长江三峡工程库区宝塔坪滑坡前缘塌岸预测及防护

Approximate forecasting methods for reservoir bank destruction and shore protection: case study

以长江三峡工程库区奉节宝塔坪滑坡为例,介绍滑坡前缘塌岸预测及防护工程设计方法,重点是石笼垫护坡设计。宝塔坪库岸段潜在的塌岸部位是滑坡前缘地带,该处阶地发育,仅第四系松散堆积物厚度即达50m以上。水库塌岸预测首先在滑坡前缘工程地质分带的基础上进行,对不同的分带用卡丘金法分别预测塌岸宽度,并对预测要点给予详细的说明。其次,分析了塌岸对滑坡稳定性的影响。这些工作揭示了滑坡体前缘防护的必要性。最后针对三峡水库运行特点及宝塔坪滑坡工程地质条件,确定滑坡前缘护坡工程方案,即自145～177m高程范围采用石笼垫和石笼挡土墙2类结构型式,并给出具体的设计方法。

Taking Baotaping landslide located at the middle part of the Three Gorges reservoir as an example, the paper has presented in detail the approximate forecasting methods for reservoir bank destruction and design theories for shore protection, with highlighting the design method for rock filled mattresses. Based on engineering geology research, it was predicted that the potential bank destruction was located in the front of the landslide where the thickness of Quaternary deposit reaches to 50m. The bank with potential destruction was further zoned into two parts of strips, the bank destruction widths were respectively predicted using Е Г Качугин method. The influence of bank destruction upon the stability of landslide has been assessed. All research works have shown that bank destruction of the front of the landslide necessitated slope protection. According to the characteristics of water level change in the Three Gorges reservoir, as well as the engineering geological condition of the landslide, the slope protection was limited between an elevation range of 145～177m and used rock filled mattresses revetment and retaining wall consisted of rock filled mattresses. Finally, the authors have concluded that rock filled mattresses used for the slope protection is the fittest one for protecting the Three Gorges reservoir bank.