No abstract

This study presents a preliminary development of a direct back analysis procedure by the meshless local Petrov-Galerkin (MLPG) method and its application to characterize soil properties using insitu test results. As compared to a direct back analysis based on the finite element method (FEM), it is intended to show that doing a direct back analysis by the MLPG method may reduce the computation costs or treat with the non-homogeneity of characterized soil properties more easily. Taking a two-dimensional (2D) solute transport problem as an illustration, an MLPG1 model of such a problem is derived to predict the solute concentration with trial coefficients of dispersion. To account for the non-homogeneity of these coefficients, variation of them is described by the moving leastsquares interpolation. The Akaike information criterion is then introduced to find those coefficients of dispersion with which errors between predicted and measured data are minimized. A benchmark problem is studied to test the precision of numerical results provided by the proposed MLPG1 model. Another example illustrates the experiences of doing an MLPGbased direct back analysis. Comparison of MLPGbased and FEM-based direct back analyses is taken.

SUMMARYEarlier solutions of deformations resulting from the movements of shear and tensile faults in a half space (Bull. Seismol. Soc. Amer. 1985; 75:1135, 1992 82:1018) have been revised in view of cross-anisotropic stress}strain relationships. The dislocation theory (Canad. J. Phys. 1958; 36:192) is reviewed and the displacement "eld due to a concentrated force in an anisotropic half space is solved analytically for developing the current research. A fault is simulated as a point source of strain nuclei in applying the dislocation theory.Data (¹err. Atmos. Oceanic Sci. 2000; 11(3):591, 631) that were used to study the Chi-Chi earthquake (M * "7.3; 1999/9/21 AM 1:47) are introduced to compare the solution with the isotropic results. Results indicate that the anisotropy of stress}strain relationships does a!ect the results of predicted deformations.

No abstract

deformations caused by the movements of a shear or tensile fault in an isotropic half-space for finite rectangular sources of strain nucleus have been extended for a transversely isotropic half-space. Results of integrating previous solutions (Int. J. Numer. Anal. Meth. Geomech. 2001; 25(10): 1175-1193) of deformations due to a shear or tensile fault in a transversely isotropic half-space for point sources of strain nucleus over the fault plane are presented. In addition, a boundary element (BEM) model (POLY3D:A three-dimensional, polygonal element, displacement discontinuity boundary element computer program with applications to fractures, faults, and cavities in the Earth's crust. M.S. Thesis, Stanford University, Department of Geology, 1993; 62) is given. Different from similar researches (e.g. Thomas), the Akaike's view on Bayesian statistics (Akaike Information Criterion Statistics. D. Reidel Publication: Dordrecht, 1986) is applied for inverting deformations due to a fault to obtain displacement discontinuities on the fault plane.An example is given for checking displacements predicted by proposed analytical expressions. Another example is generated for the use of proposed BEM model. It demonstrates the effectiveness of this model in exploring displacement behaviours of a fault.