Experimental Study On Deformation Characteristics Of Saturated Soft Clay And Coarse Particles Under Plane Strain State

Since the road length is much larger than the cross-section size,the road surface,subgrade and foundation soil may be in the state of plane strain under the load.At the same time,the cyclic dynamic characteristics such as the accumulated deformation of coarse particles in the pavement base and soft clay in the foundation under long-term traffic cyclic load are closely related to the road design and its service performance.Therefore,it is necessary to simulate the dynamic and static stress state of road soil more comprehensively and accurately and to study the cyclic dynamic characteristics of coarse-grained soil and soft clay under plane strain state.In this paper,a large number of cyclic loading tests have been carried out on soft clay and coarse-grained soil based on the dynamic-static true triaxial apparatus.The cyclic dynamic characteristics of soft clay and coarse-grained soil,such as cumulative deformation and resilience modulus,under plane strain state,have been systematically studied.The main research contents and results are as follows:（1）through a large number of plane strain state of saturated soft clay under cyclic dynamic test,study the cumulative strain,modulus of resilience,cycle of principal stress and cyclic principal stress coefficient in the law of development,found the super pore pressure under the plane strain state,accumulated strain and modulus of resilience and cyclic stress ratio（CSR）,over consolidation ratio（OCR）is closely related to loop principal stress coefficient increases with the increase of CSR and OCR,and there is limit.（2）based on the stability theory,analyzed the saturated soft clay under the plane strain state stability characteristics,through the cumulative principal strain,modulus of resilience and the relationship between CSR,obtained under the plane strain state is not the threshold of the region and the region-allow the scope of cyclic stress ratio of Wenzhou reshape soft clay,the value is within 0.362 0.372.（3）The cyclic dynamic characteristics of soft clay under plane strain state and three-dimensional stress state are compared comprehensively.It is found that the cumulative deformation and resilience modulus under plane strain state are between b_cyc=0 and b_cyc=0.4 under three-dimensional stress state,and the allowable cyclic stress ratio under plane strain state is also between b_cyc=0 and b_cyc=0.4 under three-dimensional stress state.In particular,the springback modulus under plane strain tends to rise at the later loading stage,but tends to be stable under three dimensional stress state.（4）Carry out under the plane strain state and the three dimensional stress state of the coarse grained soil contrast test,found that the accumulation of coarse grained soil under plane strain state deformation and modulus of resilience and cycle of principal stress coefficient and the three dimensional stress state b_cyc=0.4 is similar,but with b_cyc=0,great differences b_cyc=0.8,obtained under the plane strain state to allow major principal stress value within 60 kPa to 80 kPa.