土质心墙坝水力劈裂条件分析

Analysis on condition for hydraulic fracture of rockfill dam with clay core

采用基于Biot(比奥)固结理论的有效应力分析方法,对雅砻江两河口粘土心墙土石坝两种心墙坡比方案的多种特殊工况进行了比较分析,探讨了水力劈裂的发生条件及其影响因素。计算结果表明:坡比较大则心墙的抗水力劈裂能力较强。此外,对比较极端的坝壳与心墙模量组合情况下和较高蓄水速度情况下坝体的平面应变进行了有限元分析,探讨了坝壳与心墙模量关系及蓄水速度对心墙上游区域的应力分布及大小的影响,进一步探讨水力劈裂发生条件。

More special operation conditions for two core slope ratios alternatives of the rockfill dam with clay core for Lianghekou Hydropower Station on Yalongjiang River are analyzed herein with effective stress analysis based on Biot＇s consolidation theory, in which the occurrence conditions and the impact factors of the hydraulic fracture are discussed as well. The result indicates that the larger the slope ratio of the core is, the stronger the bearing capacity of hydraulic fracture will be. Furthermore, finite element analysis on the plane strain of the dam body under both the condition of more extreme combination between the moduli of both the dam shell and the core and the condition of higher impounding speed is made, and then the occurrence conditions of the hydraulic fracture are further studied along with the discussion on the relationship between the moduli of both the dam shell and the impounding speed and the impact from the impounding speed on the distribution and magnitude of stress within the upstream zone of the core.