周航, 张广泽, 赵晓彦, 等. 2024. 深部极高地应力花岗岩隧道岩爆破坏特征及成因机理研究[J]. 工程地质学报, 32(3): 1098-1111. doi: 10.13544/j.cnki.jeg.2023-0455.
    引用本文: 周航, 张广泽, 赵晓彦, 等. 2024. 深部极高地应力花岗岩隧道岩爆破坏特征及成因机理研究[J]. 工程地质学报, 32(3): 1098-1111. doi: 10.13544/j.cnki.jeg.2023-0455.
    Zhou Hang, Zhang Guangze, Zhao Xiaoyan, et al. 2024. Rockburst failure characteristics and formation mechanism of deep granite tunnel with extremely high geo-stress[J]. Journal of Engineering Geology, 32(3): 1098-1111. doi: 10.13544/j.cnki.jeg.2023-0455.
    Citation: Zhou Hang, Zhang Guangze, Zhao Xiaoyan, et al. 2024. Rockburst failure characteristics and formation mechanism of deep granite tunnel with extremely high geo-stress[J]. Journal of Engineering Geology, 32(3): 1098-1111. doi: 10.13544/j.cnki.jeg.2023-0455.

    深部极高地应力花岗岩隧道岩爆破坏特征及成因机理研究

    ROCKBURST FAILURE CHARACTERISTICS AND FORMATION MECHANISM OF DEEP GRANITE TUNNEL WITH EXTREMELY HIGH GEO-STRESS

    • 摘要: 深部极高地应力花岗岩隧道施工过程中,岩爆灾害异常突出,硬岩岩爆不同程度地造成岩体片状剥落、棱板状破裂、岩块抛掷及强烈弹射等。为了揭示花岗岩隧道岩爆成因机制,综合地质调绘、监控量测、岩爆实录统计、室内岩石力学试验、微观分析和数值模拟分析等方法对隧道高地应力及岩爆的形成、破坏特征及影响因素进行探讨分析。根据现场岩爆实录统计分析,花岗岩隧道岩爆破坏特征复杂多样,发生时间集中,高水平构造应力使靠近雅鲁藏布江河谷一侧岩爆烈度显著增大,大埋深高自重应力导致岩爆主要分布在隧道掌子面和拱顶。基于钻孔实测地应力数据和初始地应力场反演分析,发现花岗岩隧道地应力场由构造应力和自重应力共同主导,隧道沿线82.0%的区段处于高到极高地应力状态,为岩爆的发生提供内动力地质条件。室内岩石力学试验表明二长花岗岩和花岗闪长岩均具有中等岩爆倾向性,厚层状、强度大、刚度高、完整性好的岩体为岩爆提供充足的物源条件。受控于雅鲁藏布江缝合带地质构造作用以及新生代岩浆活动作用影响,花岗岩隧道呈现高地温特征,地温梯度为5.5 ℃/100 m,最高实测地温达到89.6 ℃,高温热力耦合作用加速岩爆发生并提高岩爆危险性等级。隧道施工工艺会改变围岩应力重分布,影响围岩的应力集中,造成一定的尺寸效应,影响岩爆发生的烈度等级、时间和空间分布。

       

      Abstract: During the construction of a deep granite tunnel with extremely high geo-stress,rockburst disasters are extremely serious. The rock mass flakes off,forms slab-shaped fractures,and violently ejects rocks due to rockbursts. To reveal the formation mechanism of rockbursts in the granite tunnel,the formation,characteristics,and influencing factors of tunnel high geostress and rockbursts were discussed and analyzed. This includes engineering geological survey,monitoring and measurement,rockburst record statistics,indoor rock mechanics tests,microscopic analysis,numerical simulation,et al. According to statistical analysis of rockburst records,rockburst disasters are prominent in the construction of the granite tunnel,with complex and diverse damage characteristics and concentrated occurrence times. When affected by horizontal tectonic stress,the intensity of rockbursts near the side of the Yarlung Zangbo valley increases significantly,and when controlled by vertical stress,rockbursts are mainly distributed on the face and vault. Based on measured in-situ stress data of boreholes and inversion analysis of the initial geostress field,the granite tunnel is dominated by horizontal tectonic stress and vertical stress. 82.0% of the area along the tunnel is in a state of high to extremely high geo-stress,providing internal dynamic geological conditions for the occurrence of rock bursts. Laboratory rock mechanics tests show that both monzogranite and granodiorite have a moderate rockburst tendency,and the rock mass with thick layers,high strength,high stiffness,and integrity provide sufficient provenance conditions for rockbursts. Controlled by the special tectonic structure of the Yarlung Zangbo suture zone and the influence of Cenozoic magmatic activities,the granite tunnel presents high geothermal characteristics with a geothermal gradient of 5.5 ℃/100 m,and the highest measured ground temperature reached 89.6 ℃. The high-temperature thermo-mechanical coupling accelerates the occurrence of rockburst and increases the rockburst risk level. The quality of tunnel construction technology will change the stress redistribution of surrounding rock,affect the stress concentration of surrounding rock,cause a certain size effect,and affect the intensity level,time,and spatial distribution of rockburst.

       

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