300m级超高斜心墙和直心墙堆石坝应力变形分析

Stress-deformation analysis on 300m-level super high rockfill dams with inclined and vertical cores

为了优化设计和安全评价,对某300 m级超高直心墙堆石坝和作为比较方案的斜心墙堆石坝进行了三维有限元应力变形计算。对坝体堆石料采用邓肯张E-B非线性弹性模型,对高塑性黏土与混凝土结构接触面采用Goodman单元模型,分43级荷载对坝体的施工和蓄水过程进行模拟,比较分析两种坝型在蓄水期坝体和心墙的应力和变形性状。结果表明,相对直心墙方案,斜心墙方案计算所得坝体的最大水平位移相对较小,垂直沉降较大。斜心墙方案下心墙两岸坝肩处高应力水平区域有所减小,可以适当改善心墙上游面单元的应力和变形条件。斜心墙方案下心墙的拱效应相对较弱,其抗水力劈裂的性能稍好。

For optimal design and safety assessment,a 3-D stress-deformation finite element calculation is made on a 300 mlevel super high rockfill dam with vertical core and its alternative scheme——a rockfill dam with inclined core.For which Duncan Chang E-B nonlinear elastic model is adopted for the rock-filling materials for the dam,while Goodman element model is applied to the interface between highly plastic clay and concrete structures,and then the dam construction and the reservoir impoundment processes are simulated under the load which is divided into 43 levels for comparing and analyzing the stresses and deformation behaviors of the dam bodies and the cores of both the dam types during the impoundment period.The result shows that if compared with the scheme of the dam with vertical core,the maximum horizontal displacement of dam body obtained from the calculation for the scheme of the dam with inclined core is relatively smaller and the vertical settlement is larger.Under the scheme of the dam with inclined core,the horizontal areas of high stress at the dam abutments of both the banks of the core are reduced in some extent,which can improve the stress and deformation conditions of the elements at the upstream face of the core.Moreover,the arch effect of the core is relatively weaker under the scheme of the dam with inclined core,while its performance for resisting hydraulic fracture relatively better.