成层地基中压入法沉桩引起的桩周土体变形分析

通过在桩-土界面设置接触面,选用合理的单元类型,建立了较为符合压入桩压桩实际的三维有限元模型。利用得到的有限元模型,采用单元生死技术对压入桩压桩过程进行了数值模拟,讨论了成层地基压桩过程中桩周土体的竖向应力及应变随压桩深度的动态变化。选用桩型为钢管桩,分析结果表明:随着压桩深度的增加,桩内桩周土体的竖向应力(或应变)一直表现为压应力(或压应变),且逐渐增大;桩外桩周土体的竖向应力(或应变)逐渐由压应力(或压应变)变为拉应力(或拉应变)。随着压桩深度的增加,桩内桩周土体前3层竖向应力(或应变)的变化幅度基本一致,第4层的变化幅度增大;桩外桩周土体每2层土之间的差异都较大。

Analysis on Deformation of Soil at Surrounding Pile Due to Press-in Piling in Layered Ground

Through setting pile-soil contact surface and selecting reasonable unit types,an appropriate three-dimension finite element model is given,which is in accordance with the actual piling process of press-in piles.According to the model,the piling process is simulated by using the element birth and death technology,and the dynamic change of vertical stress or strain of the soil surrounding pile in the piling process of the press-in pile in layered ground with the piling depth is discussed.The steel tube pile is selected to be analyzed,and the results show that with the piling depth increasing,vertical stress(or strain) of soil inside pile is compressive stress(or strain) and is increasing gradually;vertical stress(or strain) of soil outside pile gradually changes from compressive stress(or strain) to tensile stress(or strain).With the piling depth increasing,the magnitude of vertical stress(or strain) of the first three layers of soil inside pile changes slightly;the magnitude of the fourth layer increases.There are big differences between every two layers of soil outside pile.