福建山区高速公路路堑高边坡风险分级方法研究

RISK CLASSIFICATION METHOD FOR HIGH CUT SLOPES OF HIGHWAY IN MOUNTAINS OF FUJIAN PROVINCE

为实现路堑高边坡设计阶段风险分级,合理安排资金投入及控制边坡工程风险,基于边坡工程地质分析原理、工程实践经验总结及反馈分析,从地形条件、地质条件、气象水文及其他因素等方面构建了4类16个路堑边坡工程风险因子评价指标体系,明确各评价指标的内涵及意义,并确定其风险评分标准。以龙岩双永高速公路永定段71个高边坡为对象,依据各工点设计阶段的勘察及测设成果,确定相应风险指标的评估值,采用层次分析法确定各指标权重,将这71个边坡分选为4个不同的风险等级,并提出相应的风险防控对策,最终建立一种实用的路堑高边坡设计阶段风险分级方法。依据全线挖方最高的K227滑坡风险评价过程,例证了该风险分级方法的可行性和合理性;引入两处风险控制失败的低矮边坡实例,从反面佐证了该方法的科学性和有效性,表明其在避免遴选疏漏方面具有明显优势。本文研究成果得到了施工实际情况的很好印证,使永定段成为双永高速公路全线边坡问题最复杂,但是在施工期和运营期边坡风险控制最好的区段。

This paper aims to research risk classification for high cut slope during design stage, arrange project investment reasonably and control risk in slope engineering. The classification is based on analysis principles of slope engineering geology and correlative experience summary or feedback analysis, through the analysis of terrain conditions, geological conditions, meteorology and hydrology, and other factors. As a result, the evaluation index system of risk factors for the cut slope is built. It then clears the significance of each evaluation index and determines its risk rating criteria. The system is applied to the risk evaluation of the 71 high slopes along Shuangyong Expressway in Yongding Country. A risk classification method of high cutting slopes during design stage is established. Firstly, an assessment value of each factor is determined according to the survey and design results. Secondly, using analytical hierarchy process, the weights of factors are calculated. Thirdly, 4 different risk classes are divided and the relative countermeasures are proposed to prevent and control risk. Furthermore, the system is applied to evaluation of the K227 landslide and other two low failed slopes. The result shows that this risk classification method is reasonable and feasible, and has evident advantage of avoiding omissions for selecting dangerous slopes. The findings demonstrate this highway is the best section of risk control in construction process and operation period although it has the most complex slopes along the whole highway.