Study On The Small Strain Shear Modulus And Shear Characteristics Of Anisotropically Overconsolidated Wenzhou Clay

The saturated soft clay of lakeside facies or coastal facies is widely distributed in the coastal areas of southeast China.This kind of clay has many bad engineering properties,such as low strength,high water content,large void ratio and high compressibility.As the ultimate bearing body of the infrastructure,the soft clay foundation is easily deformed and unstable under various loads,and produces a large number of engineering problems.Based on this,it is very necessary to understand comprehensively the deformation,failure,interaction mechanism of soil and water phases in saturated soft clay,and more realistic to simulate saturated soft clay engineering.Regardless of natural factors,including geological and hydrological changes,or engineering practices such as excavation of foundation pits and preloading,it will lead to the change of soil consolidation state,which is manifested in a nisotropy and overconsolidation.In this study,a series of Wenzhou remolded clays and kaolin clays triaxial CU tests(isotropic normal consolidation,isotropic overconsolidation,anisotropic overconsolidation)and stress path test s were carried out,combing with bending element,mainly analyzing and discussing the characteristics of soft clay about relationship of stress-strain,pore pressure-strain,effective stress stress path,secant modulus,and small strain shear modulus.T his study found that different consolidation states have a great influence on the small strain shear modulus,and modified the Hardin formula by considering the anisotropic consolidation.The stress-strain relationship of soft clay shows different strain hardening or strain softening under different consolidation states.The shear strength,pore pressure coefficient,secant modulus and the effective stress path were significantly affected by the consolidation state.T he quantitative relationship between the strength q_f,the pore pressure coefficient A_f and OCR,K was established.The slope of failure line is independent of the consolidation state was found by analyzing the development of effective stress path.For Wenzhou remolded soil,its slope of failure line M_f is 1.25,and M_f is 1.12 for kaolin clay.Based on stress path test,studied the influence of stress path slope ? on shearing strength,effective stress stress path and pore water pressure.It was found that ? has little effect on the shear strength and effective stress stress path,but had a greater influence on the pore water pressure.