水电站厂房建基面大规模破碎带地基处理实践

Practice of foundation treatment of large scaled fracture zone of foundation plane of powerhouse

缅甸道耶坎二级水电站厂房建基面开挖揭露出大规模破碎带,若采用换填法处理将会影响边坡的稳定性,经比较,决定采取高压喷射注浆法对破碎带进行处理。针对不同地质条件采取了如下处理措施:对上游强风化区域采用小口径灌注桩;中部破碎带区域采用大口径高压旋喷桩加固;下游强风化建基面则进行挖除置换处理。实践证明,采用高压喷射注浆法处理含泥、土层夹石的破碎带,成桩效果好,桩身抗压强度满足设计要求。

Large fracture zone was discovered during the foundation excavation of powerhouse of Thaukyegat II Hydropower Sta-tion in Myanmar. The stability of the slope would be affected if it was treated with replacement method. So the high pressure jet grouting method was adopted in the treatment of fracture zone through comparison. The corresponding treatment measures were taken according to different geological conditions. In the upstream, the small-diameter pour pile was used in strong weathered area. In the midstream, the large-diameter high pressure jet grouting was adopted in the reinforcement. In the downstream, the excavation and replacement method is performed in the strong weathered foundation plane. The practice showed that the high pressure jet grouting method was effective in the treatment of fracture zone containing mud and stone in soil layer and the pile-forming effect was good. The compressive strength of the pile body meets the design requirement.