工程开挖的结构效应与防治对策──以兰州西郊滑坡为例

开挖引起的滑坡作用不仅取决于斜坡带本身的地质结构,更取决于工程开挖与斜坡地质结构相互作用,因此科学地工程开挖可以避免这类地质灾害的发生。本文以2001年7月1日发生在兰州西郊白垩系砂岩顺层山坡上天然气长输管道管沟深开挖引起的岩层滑动和由此造成的兰州市煤气管道大变形问题为例,揭示了层间剪切带的工程开挖效应和对边坡稳定性的控制作用,总结了此类地质灾害教训。

DISCUSSION ON STRUCTURAL EFFECT TRIGGERED BY ENGINEERING EXCAVATION AND THE CONTROL MEASURES THE CASE ANALYSIS OF WEST LANZHOU SUBURB LANDSLIDE

The landslide triggered by engineering excavation depends not only by geological structure of the slope zone itself, but also by the processes between engineering excavation and geological structure effect, thus scientific engineering excavation can avert this type of geo-hazards. In the case study of landslide triggered by the excavation of deep trench for long-distance-gas pipe line on the down-dip slope of Cretaceous sandstone and the large-deformation of Lanzhou coal-gas pipe line caused by the excavation in west Lanzhou suburb on July 1^st, 2001, the paper reveals the engineering excavation effect of interlayer shear zone and its control on slope stability, and then sums up the lesson in this type of geo-hazards. The authors proposed that, for prevention and reduction of this type of geo-hazards, the key measure is to firmly hold the idea that the engineering geological work must take overall situation into account and runs through the while process of the engineering project.