岩质高边坡运营安全风险源辨识方法

A Method for Identifying Operation Safety Risk Source of Rocky High Slope

高速公路岩质高边坡运营期病害频发,为系统识别影响运营安全的风险源,研究提出风险源辨识方法。运用贝叶斯网络技术与风险传递路径方法确定了高边坡病害风险致因,分析了病害导致运营安全的风险机理;运用逐坡普查与重点调查,了解边坡基本信息与动态信息,提出了运营期高边坡风险源检查表,确定边坡断面几何特征与水的影响两个风险源指标,边坡断面几何特征指标(A)分为坡高(A_1)、坡度(A_2)与坡顶集中荷载(A_3)3个二级指标,水的影响指标(C)以渗流流量1 m3/d阈值作为分级标准。利用工程地质类比与复核,确定边坡岩体结构(B)与破坏模式(E)两个风险源指标,边坡岩体结构指标分为基岩风化特征(B_1)、坡体结构(B_2)与结构面特征(B_3)等3个二级指标,边坡破坏模式风险源指标分为崩塌脱落(E_1)、倾倒破坏(E_2)、平面破坏(E_3)、楔体破坏(E_4)与破坏模式难以确定(E_5)等5个二级指标。通过对支挡加固设施的设计定性分析、量化监测与计算,判断原设计的适宜性,由此确定边坡支挡加固设施指标(D),该指标分为抗滑桩及桩板墙(D_1)与锚杆/锚索框架(D_2)两个二级指标,每个二级指标根据病害损伤程度不同,划分了5%,10%,20%共3个缺陷分级量化标准。重庆某高速公路运营期高边坡风险源辨识结果表明,运用该方法能够系统准确辨识运营期岩质高边坡风险源并给出具体指标分级内容,为后续风险评估的开展奠定了基础。

Diseases of expressway rocky slope frequently happen during operation period, in order to systematically identify operation safety risk sources, the method of identifying the risk source is proposed. The risk factors of high slope disease are determined through the Bayesian network technology and the risk transfer path method, and the risk mechanism of operational safety caused by disease is analyzed. Based on the slope census and key point survey, the basic information and dynamic information of slope are obtained, the risk source check list of high slope in operation period is put forward, and 2 risk source indicators which are the slope geometry and the water impact are determined. The index of slope section geometry characteristics （A） is divided into 3 secondly indexes, which are slope height （A1） , slope angle （A2 ） and top concentrated load （A3）. The index of water impact （C） is determined by seepage flow of 1 ma/d threshold as the classification criterion. By utilizing engineering geology analogy and review, 2 risk source indicators which are rock mass structure （B） and failure mode （E） are determined. The rock mass structure index is divided into 3 secondly indexes, which are bedrock weathering characteristics （B1）, slope structure （B2） and structural plane characteristics （B3 ）, the failure mode index is divided into 5 secondly indexes, which are collapse and shedding mode （E1 ）, toppling failure mode （ E2 ） , plane failure mode （ E3 ）, wedge failure mode （E4 ） and failure mode that is difficult to determine （E5 ）. Through the qualitative analysis, the quantitative on-site detection and the numerical calculation, the design suitability is judged, thus the indicator of slope support and reinforcement facility （D） is determined, the index is divided into 2 secondly indexes, which are anti slide pile and pile wall （ D1 ） and anchor/anchor cable frame （ D2）, each secondly index is determined by different degree of disease injury, the defect classification quantitative criterion are divided as 5%, 10% and 20%. A case study result of an expressway rocky high slope in Chongqing during operation period shows that the method can be used to identify the risk source of rocky high slope in operation period accurately and systematically as well as to obtain the specific index classification, which lays a solid foundation for the follow-up risk assessment.