乌江下游沿岸滑坡发育特征

乌江是黔东北和渝东南少数民族地区与外界联系的一条水上黄金通道。担负了流域内80％以上的客货运输量。满足了沿岸2000多万人民生产和生活必需品运输的需要。乌江下游的彭水县城至涪陵市是乌江进入长江航运的咽喉要道，沿岸广泛分布和频繁发生的滑坡严重地威胁着航运的安全。通过现场调查发现，在长约150km范围内，两岸共发育各类滑坡28个，发育线模数为0．187个／km。沿岸滑坡发育形式主要为岩石顺层滑坡和风化堆积层滑坡。沿岸滑坡具有群发性的分布特征，与地层岩性和河谷岸坡类型等密切相关。岩石顺层滑坡主要集中分布在顺向岸坡软、硬岩层相间地段。风化堆积层滑坡则主要分布在软岩地层及其风化物堆积的岸坡地段。构造变动、河流的切蚀作用及人类活动是滑坡发育形成的主要原因，暴雨和长时间降雨是滑坡发生的重要诱发因素。目前，多数滑坡处于稳定状态，少数滑坡受降雨及江水涨落的影响而处于周期性蠕动变形状态。三峡水库蓄水后，部分滑坡有复活的可能。

Development regularity of landslide along the banks of the lower reaches of the Wujiang River

The Wujiang River is a golden passage connecting the national minority region of the northeast of the Guizhou Province and the southeast of the Chongqing City with outside, carrying over the freight and passenger transportation quantity of 80% inside the river valley and satisfying the needs of the more than 2000 littoral residents for the necessaries of life and production. It is a waterway 150 kilometers long from the Pengshui County to the Fuling City which is the strategic passage of the Wujiang River into the Yangtzi River. Based on the extensive spot investigation, it has been found that there are 28 landslides along the banks and the average linear density of the landslide is 0.187/km. The types of the landslide are the rock bedding plane one and the cumulate and solum one which are correlated closely with the rock property of strata and the types of the river valley. The rock bedding plane landslides mainly distribute in the strike valley with intercalated beds of soft and hard rock and the accumulate and solum ones in the valleys with strata of soft rock along the River. They are mainly reasons that landslides occurs such as the geological structure and the erosion process of river and the human activities about cutting the slope toe. The rainstorm is the major inducement factor of developing landslide. Through assessment of slide stability, it is considered that the most landslides are in the basic stability condition or in the periodical creeping deformation condition influenced by the cloudburst and the rising and falling of the water level in Wujiang River. After the Three Gorges reservoir reserves water, parts of the landslides will probably lose their stability.