考虑土拱效应影响的路堤荷载下土工格室加筋体变形分析

Deformation analysis of geocell-reinforced body under embankment load considering soil arch effect

首先假定内、外土柱界面侧土压力系数和摩阻力发挥程度均与界面相对位移相关,对传统土柱模型进行了改进,得出土拱效应分析模型,进而运用自变量转换等数学方法建立路堤底部桩土应力比与桩土差异沉降的函数关系;考虑土工格室加筋体的三维形态及实际工作状态,用小挠度弹性薄板简化其计算模型,引入桩土变形及格室加筋体与上下界面摩阻效应,结合已建立的土拱效应模型构造非线性代数方程组,得到了“路堤-土工格室-桩土加固区”共同作用模型,对此模型进行迭代求解,得出计算桩土应力比、沉降及桩土差异沉降的新方法。通过实例验证与前人方法进行了结果对比,证明了该方法的合理性。最后选取重要参数进行分析,研究了桩土刚度比、路堤填土压缩模量、路堤填土内摩擦角对桩土应力比及格室体变形的影响。

Firstly,it is assumed that the soil pressure coefficient and degree of friction resistance at the interface of the inner and outer soil pillars are related to the relative displacement of the interface.Then,based on the traditional soil column model,an analysis model for soil arch effect is established,and the functional relationship between the pile-soil stress ratio and differential settlement at the bottom of the embankment is further obtained through a series of mathematical transformations like independent variable conversion.The geocell-reinforced body is simplified as a small deflection elastic sheet,and the deformation of piles and soil and the effect of interface friction are considered.By introducing the proposed soil arch effect model,nonlinear algebraic equations and an interaction model for"embankment-geocell-reinforced body-pile-soil reinforcement area"is established.To calculate this model,the iterative method is adopted.Finally,a new method for calculating the pile-soil stress ratio,the settlement of embankment and the differential settlement of piles and soil is obtained.Besides,the results are compared with those of the previous methods through example verification,which has proved the rationality of the proposed method.Finally,the effects of pile-soil stiffness ratio,compression modulus and internal friction angle of embankment fill on pile-soil stress ratio and deformation of geocell-reinforced body are studied through parameter analysis.