基于有限元超载法的重力坝深层抗滑稳定分析

Deep Anti-sliding Stability Analysis of Gravity Dams Based on FEM Overload Method

利用ABAQUS有限元分析软件,建立考虑基岩岩体软弱夹层结构面力学特性的二维重力坝深层抗滑稳定弹塑性计算模型。采用超载法进行水工混凝土重力坝深层抗滑稳定分析,通过观察塑性区是否贯通、计算收敛的情况得出各自的深层抗滑稳定安全系数,与用规范规定的刚体极限平衡法得到的计算结果进行对比。结果表明:①随着实践经验的不断积累,基本形成初步共识:以刚体极限平衡法计算的安全系数为安全度的主要判据,同时将有限元计算的坝体、地基的应力、位移值、超载系数K p等作为辅助判据,综合衡量坝的稳定安全度;②通过有限元计算,坝趾处的塑性区扩展方向及第三主应力扩展方向一般是倾向下游的,可作为刚体极限平衡法中第二滑裂面的倾向;③现行规范规定的刚体极限平衡法计算在实际应用时存在较大的局限性,通过分析可知,针对复杂坝基情况,可采用有限元计算方法来研究其抗滑稳定性。

In this paper,the ABAQUS finite elements analysis software was used to establish the deep layer anti-sliding stability elastic-plastic calculation model for gravity dams considering the mechanical properties of the surface of the bedrock soft interlayer structure.In this paper,the sliding stability of hydraulic concrete gravity dam was analyzed by means of overload method,and the safety factors of sliding stability of hydraulic concrete gravity dam were obtained by observing whether the plastic zone was closed and calculated,and then the safety factors were compared with those obtained by rigid body limit equilibrium method.The results showed that:①With the accumulation of practical experience,a preliminary consensus is basically formed:the safety coefficient calculated by the rigid body limit equilibrium method is the main criterion of safety degree,and the stress,displacement value and overload coefficient K p calculated by the finite element method are taken as auxiliary criteria to comprehensively measure the stability and safety degree of the dam.②The limit equilibrium method of rigid body stipulated in the current code has great limitation in practical application.According to the analysis in this paper,the anti-sliding stability of complex DAMS can be studied by using the finite element method.