be from 10 to 50 percent larger than the actual one, depending on the degree of anisotropy; (2) lateral wall movements and ground surface settlements can be larger than expected; and (3) unusually high loads can develop on the lower struts in cases of marginal stability.

Journal ArticleDOI
TL;DR: In this paper, the response of buried long structures to waves traveling in the longitudinal direction of the structures was studied and the structures and the surrounding soils were represented by three-dimensional finite elements.
Abstract: The response of buried long structures to waves traveling in the longitudinal direction of the structures was studied. The structures and the surrounding soils were represented by three-dimensional finite elements. The three-dimensional models, however, were reduced to two-dimensional models by using a special type of wave-transmitting element which faithfully accounts for the effects of wave propagation. The results obtained for a linear system indicate that, for large structures, soil-structure interaction effects on the computed stresses and strains are indeed significant; therefore, it will be overly conservative to use free field strains in the design. Also, the assumption of vertically propagating waves is not adequate in predicting response; therefore, appropriate considerations should be given to traveling waves.

Journal ArticleDOI
TL;DR: In this paper, a nonlinear method for seismic soil-pile-structure interaction is presented, which includes a consistent approach to determine seismic p-y relationships and a liquefaction model that is suited to pore pressure evaluation for earthquake-type irregular loadings.
Abstract: A nonlinear method for seismic soil-pile-structure interaction is presented. Primary features of the proposed method include a consistent approach to determine seismic p-y relationships and a liquefaction model that is suited to pore pressure evaluation for earthquake-type irregular loadings. The seismic- p-y relationships are determined from nonlinear stress-strain relations of soils, and include soil nonlinearity as well as pore pressure buildup effects around a pile. The performance and validity of the method were evaluated through an analysis of shaking table test on model soil-pile-structure systems. Using the proposed method, seismic response characteristics of an idealized offshore pile-supported structure at a sand site were analyzed. Results indicated that liquefaction as well as pore pressure bulidup around a pile can have a large impact on the response of pile-supported structures.

Journal ArticleDOI
TL;DR: In this paper, a finite element finite difference computer program for analysis of coupled heat and water flows in layered systems based on the Philip and DeVries theory is developed, and a field test was conducted to evaluate the heat and moisture flow predictive methods.
Abstract: Theoretical and experimental studies of heat flow and moisture movement under thermal gradients are described with particular emphasis on flows around buried electrical transmission cables. A one-dimensional finite difference computer program for analysis of coupled heat and water flows in layered systems based on the Philip and DeVries theory is developed. Theoretical analysis indicate that the most important parameters affecting rate and amount of moisture migration away from buried heat sources are the sources temperature and the soil type. A field test was conducted to evaluate the heat and moisture flow predictive methods. The results showed that water content predictions using the coupled flow computer program match poorly with the actual values, and that predicted values are very sensitive to the soil properties used. A finite element two-dimensional computer program is used to predict the variation of temperature distributions around the buried cable with time after initiation of cable heating. The results show very good agreement between measured and predicted temperature contours.

Journal ArticleDOI
TL;DR: In this paper, a number of solutions have been obtained for a typical offshore pile, to determine the influence of several input parameters on the computered cyclic response, such as the critical shear strain at which significant degradation of skin friction occurs, the rate of loading on the pile, and the distributions of static skin friction and soil modulus along the pile.
Abstract: A number of solutions have been obtained for a typical offshore pile, to determine the influence of a number of the input parameters on the computered cyclic response. More significant parameters include the critical shear strain at which significant degradation of skin friction occurs, the rate of loading on the pile, and the distributions of static skin friction and soil modulus along the pile. The analysis predicts a gradual decrease in cyclic stiffness of the pile with increasing numbers of cycles and increasing cyclic load level, but a very sudden decrease in ultimate load capacity once the (half-peak-to-peak) cyclic load level exceeds 50% to 60% of the ultimate static load capacity. These theoretical findings are broadly confirmed by the results of small-scale laboratory model tests.

Journal ArticleDOI
TL;DR: In this paper, a well-defined relationship was established between the percentage clay sizes present in a soil, the activity of the soil and the percentage of swell under a 1-psi surcharge of a sample compacted to 92% of standard AASHO density at optimum moisture content.
Abstract: Using test data of 259 naturally occurring soils obtained from 22 counties in Kansas, a well-defined relationship was established between the percentage clay sizes present in a soil, the activity of the soil and the percentage of swell under a 1-psi surcharge of a sample compacted to 92% of standard AASHO density at optimum moisture content. It has been shown that there is an excellent agreement between the predicted swelling and the actual swelling. The average error in predicting the swelling potential for the 26 soils was found to be 6.9%. The prediction equations will serve as a valuable tool in the design of any structure on compacted soils. (Authors)

Journal ArticleDOI
TL;DR: In this paper, a number of factors which influence soil-anchor interaction are evaluated, and in addition, the extent of soil disturbance and the influence of pore water pressures during testing are assessed.
Abstract: A number of factors which influence soil-anchor interaction are evaluated, and in addition, the extent of soil disturbance and the influence of pore water pressures during testing are assessed. Response under repeated and sustained-repeated loading is shown to be represented by a family of hyperbolic curves, and a failure criterion is determined by the critical strain condition below which a satisfactory response can still be subsequent to repeated loading. A strain dependent mechanism is used for defining behaviour under varying loading conditions which permits an assessment of anchor life when subjected to a package of projectd environmental conditions. Where possible the results are compared to those of other workers in the anchor field, and recommendations made which may lead to a better understanding of embedded systems.

Journal ArticleDOI
TL;DR: In this paper, a semi-empirical method is presented for predicting the magnitude of initial settlement and the likelihood of excessive creep movements, and ways of reducing detrimental undrained shear deformations in design practice are explored.
Abstract: For most foundation loading situations, initial settlements due to undrained shear deformations are small. The common practice of computing consolidation settlements using the conventional 1-dimensional model therefore generally yields total settlement estimates of sufficient accuracy for design purposes. Initial settlements can become a predominant design consideration with highly plastic or organic foundation soils, or both, however—especially when loaded to low stability factors of safety, as illustrated by three case histories. Moreover, with slow field rates of consolidation, the occurrence of large initial settlements may also be followed by excessive undrained creep deformations. A semi-empirical method is presented for predicting the magnitude of initial settlement and the likelihood of excessive creep movements. Ways of reducing detrimental undrained shear deformations in design practice are explored.

Journal ArticleDOI
TL;DR: In this article, the ultimate bearing capacity of footings on subsoil consisting of a strong sand layer overlying a weak sand deposit was investigated and a theory was developed and then results predicted.
Abstract: The ultimate bearing capacity of footings on subsoil consisting of a strong sand layer overlying a weak sand deposit was investigated. A theory was developed and then results predicted. These predictions compared well with test data on model strip and circular footings resting on dense sand overlying loose, as well as, compact sand. Design charts are presented for use in practical application. Based on these charts, a procedure to determine the ultimate bearing capacity of a strip and circular footings on a strong sand layer overlying a weak sand deposit is described.

Journal ArticleDOI
TL;DR: In this paper, the effect of nonlinear soil behavior (without slippage of gapping) on the dynamic response of piles subjected to lateral loads is explored, using a finite element model for the soil region adjoining the pile, a consistent boundary matrix at some distance to reproduce radiation effects, and an iterative, equivalent linearization technique to estimate the variation of soil properties with level of strain.
Abstract: The effect of nonlinear soil behavior (without slippage of gapping) on the dynamic response of piles subjected to lateral loads is explored, using a finite element model for the soil region adjoining the pile, a consistent boundary matrix at some distance to reproduce radiation effects, and an iterative, equivalent linearization technique to estimate the variation of soil properties with level of strain. Results obtained with this procedure are compared with those that would result from application of the p-y curves and the differences are discussed. (ASCE)