泥水盾构带压开舱时泥膜的微观孔隙及渗透性研究

发布时间：2018-01-17 20:02

本文关键词：泥水盾构带压开舱时泥膜的微观孔隙及渗透性研究　出处：《岩土工程学报》2017年03期 　论文类型：期刊论文

【摘要】：泥膜的良好闭气性是保证泥水盾构带压开舱安全顺利实施的关键之一,要想提高泥膜的闭气性,首先应了解泥膜在带压开舱过程中的孔隙结构及渗透性变化。以南京纬三路过江通道在江底砂卵石地层中进行带压开舱为背景,在自制的试验装置中进行泥浆成膜和泥膜闭气试验,然后观测泥膜的孔隙结构和孔径变化,最后分析泥膜渗透系数的变化。研究结果表明:试验泥浆在0.2 MPa气压作用下6 h,在试验地层表面形成的泥膜厚度约为5.0 mm、孔隙率约为67%,在闭气过程中泥膜会发生压缩,且第一次单位压力引起的压缩量最大;随着闭气压力的增大,大孔隙组被优先压缩;泥膜基本单元体为骨架状结构,孔隙主要是粒间孔隙与架空孔隙,孔隙分布不连续、连通性差;孔径分布范围较广,其中在0.1~3.0μm的孔隙组占有绝对优势;本次试验中压缩后泥膜的渗透系数在10-9 cm/s量级。研究结果有助于明确泥膜在闭气过程中的变化,对后续提高泥膜闭气性的研究有重要的参考意义。
[Abstract]:The good gas closure of mud film is one of the keys to ensure the safe and smooth implementation of mud water shield belt opening tank, to improve the gas closure of mud film. First of all, the pore structure and permeability change of mud film in the process of zone compression opening should be understood. The mud film formation and gas closing test were carried out in a self-made test device, and then the pore structure and pore size of the mud film were observed. Finally, the change of permeability coefficient of mud membrane is analyzed. The results show that the thickness of mud film formed on the surface of test stratum is about 5. 0 mm under the pressure of 0. 2 MPa for 6 h. The porosity is about 67. During the process of gas closure, the mud film will be compressed, and the compression amount caused by the first unit pressure will be the largest. With the increase of the gas closure pressure, the macroporous group is preferentially compressed. The basic unit of mud film is skeleton structure, the pore is mainly intergranular pore and aerial pore, the distribution of pores is discontinuous, and the connectivity is poor. The pore size distribution range is relatively wide, among which the pore group with 0.1 渭 m 3.0 渭 m has the absolute advantage. In this experiment, the permeability coefficient of the compressed sludge membrane is in the order of 10-9 cm/s. The results are helpful to clarify the change of the sludge membrane in the process of gas closure. It has important reference significance for further study on improving the gas closure of mud film.
【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(“9 7 3”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项目(2015B06014);中央高校基本科研业务费专项资金项目(2016B50714)
【分类号】：U455.43
【正文快照】： 随着泥水盾构在过江过河隧道中的广泛使用,由于刀盘刀具过量磨损、刀盘结饼等引起的停机开舱检修问题已成为制约泥水盾构发展的重要难题[1]。盾构停机常位于高水压(一般大于0.5 MPa)、强透水(渗透系数一般大于10-2 cm/s)的复杂地层中,不具备地层加固等常压开舱的施工条件,以泥

【参考文献】