雅康高速公路二郎山隧道地应力特征与围岩分级研究

发布时间：2018-12-18 16:34

【摘要】：地应力会对隧道设计与施工造成重大的影响,它受到了区域内地形与地质构造等多种因素作用。现阶段,利用钻孔进行地应力实测是最为有效的地应力场获取手段。但受到地形、技术及资金的制约,大范围的地应力钻孔实测并不现实。因此,可以通过计算机反演计算的方式获得区域的地应力。另一方面,相关数据表明,目前常用的围岩分级方法对于复杂地质条件下的深埋特长隧道适应性较差,不利于指导隧道施工与支护。因此建立了一种适用于复杂地质条件下的围岩分级判定方法,具有相当的意义。本文以雅康高速公路二郎山隧道为例,取得的研究成果如下:1.分析了二郎山隧道区域的工程地质环境。二郎山隧道在地理上处于四川盆地与青藏高原交汇的中～高山区,构造上位于我国西部著名的三大构造体系交汇的三岔口一侧。地形雄伟起伏、沟壑丛生,地质构造复杂、断层节理发育,岩层出露较为完整。2.根据CATIA与FLAC3D之间的耦合关系,编写了CATIA-FLAC3D 口转换程序。以CATIA为建模平台,建立了二郎山隧道区域三维地质模型,并利用接口程序转换到FLAC3D中进行分析模拟。依据弹性力学叠加原理,以6种边界条件来模拟自重应力与构造应力作用,得到计算应力分量,并通过与实测应力分量的回归分析得出研究区域的地应力场拟合公式。最终求得,二郎山隧道轴线最大主应力为56.61Mpa,区域内极高、高地应力地区占到隧道总长的58.47%。3.以反演计算得到的隧道初始地应力为基础,通过地质综合法与强度应力比法预测隧道轴线围岩的岩爆与大变形。求得二郎山隧道不发生岩爆的区域占隧道总长的79.7%,发生岩爆的区域以轻微岩爆为主,局部存在中等及强烈岩爆。不发生大变形的区域占到隧道总长的91.4%,发生大变形区域仅仅占到8.6%,且多为轻微大变形,少数局部地区中等～强烈大变形。4.由于现阶段常用BQ法不能较好的满足复杂地质条件下的深埋特长隧道围岩等级判定,本文在查阅国内外多种规范的基础上,参考BQ法并结合现场经验建立了二郎山隧道施工阶段的BQsg围岩分级方法,综合考虑了定性与定量性质,分层逐步对围岩分级,并运用于现场实际进行验证。
[Abstract]:The geostress will have a great influence on the design and construction of the tunnel, and it is affected by many factors, such as the topography and geological structure in the region. At present, it is the most effective method to obtain the in-situ stress field by using borehole to measure the in-situ stress. However, due to the constraints of topography, technology and funds, it is not realistic to measure the borehole stress in a wide range. Therefore, the in-situ stress of the region can be obtained by computer inversion. On the other hand, the relevant data show that the commonly used surrounding rock classification methods are less adaptable to the deep-buried super-long tunnel under complex geological conditions, which is not conducive to guiding the construction and support of the tunnel. Therefore, it is of great significance to establish a classification method of surrounding rock for complex geological conditions. Taking Erlangshan Tunnel of Yakang Expressway as an example, the research results are as follows: 1. The engineering geological environment of Erlangshan Tunnel area is analyzed. The Erlangshan Tunnel is geographically located in the mid-high mountain area where the Sichuan Basin and the Qinghai-Tibet Plateau meet, and structurally on the side of the intersection of the three famous structural systems in the west of China. The topography is majestic and undulating, the gullies are numerous, the geological structure is complex, the fault joints are developed, and the strata are relatively intact. 2. According to the coupling relationship between CATIA and FLAC3D, the CATIA-FLAC3D port conversion program is written. Based on CATIA, a 3D geological model of Erlangshan Tunnel is established, and the interface program is used to analyze and simulate it in FLAC3D. According to the superposition principle of elastic mechanics, six kinds of boundary conditions are used to simulate the action of self-gravity stress and tectonic stress, and the stress component is calculated, and the fitting formula of in-situ stress field is obtained by regression analysis with the measured stress component. Finally, the maximum principal stress of the axis of Erlangshan Tunnel is 56.61Mpa. the area is extremely high, and the area of high ground stress accounts for 58.47% of the total length of the tunnel. Based on the initial geostress obtained from the inversion calculation, the rock burst and large deformation of the surrounding rock around the tunnel axis are predicted by the geological comprehensive method and the intensity stress ratio method. It is found that the area without rockburst in Erlangshan Tunnel accounts for 79.7% of the total length of the tunnel. The area where the rockburst occurs is mainly slight rockburst, and there is moderate and strong rockburst in the local area. The area without large deformation accounts for 91.4% of the total length of tunnel, and the area of large deformation only accounts for 8.6%, and most of them are slight large deformation, and a few local areas are medium to strong large deformation. 4. At present, the BQ method can not meet the criteria of the surrounding rock grade of the deep buried extra-long tunnel under complicated geological conditions, so this paper looks up a variety of codes at home and abroad. Referring to BQ method and combined with site experience, the BQsg surrounding rock classification method in the construction stage of Erlangshan Tunnel is established. The qualitative and quantitative properties are considered synthetically, and the surrounding rock classification is graded step by stratification, which is verified by the field practice.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U452.1

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