The Influence Of Physical And Mechanical Properties Of Zhanjiang Group Structural Clay On It's Thixotropy

Beibu Gulf,located in the northwest of the South China Sea,is a semi-enclosed bay with abundant resources.In recent years,due to the particularity of geographical location,a large number of important projects had settled in Beibu Gulf region,which has witnessed rapid economic development.Zhanjiang Group structural clay is widely distributed in the Beibu Gulf coastal area.The engineering problems are more prominent because of its strong thixotropy.Although the thixotropy of soil has been systematically and thoroughly understood by human beings,the influence of the change of physical and mechanical properties on the thixotropy of structured clay in the process of excitation is still unsolved.This paper mainly studies the influence of physical and mechanical properties of Zhanjiang Group structural clay on its thixotropy.By setting three samples with different moisture contents and different void ratios,the unconfined compressive strength was determined after different curing time,and the thixotropic strength ratio was used to determine the thixotropy strength;The Zhanjiang Group structural clay with different structure was selected and maintained at different time after disturbance.Through direct shear test,the cohesion c and the angle of internal friction ? values of different structural soils with different resting time were obtained.According to these values,the influence of different structure on thixotropy of Zhanjiang Group structural clay was obtained.Through the research,the influence of the physical and mechanical properties of the soil of the Zhanjiang Group on the thixotropy of the soil before and after the disturbance was revealed,which provided theoretical basis and technical support for the design and construction of related projects.The main research work and results are as follows:(1)The basic physical properties of undisturbed soil of Zhanjiang Group structural clay were determined,besides,the natural moisture content,natural density and specific gravity are obtained.(2)Through the boundary moisture content test of undisturbed soil of Zhanjiang Group structural clay,the liquid-plastic limit were obtained,and the natural state of the Zhanjiang Group structural clay is also determined to be plastic.(3)Through unconfined compressive strength test,the strength of undisturbed and remolded soil of Zhanjiang Group structural clay was tested,and its sensitivity was calculated by formula,which is high sensitivity soil.(4)The direct shear test of the undisturbed soil of the Zhanjiang Group structural clay was carried out,and the shear strength was fitted to obtain the cohesion c and the internal friction angle ?.(5)The unconfined compressive strength of the disturbed samples with different rate of water content should be measured separately after different curing time.The thixotropic strength ratio can be obtained.It is concluded that the greater the moisture content of Zhanjiang Group structural clay is,the greater the thixotropic strength ratio will be and the stronger the thixotropy will be.(6)The unconfined compressive strength tests were carried out on the samples with different void ratios after stationary for different time.The results show that the void ratio is smaller,which the thixotropic strength ratio and the thixotropy is more stronger.(7)Through direct shear tests in different time periods,it is concluded that cohesion and internal friction angle increase with the increase of structure,and thixotropic strength ratio of cohesion increases with the increase of structure.The stronger the structure,the faster the strength recovery after disturbance,and the stronger the thixotropy.The thixotropy of Zhanjiang Group structural clay is affected by its structural strength.