朱海明, 张生魁, 刘忠明, 等. 2022. 桃子垭深埋特长隧道地应力预测及复核[J]. 工程地质学报, 30(3): 863-873. doi: 10.13544/j.cnki.jeg.2021-0028.
    引用本文: 朱海明, 张生魁, 刘忠明, 等. 2022. 桃子垭深埋特长隧道地应力预测及复核[J]. 工程地质学报, 30(3): 863-873. doi: 10.13544/j.cnki.jeg.2021-0028.
    Zhu Haiming, Zhang Shengkui, Liu Zhongming, et al. 2022. Estimation and recheck of stress field at Taoziya deep-buried super-long tunnel[J]. Journal of Engineering Geology, 30(3): 863-873. doi: 10.13544/j.cnki.jeg.2021-0028.
    Citation: Zhu Haiming, Zhang Shengkui, Liu Zhongming, et al. 2022. Estimation and recheck of stress field at Taoziya deep-buried super-long tunnel[J]. Journal of Engineering Geology, 30(3): 863-873. doi: 10.13544/j.cnki.jeg.2021-0028.

    桃子垭深埋特长隧道地应力预测及复核

    ESTIMATION AND RECHECK OF STRESS FIELD AT TAOZIYA DEEP-BURIED SUPER-LONG TUNNEL

    • 摘要: 深埋特长隧道工程的高地应力问题越来越受到重视,如何准确高效地确定工程区地应力状态,是目前关注的重点和难点。针对深埋特长隧道地应力状态的确定问题,我们提出了基于多源数据的初始原地应力方向综合确定和应力量值预测及复核的综合解决方案。通过勘察阶段有限钻孔的地应力测试,并结合区域多源地应力资料,可以综合确定地应力方向并利用修正的Sheorey模型预测隧道轴线地应力;针对预测结果,在隧道开挖施工过程中,进一步利用有限钻孔的水压致裂地应力测试检验预测结果并复核隧道应力状况。结果表明,桃子垭隧道水平最大主应力方向为N15°W~N40°W,实测三向应力关系为SHSvSh;钻孔附近的应力预测值在区域实测应力量值变化范围内,隧道埋深最大处的水平最大、最小应力值分别达24 MPa和16 MPa;隧道施工过程中的4个钻孔应力量值复核结果显示,除了局部受到岩性变化、断裂破碎带等影响出现偏差,本文预测结果与实测应力量值基本一致。笔者发展的原地应力综合预测及复核方法,一方面可以快速有效地预测深埋特长隧道等线状工程的原地应力状态,有效降低初始勘察阶段地应力测试成本,另一方面,应力量值的复核保证了应力预测结果的可靠性,可以为隧道施工方案的及时变更及预算调整等提供有力依据和数据支撑。

       

      Abstract: Stress determination of deep-buried super-long tunnel has attracted more and more attention from scientists and engineers. How to determine the stress state especially for deep and complex geological conditions with high efficiency and accuracy has become a major concern in tunnel engineering and underground excavation. We developed an intergrated stress determination method for the stress determination of deep-buried super-long tunnel during engineering design and excavation. The method includes in-situ stress orientation and magnitude estimation based on multi-source data and stress recheck after excavation. For in-situ stress determination,we utilized the hydraulic fracturing in-situ stress measurements to obtain the stress magnitude and orientation of Taoziya tunnel in one deep borehole ZK3 before excavation. We analyzed the regional stress state using multi-source data by combining geomechanical trace analysis,Anderson's faulting theory,focal mechanics and stress inversion based on focal mechanism and stress database of China Mainland. We are based on the limited number of in-situ stress measurements in survey and design stage and regional multi-source data and used the modified Sheorey model combined with Hoek-Brown criterion to predict the initial stress along the designed tunnel axis. Finally,we rechecked the predicted stresses by hydraulic fracturing in-situ stress measurements of 4 boreholes in Taoziya tunnel during the tunnel construction. Results show that the preferred principal stress orientation is around N15°W~N40°W which is consistent with the regional stress orientation obtained from multi-source data except for the focal mechanics results. The stress orientation in shallow depth may be influence by topography and deviates from deep crustal stress. The relationship between three principal stresses is SHSv>Sh,which indicates that the stress regime is in favor of reverse faulting and strike-slip faulting. The predicted stress magnitudes are in the range of field measurements and database data near the borehole. The predicted magnitudes of horizontal maximum and minimum principal stresses are around 9.8 MPa and 6.6 MPa at the buried depth of 300 m,respectively,and 16 MPa and 10 MPa at the buried depth of 600 m,respectively. In the deepest buried depth,the predicted maximum and minimum horizontal principal stresses are around 24 and 16 MPa,respectively. The stress recheck in 4 boreholes along the tunnel axis indicates that the predicted stresses using modified Sheorey model are consistent with these stress measurement results in general. Local influence of lithology changes and fault fracture zone may lead to some excepts such as local bias and deviation of stress magnitude. The integrated stress prediction and recheck approach developed in this paper can ensure the efficiency and reliability of stress prediction results and reduce the cost for in-situ stress measurement in survey and design stage. And this method can also provide powerful evidence and data support for timely change of tunnel excavation scheme and budget adjustment,which is of great importance for successful completion of the project cost control.

       

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