王智阳, 王浩杰, 张晓平. 2022. 大埋深高地应力硬岩TBM隧洞围岩破裂变形规律研究[J]. 工程地质学报, 30(5): 1678-1688. doi: 10.13544/j.cnki.jeg.2022-0281.
    引用本文: 王智阳, 王浩杰, 张晓平. 2022. 大埋深高地应力硬岩TBM隧洞围岩破裂变形规律研究[J]. 工程地质学报, 30(5): 1678-1688. doi: 10.13544/j.cnki.jeg.2022-0281.
    Wang Zhiyang, Wang Haojie, Zhang Xiaoping. 2022. Fracturing and deformation mechanism of surrounding rock of deep-buried and high in-situ stress hard rock TBM tunnel[J]. Journal of Engineering Geology, 30(5): 1678-1688. doi: 10.13544/j.cnki.jeg.2022-0281.
    Citation: Wang Zhiyang, Wang Haojie, Zhang Xiaoping. 2022. Fracturing and deformation mechanism of surrounding rock of deep-buried and high in-situ stress hard rock TBM tunnel[J]. Journal of Engineering Geology, 30(5): 1678-1688. doi: 10.13544/j.cnki.jeg.2022-0281.

    大埋深高地应力硬岩TBM隧洞围岩破裂变形规律研究

    FRACTURING AND DEFORMATION MECHANISM OF SURROUNDING ROCK OF DEEP-BURIED AND HIGH IN-SITU STRESS HARD ROCK TBM TUNNEL

    • 摘要: 大埋深、高地应力隧洞围岩变形问题是制约TBM隧洞安全及高效施工的关键性因素之一。隧洞埋深大、地应力高、岩石强度高、工程条件复杂,在施工过程中因开挖卸载,围岩变形随时间及应力集中程度不同表现出不同的破裂变形形式,引发拱顶沉降、拱底隆起,严重威胁施工人员及机械设备安全。本文选取引汉济渭工程秦岭隧洞岭北段K45+534.70~K45+701.92区间,分析了围岩破裂形式、隧洞拱肩及拱顶变形特征,探讨了高地应力条件下围岩破裂变形过程,揭示了围岩破裂变形规律及内在机制,提出了高地应力硬岩隧洞围岩破裂变形支护措施。结果表明:大埋深、高地应力围岩在切向应力作用下发生以劈裂为主的张剪破坏,表现为岩爆及静态脆性破坏(片帮、溃屈、板裂)两大类。隧洞围岩破裂变形分为急剧变形、快速变形及缓慢变形3个阶段,前两个阶段可达总变形量的60% ~80%;隧洞拱顶变形随应力条件不同可能出现二次甚至三次加速变形,初次加速主要原因为张开裂隙、岩板剪胀及部分岩板挠屈弯折,发生速度快、持续时间短;二次加速主要由岩板挠屈弯折及岩块碎胀引起,变形速度小但持续时间长。针对高地应力隧洞围岩破裂变形特征,提出了包括吸能锚杆、钢筋挂网、钢纤维混凝土等在内的围岩支护措施,为相似工程TBM隧洞安全高效施工提供了工程经验与理论依据。

       

      Abstract: The deformation of surrounding rock in deep depth caused by high in-situ stress is a key factor that restricts the safe and efficient construction of TBM tunnel. As a result of deep depth,high in-situ stress,and hard rock,there are different kinds of failures in the surrounding rock after the excavation unloading. The failure pattern varies with time and the degree of stress concentration. It may cause vault settlement and arch bottom uplift,which greatly threaten the safety of construction personnel and equipment. The failure pattern and deformation of surrounding rock of Yin-Han-Ji-Wei water conveyance tunnel(K45+534.70-K45+701.92) are monitored and examined in this present paper. The process of surrounding rock failure is analyzed. The law of deformation of arch shoulder and vault is revealed,and the support measures for deformation of hard rock with high in-situ stress are put forward. As a result of tangential stress of surrounding rock,tensile-shear failure is mainly caused by splitting. The failures of surrounding rock include rock burst and static brittle failure(rib spalling,exfoliation,slabbing failure). The deformation of surrounding rock can be divided into three stages: rapid deformation stage,transitional stage and slow deformation stage. The deformation at initial two stages is about 60% ~80% of ultimate deformation. Accelerated deformation may occur two or three times in some conditions. The first acceleration is mainly caused by the opening cracks,the dilatation of rock slab and the partial flexion,which occurs quickly and lasts for a short time. However,the second acceleration deformation is mainly caused by the deflection of rock slab and the expansion of rock block. Its deformation speed is small but the duration is long. The surrounding rock support measures including NPR bolt,steel arch and steel fiber reinforced concrete are put forward,which provides engineering experience and theoretical basis for the safe and efficient construction of similar TBM tunnels.

       

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