木里河立洲拱坝整体稳定地质力学模型试验研究

采用三维地质力学模型超载法试验，对立洲拱坝的整体稳定性进行研究，在模型中充分反映断层、层间剪切带、裂隙密集带及长大裂隙等复杂地质构造对拱坝与地基整体稳定性的影响。通过超载法破坏试验获得坝体、坝肩、坝基岩体及结构面的变形特征、破坏失稳过程、破坏形态和破坏机制，揭示影响稳定的控制性因素和工程薄弱部位，确定拱坝与地基在各阶段的超载安全系数为：起裂超载安全系数K1 = 1.4～2.2，非线性变形超载安全系数K2 = 3.4～4.3，极限超载安全系数K3 = 6.3～6.6。通过对比分析类似拱坝工程的超载法试验结果可知，立洲拱坝的超载安全系数在统计分布范围之内，但两坝肩中上部的岩体和结构面局部破坏较严重，需对这些薄弱部位进行重点加固处理，以进一步提高坝与地基的整体稳定安全性。

GEOMECHANICAL MODEL EXPERIMENT OF GLOBAL STABILITY OF LIZHOU ARCH DAM ON MULI RIVER

The global stability of Lizhou arch dam is studied by overloading model test in the 3D geomechanical model，the complex geological structures including faults，interlayer shear zones，fissure zones and large fissures affecting the global stability are considered and simulated. Through the overloading destructive test，the deformation characters，the failure process，pattern and mechanism of dam，rocks and structure planes in foundation and abutment are obtained. The controlling factors and weak regions impacting the stability are revealed. And the overloading safety factors of dam and foundation at each destructive stage are determined as follows：the crack initiation overloading factor K1 = 1.4–2.2，the nonlinear deformation overloading factor K2 = 3.4–4.3，the ultimate overloading factor K3 = 6.3–6.6. Furthermore，comparing with other similar projects，the safety factor of Lizhou dam is within the statistical range of overloading test safety factors. While local parts of rocks and structure planes in middle and upper abutments are damaged seriously，their reinforcements should be paid more attention to improve the global stability of Lizhou arch dam.