双线平行隧道盾构施工引起的地表沉降研究

发布时间：2018-03-25 13:15

本文选题：并行隧道施工　切入点：反分析　出处：《大连海事大学》2017年硕士论文

【摘要】：随着城市的快速发展,土地资源变得越来越珍贵,对地下空间的开发越来越受到人们的重视。在对地下空间的利用中,一种高效的方式就是隧道。在隧道的设计时,经常会采用并行的两孔的布置形式。两孔隧道的施工会产生一定程度的相互影响,这种相互作用不仅影响围岩的应力状态和位移,而且对地表位移及支护荷载产生一定的影响。因此,对并行隧道施工的相互影响进行深入系统地探讨是十分必要的。本文首先回顾了双线平行隧道的研究现状,接下来对大连香工街～沙河口站区间隧道盾构施工方式及沉降测量方法进行了简要介绍。然后对双线隧道盾构施工引起的地表沉降机理进行了研究和分析,最后介绍了数值模拟软件FLAC3D以及盾构掘进的FLAC3D实现。在进行了地质参数敏感性反分析和上软下硬地层地铁盾构施工反分析之后,结合双孔并行隧道施工的实际情况建立一个双孔并行隧道先后开挖的三维计算模型。通过不同计算模型的对比,得出了影响地表沉降的四个因素:隧道的间距、围岩条件、掘进方式以及隧道埋深,得出以下主要结论:(1)在其他条件不变时,地表横向沉降范围随着上覆土层厚度的变大而变大,而地表的最大沉降量的变化趋势与地表横向沉降范围的变化趋势相反(2)在其他条件不变时,隧道的间距越大,地表沉降曲线的双峰形态越明显。当间距大于3D时,地表沉降曲线与两条隧道分别施工的叠加曲线几乎相同。(3)盾构隧道穿过的土层的主要成分是粉细砂、粉质粘土。当粉细砂不含水或者含水量很小时,其稳定性非常好。因此,当开挖土体的主要成分是粉细砂时,盾构施工所造成的地表沉降往往很小。相比来说,粉质粘土的稳定性就差得多。粉质粘土条件盾构施工所造成的地表的沉降很大。因此,在对地铁线路进行规划时,应该尽量避开粉质粘土地层。(4)不同的施工方式造成的地表沉降也不同。其中同向同时开挖造成的地表沉降最大,逆向同时开挖造成的沉降比前者小,同向不同时开挖造成的地表沉降最小。在施工条件允许时,应尽量采用同向不同时的开挖方法。(5)在复杂条件下对隧道地质参数敏感性进行反分析,中风化钙质板岩的C1、φ1对于测点位移的影响是最大的,其他参数对拱顶和拱底的影响都不大。从位移的极差值曲线图分析可以看出,强度参数对位移的影响比刚度参数的要大,主要通过C、φ值对位移产生影响。将反演参数计算值与已知监测位移值进行对比分析,结果表明实际现场监测值略小于数值计算结果,相对误差最大为9.62%,反演的结果令人满意,证明了反分析参数的可靠性。
[Abstract]:With the rapid development of cities, land resources become more and more precious, and people pay more and more attention to the development of underground space. In the use of underground space, a highly efficient way is tunnel. The construction of the two-hole tunnel will have a certain degree of interaction, which not only affects the stress state and displacement of the surrounding rock, but also affects the stress and displacement of the surrounding rock. Therefore, it is necessary to study the interaction of parallel tunnel construction deeply and systematically. Firstly, this paper reviews the research status of two-line parallel tunnel. Then, the construction method and settlement measurement method of shield tunneling between stations of Xianggong Street and Shahekou in Dalian are briefly introduced, and then the mechanism of ground subsidence caused by shield construction of double-line tunnel is studied and analyzed. Finally, the numerical simulation software FLAC3D and the FLAC3D realization of shield tunneling are introduced. Combined with the actual situation of double-hole parallel tunnel construction, a three-dimensional calculation model of two-hole parallel tunnel excavation was established. Through the comparison of different calculation models, four factors affecting surface subsidence were obtained: tunnel spacing, surrounding rock condition, and so on. The main conclusions are as follows: 1) when the other conditions are unchanged, the lateral settlement range of the surface increases with the thickness of the overlying soil layer. However, the variation trend of the maximum settlement of the surface is opposite to that of the lateral settlement range of the surface. When the other conditions are not changed, the larger the tunnel spacing is, the more obvious the bimodal shape of the surface settlement curve is. The surface settlement curve is almost the same as the superposition curve of the two tunnels respectively.) the main components of the soil layer through the shield tunnel are fine silty sand and silty clay. When the silt has no water or water content is very small, its stability is very good. When the main component of the excavated soil is silty sand, the ground subsidence caused by shield tunneling is often very small. Compared with the silty clay, the stability of silty clay is much worse. In the planning of subway lines, the ground subsidence caused by different construction methods should be avoided as far as possible, and the settlement caused by simultaneous excavation in the same direction is the largest, and the settlement caused by the reverse simultaneous excavation is smaller than that caused by the former. The surface subsidence caused by different excavation in the same direction is the smallest. When the construction conditions permit, the excavation method of the same direction and different time should be used as far as possible, and the sensitivity of the geological parameters of the tunnel should be analyzed back under the complicated conditions. The effect of C _ 1 and 蠁 _ 1 on the displacement of measured point is the biggest in the medium weathered calcareous slate, but the other parameters have little effect on the arch roof and arch bottom. From the analysis of the extreme difference curve of displacement, it can be seen that the influence of strength parameter on displacement is greater than that on stiffness parameter. The results show that the actual field monitoring value is slightly smaller than the numerical value, the maximum relative error is 9.62 and the inversion results are satisfactory. The reliability of the back analysis parameters is proved.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.43

【相似文献】