郑万铁路许良隧道围岩稳定性分析与初支优化研究

发布时间：2019-03-15 15:01

【摘要】：当前,评价浅埋隧道围岩稳定性的方法往往比较单一,得到的评价结果难免会以偏概全,这在很多时候会造成难以估量的经济损失。本文以郑万高铁许良隧道为依托,综合采用有限元极限状态分析法、约束特征曲线法来评价许良隧道的安全性,同时,结合现场实测数据对其进行了验证。以此为基础,对许良隧道现有支护方案进行了优化,提出了切实可行的意见和建议,另外,对工程实践中常见的锚杆两种锚固方式的锚固效果进行了对比试验,主要包含以下几个方面的研究成果:(1)许良隧道进口段85m和出口段320m范围内,围岩稳定性差,隧道边墙处存在剪切滑移破坏的风险,在施工过程中应做好防范和应急措施,避免人员伤亡。(2)许良隧道采用的锚杆+喷射混凝土+型钢钢架组合支护方式整体刚度偏大,建议采取柔性支护方式进行支护;(3)现场实测数据表明,在当前设计支护方式下,隧道拱顶沉降和净空收敛趋于稳定,最终位移值在规范要求的范围之内;初期支护受力经过检算,小于支护结构的极限强度;(4)在原设计支护方式基础上,取消型钢钢架后,隧道净空位移增大约9.0%,喷射混凝土轴力增长约3.3%,弯矩增长约22.9%,锚杆受力增长约11.6%,取消前后影响不大且受力和位移均在可控范围之内,表明在保证锚杆施做质量的前提下取消钢架不会影响到许良隧道的安全。(5)在现有施工工艺的前提下,全长砂浆对锚杆的锚固效果要优于水泥基药卷,建议类似工程锚杆施工中采用砂浆进行全长粘结锚固。
[Abstract]:At present, the method of evaluating the stability of the surrounding rock of shallow tunnel is often relatively single, the evaluation results will inevitably be partial, which will cause incalculable economic losses in many cases. In this paper, the finite element limit state analysis method and the constraint characteristic curve method are used to evaluate the safety of Xueliang tunnel based on Zheng Wangao Tieshiliang tunnel. At the same time, the safety of Xuliang tunnel is verified in combination with the measured data in the field. On the basis of this, the existing supporting scheme of Xuliang tunnel is optimized, and feasible suggestions and suggestions are put forward. In addition, the anchoring effect of two kinds of anchor methods commonly used in engineering practice is compared and tested. The main results are as follows: (1) within 85m and 320m of entrance section and 320m exit section of Xueliang tunnel, the stability of surrounding rock is poor, and the risk of shear-slip failure exists in the side wall of the tunnel, so precautions and emergency measures should be taken in the construction process. Avoid casualties. (2) the bolting shotcrete steel frame combination supporting method adopted in Xuliang tunnel is on the large side, so it is suggested to adopt the flexible supporting method; (3) the measured data show that the settlement of tunnel arch and the convergence of clearance tend to be stable under the current designed support mode, and the final displacement is within the range required by the code. The strength of the initial support is less than the ultimate strength of the supporting structure after checking and calculating. (4) on the basis of the original designed support method, the net space displacement of the tunnel increases by about 9.0%, the axial force of shotcrete increases by 3.3%, the bending moment increases by 22.9%, and the force of anchor rod increases by 11.6% after canceling the steel frame. It is shown that canceling the steel frame will not affect the safety of Xueliang tunnel under the premise of ensuring the quality of bolt construction. (5) under the premise of existing construction technology, the steel frame will not affect the safety of Xueliang tunnel. (5) under the premise of existing construction technology, the steel frame will not affect the safety of Xueliang tunnel. The anchoring effect of full-length mortar is better than that of cement-based explosive roll. It is suggested that the full-length bonding anchoring of anchor rod in similar engineering should be carried out by mortar.
【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】：U451.2

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