风化含水岩层非对称小净距隧道施工力学特性研究

发布时间：2018-05-19 13:25

本文选题：非对称小净距隧道 + 隧道分类　；参考：《西南交通大学》2017年硕士论文

【摘要】：在非对称小净距隧道进行设计时,对隧道进行深、浅埋的分界是计算围岩垂直荷载的主要依据;对非对称小净距隧道进行影响分类可以为支护结构的选取和支护结构的施作时机提供重要的参考。然而目前,在此方面尚无成熟的理论和相关规范可供参考。此外,随着水下隧道、海底隧道以及富水地层中地下铁路的大量修建,渗流分析、流固耦合分析与不良地层的加固处理技术仍有待研究。首先,基于塌落拱理论和塑性区分析,对非对称小净距隧道的深、浅埋进行了判定;确定了双洞之间影响严重,应当尽量避免小于的最小净距值;通过应变能密度转换规律的理论分析,给出了简化的应变能密度计算公式。综合上述研究,提出了非对称小净距隧道的影响分类表。其次,通过有限元进行数值模拟,研究了在各级围岩情况下和采用不同开挖方式时,隧道衬砌结构的变形和内力情况,提出了优化的开挖方法以及左右洞施工顺序等。研究了注浆加固和对拉预应力锚杆等对改善中岩墙稳定性的作用,以及不同注浆加固范围、预应力锚杆的布设形式和各种加固手段的主要适用条件等。再次,通过渗流分析,模拟出降水条件和自然水面下隧道开挖后的渗流场的稳态状态,研究了隧道开挖后渗流场的变化;通过理论公式和数值模拟对隧道内涌水量进行计算;通过流固耦合分析,研究掌子面前方的土体应力场、位移场的变化规律,以及基于Coulomb失效准则研究掌子面渗流对掌子面稳定性的影响。最后,基于渗透原理和宾汉流体本构模态,建立了黏性浆液以恒定注浆速率在岩石裂隙中扩散的理论模型,推导出了渗流模型和假定裂隙模型两种模型的岩石裂隙浆液扩散压力场与渗流场随时间和空间的计算公式,并利用数值模拟进行了验证。通过理论解析和数值模拟,研究了考虑流固耦合作用后不同注浆速度下注浆压力、注浆半径、裂隙率和渗透率随时间的变化。
[Abstract]:In the design of asymmetric small clear distance tunnel, the deep and shallow boundary of tunnel is the main basis to calculate the vertical load of surrounding rock. The influence classification of asymmetric small spacing tunnel can provide an important reference for the selection of supporting structure and the timing of supporting structure. However, at present, there is no mature theory and relevant norms for reference. In addition, with the construction of underwater tunnel, undersea tunnel and underground railway in water-rich stratum, seepage analysis, fluid-structure coupling analysis and reinforcement of bad stratum are still to be studied. Firstly, based on the theory of collapse arch and the analysis of plastic zone, the depth and shallow burying of asymmetric small net distance tunnel are judged, and the influence between the two holes is serious, so the minimum net distance value should be avoided as far as possible. A simplified formula for calculating strain energy density is given through theoretical analysis of the transformation law of strain energy density. Based on the above research, a classification table of the effects of asymmetric small spacing tunnels is proposed. Secondly, the deformation and internal force of tunnel lining structure are studied under various surrounding rock conditions and different excavation methods by finite element method, and the optimized excavation method and construction sequence of left and right tunnels are put forward. The effects of grouting reinforcement and prestressed anchor rod on improving the stability of middle rock wall, as well as the different grouting reinforcement range, the layout of prestressed anchor rod and the main applicable conditions of various reinforcement methods are studied. Thirdly, through seepage analysis, the steady state of seepage field after tunnel excavation under natural water surface is simulated, the change of seepage field after tunnel excavation is studied, and the water inflow in tunnel is calculated by theoretical formula and numerical simulation. Through the fluid-solid coupling analysis, the variation law of soil stress field and displacement field in front of palm surface is studied, and the influence of percolation on the stability of palm surface is studied based on Coulomb failure criterion. Finally, based on the permeation principle and the constitutive mode of Bingham fluid, a theoretical model for the diffusion of viscous slurry in rock fractures at a constant grouting rate is established. The calculation formulas of diffusion pressure field and seepage field with time and space of rock fissure slurry in two models of seepage model and assumed fracture model are derived and verified by numerical simulation. Through theoretical analysis and numerical simulation, the variation of grouting pressure, grouting radius, fracture rate and permeability with time under different grouting velocities considering fluid-solid coupling is studied.
【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】：U455.4

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