大断面黄土偏压隧道开挖侧向边坡稳定性影响分析  

Analysis of Lateral Slope Stability During Construction of a Loess Tunnel with a Large Section

作　　者：陈思阳[1,2] 朱彦鹏[1,2] 李忠[1,2] 黄丽华[1] 张浩亮[1] 

机构地区：[1]兰州理工大学土木工程学院,兰州730050 [2]兰州理工大学西部土木工程防灾减灾教育部工程研究中心,兰州730050

出　　处：《现代隧道技术》2014年第1期82-89,共8页Modern Tunnelling Technology

基　　金：国家科技支撑计划项目(2011BAK12B07);甘肃省自然科学基金(1107RJYA276)

摘　　要：大断面黄土偏压隧道穿越边坡时,由于隧道开挖断面大,施工频繁扰动土体,容易诱发滑坡、崩塌等工程风险。文章结合对隧址边坡进行预先加固的具体工程试验段,以边坡的稳定性计算为核心,选用改进的强度折减法,同时考虑抗拉强度指标与抗剪强度指标的折减;利用FLAC3D建立三维数值模型,模拟分析短台阶、CD、CRD三种施工方法对边坡稳定性的影响。工程实践表明:在大断面偏压黄土隧道开挖侧边坡潜在滑面不明确情况下,用改进后的强度折减法,分析开挖对侧向边坡稳定性的影响,其结果与实际情况比较符合;隧道连续开挖对侧向边坡稳定性影响明显;在边坡支护情况下,综合各项因素,大断面偏压黄土隧道宜采用CRD法开挖。For a loess tunnel with a large section passing through a lateral slope, some engineering risks like landslide or collapse are easily induced by tunneling construction, which frequently disturbs the soil mass. Based on a test section of a specific project, the lateral slope was reinforced before tunnel construction. With stability calculation for the lateral slope and using the improved strength reduction method, as well as reductions to the tensile strength index and shear strength index, the impacts of the three tunneling methods of short bench, CD, and CRD on lateralslope stability were simulated and analyzed using the FLAC3D numerical model. Engineering practice shows that the analytical results by improved strength reduction method generally agree with the actual ones under the condition of the undefined potential sliding surface of the lateral side slope, the effects on stabilityof the lateral slope is evident under continuous excavation, and the CRD method is most suitable for the construction of a unsymmetrical loading loess tunnel with a large section once the lateral side slope is reinforced.

关 键 词：隧道开挖 边坡稳定性 强度折减法 数值模拟 

分 类 号：U456.31[建筑科学—桥梁与隧道工程]