-
摘要: 为在施工前预防隧道塌方, 优化隧道设计, 以卧龙岗隧道施工塌方风险为研究对象, 对隧道初期支护进行了安全性分析, 明晰了诱发隧道塌方的风险因素, 结合隧道工程地质情况辨识了风险源, 采用层次分析法对风险源进行了重要性排序, 通过专家调查法对塌方风险发生的概率等级和风险损失等级进行了调查统计, 并运用风险矩阵法确定了塌方风险等级。分析结果表明: 初期支护及时封闭、临时支撑拆除时机、二次衬砌紧跟与爆破震动是塌方发生重要诱因, 卧龙岗隧道塌方风险等级为Ⅲ级, 风险等级较高。Abstract: In order to prevent tunnel collapse and optimize tunnel design before tunnel construction, the collapse risk of Wolonggang Tunnel was taken as research object, the safety of tunnel primary shoring was analyzed, the risk factors of tunnel collapse were cleared, risk sources were identified combined with tunnel geology conditions, and analytic hierarchy process was used to rank the importantces of risk resources.The probability grades and risk loss grades were confirmed through expert investigation, and the grades of collapse risk were given by using risk matrix technique.Analysis result indicates that tunnel collapse inducements include the prompt closing of primary shoring, the removing occasion of temporary timbering, the close following of secondary lining and blasting concussion.The collapse risk grade of Wolonggang Tunnel is grade Ⅲ and is higher.
-
Key words:
- tunnel construction /
- collapse risk source /
- risk grade /
- safety evaluation /
- control measure
-
表 1 荷载分担比例
Table 1. Sharing proportions of loads
工况 荷载分担 1 初期支护闭合, 无临时支撑, 荷载分担比例分别为30%、100% 2 初期支护未闭合, 开挖两导洞, 荷载分担比例分别为15%、30% 3 初期支护未闭合, 拆掉临时支撑, 荷载分担比例为30% 4 初期支护闭合, 未拆掉临时支撑, 临时支撑间添加水平支撑, 荷载分担比例为30% 5 初期支护未封闭, 拆掉临时支撑, 荷载分担比例为30% 6 初期支护封闭后, 拆掉临时支撑, 荷载分担比例为30% 表 2 衬砌材料参数
Table 2. Material parameters of tunnel lining
名称 弹性模量E/kPa 重度γ/(kN·m-3) 面积A/m2 惯性矩I/m4 衬砌 2.3×107 22 0.28 0.001 83 表 3 模型材料力学参数
Table 3. Mechanical parameters of model material
围岩级别 变形模量/(kPa) 重度/(kN·m-3) 泊松比 计算摩擦角/(°) Ⅴ级 1.5×106 18 0.4 42 表 4 计算结果对比
Table 4. Comparison of numerical results
工况 荷载分担比例/% 弯矩/(kN·m) 轴力/kN 安全系数 1 30 110.7 1 130.3 2.28 100 353.7 3 664.9 0.72 2 15 119.8 492.1 1.21 30 227.3 949.2 0.64 3 30 201.2 1 051.4 0.85 4 30 113.0 1 115.3 2.22 5 未拆撑 30 241.7 969.0 0.59 已拆撑 30 201.0 1 052.5 0.86 6 未拆撑 30 107.9 1 122.6 2.35 已拆撑 30 98.4 1 141.3 2.59 表 5 塌方风险判断矩阵
Table 5. Judgment matrix of collapse risk
塌方 爆破震动过大 超前支护不及时 初期支护未及时封闭 监控量测不及时 浅埋、偏压 二衬未紧跟 临时支撑一次拆除时机 爆破震动过大 1.00 0.33 0.14 3.00 0.17 0.33 0.20 超前支护不到位 3.00 1.00 0.25 4.00 0.33 3.00 0.33 初期支护未及时封闭 7.00 4.00 1.00 7.00 3.00 5.00 4.00 监控量测不及时 0.33 0.25 0.14 1.00 0.14 0.33 0.25 浅埋、偏压 6.00 3.00 0.33 7.00 1.00 5.00 3.00 二衬未紧跟 3.00 0.33 0.20 3.00 0.20 1.00 0.33 临时支撑一次拆除时机 5.00 3.00 0.25 4.00 0.33 3.00 1.00 表 6 一致性检验
Table 6. Consistency check
塌方 Wi (AW)i (AW)i/(nWi) 爆破震动过大 0.04 0.31 1.11 超前支护不到位 0.10 0.77 1.10 初期支护未及时封闭 0.37 2.94 1.14 监控量测不及时 0.03 0.22 1.05 浅埋、偏压 0.24 1.92 1.14 二衬未紧跟 0.07 0.49 1.00 临时支撑一次拆除时机 0.15 1.16 1.10 λmax 7.64 -
[1] 喻军, 刘松玉, 童立元. 半硬半软岩隧道塌方的力学特性及处理方法分析[J]. 工程地质学报, 2009, 17(2): 263-267. doi: 10.3969/j.issn.1004-9665.2009.02.019YU Jun, LIU Song-yu, TONG Li-yuan. Mechanical characteristics and treat ment method of collapse of tunnel with half-hard and half-soft rocks along its transverse section[J]. Journal of Engineering Geology, 2009, 17(2): 263-267. (in Chinese) doi: 10.3969/j.issn.1004-9665.2009.02.019 [2] 吴强, 刘新荣, 杜小平, 等. 马垭口隧道塌方事故发生机理的研究[J]. 地下空间与工程学报, 2009, 5(6): 1241-1247. https://www.cnki.com.cn/Article/CJFDTOTAL-BASE200906037.htmWU Qiang, LI U Xin-rong, DU Xiao-ping, et al. Study on collapse mechanism in the Mayakou Tunnel[J]. Chinese Journal of Underground Space and Engineering, 2009, 5(6): 1241-1247. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-BASE200906037.htm [3] 汪成兵, 朱合华. 隧道塌方机制及其影响因素离散元模拟[J]. 岩土工程学报, 2008, 30(3): 450-456. doi: 10.3321/j.issn:1000-4548.2008.03.025WANG Cheng-bing, ZHU He-hua. Tunnel collapse mechanism and numerical analysis of its influencing factors[J]. Chinese Journal of Geotechnical Engineering, 2008, 30(3): 450-456. (in Chinese) doi: 10.3321/j.issn:1000-4548.2008.03.025 [4] 杨晓华, 谢永利. 公路隧道坍方综合处治技术[J]. 长安大学学报: 自然科学版, 2004, 24(1): 61-64. https://www.cnki.com.cn/Article/CJFDTOTAL-XAGL200401015.htmYANG Xiao-hua, XIE Yong-li. Synthetical treatment technique for highway tunnel collapse[J]. Journal of Chang'an University: Natural Science Edition, 2004, 24(1): 61-64. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-XAGL200401015.htm [5] 陈洁金, 周峰, 阳军生, 等. 山岭隧道塌方风险模糊层次分析[J]. 岩土力学, 2009, 30(8): 2365-2370. doi: 10.3969/j.issn.1000-7598.2009.08.030CHEN Jie-jin, ZHOU Feng, YANG Jun-sheng, et al. Fuzzy analytic hierarchy process for risk evaluation of collapse during construction of mountain tunnel[J]. Rock and Soil Mechanics, 2009, 30(8): 2365-2370. (in Chinese) doi: 10.3969/j.issn.1000-7598.2009.08.030 [6] 周建昆, 吴坚. 岩石公路隧道塌方风险事故树分析[J]. 地下空间与工程学报, 2008, 4(6): 991-998. https://www.cnki.com.cn/Article/CJFDTOTAL-BASE200806002.htmZHOU Jian-kun, WU Jian. Fault tree analysis of the collapse riskin rock highway tunnel[J]. Chinese Journal of Underground Space and Engineering, 2008, 4(6): 991-998. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-BASE200806002.htm [7] 北京市地质工程勘察院. 卧龙岗隧道详细工程地质勘察报告[R]. 北京: 北京市地质工程勘察院, 2008.Beijing Institute of Geological Engineering. The Wolongang Tunnel engineering geology survey report details[R]. Beijing: Beijing Institute of Geological Engineering, 2008. (in Chinese) [8] JTJ004—89, 公路工程抗震设计规范[S].JTJ004—89, specifications of earthquake resistant designfor highway engineering[S]. (in Chinese) [9] JTG D70—2004, 公路隧道设计规范[S].JTG D70—2004, codefor design of roadtunnel[S]. (in Chinese)