泥质粉砂岩地层土压平衡盾构渣土改良试验研究与应用

发布时间：2018-05-06 06:18

本文选题：土压平衡盾构 + 渣土改良　；参考：《中南大学》2014年硕士论文

【摘要】：摘要：在土压平衡盾构掘进过程中,为了使盾构掘进顺利、减小对地层扰动且有效维持掌子面稳定等目的,需要对渣土进行改良。本文以南昌地铁1号线五标盾构区间为依托,采用现场调研、室内试验、现场应用验证等手段,重点对盾构在泥质粉砂岩均一地层砂砾石与其组成的上软下硬地层中掘进的渣土改良进行了研究探讨。论文主要研究内容及成果如下： (1)基于所依托工程的地质水文情况,对土压平衡盾构所掘进地层的泥质粉砂岩进行矿物成分分析和液塑限试验,并对富水砂砾石进行筛分等试验,推测盾构在掘进过程中存在结”泥饼”和喷涌等渣土改良问题。 (2)针对可能出现的渣土改良问题,拟定室内试验方案对渣土进行改良试验以得到盾构掘进的改良参数。根据各添加剂的改良机理拟采用泡沫剂进行改良。同时,为了鉴定改良剂的发泡和稳定性能,设计了两个装置对泡沫剂的性能进行鉴定。其后进行了坍落度试验,确定了针对几种典型渣土的改良参数。以此根据坍落度选定了渣土改良的含水率及最优泡沫比。 (3)考虑到渣土改良的最优泡沫比范围较大的问题,以渣土改良室内试验结果为基础,同时根据渣土状态的影响因素,对盾构施工时的渣土改良泡沫剂用量进行了优化。 (4)考虑现场地质条件、隧道设计与施工参数,推导出计算公式确定现场施工的渣土改良参数。通过对现场的改良参数进行采样以及参数统计对渣土改良新方案进行效果验证。实践表明渣土改良新方案能够有力地指导现场施工,有效地预防泥质粉砂岩地层中盾构结”泥饼”和上软下硬地层中喷涌等问题。
[Abstract]:Abstract: in the process of earth pressure balanced shield tunneling, it is necessary to improve the residual soil in order to make the shield tunneling smooth, reduce the disturbance to the stratum and maintain the stability of the face effectively. Based on the five-mark shield machine section of Nanchang Metro Line 1, this paper adopts field investigation, indoor test, field application verification and so on. The improvement of residual soil driven by shield tunneling in the homogeneous formation of argillaceous siltstone and its composition in the upper soft and lower hard formations is studied and discussed in this paper. The main contents and results of this thesis are as follows: (1) based on the geological and hydrological conditions of the supported engineering, the mineral composition analysis and liquid-plastic limit test of argillaceous siltstone excavated by earth pressure balance shield tunneling are carried out, and the screening tests of water-rich sand and gravel are carried out. It is inferred that there are problems of mud cake formation and residual soil improvement in shield tunneling process. 2) aiming at the possible residual soil improvement problem, an indoor test scheme was developed to improve the residual soil in order to obtain the improved parameters of shield tunneling. According to the improvement mechanism of each additive, foam agent is used to improve the properties. At the same time, in order to identify the foaming and stability of the modifier, two devices were designed to evaluate the properties of the foam agent. Then the slump test was carried out, and the improvement parameters for several typical residual soils were determined. According to the slump, the moisture content and the optimum foaming ratio of residual soil were selected. (3) considering the problem that the optimum foaming ratio of residual soil improvement is large, based on the results of laboratory test of residual soil improvement, and according to the influence factors of residual soil state, the amount of residue modified foaming agent in shield tunneling construction is optimized. (4) considering the field geological conditions, tunnel design and construction parameters, the calculation formula is derived to determine the residual soil improvement parameters in site construction. The effect of the new scheme of residual soil improvement was verified by sampling the improved parameters in the field and statistics of the parameters. The practice shows that the new scheme of residual soil improvement can effectively guide the field construction and prevent effectively the problems of shield forming "mud cake" in muddy siltstone formation and jet in upper soft and hard stratum.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.43

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