摘要:

AbstractIt is classically assumed that the pressuremeter modulus (determined from the initial slope of the pressuremeter expansion curve) can be used as an estimate for the soil's shear modulus, provided disturbance effects can be neglected. This approximation is only rigorous in the plane‐strain case and requires that the height of the cell be large in comparison with its diameter. The present paper allows to quantify the error that results from this approximation as a function of the height over diameter ratio. The analysis is based on an application of the variational principles of elasticity. It is shown that the static and the kinematic approaches lead, respectively, to a lower‐ and an upper‐bound estimate of the pressuremeter modulus expressed in terms of the soil's elastic coefficients.The calculations are completely carried out in the case of an infinite cavity subjected to a pressure on a finite length. It is shown that the plane‐strain approximation overestimates the shear modulus. Based on the kinematic approach, a method is developed to derive the shear modulus from the pressuremeter modulus which accounts for the finite slenderness of the cell. This method can be extended to more complex geometries and material properties, including soil heterogeneity and ani

ISSN:0363-9061    

DOI:10.1002/nag.1610160502

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractIn this note the accuracy of the elastic standard 4‐node plane‐strain finite element is investigated by comparing numerically calculated eigenvalues of the element stiffness matrix to those according to higher‐order algebraic approximations. From this study it may be concluded that the ‘hourglass’ eigenmodes are the only inaccurate ones. For selective reduced numerical integration the hourglass eigenvalues may be expected to be of the order of 1/2 to 2/3 of the analytic

ISSN:0363-9061    

DOI:10.1002/nag.1610160503

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThis paper addresses the issue of uncertainty treatment in geotechnical engineering. Emphasis is placed on modelling and analysis of non‐random uncertainties using fuzzy sets. Although uncertainties were modelled with fuzzy sets in this study, subsequent analysis or processing of the uncertain information was performed using traditional, non‐fuzzy techniques. These techniques, including the vertex method and Monte Carlo simulation, are discussed in detail. An example application using soil liquefaction susceptibility is presented. The paper concludes that non‐random uncertainties can be successfully modelled and processed using fuzzy

ISSN:0363-9061    

DOI:10.1002/nag.1610160504

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA finite element code is developed to model the structure‐frozen soil/ice interaction using a time incrementing, fully implicit, iterative algorithm, and a constitutive model based on the concept that total strain tensor consists of an elastic and a creep component. The code is used to investigate the applicability and limitations of the power law as the creep model for frozen soil by simulating two pressuremeter tests. Two extended phenomenological models based on the generalized power law are used in axisymmetric finite element analyses to simulate two, long‐term, stage‐loaded pressuremeter tests, and comparison of results with test data indicates that one model demonstrates a better ability to approximate the actual response to subsequent load steps, under certain restrictions. Stress analyses demonstrate the ability of the constitutive model to show transient as well as subsequent quasi‐stationary stress stages in creep analysis. Additional simulations of short‐term pressuremeter tests on ice are performed to further illustrate some limitations of the power‐law model. Examples for prediction of creep settlements on frozen geomaterials are demonstrated by considering the interaction of fully flexible circular footings and concrete cylindrical footings (of different embedment depths) with f

ISSN:0363-9061    

DOI:10.1002/nag.1610160505

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610160506

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610160507

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610160508

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610160501

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY