Theories And Methods For Parameters Back Analysis Of Seepage Flow Stress Coupling In Soft Rock

Seepage flow stress coupling analysis and back analysis of the coupled parameters in soft rock belong to the frontier topics in geotechnical engineering, where the difficulties are how to build up the seepage flow stress coupling constitutive laws and back analysis methods of coupled parameters. The prophase research of the topics include axial and tri-axial compression and permeability test, which is experimental research of two kinds of typical soft rock, clayey siltstone and brown mudstone, constitutive law research of soft rock and numerical methods research of seepage flow stress coupling in soft rock. With regard to the numerical methods of seepage flow stress coupling in soft rock, this thesis mainly studied the calculating methods of seepage flow stress coupling, numerical simulation by using finite element method and the back analysis methods of coupled parameters.The main works and achievements of this thesis are listed as the following:(1) The principle of seepage flow-stress coupling was studied, based on the formal research according to the law of seepage flow-stress coupling.(2) After introduced the stress adjusting coefficient to consider the stress redistribution, an elastic-plastic analytical solution of deep-lying circle tunnel under hydraulic coupling conditions is established.(3) Based on existing researches about anisotropic seepage- elastic stress coupled problems, a new algorithm for seepage-elastic-plastic stress coupled problem, which could reflect the situation that principled stresses is not coincide with principal permeabilities, is established. Moreover, a numerical FEM simulation program is developed on Matlab platform.(4) In order to improve the optimization backanalysis method, depending on the Complex-Variable-Differentiation Method(CVDM) the sensitivity coefficient are calculated, and a backanalysis algorithm is established on MATLAB platform. This method and program are proved feasible and effective by their application examples for elastic problems, elastic-plastic problems and seepage-elastic stress coupled problems and a soft rock tunnel enginering example considering the coupled interaction of seepage and elastic-plastic stress.Finally, the future research works were discussed.