三峡库区云阳塞坝"平台式"斜坡变形机理分析  

Analysis of deformation mechanism of Saiba slope with flat roof in the Three Gorges Reservoir area

作　　者：王建锋[1] 苏爱军 尹先忠 刘大显 王怀球 吴梦喜[1] 

机构地区：[1]中国科学院力学研究所,北京100080 [2]长江水利委员会综合勘测局,武汉430074

出　　处：《水文地质工程地质》2003年第4期1-6,共6页Hydrogeology & Engineering Geology

基　　金：中国科学院知识创新工程重要方向项目"滑坡灾害防治中的工程力学问题研究 (KJCX2 -SW -L1 )";长江水利委员会综合勘测局项目"三峡库区平推式滑坡发生机理研究"

摘　　要：以三峡库区云阳塞坝滑坡为例,分析了层状砂泥岩区缓坡平台上崩滑堆积物中因开挖引起变形的机理。研究表明,崩滑堆积物呈蜂窝状分布的富水含水层,因远距离开挖失水而导致的不均匀变形,是地面出现拉裂的主要原因;平台中的公路开挖所诱发的边坡回弹变形仅限于局部范围。这两类变形的发生在时间上或相应的施工期间可能表现为表观的"同步"现象,但不均匀变形随着含水层排水的完成而结束,而开挖所诱发的回弹变形,则可以随着外界条件的变化而不断发展,直至发生滑坡。在空间上,两类变形具有不同的特征,其中,不均匀固结变形的发生以不规则的孤立含水层为中心向外发展,而回弹变形则局限于临空面附近,远离临空面时变形量和变形速率迅速减小。在富含地下水的松散堆积物中进行工程施工时,区分两类变形机理和效应,对于减少滑坡误判,正确进行工程设计,减少工程造价具有重要意义。Taking Saiba landslide as an example, the paper analyses the deformation mechanism of the landslide, which consists of collapse accumulation and sliding deposits on a flat roof of bedrock in sandstone and mudstone stratum with laminar structure. Exploration works have shown that there are alveolate isolated aquifers in the loose deposits with rich groundwater. By direct viewing, the landslide was caused by road excavation in 1998. However, detailed researches have shown that it is asymmetry consolidation deformation due to rapidly discharge of the groundwater during the excavation resulted in ground breakage. The discharge take place about 200m away from the central deformation area. The road excavation in the front of the flat roof has just induced rebounding deformation of limited area. The authors think that the two kinds of deformation may be developed during the same construction and thus looks like both being in step, but not the same event in cause of formation. Generally speaking, the asymmetry consolidation deformation will be over as the discharge of the groundwater being finished, while the rebounding deformation will either continue until a limited volume of sliding happened or stop after a period of time of construction finished, latter depended on the special geological conditions of a construction site. Further more, for the asymmetry deformation always developed from the central of the alveolate isolated aquifers to periphery, and the rebounding deformation limited near the free face of the excavation with decreasing deformation ratio step by step. The authors conclude that the two kinds of deformation generally do not constitute a great landslide, and thus it is very important for engineers in the field to distinguish them right for rational engineering design and construction and thus to saving construction cost.

关 键 词：三峡库区 塞坝滑坡 固结效应 回弹变形 参数反分析 变形机理 斜坡 

分 类 号：P642.22[天文地球—工程地质学] TV698.232[天文地球—地质矿产勘探]