Study Of Damage Distortion Evolvement Speciality Of Structural Loess

Based on the systemical analysis of structral properties, strain localization, mechanical characteristics, choosed theory of breakage mechanism mechanics that can sufficiently describe structural soils as basic framework at present, systematical research on breakage mechanics, mechanical properties, numerical simulation, binary medium constitutive model breakage parameter, effect factors, shear hand startup and expand of structural geomaterials is carried out by laboratory tests, theoretical study for Yanglin region loess, taken means of saturation instead of suction and binary medium constitutive model into moistening deformation analysis of the loess road foundation.The main achievements obtained in the thesis are as follows:On basis of systematic research theory of breakage mechanics, analyse the load sharing ratio rule,breakage parameter evolvement equation and method of definition for binary medium constitutive model, analyzed data of tri-axial test, according as relation of stress-strain for undisturbed and disturbed loess, defined a sort of evolvement equation aim at simple parameter and double parameter model, and studied influence to it forσ3 and containing water.Based on the concept of the binary medium model for geomaterials, a mesoscopical numerical method which can simulate the breakage processes of geomaterials is proposed. The FEM program is coded and used to axis symmetry and plane strain model, also used to dissaturation and saturation soil, it can simulate the breakage process of structure loess under different lateral stresses. The numerical method can trace the processes of bonding elements breaking and transforming to frictional elements, reappearance process of failure rule of soils.Imposing binary medium constitutive model of structure soil, breakage ratio evolvement equation of simple and double parameter, progress rather general numerical simulate of strain localization destroy rule unde well-proportioned tri-axial test sample,setting differ position interior weakness element and limitation element on differ position boundary, and studied element size for strain localization influence, received some meaning conclusion such as shear band is aubsection, unattached damage area originaly, follow load increase,gradually connect, form continum failure band, proved the phenomenon of discontinity be observed in the laboratory. Explain the advantage of using binary medium constitutive model in strain localization analysis.Utilizing idea and method of binary medium constitutive model and saturation instead of suction, importing it into unsaturation soil concretion equation, imposed the compute method of instead pore water pressure, reduced finite element formula of structure loess moistening deformation, code the rain water infiltration finite element program, processed numerical simulate freeway roadbed side sinkage deformation due to rainwater infiltration combined Guanzhong area. Shaanxi province, reappearance process of defrmation form the rainfall infiltration, and to provide a new way and method to verify the researches of the load deformation characteristics, humidification characteristics.