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秦岭造山带基本呈东西走向,由于经历了长期的构造运动、岩浆活动和变质作用,形成了“三块两缝合带”的构造格局。整体来说,区域内断裂构造发育,岩性复杂,构造应力高且以水平应力为主。在秦岭地区,我国已陆续建成了宝成铁路、西康铁路、秦岭公路等一系列交通工程,但由于受复杂构造、地应力及岩性的影响,隧道建设过程中遇到如收敛变形量大、变形不易控制等诸多难题。为详细研究秦岭地区浅层地应力分布特征,通过收集秦岭造山带自西向东区域内29个钻孔的地应力实测资料,筛选出受局部影响较小的101组数据作为统计样本进行分析,分析了秦岭地区最大水平主应力、最小水平主应力以及侧压系数随埋深分布特征,并验证了构造应力方向以NNE,NNW为主,反映了顺时针NE-SW和逆时针NW-SE的构造方向特征。
The Qinling orogenic belt basically shows east-west trend. Due to long-term tectonic movement, magmatic activity and metamorphism, the formation pattern of “three suture zones” has been formed. On the whole, faults within the region developed with complex lithology, high tectonic stress and horizontal stress. In the Qinling area, a series of traffic projects such as Baocheng Railway, Xikang Railway and Qinling Highway have been built in succession in our country. However, due to complex structure, in-situ stress and lithology, the tunnel construction encountered many problems such as large convergence and deformation, Deformation is not easy to control and many other problems. In order to study the distribution characteristics of shallow geostress in Qinling area in detail, by collecting the measured data of 29 boreholes from the west to the east of the Qinling orogenic belt, the data of 101 groups with small local influence were selected as the statistical samples for analysis. The maximum horizontal principal stress, minimum horizontal principal stress and lateral pressure coefficient are distributed along depth in Qinling area, and the tectonic stress directions are mainly NNE and NNW, which reflect the tectonic direction of NE-SW and NW-SE feature.