深窄基坑降排水及开挖施工技术

Construction technologies of dewatering,drainage and excavation of narrow and deep foundation pit

猴子岩水电站大坝坝基最大下挖深度达80 m,深窄基坑施工过程中,遇到施工道路布置、基坑边坡稳定、高强度开挖运输、基坑排水等各种复杂技术难题,尤其是深基坑黏质粉土液化层施工道路布置及路基处理、深基坑厚层黏质粉土开挖及其降排水等问题。针对上述问题,开展了快速开挖施工技术与实施方案的研究,提出了基坑降排水及快速开挖应对措施,其经验可供类似混凝土面板堆石坝施工借鉴。

In the excavation of narrow and deep foundation pit of Houziyan Hydropower Station, with the maximum excavated depth of 80m, the construction encounters a variety of challenges such as difficult layout of construction roads, unstable slope sta-bility of foundation pit, high intensity excavation and transportation as well as large drainage volume, especially the road layout and subgrade treatment due to liquefied layer of clayey silt, and the excavation, dewatering and drainage for thick clay-silt over-burden. For solving these problems, studies on construction technology and rapid excavation is carried out and corresponding countermeasures are proposed.