深厚覆盖层上土石坝动力分析黏弹性边界处理方法

发布时间：2018-09-18 07:03

【摘要】：当覆盖层地基深度相对其上土石坝坝高较大时,大坝动力分析计算中常将覆盖层地基截断,只取临近坝体部分覆盖层地基连同坝体一起作为计算分析对象。用黏弹性边界条件代替固定边界条件,可以消除或有效降低由于截断边界造成外行波无法透过边界而引起的计算误差。本文采用施加等效地震惯性力的方法实现黏弹性边界条件下的地震动输入、采用等效线性化方法反映覆盖层地基边界上黏弹性边界条件的非线性特性,建立了基于黏弹性边界条件的深厚覆盖层上土石坝动力反应分析方法。研究表明:施加等效地震惯性力的方法可以简单而有效地解决黏弹性边界条件下的地震动输入问题;固定边界条件大幅提高了坝体在地震作用下的动力反应水平,使得计算的结果偏于安全。
[Abstract]:When the depth of the overburden is larger than the dam height of the upper earth rockfill dam, the overburden foundation is often truncated in the dynamic analysis calculation of the dam, and only part of the overburden foundation near the dam body is taken as the object of calculation and analysis along with the dam body. By replacing the fixed boundary condition with the viscoelastic boundary condition, the calculation error caused by the truncation of the boundary can be eliminated or reduced effectively. In this paper, the method of applying equivalent seismic inertial force is used to realize the input of ground motion under the viscoelastic boundary condition, and the equivalent linearization method is used to reflect the nonlinear characteristics of the viscoelastic boundary condition at the boundary of the overburden layer. Based on viscoelastic boundary conditions, a dynamic response analysis method for earth-rock dams on deep overburden is established. The results show that the method of applying equivalent seismic inertial force can solve the problem of earthquake input under viscoelastic boundary condition, and the fixed boundary condition can greatly improve the dynamic response level of dam body under seismic action. The result of calculation is biased to safety.
【作者单位】：流域水循环模拟与调控国家重点实验室;中国水利水电科学研究院岩土工程研究所;水利部水工程抗震与应急支持工程技术研究中心;
【基金】：国家自然科学基金项目(51509272,51679264) 中国水科院基本科研业务费项目(GE01458292017) 国家重点基础研究发展计划暨973计划课题(2013CB036404) “十二·五”国家科技支撑计划课题(2013BAB06B02) 水利部公益性行业科研专项项目(201501035)
【分类号】：TV312;TV641

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