八一水库大坝除险加固及其安全评价

Safety Evaluation and Reinforcement for Bayi Reservoir

八一水库大坝安全类别为三类,急需进行除险加固。大坝除险加固采取了坝基与坝肩帷幕灌浆、坝体冲抓套井回填、平整防护坝坡、重建排水棱体等工程除险。以加固后的典型坝体横剖面为研究对象,采用有限单元法对正常蓄水位、设计洪水位和校核洪水位等工况下的坝体渗透稳定性进行分析,并采用刚体极限平衡法计算相应工况下的坝体抗滑稳定安全系数。计算结果表明:坝体除险加固后,大坝浸润线位置明显降低,坝体渗流量非常小,渗透坡降均小于允许渗透坡降,上下游坝坡抗滑稳定安全系数均大于规范要求。这说明采用的坝体除险加固措施是有效的,能保证加固后坝体安全运行。

The dam safety of Bayi reservoir has been evaluated as the third type of defective and dangerous reservoir,which needs reinforcements as soon as possible.Firstly,the reinforcement measures are adopted, which consist of curtain grouting in the foundation and dam body ,construction of new prism drainage adjacent stream dam face.Then,taking the typical dam cross secti abutment, backfilling impervious wall of dug wells in to dam toe, slope protection on upstream and down- on after reinforcements as the research object, the dam seepage stability under normal pool level ,design flood level and flood check level are analyzed separately with the finite element method, the corresponding stability safety factors against sliding are calculated with the rigid block limit equilibrium method.The calculation results show that：seepage surface of the reinforced dam is sig- nificandy reduced,the dam seepage flow is significantly reduced,exit gradient is less than permissive gradient with each condition, and the corresponding anti-slide safety factor is greater than permissive value.That means the reinforcements measures are effective and the reinforced dam can operate well.