易贡远程高速滑坡形成原因试验探索

EXPERIMENTAL STUDY ON FORMATION OF YIGONG LONG-DISTANCE HIGH-SPEED LANDSLIDE

针对易贡远程高速滑坡的高速、长距离等特点,结合环剪试验可模拟大位移剪切的特点,通过不同剪切速率下环剪试验以及排水和不排水条件下的对比环剪试验分析易贡远程高速滑坡的形成原因。结果表明,高速剪切使孔隙水压力不能及时消散,剪切过程引发孔隙水向剪切面运移,剪切面土体含水量和细粒含量明显高于剪切面上下层土体,以致剪切面液化。不排水剪切条件下的有效内摩擦角比排水剪切大幅降低,初步揭示了剪切速度越高,土体强度越低,两者交互作用的滑坡加速促进原因。

Aiming at the character of long-distance high-speed movement of Yigong landslide, and based on the advantage of large displacement shear test of ring shear apparatus, ring shear tests with different shear speeds and those under drained and undrained conditions are carried out to learn the mechanism of long-distance high-speed landslide. Results show that the pore water pressure cannot dissipate punctually, and the pore water migrates to the shear plane slowly during the experiment. Water content and fine particle content of the shear plane are higher than those of the original and other layers obviously, which leads to the liquefaction of shear plane in the consolidation shear test. Effective internal friction angle of the consolidation undraining shear test is greatly lower than the draining one; the higher the shear speed is, the lower the strength is. This can interpret the formation of Yigong long-distance high-speed landslide.