Horizontal Bearing Characteristics And Simplified Methods Of Double-row Steel Sheet Pile Structure Considering Pile Shape Effect

With the rapid development of coastal construction in our country,soft soil foundation which is widely distributed in southeast coastal area urgently needs to be developed.As a kind of foundation structure suitable for soft soil foundation,research on its bearing characteristics is very necessary.Firstly,basic laboratory physical and mechanical tests were carried out on the original clay soil samples retrieved from the eastern part of Tianjin Port.Then,EMDCSS cyclic single room system was used to carry out cyclic shear tests on saturated clay soil samples.In the consolidated and undrained state,the dynamic properties of soil samples under different dynamic shear stress ratios(CSR was set at 0.05,0.10,0.15,0.20,0.25,respectively)and different cyclic shear frequencies(cycle time T was set at 2s,4s,6s,8s,respectively)were studied,and the relationship between cumulative strain,cyclic stiffness and cyclic cycle N was studied.The pore water pressure of soil samples varied with the cyclic shear period in the cyclic shear process with different dynamic shear stress ratios,and the influence of different shear stresses on the shear strength of soil samples after 10,000 cyclic shear was studied,and the pore pressure calculation formula of the soil samples was fitted.The relationship between cumulative strain and cyclic shear stress was studied by dynamic simple shear tests under consolidated drainage.Then,using the finite element analysis software ABAQUS,combined with the soil properties obtained from the previous tests,the model of the double-row steel sheet pile structure was studied.When steel sheet piles with different web and wing angles and different lock stiffness are subjected to horizontal static force at the top,the structure’s horizontal bearing capacity law and pile side earth pressure distribution are studied.Combined with Rankine’s classical earth pressure theory,the calculation method of earth pressure resultant force is proposed.The distribution of pile bending moment is extracted and analyzed briefly.Finally,in the finite element model,the elastic modulus and undrained shear strength of the soil after cyclic shear were brought into the foundation soil model by combining the soil properties obtained from the static shear test after cyclic shear test in the dynamic simple shear test.The quasi-static analysis was carried out on the horizontal cyclic bearing characteristics of the double-row sheet pile structure with different shapes,and the comparison analysis was carried out with the static load to observe the changes of the horizontal bearing capacity.Combined with the simplified calculation formula of horizontal cyclic bearing capacity proposed above,the calculation formula of horizontal cyclic bearing capacity suitable for different cyclic loading states is fitted.The distribution of pile bending moment is extracted and analyzed briefly.