层状砂土中静压桩沉桩过程的颗粒流模拟研究

Research on Particle Flow Simulation of Pile Sinking Process of Jacked Pile in Layered Sand

基于离散元理论,通过二维颗粒流数值分析模型研究了静压桩在层状砂土中的沉桩特性,对不同密实度层状砂土中沉桩引起的桩身和桩端土体位移进行了比较,分析了桩端周围土体孔隙率和端阻力的变化趋势。研究结果表明:沉桩引起的土体位移模式随土层分层的不同而不同,在上层中密、下层密实的砂土中,分层处的土颗粒偏向上运动,端阻力随桩身压入先增加后稳定再增加,端阻力的超前深度小、滞后深度大;在上层密实、下层中密的砂土中,分层位置的土颗粒向下运动,端阻力随桩身压入先增加后减小再稳定,端阻力的超前深度大、滞后深度小。

Based on the discrete element theory,a two-dimensional particle flow numerical analysis model was established to study the pile sinking characteristics of jacked pile in layered sand.The soil displacement of pile body and pile end caused by pile sinking in layered sand of different density was compared.The trends of soil porosity around pile end and pile end resistance were analyzed.The results show that the soil displacement mode caused by pile sinking varies with different soil layers.In upper medium-dense and lower dense sand,the soil particles at the layer are inclined to move upward,and the pile end resistance increases to stability and then increases with pile penetration.The advance depth of the end resistance is small and the lag depth is large.In upper dense and lower medium-dense sand,the soil particles in the layered position move downward,and the end resistance increases first and then decreases to stability with the pile penetration.The advance depth of the end resistance is large and the lag depth is small.