黏土心墙坝水力劈裂发生机理及判别方法

Discussion on Hydraulic Fracturing Identification of Clay Core Rockfill Dams

摘要: 采用基于Biot固结理论的有效应力分析方法,对某黏土心墙土石坝进行了数值计算,分析坝体的有效小主应力、总小主应力及应力水平的分布特点,并在分析黏土心墙坝水力劈裂发生机理的基础上,对坝体心墙发生水力劈裂的可能性进行判断.结果表明:分别采用有效应力法和总应力法判断水力劈裂是否发生,二者结果是一致的;此外,蓄水后心墙上游侧应力水平较大,其可能的剪切破坏会导致心墙产生裂缝,进而引发心墙水力劈裂,因此,判断心墙水力劈裂是否发生时,应考虑应力水平的影响.

Abstract: In this paper, a clay core rockfill dam is analyzed with numerical method based on Biot's consolidation theory.The mechanism of the hydraulic fracturing is discussed.And the possibility of hydraulic fracturing is analyzed by considering the effective minor principal stress, total minor principal stress and the stress level based on the numerical results of earth core dams.It indicates that the results based on the effective stress method are the same to those based on the total stress.Moreover, the effects of stress level should be taken into count for the judgment, since hydraulic fracturing can be caused by the corewall crack which is induced by the high lateral stress level on the eorewall in upper after impoundment.