【摘要】 运用三维非线性有限差分数值分析方法,研究小湾拱坝在多种工况下的应力场和位移场以及蚀变带、卸荷松弛岩体对拱坝安全度的影响。坝体建基面的抗剪验算表明小湾拱坝建基面的面安全度偏低,其主要原因除了小湾拱坝所受水推力超大外,建基面上由于开挖引起的岩体松弛效应也是重要原因。分析表明坝踵部位的受拉屈服范围已经接近于帷幕位置,必须引起重视并采区必要的防范措施。坝体分别按线弹性和非线性弹塑性进行超载分析,上游水压力超载引起小湾拱坝丧失承载力的安全度,前者约为6.5,后者约为3.5,因此小湾拱坝的整体安全度为3.5,应受坝体强度控制,右岸坝基安全度小于左岸。根据屈服破坏区的分布指出在右岸高程1 160～1 190 m之间由于坝肩下游深沟和蚀变带的存在,在超载系数大于5.0时,该将出现贯通性屈服。更多还原

【Abstract】 With 3D nonlinear finite difference method,the influences of deformation,stress,corrosive rock masses and loose strips on dam safety are researched.The result indicates the surface safety degree of bedding is low due to the great water pressure and the bedrock loose effect;the tension plastic zone of dam heel rock masses is closed to the impervious certain,which must be regarded and such measurement is necessary.Elastic and elastoplastic model are adopted respectively on dam material in the overload analysis;Xiaowan arch dam’s safety degree caused by upstream overloading water pressure is 6.5 and 3.5 respectively.So the global safety degree is 3.5 and controlled by the dam strength.Through the distribution and spread process of plastic zone,the rock masses between the elevations 1 160 m and 1 190 m are in transfixing plastic due to the existing of deepl valley and corrosive when the overload coefficient reached 5.0.更多还原