南水北调中线膨胀土开挖边坡破坏特点与机制

摘要

There are 387 km long of expansive rock/soil along the Middle Route Project of South-to-North Water Diversion. During the construction, more than one hundred landslides of different sizes occurred due to the excavation. We analyze and sum-marize the failure characteristics and formation mechanism of these expansion soil/rock slopes along the channel from the aspects of time-space distribution, climate environment, geological condition, rock/soil structure and expansion level. It shows that fre-quency of landslide is mainly controlled by the climatic conditions, lithology, expensiveness, structural plane and rock/soil struc-ture, among which, the soil structure and climatic condition are the main factors that caused stability difference along the route. The development degree of longer and larger structure plane will directly affect the size and numbers of landslides.%南水北调中线工程沿线分布有近387 km长的膨胀土(岩)，渠道边坡开挖施工期内共出现百余处大小不一的滑坡。针对施工期膨胀土开挖边坡稳定性差异，从时空分布、气候环境、地质条件、岩土结构以及膨胀性等级多个方面，分析总结了渠道边坡的破坏特点和形成机制。研究表明，渠道开挖过程中滑坡发生频度主要受控于岩性、膨胀性、结构面、岩土体结构及气候环境等因素，且土体结构和气候环境是造成施工期边坡稳定性差异的主要因素，而长大结构面的发育程度则直接影响和控制着滑坡形成的规模及数量。