双K断裂准则在丹江口大坝安全性评定中的应用

Application of double-K fracture criterion in evaluating Danjiangkou dam safety

对工程中出现的裂缝可用双K断裂准则进行裂缝的稳定性分析和结构的安全性评定。本文结合丹江口大坝18坝段上游竖向裂缝在水压力下的稳定性分析,介绍了双K断裂准则应用于工程的具体实施过程。将大坝混凝土钻芯芯样制成的圆柱体楔入劈拉试件,通过试验测定混凝土双K断裂参数,并分别采用三维数值法和解析法算得水压力作用下缝端应力强度因子值。比较缝端应力强度因子值和双K断裂参数的大小及相互关系,获得裂缝的扩展状态,合理指导对裂缝进行有针对性的处理。本文为双K断裂准则的工程应用提供借鉴和参考。

Double-K fracture criterion can be used to evaluate crack stability and structure safety in practi-cal engineering. The process concerned with application of double-K criterion is specifically introduced with analyzing upstream vertical crack stability under water pressure in No. 18 dam of Danjiangkou. In this pa-per, double-K fracture toughness parameters were obtained by cylinder wedge-splitting tests, the specimens of which were incised by cores drilled from dam. And stress intensity factors at crack tip were separately calculated by three-dimensional numerical method and analytical method. Through comparing the relation-ship between double-K fracture toughness parameters and stress intensity factors at crack tip, the propagat-ing status of crack was determined, hence to take suitable measures against the crack reasonably. This pa-per provides some implications and references for applying double-K fracture criterion in practical engineer-ing in future.