深覆盖层上土石坝竣工期坝体及防渗墙应力应变分析

Stress and strain analysis of earth-rock dam body and cut-off wall in completion period and on deep overburden

在深覆盖层上修建土石坝,坝基的渗流控制是首要问题,防渗体系的选择尤为重要,坝体填筑料与防渗墙材料往往不同,应力应变特性复杂。为此,本文以某深覆盖层上均质土石坝为例,采用三维有限元方法开展数值分析,模型中采用Duncan-Chang双曲线本构模型,对坝体及混凝土防渗墙进行模拟计算。结果表明:坝体最大位移出现在坝体中下部,坝体与防渗墙接触面顶部区域填筑料位移较小,防渗墙最大水平位移出现在墙体中下部;坝体均受压应力,坝体与防渗墙接触面应力变化明显,防渗墙最大应力出现在墙体中下部。

To build an earth-rock dam on a deep overburden,the seepage control of dam foundation is the primary issue,and the selection of anti-seepage system is particularly important.The dam filling material is often different from the anti-seepage wall material,and the stress and strain characteristics are complex.Taking a homogeneous earth-rock dam on a deep overburden as example,numerical analysis was conducted by three-dimensional finite element method.Duncan-Chang hyperbolic constitutive model is used to simulate the dam body and concrete cut-off wall.The results of analysis demonstrate the maximum displacement of dam body appears in the middle and lower parts of dam body;the filling material displacement in the top area of the contact surface between dam body and cut-off wall is small;the maximum horizontal displacement of cut-off wall appears in the middle and lower parts of wall;the dam body is completely under compressive stress;the stress on the contact surface between dam body and cut-off wall varies significantly;the maximum stress of the cut-off wall appears in the middle and lower parts of the wall.