天然地基与加固地基条件下拱坝模型破坏试验研究

Experimental Investigation on Arch Dam Model Failure under Natural Foundation and stabilized Foundation

位于云南澜沧江上的小湾水电站拱坝为目前世界同类型坝中最高的一座。坝址具备修建高拱坝的优越地形条件,但其地质条件复杂,左右坝肩抗力体内存在部分地质缺陷,直接影响到拱坝与地基系统的正常运行和整体稳定。针对小湾拱坝1 210 m高程坝肩的地形地质条件,采用地质力学模型试验方法,用超载法进行破坏试验研究,并进行了坝肩天然地基未加固和坝肩地基加固两种方案的对比分析研究。通过两个方案的平面地质力学模型试验,对比分析了两种方案坝体、坝肩的变位分布规律及模型破坏过程和破坏形态、坝肩稳定超载安全度,研究成果表明:坝肩加固后超载能力得到了提高,破坏形态得到了改善,加固效果明显。

Xiaowan arch dam located on Lancangjiang River of Yunnan Province is one of highest dams of the same type in the world now.Topographical conditions at the dam site satisfies the requirements for building high dam,however,geological conditions here are complicated and some geological defects exist in resisting rock masses in both dam abutments,which have direct affects on normal operation of dam and foundation system and monolithic stability.In this paper,for topographical and geological conditions of Xiaowan arch dam abutments at elevation of 1210m,comparative analysis and study are performed for natural foundation and stabilized foundation at dam abutments by using geomechanical model test method and overloading failure test study.In addition,two dimensional geomechanical model tests are conducted for above-mentioned two schemes to compare deflection distributions of dam body and dam abutments,model failure process and forms and stability safety degree under dam abutment overloading condition.The test results show that overload capacity of dam abutment is improved after stabilization,failure forms are improved.Dam abutment stabilization is very effective.