土石坝心墙应力变化对渗透系数的影响研究  

Study on influence of earth-rockfill dams core wall stress variation on permeability coefficient

作　　者：池俊梦 张幸幸[2] 张茵琪[2] 董福品[1] 邓刚[2] 

机构地区：[1]华北电力大学可再生能源学院,北京102206 [2]中国水利水电科学研究院流域水循环模拟与调控国家重点实验室,北京100038

出　　处：《人民长江》2017年第19期97-101,115,共6页Yangtze River

摘　　要：试验和现场监测均表明,土石坝心墙的渗透系数并非是一个常数,而是随着其应力状态和密度的变化呈一定的空间分布。一般而言,心墙土在填筑过程中渗透系数的空间变化因自重荷载大小而产生,密度大的下层土渗透系数小于上层土;不同应力状态下,渗透系数也有一定规律。根据某土石坝心墙土料的等向压缩试验确定心墙各高程处的实际密度,基于该土料在不同密度条件下的渗透系数试验成果,确定各高程处心墙的实际渗透系数。考虑上述土料渗透系数的空间变化后,开展心墙孔压、应力状态的有限元数值模拟。将该结果与常规心墙采用单一渗透系数的计算方法对比发现,考虑心墙渗透系数的空间分布,能够更合理地反映心墙的实际孔压分布和应力状态。Tests and field monitoring both indicate that the permeability coefficient of earth-rockfill dam core wall is not a constant,but varies with the stress state and density,presenting a spatial distribution. Generally speaking,the spatial variation of core wall soil permeability coefficient is caused by gravity load in the process of filling,and the soil density of lower core wall is bigger than that of the upper core wall,thus its permeability coefficient is smaller than that of the upper soil. Under different stress states,the permeability coefficient also follows certain pattern. The actual density at a certain height of the core wall is determined according to the isotropic compression test. The actual permeability coefficient at any heights of the core wall is also determined based on the permeability coefficient test data under different densities. Considering the spatial variation of permeability coefficient,FEM simulation is carried out to obtain the state of pore pressure and stress of the core wall. The simulated results are compared with the conventional single permeability coefficient calculation results,and it is found that the consideration on variation of permeability coefficient can reflect pore pressure distribution and stress state of core wall more reasonably.

关 键 词：渗透性能 应力分布 心墙 土石坝 

分 类 号：TV641.1[水利工程—水利水电工程]