江垭水电站地下厂房岩锚吊车梁岩台开挖

岩锚梁的岩台开挖是岩锚梁施工的关键技术，施工时，不仅要确保岩台在开挖过程中的稳定，而且也要确保岩台开挖前后的稳定，同时还要确保在后序开挖过程中不对已浇筑的岩锚梁自身结构的稳定性产生影响。江垭电站的岩锚梁施工，以工程地质体制论为理论基础，岩台开挖分４步进行：第１步在岩台以上２ｍ范围内进行预裂爆破；第２步进行岩面光面爆破；第３步在岩台以下２ｍ范围内进行预裂爆破；第４步在第３开挖层进行预裂爆破。岩台开挖

Excavation of rock bench of anchored concrete beam for bridge crane of Jiangya underground powerhouse

The rock bench excavation is a key technique for construction of crane beam anchored on rock.During the constuction,it is important that the stability of the rock bench should be ensured in and after the excavation,and that the structural stability of the completed anchored concrete crane beam should be ensured not to be influenced by the subsequent excavation.The construction of the anchored crane beam at Jiangya Hydropower Station was based on the control theory for engineering geologic body,the rock bench excavation was conducted in four steps:(1) presplit blasting in a 2-m-high rock layer above the rock bench;(2) smooth blasting in the same rock layer;(3) presplit blasting in a 2-m-high rock layer below the rock bench;(4) presplit blasting in the third excavation layer.After excavation,the rock bench had a regular shape and a clear profile.The influence depth of fissures caused by blasting met the design reguirement.The rock bench excavation was successful.