大藤峡水利枢纽工程二期围堰拆除设计优化研究

Optimization Design of the Second-phase Cofferdam Demolition of Datengxia Water Conservancy Project

大藤峡水利枢纽工程二期围堰拆除工程量大、工期紧、难度大,为优化其拆除设计,采用1∶80整体模型试验,拟定不同方案,结合相关水力条件、消能防冲、投资、工期等因素,分别对上下游横向围堰和纵向围堰的拆除范围和高程进行优化研究。优化后,上游横向围堰右岸侧拆除至31.17 m高程,泄水闸段拆除至25 m高程;纵向围堰上游段拆除长度275 m,拆除至36 m高程,剩余50 m不拆;下游横向土石围堰全部拆除,纵向围堰拆除至30 m高程,拆除长度202 m。优化后的拆除方案满足设计水力条件,降低了施工难度,减少了拆除工程量和投资。

The second-phase cofferdam demolition of the Datengxia Water Conservancy Project has large quantities,a tight construction period,and great difficulty.To optimize the demolition design,this paper optimizes the demolition range and elevation of upstream and downstream transverse cofferdams and longitudinal cofferdams by a 1∶80 overall model test,which is combined with factors such as relevant hydraulic conditions,energy dissipation and erosion prevention,investment,and construction period.After optimization,the right bank side of the upstream transverse cofferdam is demolished to the elevation of 31.17 m and the sluice gate section is the elevation of 25 m.The demolition length of the upstream section of the longitudinal cofferdam is 275 m,and it is demolished to the elevation of 36 m with the remaining 50 m not being demolished.The downstream horizontal earth-rock cofferdam is completely demolished,and the longitudinal cofferdam is demolished to the elevation of 30 m,with a demolition length of 202 m.The optimized demolition scheme meets the designed hydraulic conditions,reduces the construction difficulty,and decreases the demolition quantities and investment.