基于滑距计算与危险性评价的某平推式滑坡防治对策研究

Prevention and Control Countermeasures of Translational Landslide Based on Sliding Distance Calculation and Hazard Evaluation

为评价兰渝铁路某隧道出口滑坡对居民区和铁路运营安全的影响,通过现场调查、井中电视、理论公式计算、数值模拟等手段,分析了兰渝铁路某隧道出口大型岩质平推式滑坡的成因机理,依据滑坡稳定性评价、滑距计算和离散元数值模拟开展了危险性分区,提出了经济合理的防治对策。研究表明:降雨入渗滑坡后缘张拉裂缝,并形成后缘静水压力和滑面扬压力,最终诱发该滑坡失稳滑动;滑坡滑动距离>0.89 m的年发生概率<4.1%,滑坡滑动距离>2.15 m的年发生概率<0.17%;滑坡滑动2.15 m后,滑坡将处于稳定状态。滑坡滑动2.15 m后,滑坡前缘居民区处于极高危险区,隧道出口为中危险区,建议采取截排水+抗滑桩为主的工程治理措施。研究成果可在平推式滑坡的预测预警中加以应用。

To evaluate the impact of landslide on residential areas and the operational safety of the Lanzhou-Chongqing railway,we carried out field investigation,borehole teleview,mathematical formula calculation and numerical simulation to analyze the formation mechanism of large-scale translational landslide at tunnel exit.According to the result of landslide stability evaluation,sliding distance calculation and numerical modeling,we obtained the risk zoning and put forward some economic and reasonable countermeasures.The results demonstrate that:1)hydrostatic-pressure and uplift pressure generated by rainfall infiltration in landslide’s back edge induced the landslide instability;2)the annual probability of landslide sliding over 0.89 m is small than 4.1%,and 2.15 m 0.17%.After the landslide slides over 2.15 m,the landslide will be stable but poses high risk to the residential area in landslide’s front edge and medium risk to the tunnel exit.We suggest taking engineering measures integrating cut off drainage and anti-slide pile.The results are applicable to the prediction and early-warning of translational landslide.