高土石围堰复合土工膜应变集中计算方法研究  

Study of calculation methods of composite geomembrane concentration in high earthrock cofferdam

作　　者：王永明[1] 邓渊[1] 任金明[1] 朱晟[2] 蔡建国[1] 梁现培[1] 

机构地区：[1]中国电建集团华东勘测设计研究院有限公司,浙江杭州310014 [2]河海大学水文水资源与水利水电工程科学国家重点实验室,江苏南京210098

出　　处：《岩石力学与工程学报》2016年第A01期3299-3307,共9页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51409264);中国电建集团华东勘测设计研究院立项课题(KY2015–02–08)~~

摘　　要：复合土工膜是由高分子聚合物制成的一种平面柔性薄膜并在其侧面黏有织物的土工合成材料,因其具有良好的防渗性能及施工简便等优点而得到广泛应用。针对我国水电工程中大量运用复合土工膜快速修建高水头土石围堰过程中普遍存在拉断、撕裂等集中破坏渗漏现象,分析发现复合土工膜在刚性基础锚固或防渗墙接头等工程结构物的软硬交界区域因应变集中且超出其极限延伸率而导致结构性的损坏,而目前计算方法均难以反映该性状。从复合土工膜材料力学性能、复合膜与周围填料及锚固接头相互作用机制出发,参照面板坝周边缝单元有限元处理模式,建立反映复合土工膜应变集中的"周边膜"单元的几何与物理描述方法,并将其本构关系及位移模式植入三维有限元程序,计算获取了高度为85 m的白鹤滩水电站上游围堰复合土工膜应变集中部位的应变状态,为高水头、大变形等复杂受力条件下复合土工膜的安全利用和推广起到有益的理论支持作用。Composite geomembrane is a type of geosynthetics with the main components of geomembrane at one side or both sides stuck with geotextile. Composite geomembrane has been widely applied in the field of water conservancy, transportation and disposal of nuclear waste landfill for its low permeability, strong deformation adaptability, convenient erection and dismantling. Aiming at the problem of centralized damage and leakage induced by tensile failure or tear of composite geomembrane in the extensive use of rapid construction of high water head rockfill cofferdam, some analysis were conducted and revealed that structural damages were induced by strain concentration which exceed the limit elongation of composite geomembrane located in these junctional zone between hard foundation and soft composite material. Based on the theoretical analysis of composite geomembrane material mechanical properties as well as microscopic mechanism interaction between the geomembrane and joint, the description method of geometry and physics of composite geomembrane strain concentration were suggested. The corresponding peripheral membrane element FEM prediction mode was alsoput forward based on the treatment method of Concrete Face Rockfill Dam peripheral joint. The constitutive relation and displacement model were planted in the 3D FEM program. The strain concentration behavior of geomembrane in Baihetan hydropower 85 m height earth-rock cofferdam was obtained. Valuable data and conclusions were obtained to guide the safe utilization and generalization of composite geomembrane in high water head condition and complex stress state.

关 键 词：土力学 复合土工膜 高土石围堰 交界区域 应变集中 周边膜单元 白鹤滩水电站 

分 类 号：TV41[水利工程—水工结构工程]