深厚砂质覆盖层土坝的弹塑性地震反应分析  

Elastoplastic seismic response analysis of earth dam on deep sandy alluviums

作　　者：方火浪[1,2] 张轶群[1] 郭婧[1] 银鸽[1] 

机构地区：[1]浙江大学防灾工程研究所,杭州310058 [2]浙江大学软弱土与环境土工教育部重点试验室,杭州310058

出　　处：《岩土力学》2013年第11期3197-3204,共8页Rock and Soil Mechanics

摘　　要：由于可液化砂质土应力-应变特性模拟的复杂性及数值计算的不稳定性,深厚砂质覆盖层土坝的弹塑性地震反应分析是土坝抗震研究中的一个尚未完全解决的课题。采用u-p完全耦合的饱和多孔介质有限元分析方法和砂土多重机构弹塑性模型,对遭受M6.7级地震的国外某深厚砂质覆盖层土坝进行弹塑性地震反应分析,研究了坝体和地基的动力反应特性及其超静孔隙水压力产生、扩散和消散的变化规律。结果表明:计算得到的坝体加速度和永久变形与实测值存在一定的差异,但基本上反映了坝体加速度与永久变形的实际分布情况,从而说明采用的本构模型和计算方法具有一定的精度;由于坝体和坝基的超静孔隙水压力较小,且坝体永久变形不大,可以不对坝体和坝基进行加固处理;坝趾附近浅层地基的超静孔隙水压力较大,有可能发生液化,因此,须采取相应的抗液化加固措施。The elastoplastic seismic response analysis of earth dam on deep sandy alluviums is an unresolved issue in the seismic study of earth dam due to the complexity of modelling the stress-strain characteristics of sandy soils and the instability of numerical computation. Elastoplastic seismic response analysis of an earth dam on deep sandy alluviums during M6.7 earthquake is carried out by using the u-p fully coupled finite element method for the saturated porous media and the multi-mechanism elastoplastic constitutive model for sandy soils. The dynamic behaviors of dam and foundation and the variations of the excess pore water pressure in generation, diffusion and dissipation are investigated. The results show that there are some differences between the calculated and measured values in accelerations and permanent deformations; but the calculated ones basically reflect their actual distributions; and then the certain accuracy of the constitutive model and numerical method is validated. Based on the numerical analysis results, it can be concluded that the reinforcement measure for the dam and its underlying foundation is not necessary, because the excess pore water pressures in these zones and the permanent deformation of the dam are small However, an anti-liquefaction reinforcement measure should be taken since the excess pore water pressure is great and the liquefaction may occur in the shallow layer of sandy alluviums near the dam toe.

关 键 词：土坝 地震 动力反应 永久变形 砂土液化 

分 类 号：TU311-3[建筑科学—结构工程] TV312[水利工程—水工结构工程]