考虑长期蠕变劣化的昔格达黏土岩公路路堑边坡稳定性评价及防护对策建议——以西攀高速公路边坡为例  

Stability assessment of the road cut slopes in the Xigeda mudstone considering long-term creep deterioration and suggestion for countermeasures:A case study of cut slopes along the Xichang-Panzhihua Expressway

作　　者：伍运霖 刘天翔 王丰 杜兆萌 雷航 WU Yunlin;LIU Tianxiang;WANG Feng;DU Zhaomeng;LEI Hang(Sichaun Highway Planning,Survey,Design and Research Institute Ltd.,Chengdu,Sichuan 610000,China)

机构地区：[1]四川省公路规划勘察设计研究院有限公司,四川成都610000

出　　处：《中国地质灾害与防治学报》2024年第4期56-66,共11页The Chinese Journal of Geological Hazard and Control

基　　金：四川省交通运输科技项目(2023-A-02,2024-A-04);四川省科技计划资助(2022YFG0141);四川省公路规划勘察设计研究院有限公司科研项目(KYXM2021000049)。

摘　　要：昔格达黏土岩存在长期蠕变劣化强度折减及饱水软化等不利工程特性,为典型易滑地层。此地层路堑边坡在运营期会持续劣化、稳定性降低,极易产生滑坡,对公路运营安全产生重大威胁。通过对西攀高速公路K2378+900右侧滑坡进行地质分析、数值模拟计算及相互验证,得到边坡在开挖建成及临滑两阶段的抗剪强度参数值,并据此计算出昔格达黏土岩长期蠕变劣化黏聚力(c)及内摩擦角(φ)值的折减系数分别为0.87,0.84。对5类、17种昔格达黏土岩边坡进行最危险滑裂面搜索及稳定性的计算分析得出:在抗剪参数按0.84~0.87长期蠕变劣化折减时,边坡的稳定系数平均降低0.184。基于此,对边坡稳定系数取值、坡比、支挡加固方式等昔格达黏土岩公路边坡长期稳定的关键因素提出了针对性管控建议,指出采用“缓放坡+宽平台+弱加固”的建设及处治思路更有利于昔格达黏土岩边坡长期稳定。研究结果为昔格达岩层区公路建设及边坡防护处治提供了重要指导和借鉴意义。The Xigeda clay-rock strata exhibit typical characteristics of long-term creep deterioration and saturation softening,which is typical slide-prone stratum.Landslides are easily formed in Xigeda strata cut slope due to the continuous deterioration and stability reduction during the operation period,which poses great threats to operational safety.The reduction coefficients for the c andφvalues due to long-term creep deterioration of Xigeda clay-rock are determined as 0.87 and 0.84 respectively.These values are derived from shear strength parameters of slope excavation and sliding obtained through geological analysis,discrete element numerical simulation,and mutual verification involving the K2378+900 right-side landslide on the Xichang-Panzhihua Expressway.By conducting critical slip surface searches and stability calculations for 17 distinct Xigeda clay-rock slopes representing 5 different types,the average decrease of stability coefficient is found to be 0.184 when shear parameters are reduced in accordance with creep deterioration within the range of 0.87~0.84.Consequently,targeted recommendations are proposed for key factors influencing the long-term stability of Xigeda clay-rock slopes,encomPassing safety coefficients,slope ratios,and reinforcement measures.It is demonstrated that employing a construction approach characterized by a gentler slope,wider platforms,and less intensive reinforcement is proved to be more conducive to the slope long-term stability.The research results provide important guidance and reference for highway construction and slope protection treatment within the Xigeda stratum area.

关 键 词：昔格达层 蠕变劣化 数值模拟 长期稳定 防护建议 

分 类 号：P642.22[天文地球—工程地质学]