大朝山水电站地下厂房洞室群立体开挖施工

大朝山水电站地下厂房设计最大开挖尺寸为233.90 m×26.40 m×67.30 m(长×宽×高),总开挖量27.92万m3,原计划1999年12月开挖结束. 为确保施工进度和工程安全,经优化方案比较,采用"竖向多层次、平面多工序"的立体开挖方案,于1999年8月5日全面停止爆破,开挖工期提前近5个月.同时,由于立体开挖方案的顺利实施,使得母线洞、压力引水隧洞及尾水管洞等地下洞室提前与主厂房贯通,各交岔洞口柔性支护及时完成,确保了地下厂房洞室群开挖期间整体稳定,保证了施工安全和工程安全.提前工期效益及间接经济效益显著.

Three-dimensional excavation of the cavern group for underground powerhouse of Dachaoshan Hydropower Station

The maximum design excavation dimensions of the underground powerhouse of the Dachaoshan Hydropower Station are 233 90 m long, 26 40 m wide and 67 3 m high, with the total excavation volume of 279,200 m 3 The excavation would be completed in December 1999 in the original plan In order to ensure the construction progress and the safety of the project and according to the optimization and comparison of the excavation alternatives, a three dimensional excavation alternative of "many layers in vertical direction and more working procedures in plane" was adopted On August 5, 1999, the blasting was completely stopped and the excavation period was shortened about five months Due to the smooth implementation of the three dimensional excavation scheme, the caverns such as busbar chamber, pressured diversion tunnel and tailrace tunnel was completed ahead of time The soft support for every crossing tunnel mouth was finished in time All these ensured the integral stability of the caverns for the underground powerhouse during the excavation and guaranteed the safety of construction The construction ahead of time and indirect economic benefits were outstanding