秦岭深埋引水隧洞地应力综合测量及区域应力场分布规律研究

COMPLEX MEASUREMENTS OF GEO-STRESS IN DEEP DIVERSION TUNNEL AND RESEARCH ON DISTRIBUTION LAW OF REGIONAL STRESS FIELD IN QINLING MOUNTAIN

首次将三维水压致裂法和常规水压法应用于秦岭近1 000 m埋深引水隧洞地应力场研究,并对2种方法所得结果进行对比分析,结果表明:2种方法所测最大水平主应力范围主要为20～31 MPa,量值基本一致;最大水平主应力方向集中为NW～NWW向,印证了三维水压致裂法地应力测试结果的可靠性。最大水平主应力方向在隧洞深埋洞身段近EW向,与该区域内古残余构造应力分布相符,进一步反映了秦岭区域应力场的复杂性。同时,结合实测结果及隧洞围岩力学参数,对深埋隧洞开挖后应力重分布范围、测试部位的应力水平等问题进行分析和评价。最后,概括了秦岭区域地应力场分布规律,并绘出地应力实测结果分布图,这对于深入了解秦岭区域构造演化规律及科学指导越岭工程的设计和施工都具有重要的理论价值和实践价值。

The there-dimensional（3D） and normal hydro-fracturing tests are firstly applied to study the geo-stress field in deep depth of near 1 000 m diversion tunnel in Qinling mountain, and the results obtained from the two methods are analyzed comparatively. The results show that the magnitude of maximum horizontal principal stress from the two methods is accordant and the value is 20 - 31 MPa： and the orientation is mainly in NW to NWW direction. The results verify the reliability of the geo-stress test result of 3D hydro-fracturing method. Specially, the orientation of maximum horizontal principal stress is nearly in EW direction in rockmass of deep tunnel, which is consistent with the distribution of region ancient residual tectonic stress, and further shows that the distribution of regional stress in Qinling mountain is complex. Based on the measurement results and mechanical parameters of surrounding rock around tunnel, many problems about the stress such as redistribution range of stress after excavation stress level of measured region, etc., are all analyzed and evaluated. At last, the distribution law of geo-stress in Qinling area is generalized and the geo-stress measurement results are specially summarized in map, all of which can supply the theoretical and practical values for the detailed understanding of Qinling region evolution law and the design and construction of projects through the mountains.