川北某码头工程后缘滑坡机理及治理措施

Mechanism and treatment measures of landslide at back edge of wharf project in northern Sichuan

川北某码头堆场开挖过程中,后缘土体边坡发生开裂变形,并迅速沿基岩顶面滑动形成滑坡,随后滑坡后缘以上土体由于滑坡的牵引形成两级弧形变形裂缝。从滑坡前地形变化、滑坡后滑面特征、后缘裂缝特征等入手,在原勘察资料的基础上,结合现场调查、坑探,采用极限平衡力学分析的方法,对该处滑坡的滑动机理、稳定状态及治理措施进行研究。结果表明,滑坡发生的主要内因在于基覆界面附近土体含水量过高,抗剪强度过低,施工开挖形成临空面后,基覆界面附近剪应力集中超过土体抗剪强度,诱发滑坡,并提出相应的治理措施建议。

During the excavation of a wharf yard in northern Sichuan, the soil slope at the back edge cracked and deformed, and quickly slid along the top of the bedrock to form a landslide. Then the soil above the back edge of the landslide formed two-stage arc deformation cracks due to the traction of the landslide. In this paper, starting from the terrain changes before the landslide, the characteristics of the sliding surface and the cracks at the back edge after the landslide, on the basis of the original survey data, combined with field investigation and pit exploration, the sliding mechanism, stable state and treatment measures of the landslide are studied by using the method of limit equilibrium mechanics analysis. It is concluded that the main internal cause of landslide is that the water content of soil near the foundation cover interface is too high and its shear strength is too low. After the free face formed by construction excavation, the shear stress concentration near the foundation cover interface exceeds the shear strength of soil, inducing landslide, and the corresponding treatment measures are proposed.