苗尾水电站倾倒边坡顺层开挖变形响应

DEFORMATION OF TOPPLING SLOPE UNDER BEDDING EXCAVATION OF MIAOWEI HYDROPOWER STATION

我国西南地区水电建设中发现了较多深层倾倒变形边坡,在顺层开挖条件下出现小开挖引起大变形的现象,研究该类边坡的开挖变形响应对于指导工程设计具有重要意义。以澜沧江苗尾水电站左右坝肩边坡为例,结合现场资料、变形监测数据等对倾倒边坡顺层开挖条件下的变形响应进行综合分析。结果表明,倾倒边坡开挖后,边坡的变形高度和开挖高度具有较强的相关性,初始变形位于开挖面以上一定范围,随着边坡向下开挖,变形向上部延展,当坡脚开挖或软化时,变形范围将达到最大,并集中于坡顶1/3~1/5边坡高度范围内,“坡脚小开挖,上部大变形”特征明显。

In the hydropower construction in Southwest China,there are many deep toppling deformation slopes,and the phenomenon of large deformation caused by small excavation occurs under bedding excavation.It is of great significance to study the excavation deformation response of such slopes for guiding the engineering design.Taking the left and right abutment slopes of Miaowei hydropower station on Lancang River as an example,combined with the field data and deformation monitoring data,the deformation response of the topping slope under the condition of bedding excavation is comprehensively analyzed.The results show that there is a strong correlation between the deformation height of the slope and the excavation height after the excavation of the topping slope.The initial deformation is located in a certain range above the excavation surface.As the slope is excavated downward,the deformation extends upward.When the slope toe is excavated or softened,the deformation range will reach the maximum,and will be concentrated in the range of 1/3~1/5of the slope height at the slope top.The characteristics of“small excavation at the slope toe and large deformation at the upper part”are obvious.