川藏公路前-龙段Ⅰ#滑坡稳定性评价及治理建议

Stability analysis and treatment method for 1# landslide in Qian diao qiao-Longdanxi section of Sichuan-Tibet Highway

川藏公路前-龙段位于二郎山东坡,天全河上游,全长22.8km。该段河谷深切、地形陡峻、雨量丰沛、灌木丛生,线路沿河流右岸逆流而上。1994年该段公路进行技术改造。在改造过程中,大部分路段裁弯取直,下挖降坡,以直接切坡方式通过岩性破碎、构造复杂的区域。由于破坏了原坡体的稳定性,加之雨季施工,因而相继发生了大柏牛崩塌、严江坪滑坡、门坎山滑坡、鸳鸯崖滑坡、龙胆溪滑坡。1997年雨季,此段又发生了1#、2#及3#滑坡。其中,1#滑坡范围大、危害严重、滑体十分破碎、成因复杂、极具代表性。文章介绍了前-龙段地质情况及滑坡分布,重点研究Ⅰ#滑坡,对其稳定性进行详细的分析,得出该滑坡整治工程非常必要、切实可行的,它已经起到了作用的结论。并指出该滑坡目前存在的问题及解决办法。总结了山区道路建设地质选线和滑坡治理的原则。

The Qian diao qiao-Longdanxi section of Sichuan-Tibet road has a length of 22.8 kilometers, locating at the east slope in Erlang mountain, upper reach of the Tianquan River. The fiver valley is deep, the topography is steep, the rainfall is plentiful, the bush grows thickly and the road sways along the fight bank of the river. This section of highways were technologically treated in 1994. In the course of treatment, most highway section＇s curve cut-off, dig to lower the slope, pass the broken rock, complicated structure area by cutting slopes directly. Because the stability of the original slope body was destroyed and it was constructed in rainy season, there are five landslides and collapses in Daboniu, Yanjiangping, Mengkan mountain, Yuanyang precipice and Longdanxi respectively. In rainy season of 1997,1# , 2# and 3# landslides of this section come down again. Among them, 1# landslide is representative with large dimension, great danger, broken slippery body and complex composition. The report introduces the section＇ s geological situation and landslide distribution first, then analyses 1# landslide＇s stability, and points out the problems in the landslide and the counter measures. In the end, the report summaries the principles that should be followed in site selection, landslide survey and mountainous road construction design.