基于非线性损伤本构模型的胶凝砂砾石坝超载分析

Analysis of Overload of Cemented Gravel Dam Based on Nonlinear Damage Constitutive Model

为揭示胶凝砂砾石坝损伤机制,基于胶凝砂砾石力学特性和应变破坏准则建立其非线性损伤本构模型,编制了相应的程序,并采用室内试验验证了该模型的合理性。采用该模型对胶凝砂砾石坝进行超载数值模拟,研究其坝体应力、结构破坏过程,结果表明胶凝砂砾石坝在超载后坝踵、坝趾均存在破坏风险,其中坝踵开裂风险较大。基于损伤本构模型进行超载分析还可知,胶凝砂砾石坝破坏模式为坝体和坝基材料变形不协调,使得随着超载倍数增大,坝体、坝踵产生屈服损伤,并逐渐开裂,裂纹沿上游建基面向下游扩展,而线弹性模型模拟无法获得该规律,因此基于非线性损伤本构模型的胶凝砂砾石坝受力分析可预测结构的失效模式,为结构设计提供依据。

In order to reveal the damage mechanism of cemented sand-gravel dam,the nonlinear damage constitutive model was established based on the tensile-compression anisotropy and strain failure criterion of cemented sand-gravel and the corresponding program was compiled.The rationality of the model was verified by laboratory tests.The overload numerical simulation of the cemented sand-gravel dam was carried out by using this model,and the stress and structural failure process of the dam body were studied.The results show that there is a risk of damage to the dam heel and dam toe of the cemented sand-gravel dam after overload and the risk of dam heel cracking is larger.The overload analysis based on damage constitutive model also shows that the batholith of cemented gravel dam failure mode is due to the deformation of dam body and dam foundation materials not harmonious,with the increase of overload ratio,the dam heel begins to produce the yield damage,and gradually cracks,cracks along the upstream foundation for downstream extension,the linear elastic model simulation results cannot obtain the law.Therefore,the stress analysis of cemented sand-gravel dam based on nonlinear damage constitutive model can predict the structural failure mode and provide the basis for structural design.