占压下埋地聚乙烯管力学响应的数值模拟

Numerical Simulation of Mechanical Response of Buried Polyethylene Pipes Under Surface Load

通过特定应变率下聚乙烯(PE)管的单轴拉伸试验,拟合得到PE本构模型的参数,确定了其屈服应力,建立了关于管道横截面对称的长方形管土模型,研究了埋地PE管在静载正压占压载荷作用下的力学响应,分析了占压参数(占压区长、占压区宽)的影响。结果表明,占压下埋地聚乙烯管竖直方向最大偏移发生在轴向横截对称面上;管内最大Mises应力随占压载荷的增大而增大,但其位置从管顶(底)转移至起拱线上;管道屈服时,占压载荷随着占压参数的增大,呈指数下降趋势。

Based on uniaxial tensile test at a given strain rate, the constitutive model parameters of polyethylene （PE） were obtained by fitting method, and its yield stress was determined. The mechanical response was studied using finite element method with a rectangular pipe-soil model, which was symmetrical about the pipe cross section, and influences of the surface load parameters （length of surface load area=L, width of surface load area=W） were analyzed. The results showed that the maximum vertical direction offset of buried PE pipe under surface load occurred in the axial cross-sectional plane of symmetry, the maximum Mises stress increased and its location changed as the surface load increased, and the surface load decreased exponentially as L and W increased when PE pipe yielded.