摘要:

AbstractA numerical procedure has been developed for predicting dilation (porosity) and gas permeability changes in rock salt. The hierarchical single‐surface constitutive model of Desai and co‐workers is used a finite element program to calculate the state of stress and strain surrounding excavations in rock salt. The elastoplastic constitutive model accounts for strain hardening, a non‐associative volumetric response and stress‐path‐dependent behaviour. The calculated stress and strain fields are used in a flow model based on the equivalent channel concept to predict permeability. Parameters for both the mechanical and permeability models are developed from laboratory test results. Two field experiments adjacent to underground excavations are modelled. The extent of the dilated rock zone around the excavation is predicted well, but the magnitude of the porosity and gas permeability is underpredicted very near the excavations. This discrepancy is attributed to model parameters derived from loading‐only laboratory tests, whereas significant unloading occurs in the field. The shape of the yield surface was found to be an important factor in dilation and permeability predictions. Similar stress, strain and permeability fields were obtained with different model types (plane strain or axisymmetric) and initial stress states, and with instantaneous and progressive

ISSN:0363-9061    

DOI:10.1002/nag.1610160802

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractTwo liquefaction effects are described here which account for the fluidization phenomena observed in the collapse of water‐saturated sloped‐embankments. A surface erosion effect is a process in which the top layer of a submerged embankment liquefies. The subsequent reconstitution is a gradual process for which the time dependence is calculated.Internal liquefaction takes place suddenly and a criterion is derived to describe its onset. It is shown that the process is associated with the change from loading to unloading of an external shearing loaded on top of the slope and that there is no stable elastic unloading proc

ISSN:0363-9061    

DOI:10.1002/nag.1610160803

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe governing equation for steady flow in a homogeneous, partially saturated, porous medium can be written in a linear form if one adopts a hydraulic conductivity function which varies exponentially with capillary‐pressure head. The resulting linear field equation is a steady Fokker–Planck equation and is well‐suited to numerical solution by the boundary integral equation method (BIEM). The exponential conductivity function is often used in soil physics and is known to be a reasonable approximation over limited ranges of pressure head. A computer code based on the BIEM for obtaining numerical solutions is described and tested. The BIEM is found to exhibit quadratic convergence with element size reduction on smooth solutions and on singular problems, if mesh grading is used. Agreement between results from the BIEM code and a finite element code that solves the fully non‐linear problem is excellent, and is achieved at a substantial advantage in computer processing time. As an illustrative example, the code is applied to determine the distribution of moisture in the vicinity of a

ISSN:0363-9061    

DOI:10.1002/nag.1610160804

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractAn empirically established rule of Wroth1for the dependence of the shear modulus on the mean effective pressure and the overconsolidation ratio in clays is investigated within the framework of non‐linear elasticity. The resulting isotropic‐deviatoric coupling is derived and compared to experime

ISSN:0363-9061    

DOI:10.1002/nag.1610160805

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610160806

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610160801

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY