贵阳黔春大道七冲村二号隧道施工数值模拟

发布时间：2018-02-05 20:07

  本文关键词： 浅埋 偏压 大跨度 三台阶七步工法 数值模拟　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：当前常用于浅埋偏压大跨度隧道开挖方法主要有全断面法、台阶法、环形开挖预留核心土法、CD工法、CRD工法、单侧壁导坑法、双侧壁导坑法等,各类施工工法有其自身可以施工的工程地质状况。大跨度隧道由于断面较大,洞内岩体开挖后围岩有较大的卸荷和变形空间,局部岩体可能出现变形过大而发生破坏,采用合理的施工工法在开挖过程中对围岩的卸荷和变形加以控制,是保证施工顺利进行的有效手段。采用不同的施工工法,开挖断面大小和对围岩的扰动程度不同,围岩的变形和应力释放情况也不同,再者,不同的施工工法所需要的材料成本、人工成本、机械成本和时间成本相差比较大,这和施工企业的经济效益密切相关。本文以贵阳市黔春大道七冲村二号隧道为研究对象,该隧道属于典型的浅埋偏压大跨度隧道,通过在现场进行监测试验和MIDAS-GTS有限元软件数值模拟相结合的方法,对本隧道开挖过程中所采用的工法进行研究。具体研究内容如下:(1)按试验要求在七冲村二号隧道开挖过程中对选定三台阶七步工法开挖断面进行了围岩与初衬间土压力、初衬与二衬间压力、围岩位移、钢拱架应变和二衬应变的监测工作,并对监测数据进行整理分析,得出实际开挖过程中围岩和支护结构的受力特性,说明三台阶七步工法可以适用于浅埋偏压大跨度隧道的开挖。(2)建立实际施工采用的三台阶七步工法数值模拟模型,对开挖状态下的围岩塑性区、围岩应力分布、围岩位移、初衬应力和二衬应力进行研究,得出围岩和支护结构的应力、应变的特点。将三台阶七步法开挖模型计算结果进行提取并与现场监测所得数据进行对比分析,证明该数值模型可以准确反应客观施工过程。(3)对选定隧道YK2+760断面进行三台阶七步法、单侧壁导坑法和双侧壁导坑法开挖进行数值模拟,对三种开挖工法下的围岩塑性区、围岩应力分布、围岩竖向位移和水平位移、初衬应力和二衬应力进行对比分析,得出三种施工工法下各自围岩和支护结构的应力、应变特点,找出各应力、应变指标之间的差异大小,说明三种工法均可满足现场施工需要,施工过程中可以根据具体工程地质条件需要,选择合适的开挖工法,以达到指导施工的目的。
[Abstract]:At present, the main excavation methods are full section method, step method, ring excavation reserved core earth method and CRD method, single side wall method, double side wall method and so on. All kinds of construction methods have their own engineering geological conditions. Due to the large section of large-span tunnel, the surrounding rock mass in the tunnel has larger unloading and deformation space after excavation. The local rock mass may be deformed and destroyed, so the unloading and deformation of surrounding rock can be controlled by reasonable construction method. Using different construction methods, the excavation section size and disturbance degree of surrounding rock are different, and the deformation and stress release of surrounding rock are also different. The material cost, labor cost, mechanical cost and time cost of different construction methods are quite different. This is closely related to the economic benefits of construction enterprises. This paper takes Qianchun Avenue Qichongcun No.2 Tunnel in Guiyang as the research object. The tunnel belongs to the typical shallow buried bias pressure long span tunnel. The method of combining the monitoring test with the numerical simulation of MIDAS-GTS finite element software on the spot is presented. In this paper, the working methods used in the excavation of this tunnel are studied. The specific research contents are as follows: 1). According to the test requirements, the earth pressure between surrounding rock and initial lining was carried out in the excavation process of Qichongcun No. 2 tunnel. Monitoring of initial and second liner pressure, surrounding rock displacement, steel arch frame strain and second lining strain, and analysis of monitoring data, the stress characteristics of surrounding rock and supporting structure during actual excavation are obtained. It shows that the three-step and seven-step method can be applied to the excavation of shallow buried biasing large-span tunnel. The numerical simulation model of the three-step seven-step construction method used in actual construction is established, and the plastic zone of surrounding rock under excavation state can be obtained. The stress distribution of surrounding rock, displacement of surrounding rock, initial lining stress and second lining stress are studied, and the stress of surrounding rock and supporting structure is obtained. The characteristics of strain. The calculation results of three-step and seven-step excavation model are extracted and compared with the field monitoring data. It is proved that the numerical model can accurately reflect the objective construction process.) the excavation of selected tunnel section YK2 760 can be numerically simulated by three-step seven-step method single-side wall method and double-side wall method. The plastic zone of surrounding rock, the stress distribution of surrounding rock, the vertical displacement and horizontal displacement of surrounding rock, the initial lining stress and the second lining stress under three excavation methods are compared and analyzed. The stress and strain characteristics of each surrounding rock and supporting structure under three construction methods are obtained, and the difference between the stress and strain indexes is found out, which indicates that the three construction methods can meet the site construction needs. In order to guide the construction, the appropriate excavation method can be selected according to the specific engineering geological conditions in the construction process.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.4
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本文编号：1492658