加筋土挡墙水平位移解析计算与参数分析

加筋土挡墙因具有造价低廉、施工简便等优点而在公路、铁路等交通基础设施中被广泛应用。作为一种轻型柔性支挡结构,加筋土挡墙易产生较大的水平位移。目前已有的加筋土挡墙水平位移计算公式大多忽略了加筋区整体在土压力作用下产生的水平位移,有必要提出一种准确计算加筋土挡墙总水平位移的解析式。将加筋土挡墙总水平位移分为加筋区内部筋材伸长产生的水平位移和加筋区整体在土压力作用下产生的水平位移两部分。假定加筋区内部破裂面由0.3H法确定,根据胡克定律建立计算加筋区内部由于筋材伸长产生的水平位移解析式;假定加筋区为一复合弹性体,根据虚功原理建立加筋区整体在土压力作用下产生的水平位移解析式,两部分共同构成了加筋土挡墙的总水平位移。结果表明:随着填土模量、填土内摩擦角、填土黏聚力、筋材抗拉刚度和筋材长度的增大,加筋土挡墙的最大水平位移逐渐减小;筋材伸长产生的位移占总位移的比值随填土模量、填土内摩擦角、筋材长度的增大而增大,随填土黏聚力和筋材抗拉刚度的增大而减小;与原型试验测试值和数值模拟值相比,该解析计算结果可反映加筋土挡墙墙体位移沿墙高的分布规律,同时与既有经验公式相比,该方法计算结果更接近实际值。

Analytical Calculation and Parametric Analysis of Lateral Displacement of Reinforced Soil Retaining Walls

Reinforced soil retaining walls are widely used in transportation infrastructures, such as highway and railway engineering, because of their characteristics of low cost and easy construction. As a type of light retaining structure, the reinforced soil retaining wall is more susceptible to large lateral deformation. Considering that the current calculation formulas for the lateral displacement of reinforced soil retaining walls mostly ignore the displacement of the unreinforced zone under the earth pressure, it is necessary to propose an accurate analytical formula to calculate the lateral displacement of reinforced soil retaining walls. The lateral displacement of reinforced soil retaining walls was divided into two parts:the displacement induced by the reinforcement extension in the reinforced zone and the displacement in the unreinforced zone. It is assumed that the rupture surface of the reinforced zone was 0.3H curve and the displacement in the reinforced zone was calculated based on Hooke's law. The reinforced zone was assumed to be a composite elastic zone and the displacement of the unreinforced zone was calculated based on the principle of virtual work. The analytical formula was established based on these expectations. The parametric analysis shows that the maximum displacements decrease when accompanied by increasing the filling modulus, friction angle, cohesion, tensile stiffness, and length of reinforcement. The ratio of displacement in the reinforced zone to the total displacement increases when increasing the filling modulus, friction angle, and reinforcement length and it decreases when increasing the cohesion of fill and tensile stiffness of reinforcement. The displacements calculated using this formula have similar trends with the results measured in the field and results calculated using numerical simulation. Meanwhile, the maximum displacements calculated using this formula are closer to the actual values when compared with the existing empirical methods.