Experimental Research On Lateral Dynamic Response And P-Y Curves Regularity Of Symmetrical Double Pile

Based on the symmetric double inclined piles and the symmetric double vertical piles shaking table test,the variation law of the main trace of pile-soil dynamic p-y curve was analyzed.Based on Open Sees,a 3D model was built for the purpose of the numerical simulation of lateral dynamic response of symmetric double piles.The main researches are as follows:(1)Firstly,in the shaking table test design,a variety of high-precision sensors were used to obtain acceleration,displacement and pile body strain.The situation of the non-liquefied soil and saturated soil were considered in the test respectively,and research on the lateral dynamic response characteristics of symmetrical double piles was carried out by inputting sinusoidal waves and seismic waves on the shaking table.The data of the test was analyzed by Matlab to study on the variation of the main track of pile-soil dynamic p-y curve.(2)Secondly,the modeling process,the calculation principle,the key problems in nonlinear dynamic analysis and the advantages in dynamic and seepage coupled simulation analysis of Open Sees were systematically expounded.Gi D was used to mesh the 3D model in pretreatment,which was converted into TCL commands that can be read by Open Sees.TCL commands were modified and a lot of code was added on them in order to complete the final model.All the working conditions of the shaking table test were input to the 3D model,and the final numerical simulation results were obtained.(3)Thirdly,the numerical simulation results were compared with the experimental results,including the acceleration of the table and cap and displacement time history curves.The results showed that the numerical value and curve changing trend of acceleration and displacement of table and pile cap in non-liquefied sandy soil were basically the same as those of the test,which indicated that it was reasonable to simulate the acceleration and displacement of pile foundation with Open Sees;Meanwhile,it was found that in the case of non-liquefied sand,the magnifying effect of the caps of symmetrical double piles on the table was not obvious;But in saturated soil,the amplification effect of symmetrical double-straight piles was obviously higher than that of inclined piles,and the amplification effect of pile cap displacement was especially remarkable,which indicated that inclined piles have certain advantages in resisting lateral dynamic load in saturated soil.The simulated pore pressure ratio curves were basically consistent with the experimental results,and the simulated results in the stationary section of the upper pore pressure were slightly larger than the experimental results,indicating that the dissipation velocity of pore pressure in the upper soil layer was faster than the simulated results.(4)Finally,based on the 3D numerical model established in this paper,the lateral dynamic response characteristics of symmetrical double-pile foundation under different frequencies of sinusoidal waves were numerically simulated.The results showed that the lateral dynamic response of symmetrical double-straight piles was slightly sensitive under the sinusoidal wave of different frequencies in non-liquefied sand,and the double-inclined piles did not show great advantages.In saturated sand,double inclined piles under the sinusoidal wave of different frequencies had certain advantages.