反压条件下泥水盾构开挖面泥膜致密性评价试验

发布时间：2018-04-01 03:21

本文选题：盾构隧道　切入点：泥膜致密性评价　出处：《中国公路学报》2017年08期

【摘要】：为了准确评价泥水盾构存在反向水压条件下开挖面形成泥膜的致密程度,利用自制的可施加反压的泥浆渗透装置,开展6组不同压力条件下的泥浆渗透试验,通过测试试验过程中的滤水量和地层孔压的变化,以及形成泥膜的厚度和含水量,计算泥膜渗透系数、干密度及有效泥浆压力转化率等指标,分析有、无反压条件下泥膜的致密程度差异及其形成机理。研究结果表明,反压的存在降低了有效泥浆压力转化率,使得形成的泥膜孔隙比和渗透系数更大,干密度更小,即泥膜结构更为疏松;采用滤水量与泥膜体积的比值较单独采用滤水量可以更准确地评价泥膜的致密程度,其比值越大表示单位体积的泥膜内含有的土颗粒越多,泥膜结构越致密。研究结果对实际工程中泥膜质量的评价及开挖面稳定性分析有重要意义。
[Abstract]:In order to accurately evaluate the densification degree of mud film formed by dredging surface under the condition of reverse hydraulic pressure in mud shield, six groups of mud permeation tests under different pressure conditions were carried out by using a self-made mud permeation device which can be applied to reverse pressure.By testing the variation of filtration water and pore pressure in formation, the thickness and water content of mud film, the permeability coefficient, dry density and conversion rate of effective mud pressure are calculated.The densification degree of mud film and its formation mechanism are different under the condition of no back pressure.The results show that the existence of backpressure reduces the conversion rate of effective mud pressure and makes the pore ratio and permeability coefficient of mud membrane larger and the dry density smaller that is to say the structure of mud membrane is more loose.The ratio of filtration water to sludge membrane volume can evaluate the density of mud membrane more accurately than that of single filter water volume. The larger the ratio is, the more soil particles are contained in the membrane per unit volume, and the denser the membrane structure is.The results are of great significance to the evaluation of mud film quality and stability analysis of excavated surface in practical engineering.
【作者单位】：河海大学岩土力学与堤坝工程教育部重点实验室;河海大学土木与交通学院;
【基金】：国家重点基础研究发展计划(“九七三”计划)项目(2015CB057803) 国家自然科学基金项目(51408191) 中央高校基本科研业务费专项资金项目(2015B06014)
【分类号】：U455.43

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