岩溶隧道的围岩稳定和防突厚度并非一成不变,而受溶洞尺寸的影响较大,其影响规律和机理尚未明晰。基于FLAC3D数值模拟方法,构建隧道-溶洞三维计算模型和围岩能量可视化程序,系统研究溶洞尺寸对隧道围岩力学响应及能量演化规律的影响。结果表明:数值计算结果与实际监测结果吻合良好,验证了模型可靠性;隧道开挖后,溶洞半径与隧道跨度之比(T)对隧道围岩应力的影响较大,拉应力集中程度与溶洞尺寸正相关;随着T的增大会扩大位移分布范围,但通过缓冲空间释放应力,导致最大沉降和隆起值减小;大溶洞促使能量释放范围扩大但强度降低,表明应力扰动更分散;随着T的增大,最小防突层厚度逐渐增长,但增大幅度逐渐减小,逐渐趋于饱和。研究成果可为岩溶区隧道稳定性控制提供理论参考。
The stability of the surrounding rock and outburst prevention thickness of karst tunnel are not invariable. Still, it is greatly affected by the size of karst tunnel, and the influence law and mechanism are not clear. Based on FLAC3D numerical simulation method, the three-dimensional calculation model of tunnel karst cave and the surrounding rock energy visualization program are constructed, and the influence of karst cave size on the mechanical response and energy evolution law of tunnel surrounding rock is systematically studied. The results show that: The numerical results are in good agreement with the actual monitoring results, which verifies the reliability of the model; After tunnel excavation, the ratio of karst cave radius to tunnel span (T) has a great influence on the stress of surrounding rock of tunnel, and the degree of tensile stress concentration is positively correlated with the size of karst cave; With the increase of T, the distribution range of displacement is expanded, but the stress is released through the buffer space, resulting in the decrease of the maximum settlement and uplift value; The large karst cave makes the energy release range expand but the intensity decreases, indicating that the stress disturbance is more dispersed; With the increase of T, the minimum outburst prevention layer thickness gradually increases, but the increase amplitude gradually decreases, and gradually tends to saturation. The research results can provide theoretical reference for tunnel stability control in karst area.
[1] Pengtao A, Maosiang L, Shaokun M, et al. Analysis of the thickness of the outburst prevention layer in karst tunnels under the control of compressive faults[J]. Tunnelling and Underground Space Technology, 2024, 147: 105710.
[2] 雷霆,关欣,洪帆,等. 顶部溶洞水压对隧道突涌水灾害影响的数值分析[J]. 隧道建设, 2017, 37 (2): 167-173.
[3] 韩小敏. 野三关隧道大型高压富水充填溶腔运营期深化处理技术[J]. 中国铁路, 2021 (3): 33-40.
[4] Yan F, Qiu W, Sun K, et al. Investigation of a large ground collapse, water inrush and mud outburst, and countermeasures during subway excavation in Qingdao: A case study[J]. Tunnelling and Underground Space Technology, 2021, 117: 104127.
[5] Huang L, Ma J, Lei M, et al. Soil-water inrush induced shield tunnel lining damage and its stabilization: A case study[J]. Tunnelling and Underground Space Technology, 2020, 97: 103290.
[6] 周小龙,李澳,冯雪冬. 岩溶地区隧道围岩临界防突厚度数值分析[J]. 武汉工程大学学报, 2024, 46(4): 452-459.
[7] Zhang L W, Fu H, Wu J, et al. Effects of Karst Cave Shape on the Stability and Minimum Safety Thickness of Tunnel Surrounding Rock[J]. International Journal of Geomechanics, 2021, 21(9). 1943-5622.
[8] Zheng K, Shi C, Lou Y, et al. A computational method for tunnel energy evolution in strain-softening rock mass during excavation unloading based on triaxial stress paths[J]. Computers and Geotechnics, 2024, 169: 106212.
[9] Wu Y, Yang Z. A depth-averaged SPH-FV landslide dynamic model for evaluating hazard zones[J]. Computers and Geotechnics, 2024, 169: 106210.
[10] 安艳军,乔栋磊,万创业,等. 深埋隧道溶洞岩体防突层安全厚度研究[J]. 低温建筑技术, 2024, 46(2): 115-118,128.
[11] 冯雪冬. 岩溶地区引水隧洞突水机理与围岩稳定性分析[D]. 武汉:武汉工程大学, 2022.
[12] 李亚鑫. 岩溶隧道释能降压防突层安全厚度及其施工方案优化研究[D]. 成都:四川农业大学, 2022.
[13] 张桥. 小三峡岩溶隧道围岩防突层安全厚度有限元分析[J]. 中国岩溶, 2020, 39 (4): 614-621.
[14] 姚毅,常富贵,温元平,等. 基于能量可视化的岩溶隧道破坏机理研究[J]. 地下空间与工程学报, 2024, 20 (增2): 841-847.
[15] Liu Y, Zhang R, Hou S, et al. Investigation of energy evolution process of rock mass during deep tunnel excavation based on elasto-viscoplastic damage model and time-dependent energy indices[J]. Acta Geotechnica, 2024, 20(4): 1549-1570.
[16] 朱斯陶,姜福兴,王绪友,等. 特厚煤层掘进面围岩能量积聚特征及诱冲机制研究[J]. 岩土工程学报, 2019, 41 (11): 2071-2078.
[17] 张国华,李子波,李豫波,等. 煤厚变化区围岩能量积聚规律及开采方向对其影响[J]. 煤矿安全, 2024, 55 (9): 118-127.
[18] 劳志伟. 基于能量原理的隧道围岩与支护作用机制研究[D]. 成都:西南交通大学, 2022.
