前坪水库溢洪道控制段基础处理研究

前坪水库溢洪道控制段基础开挖至建基面后,地质条件与前期地勘资料变化较大,经补充地质勘测,控制段位于安山玢岩与辉绿岩接触带处,建基面大部分位于强风化岩层上,岩石风化程度较深,辉绿岩岩体风化程度不均一,勘探点最大揭露深度为10.2 m,岩体性质不均匀,软硬相间,存在局部应力集中及不均匀沉降等风险。为较好解决控制段基础存在的问题,对溢洪道控制段基础进行了开挖换填混凝土、抗滑桩、钢筋混凝土抗滑槽等方案的优化研究,从技术、经济等进行综合比选,达到了基础处理的目的,也为其他工程提供参考和借鉴。

Foundation treatment for spillway control section of Qianping reservoir

In the spillway control section of the Qianping reservoir, excavation to the foundation surface reveals its geological conditions greatly different from the survey data obtained previously. A supplementary geological survey verified that this section is actually located in a contact zone between andesitic porphyrite and diabase with its base plane mostly on a strongly weathered deep bedrock. The weathering degree of diabase rock is non-uniform with the maximum exposure depth of 10.2 m at the exploration hole; the nature of rock mass is heterogeneous, featured with a soft-hard interphase layer and a potential risk of local stress concentration and uneven settlement. To solve these problems, we optimize the foundation treatment of the spillway control section and achieve the treatment goals through several measures such as excavation and replacement of concrete, anti-slide piles, and reinforced concrete anti-slide slots.