发电洞竖井外壁围岩爆破对混凝土质量的影响

“6 35”水利枢纽已浇筑的发电洞竖井混凝土受到多种强腐蚀介质的侵蚀影响 ,需在竖井外壁进行加强性工程防腐处理 .根据竖井的结构特点 ,为了确保竖井及其上部坝体的稳定 ,采用保留原井壁混凝土 ,并沿竖井外壁围岩开凿环形天井的施工方案 .着重讨论竖井外壁围岩环形天井爆破开挖方案 ,提出井壁混凝土爆破安全振速不得大于 7cm/s ,新浇混凝土 (7d龄期 )安全振速不得大于3cm/s的各有关爆破控制参数和相应的减振措施 ,并通过爆破前后混凝土井壁声波测试对比分析 ,进一步验证爆破方案的可行性和安全性

Impact of Outer Sidewall Adjoining Rock Burst at Shaft Section of Power Tunnel on Concrete Quality

In order to protect the cast concrete at the shaft well section of the power tunnel against corrosion by several strong corrosive mediums,a protection project at the outer sidewall of the shaft well is needed.In accordance with the structural features of the shaft,an engineering scheme of excavating ring shaped raiser around the adjoining rock of the outer sidewall of the shaft well while maintaining the previously cast concrete is adopted to ensure the stability of the shaft and the dam on the shaft.The burst and excavation scheme of the ring shaped raiser is discussed here,for safety,it is proposed the vibration speed of the shaft well burst be less than 7?cm/s,and that the safe vibration speed of the newly cast concrete (within 7 days)be less than 3cm/s.The concrete sidewall acoustic tests before and after the burst prove,the feasibility and safety of the proposed burst scheme to be good.