裂纹内水压分布对重力坝断裂特性的影响  

Effect of in-crack water pressure distribution on the fracture behavior of concrete gravity dams

作　　者：刘钧玉[1,2] 林皋[1] 胡志强[1] 李建波[1] 

机构地区：[1]大连理工大学,辽宁大连116024 [2]沈阳工业大学,辽宁沈阳110178

出　　处：《土木工程学报》2009年第3期132-141,共10页China Civil Engineering Journal

基　　金：国家自然科学基金重点项目(90510018);教育部创新团队项目(IRT0518);辽宁省博士启动基金(20051077)

摘　　要：应用比例边界有限元法(SBFEM)研究裂纹内水压及其分布对裂纹尖端应力强度因子变化的影响。SBFEM的突出优点是可以直接给出位移场和应力场沿径向变化的解析解,因而非常适用于断裂等奇异性问题的求解,并且对两种介质界面断裂问题的计算也非常方便。以重力坝坝踵界面裂纹为例计算裂纹内不同水压分布规律、介质的不同弹模比值以及不同的裂纹长度对应力强度因子的性质及其数值大小变化的影响。计算结果表明,不考虑裂纹内水压或裂纹内水压强度较小时,在坝基弹模较低的条件下,重力坝坝踵界面裂纹处于压剪状态;但当裂纹内水压强度较大时,则转换为拉剪状态。裂纹内存在水压作用时,随着水压变化规律以及两种介质弹模比的变化,KⅠ和KⅡ的变化也很明显。研究结果对工程上评价重力坝的断裂特性将具有重要意义。Effects of in-crack water pressure and distribution on the stress intensity factors （SIF） of concrete dams are investigated by using the scaled boundary finite element method （SBFEM）, the advantage of which is that it gives analytical solutions of displacement and stress fields in the radial direction and thus facilitates its application to problems with singularities, such as in fracture mechanics. In addition, SBFEM can conveniently handle interfacial cracks between the two different materials. Taking the heel crack of a concrete gravity dam as an example, the effects of water pressure distribution inside the crack, ratio of Young＇ s modulus between the two materials as well as crack length on the SIF are studied. For the case of low water pressure or no pressure, the crack is predicted to be in the state of compression-shear if the modulus of the foundation rock is relatively low. The crack subjected to higher water pressure would be in a tension-shear state. It is also suggested that when the inner water pressure exists, KⅠ and KⅡ vary distinctly with the magnitude of water pressure and the ratio of Young＇s modulus.

关 键 词：应力强度因子 比例边界有限元法 界面裂纹 重力坝 

分 类 号：TV642.3[水利工程—水利水电工程] O346.1[理学—固体力学]