奉节白衣庵滑坡演化的工程地质与历史地质分析

ENGINEERING GEOLOGICAL AND HISTORIC GEOLOGICAL ANALYSIS OF BAIYI'AN LANDSLIDE EVOLUTION IN FENGJIE COUNTY

在对三峡库区白衣庵滑坡进行的大量野外地质调查和试验的基础上,对众多勘探资料进行研究;从工程地质与水文地质分析出发,揭示白衣庵古滑坡的解体演化规律和发展趋势。从第四系地层沉积关系和年龄、特殊地层变形破坏形迹及地质事件的相互关联性出发,对白衣庵古滑坡进行历史地质综合分析,阐明其发育演化历史,从而判别其稳定性。研究结果表明,白衣庵滑坡整体是稳定的,但局部不稳定,将以中小型滑坡为主的形式逐渐发生解体。采用古滑坡的工程地质与历史地质联合分析法,可揭示大型古滑坡在不同地质环境下的发生发展规律及其多样性,有利于从宏观上把握滑坡目前所处的发展演化阶段,以正确评价和预测滑坡稳定性的发展趋势。

ENGINEERING GEOLOGICAL AND HISTORIC GEOLOGICAL ANALYSIS OF BAIYI＇AN LANDSLIDE EVOLUTION IN FENGJIE COUNTY LI Xiao, ZHANG Nianxue, Lee Souting, LIAO On the basis of the detailed geology surveying and testing, many exploration data are analyzed for Baiyi＇an Landslide in the area of Three Gorges Reservoir, Yangtze River, China. At the aspects of engineering geology and hydrogeology analysis, the disintegration evolution and development trends of the landslide are revealed. According to the relationships of Quaternary sediments and the ages, the traces of deformation and failure of the special stratum, and the geological events, the historic geology of Baiyi＇an Landslide is analyzed and the evolutional history of Baiyi＇an Landslide is studied. It is shown that Baiyi＇an Landslide is stable as a whole, but instable locally. The small or medium landslides may result in disassembly of Baiyi＇an Landslide. Debris flow may be locally triggered by intense rainfall. The dangerous parts of Baiyi＇an Landslide must be reinforced. The terraces in the front of Baiyi＇an Landslide are in favor of stability and it should be protected for reservoir operation. Small or medium landslides and debris flow are the main geologic hazards of Baiyi＇an Landslide area. During the long-term evolution of large ancient landslides, some geologic events happen occasionally, as a result that some geologic traces remain inside or on the landslides. By analyzing the geologic events and phenomena, the development trend of the landslide can be examined. It is necessary that the detailed geologic investigation should be carded out so that the minute and unobvious trails can be found out. By the combination analysis of historic geology with engineering geology of ancient landslide, evolution and characteristics of large ancient landslide can be revealed under the various geologic environmental conditions. The method can be used to qualitatively realize the stages of evolution of landslide and to evaluate landslide stability and its development trend.