拱坝侵彻损伤效应与安全控制(Ⅳ):坝肩稳定及安全预警指标

Penetrated damage effects and safety control of arch dam(Ⅳ):abutments stability and early warning index

拱坝遭受侵彻损伤后,应力重新调整,坝体极限承载力与坝肩稳定性随之下降。首先研究拱端合力(总推力)推力角的减小率,以此判断坝肩的整体稳定性;接着研究各层拱圈拱端推力角的减小率,初步判断坝肩的局部稳定性及危险部位;然后采用刚体极限平衡法,依据地形地质条件,选取局部稳定存疑的坝肩岩体,计算其抗滑稳定安全系数,进一步细判其局部抗滑稳定性,同时建议了坝肩整体及局部稳定安全的3级预警指标;最后,以某拱坝为例进行了拱坝坝体遭受侵彻损伤后坝肩稳定性判断和预警信息的模拟发布。最终成果与先前发表的论文成果结合,可为拱坝侵彻损伤效应分析与安全预警发布提供支撑。

Once the arch dam is suffered from penetrated damage,the stress will be readjusted accordingly.As a result,in addition to the bearing capacity of dam body,the stability of dam abutments will be reduced,too.Firstly,the monolithic stability of dam abutment is judged by studying the reduction rate of the thrust angle of arch end resultant force(total thrust).Then,the reduction rate of the abutment thrust angle of each arch ring is studied to preliminarily estimate the local stability and dangerous position of dam abutment.Afterwards,the rigid body limit equilibrium method is used to select the dam abutment rock mass with local stability problems according to the topographic and geological conditions,and the residual value of safety factor of anti-sliding stability is calculated to further determine the local anti-sliding stability.The three-level warning indexes for the overall and local stabilities of dam abutment are also proposed.Finally,the abutment stability of arch dam before and after penetration damage is analyzed for an arch dam example,and the early-warning information is simulated and released.Together with the results of previous papers published in this journal,the outcomes illustrated in this paper can provide support for the analysis of arch dam penetration damage effect and safety warning.