Experimental Study On Static And Dynamic Characteristics Of Anisotropic Soft Soil Under The Rotation Of Principal Stress Axis

The construction of high way,airport runway,cross sea bridge and other traffic engineering in soft clay foundation under the action of cyclic traffic load,often produce a large settlement after the construction of them,This is because the stress path in the soft clay is very complex under the action of dead load and traffic load,Which is mainly in case of the following two aspects,first,the soft clay has obvious anisotropy,One hand,it is related to K0 consolidation,on the other hand,it is caused by the stress of the subgrade.Second,in the cyclic traffic load,the main stress axis in the soft clay unit can be rotated continuously.Thus,it is an important means to solve the problem of soft soil foundation engineering disaster by carrying out the anisotropic soft clay in the principal stress axis rotation of the study on static and dynamic characteristic test.In this paper,the main research object is Wenzhou soft clay,the main research contents are as follows:First of all,This paper invented a remolded instrument preparation that is high pressure consolidation apparatus,We can get high-quality remodeling soft clay through a series of processing process with the using of the instrument,Undisturbed soil samples and remodeling soil samples were taken and the deposition direction was 0 °,30 °,45 °,60 °,90 °.For each angle of undisturbed and remolded soil samples were followed by compression test,penetration test,direct shear test,the results showed that: both the remolded samples and undisturbed soil samples exist anisotropy,mainly in the compression modulus,permeability,shear strength and other aspects.Secondly,with GDS hollow torsional shear systems,through undisturbed Wenzhou saturated soft clay undertaken with additional large principal stress directions were respectively 0 °,30 °,45 °,60 °,90 ° directional shear test,The results show that the variation law of the main stress,the main strain,the stress-strain relationship curves of different principal stress directions are different,and the peak value of the stress and the internal friction angle are also different,partial stress peak at 0 ° cut is max,while the max of effective internal friction angle is in 45 ° shear.Third,with GDS hollow torsional shear systems,By using a self-linear waveform and loading a cardiac stress paths,to simulate the stress paths of rotation of principal stress axes with actual traffic loading Soil engineering,we studied the effect of soft clay strain,pore pressure,the law of development elasticity modulus with the continuous rotation of principal stress axis,results also found that: Compared with the results of dynamic triaxial test without considering the direction of the principal stress,the principal stress axis rotation can accelerate soft clay strain ? pore pressure and the soften of soil.This article established the prediction equation of accumulation strain with considering the role of principal stress rotation in the end.