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深厚覆盖层上的长河坝心墙堆石坝坝高240 m,坝基防渗墙采用顶部设置灌浆廊道的方式与坝体心墙相连接,廊道受力条件复杂,已有类似工程出现廊道破坏导致漏水的现象。采用基于子模型法的三维非线性有限元对该部位结构进行重点研究,以薄层单元模拟各种接触面,坝体材料及覆盖层采用Duncan双曲线E-μ模型,考虑大坝实际填筑施工过程和水库蓄水过程,对坝基廊道与防渗墙的应力变形状况进行分析。计算结果表明,由于在河床段沿坝轴线均不设横缝,廊道横河向正应力值较大,且极值出现在左右岸1/4跨的位置;廊道底板顺河向拉应力较大,将导致底板产生纵向裂缝;廊道与两岸灌浆平洞的结构缝三向变形形态复杂,止水设计困难。应对廊道的结构型式进行调整以及采取一定的工程措施以保障防渗系统的安全性。
The dam with a depth of 240 m on the deep overburden is connected with the core wall of the dam by means of a grouting corridor at the top of the dam foundation. The corridor has complicated loading conditions and similar corridors have appeared Road damage led to the phenomenon of leakage. The three-dimensional nonlinear finite element method based on the sub-model method is used to study the structure of the site. Various contact surfaces are simulated by thin-layer elements. The Duncan hyperbola E-μ model is adopted for the dam material and the covering layer. Construction process and reservoir water storage process, the dam foundation corridor and cut-off wall stress and deformation analysis. The calculation results show that due to no transverse joints along the axis of the dam in the riverbed section, the transverse normal stress in the corridor is large and the extreme value appears in the position of 1/4 span on the left and right banks. The corridor floor tensile stress Larger, will lead to the longitudinal cracks in the floor; corridor and cross-strait grouting hole three-dimensional deformation of the complex shape, water stop design difficulties. Corridor structure should be adjusted and take some engineering measures to protect the impermeability of the system.