考虑堆石料空间变异性的心墙坝地震安全性随机有限元分析  

Random Finite Element Analysis of Seismic Safety of Core Dams Considering the Spatial Variability of Rockfill Materials

作　　者：杨鸽 朱晟[3] D.V.Griffiths[4] YANG Ge;ZHU Sheng;D.V.GRIFFITHS(Hangzhou National Hydropower Station Dam Safety and Emergency Engineering Technology Center Co.,Ltd.,Hangzhou 311122,Zhejiang,China;PowerChina Huadong Engineering Corporation Limited,Hangzhou 311122,Zhejiang,China;Institute of Hydraulic Structures,Hohai University,Nanjing 210098,China;Department of Civil and Environmental Engineering,Colorado School of Mines,Golden,CO 80401,USA)

机构地区：[1]杭州国家水电站大坝安全和应急工程技术中心有限公司,浙江杭州311122 [2]中国电建华东勘测设计研究院有限公司,浙江杭州311122 [3]河海大学水工结构研究所,江苏南京210098 [4]科罗拉多矿业大学土木与环境工程学院,科罗拉多戈尔登81401

出　　处：《水力发电》2022年第1期77-84,90,共9页Water Power

摘　　要：土石坝堆石料物理力学性质具有一定的不确定性,探讨了堆石料的空间变异性对心墙坝地震安全性的影响。以某高心墙堆石坝为例,采用基于局部平均细分法的随机有限元法,模拟了考虑筑坝堆石料空间变异性时心墙坝的地震响应以及永久变形情况,对比分析了随机有限元法和常规确定性有限元法的计算结果,并对随机物理参数的敏感性进行了分析。研究结果表明,考虑筑坝材料空间变异性时,①大坝峰值加速度响应的取值和频谱特性都发生一定程度的离散,为使设计方案的保证率达到90%以上,需将确定性分析得到的峰值加速度放大1.1倍~1.2倍;②大坝震后最大沉降的离散程度相比更大,为使设计方案的保证率达到90%以上,需将确定性分析结果放大1.4倍~1.6倍;③心墙坝动力响应对堆石料的干密度和孔隙率的敏感性强于对平均粒径和不均匀系数的敏感性,但当平均粒径和不均匀系数的变异性较大时,大坝响应仍表现出明显的离散性。Due to the uncertainty of the physical and mechanical properties of rockfill materials,the impact of the spatial variability of rockfill materials on the seismic safety of core dams are studied.Taking a high core rockfill dam as an example,the random finite element method(RFEM)based on the local average subdivision method is used to simulate the seismic response and permanent deformation of the core dam when the spatial variability of rockfill material is considered.The simulation results of the RFEM and conventional deterministic finite element method is compared,and the sensitivity of random physical parameters is also analyzed.On this basis,it is proposed that when considering the spatial variability of the dam material,(a)the value of the peak acceleration response of the dam and the frequency spectrum characteristics are both discrete to a certain degree,so in order to achieve a design guarantee rate of more than 90%,it is necessary to amplify the peak acceleration obtained by deterministic analysis by 1.1 to 1.2 times;(b)the dispersion of the maximum settlement of the dam after the earthquake is greater,so in order to achieve a design guarantee rate of more than 90%,the deterministic analysis result needs to be enlarged by 1.4 to 1.6 times,and(c)the dynamic response of the core dam is more sensitive to the dry density and porosity of the rockfill material than to the average particle size and uneven coefficient,but when the variability of the average particle diameter and uneven coefficient is strong,the dam response still shows obvious dispersion.

关 键 词：土石坝 心墙坝 地震安全性 堆石料的不确定性 空间变异性 随机有限元法 

分 类 号：TV641.41[水利工程—水利水电工程] TU435[建筑科学—岩土工程]