长大山岭隧道斜井与正洞交叉段数值模拟及分析

发布时间：2018-05-09 11:34

本文选题：斜井 + 正洞　；参考：《重庆交通大学》2014年硕士论文

【摘要】：在长大山岭隧道施工中,斜井与正洞交叉段的临空面大,受力结构复杂,在对开挖方法的确定、交叉段处岩土体的加固支护,以及施工监控量测方面均有特殊的要求。其受力分析、支护措施、施工步序、控制爆破等的理论研究尚不完善,还处于总结和积累经验阶段,因此,结合工程实践研究和分析长大隧道交叉段施工力学行为,具有一定的现实意义。交叉段开挖完后,交叉段两侧正洞的开挖将再一次引起斜井与正洞交叉段岩体和支护结构的应力释放和重分布,造成该段岩体和支护结构力学行为发生变化,而斜井与正洞相交角度的不同,对交叉段岩体和初支结构的力学行为产生的影响也将不同。然而,目前国内外关于长大隧道斜井与正洞交叉段在施工状态下的力学行为研究还较少,因此,开展长大隧道斜井与正洞交叉段的开挖、初期支护应力和变形的研究,分析斜井与正洞相交角度对交叉段及正洞普通段应力和变形的影响,无论是对理论体系的完善,还是对长大隧道的建设均具有十分重要的意义。本文以厦深铁路大南山隧道为工程背景,针对Ⅲ级围岩,采用数值模拟方法,建立了斜井与正洞交角分别为30°、60°、90°,以及大南山隧道1#斜井与正洞交叉段双联方案等四个模型,分析了斜井与正洞相交角度对交叉段围岩的应力、塑性区、喷射混凝土的应力、隧道的变形的影响,比较了单斜井正交方案和双联方案力学行为上的不同。研究发现,对于交叉段围岩最大主应力σ1,相交角度越小,交叉段刚开挖完时最大拉应力越大,当角度由90°变成60°时,增加3%,当角度由60°变成30°时,增加68%,相交角度越小,拉应力增长越快；对于交叉段围岩最小主应力σ3,相交角度越小,交叉段最大压应力越大,在交叉段刚开挖完的情况下,当角度由90°变成60°时,增加49%,当角度由60°变成30°时,增加40%；在交叉段两侧正洞贯通后,当角度由90°变成60°时,增加41%,当角度由60°变成30°时,增加30%：对于交叉段围岩的塑性应变最大值,相交角度30°比60°和90°大了一个数量级,而相交角度60°和90°交叉段处的塑性应变最大值相差不大；对于交叉段正洞垂直变形,相交角度越小,拱顶下沉越大,在斜井与正洞非正交的情况下,偏锐角侧拱顶下沉大于偏钝角侧；大南山隧道1#斜井与正洞交叉段双联方案交叉段围岩和初期支护的应力、变形大于单斜井方案；应加强对交叉段的支护,做好锁口工作。
[Abstract]:In the construction of Changshanling tunnel, the face of the cross section between inclined well and main hole is large and the stress structure is complicated. There are special requirements in the determination of excavation method, the reinforcement and support of virgin soil in the crossing section, as well as the construction monitoring and measurement. The theoretical study of force analysis, supporting measures, construction sequence and controlled blasting is not perfect, and it is still in the stage of summing up and accumulating experience. Therefore, combined with engineering practice, the construction mechanics behavior of cross section of long and long tunnel is studied and analyzed. Has certain realistic significance. After the excavation of the cross section, the excavation of the main hole on both sides of the cross section will once again cause the stress release and redistribution of the rock mass and the supporting structure in the cross section of the inclined shaft and the main hole, resulting in the change of the mechanical behavior of the rock mass and the supporting structure. The influence of the angle of intersection between inclined well and normal hole on the mechanical behavior of rock mass and initial branch structure of cross section is also different. However, at home and abroad, there are few studies on the mechanical behavior of the cross section between the inclined well and the main tunnel in the long tunnel. Therefore, the research on the excavation, initial support stress and deformation of the cross section of the inclined well and the main hole in the long tunnel is carried out. It is of great significance to analyze the influence of intersection angle between inclined well and normal hole on stress and deformation of cross section and common section of main tunnel, not only to the perfection of theoretical system, but also to the construction of long and long tunnel. In this paper, based on the engineering background of Dannanshan Tunnel of Xia-Shen Railway, and aiming at the third grade surrounding rock, four models are established, such as the angle between inclined well and main hole is 30 掳~ 60 掳~ 90 掳, and the double scheme of crossing section between inclined well and main hole of Dannanshan Tunnel is established. The effects of the angle of intersection between inclined well and main hole on the stress, plastic zone, stress of shotcrete and deformation of tunnel are analyzed, and the difference of mechanical behavior between orthogonal scheme and double scheme of single inclined well is compared. It is found that the smaller the intersection angle is, the greater the maximum tensile stress is when the cross section is just excavated. When the angle is changed from 90 掳to 60 掳, the maximum principal stress 蟽 1 increases by 3 points, and when the angle is changed from 60 掳to 30 掳, the increase of 68% and the angle of intersection are smaller. For the minimum principal stress 蟽 3 of the surrounding rock of the cross section, the smaller the intersection angle is, the greater the maximum compressive stress of the cross section is. When the angle of the cross section is just excavated, when the angle is changed from 90 掳to 60 掳, the increase of 49% is increased, and when the angle is changed from 60 掳to 30 掳, When the angle is changed from 90 掳to 60 掳, the increase is 41%, and when the angle is changed from 60 掳to 30 掳, the increase is 30%: for the maximum plastic strain of the surrounding rock of the cross section, the intersection angle of 30 掳is an order of magnitude greater than that of 60 掳and 90 掳. For the vertical deformation of the cross section, the smaller the intersection angle, the greater the dome sinking, and when the inclined shaft and the main hole are not orthogonal, the maximum plastic strain at the intersection angle of 60 掳and 90 掳is not different. The stress of surrounding rock and initial support in the cross section of 1# inclined well and main hole in Dannanshan Tunnel is greater than that in single inclined shaft, and the support of crossing section should be strengthened and the locking work should be done well.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455

【参考文献】