洪家渡水电站工程地质问题及对策

洪家渡水电站坝区内发育有大小冲沟10条，其中4条与水工建筑有关，计有21条断层，通过水工建筑物的有6条；岩体呈不同程度的弱风化至强风化，卸荷裂隙较发育，1号塌滑体达98万m^3，2号塌滑体有60万m^3，主要工程地质问题有：左岸坝肩开挖高边坡，地下洞室群进口顺向坡稳定问题，大坝渗透稳定问题，基坑涌水问题等；采取的主要对策有：左坝肩高边坡布设预应力锚索、系统锚杆、挂网喷混凝土、打排水孔、坡顶设排水沟；塌滑体用抗滑桩加固、地下设排水廊道、地面设排水沟；对大坝渗透用帷幕灌浆、回填混凝土进行处理。

Main engineering geological problems of Hongjiadu Hydropower Station and their countermeasures

There are 10 erosion ditches in the dam area of the Hongjiadu Hydropower Station, among which there are 4 ditches that are related to the hydraulic structures. The rock properties in this area are T 1y 1, T 1y 2,T 1y 3 and T1yn1, with developed fissures. There are 21 faults, 6 of them pass through the hydraulic structures. No.1 landslide body has a volume of 980 thousand m 3 and No.2 landslide body 600 thousand m 3. The main engineering geological problems are as follows: high side slope excavation at the left dam abutment, the stability of two landslide bodies in the underground caverns, the seepage stability of dam, the free flowing water in the foundation pit, etc. The following main measures have been taken to treat above mentioned problems. In the excavation of the high side slope at the left dam abutment, we adopted pre stressed anchorage cable, system anchorage rods, web shotcrete, drainage hole, drainage ditches at the top of the side slope. The anti slide piles have been used to reinforce No.1 landslide body. The underground drainage galleries in four layers and some ground drainage ditches have been arranged. For the seepage control of dam, the curtain grouting and back filled concrete have been adopted. Now the No.1 and No.2 diversion tunnels have been completed. It was proved that the analysis is correct and the measures adopted are proper.