硬填料坝应力计算方法探讨与特性分析

Calculation methods and stress characteristics of a hardfill dam

通过对一个100 m高典型硬填料坝的应力变形分析,指出坝体填筑过程和硬填料随龄期和应力状态变化的应力-应变特征的模拟对坝体应力变形结果影响显著不容忽略。采用二元本构模型和仿真计算方式,研究了地基弹性模量对坝体应力和强度安全性的影响。地基的变形对坝体应力有显著的影响。地基弹模较低时与较刚性地基的坝体应力情况差异很大。地基弹模较低时,竣工期坝基面中部的拉应力和坝址与坝踵处的压应力都很大,可能并不满足抗拉和抗压强度。与竣工期相比,挡水期坝基面的压应力增加,拉应力减小,抗压强度安全性减小,抗拉强度安全性增加。对于硬填料坝,竣工期和挡水期的抗剪强度安全系数均很高,一般可不进行抗剪强度的计算。

The stress and deformation of a typical 100-meter-high hardfill dam is investigated. Both the process of the construction of the dam and the stress-strain relationship of the hardfill material which varied with the construction age and stress state have a great impact on the stresses and the deformation of the dam. The elastic modulus of the foundation has a great impact on the stresses of the dam. The stresses are quite different in a dam with a low elastic modulus compared with that with a rigid foundation. While the elastic modulus of the foundation decreases, the minor principal stress of the dam at the middle of the horizontal section adjacent to the foundation decreases; and the maximum principal stress at toe and heel of the dam increases at an empty reservoir. Both the tensile strength and compressive strength of the material may not meet the requirements of the dam on a foundation with a low elastic modulus. The compressive stress above the basement increases and the tensile stress decreases at a full reservoir compared with that in the empty reservoir. The anti-compressive safety factor of the dam decreases and the anti-tensile safety factor increases at full reservoir. The factor of shear strength safety is always high. Hence the analysis of a hardfill dam should be focused on the compressive and tensile strength safety.