膨胀土浸水过程中水平受荷单桩p-y曲线研究

Study on p-y Curve of Laterally Loaded Single Pile in the Immersion Process of Expansive Soil

为了建立膨胀土地基浸水过程中不同含水率的水平受荷单桩p-y曲线,首先开展膨胀土浸水前和浸水饱和2种工况下的水平受荷单桩模型试验,分析桩身弯矩变化规律;然后基于温度场等效湿度场理论,采用ABAQUS有限元软件对模型试验进行模拟,通过无荷载膨胀率试验和模型试验验证有限元计算模型的准确性.在此基础上,建立浸水过程中其他5种不同含水率工况的计算模型,对有限元计算结果进行了处理分析.研究得到以下结论:(1)同级荷载作用下,膨胀土浸水饱和后的桩身弯矩值比浸水前的值偏大,当荷载等级增大时,膨胀土浸水前后桩身弯矩的差值也会随之增大,此时桩身弯矩零点位置也明显下移;(2)得到了水平受荷单桩在7种不同含水率工况下的有限元计算p-y曲线族;(3)确定了膨胀土地基浸水过程中水平受荷单桩的理论p-y曲线函数表达式,并通过模型试验和有限元模拟验证了其合理性.

In order to investigate the influence of different water content on the pile-soil interaction of laterally loaded single pile in the immersion process of expansive soil foundation.The model test of laterally loaded single pile under two working conditions of expansive soil before immersion and immersion saturation was carried out firstly.Meanwhile,the variation rule of piles body moment was also analyzed.Then,the model test was simulated by ABAQUS finite element software based on the theory of temperature field equivalent to humidity field.The accuracy of the finite element calculation model was verified by free expansion ratio tests and model tests.On this basis,the calculation models of other five different water content working conditions in the immersion process were established,while the finite element calculation results were also processed and analyzed.The study drew the following conclusions:(1)Under the same level of load,the bending moment of the pile after immersion is larger than that before.When the load level increases,the difference between the bending moment of the pile before and after immersion increases,and the zero point of the bending moment of the pile moves down obviously.(2)The p-y curve of finite element calculation for laterally loaded single pile under seven different water content working conditions is obtained.(3)The theoretical p-y curve function expression of laterally loaded single pile in the immersion process of expansive soil foundation is determined,and the correctness is verified by model test.