基于数值模拟的土工膜防渗坝变形响应研究

Research on Deformation Response of Geomembrane Anti-seepage Dam Based on Numerical Simulation

为研究石渣坝复合土工膜的变形特性,本文依托实际工程,基于有限元建立三维数值计算模型,主要分析蓄水前后坝体和复合土工膜的变形特性,论证该土工膜作为防渗材料的合理性。结果表明:(1)蓄水期和竣工期相比,坝体水平位移发生明显变化,其中,向上游的位移从7.8cm减小到4.0cm;而向下游的水平位移从-6.7cm增大至-7.2cm。此外,坝体的沉降变化不明显,蓄水前后沉降的最大值分别为-22.6cm和-22.9cm;(2)蓄水对坝体的安全具有积极意义,坝体不会发生剪切应变;(3)复合土工膜横向和纵向的安全系数分别为18.84和15.57,均满足规范要求的大于5的规定,可保证土工膜安全运营。

In this paper,based on the finite element numerical method,the deformation response of the geomembrane anti-seepage dam is studied,and the deformation characteristics of the dam body and the composite geomembrane are mainly analyzed,and the following conclusions are obtained:(1)Compared with the hydraulic storage period and the completion period,the horizontal displacement of the dam body has changed significantly.Among them,the upstream displacement has decreased from 7.8 cm to 4.0 cm;while the downstream horizontal displacement has increased from-6.7 cm to-7.2 cm.In addition,the settlement of the dam body did not change significantly,and the maximum settlement values before and after impoundment were-22.6 cm and-22.9 cm,respectively;(2)Relatively speaking,the water level rise caused by impoundment has a positive impact on the safety of the dam body.Specifically,the extreme value of the stress level of the dam body after impoundment can be reduced from 0.78 to 0.73,while the extreme value of the large principal stress can be reduced.and the small principal stress extreme value changes less;(3)The main reason for the deformation of the geomembrane under horizontal load is that the deformation of the geomembrane is basically the same as that of the dam surface after water storage.In addition,the extreme value of tensile force per unit width occurs on the right side of the bottom of the dam surface,and the horizontal and vertical safety factors are 18.84 and 15.57,respectively,which both meet the requirements of the specification to be greater than 5,which can ensure the safe operation of the geomembrane.