【作者】 张德萍；

【导师】 夏柏如； 周与诚；

【作者基本信息】 中国地质大学（北京） ， 地质工程， 2010， 硕士

【摘要】 第四系软弱地层是城市地下空间中常见的地层,而其中的粉细砂地层特别是饱和的粉细砂地层,一般都比较松散,无粘聚力,砂土体的自稳力能很差,在这种富含地下水的粉细砂地层中利用浅埋暗挖法修建城市地铁隧道,极易发生涌水、涌砂、地层塌陷等工程事故。为了保证隧道开挖工作面的稳定以及控制地表沉降,使工程施工能安全顺利进行,对富含地下水的粉细砂地层进行注浆堵水加固是施工过程中不可缺少的重要环节。本文结合北京地铁亦庄线亦庄火车站后渡线浅埋暗挖隧道注浆工程,利用理论分析、现场试验、实验室试验等方法对在饱和粉细砂地层的注浆作用机理以及作用效果进行分析研究,得出以下结论:(1)水平袖阀管后退式分段注浆工艺采用管内止浆塞分段止浆,止浆效果明显,并能实现定域、定压、定量、往复精细注浆。采用水平袖阀管后退式分段注浆技术对饱和粉细砂地层其进行超前预注浆堵水、加固,可以达到很好的堵水、加固的目的和效果。(2)对饱和粉细砂地层进行注浆堵水、加固,可以选用改性水玻璃浆液以及TGRM超细水泥浆液,并采用反复注入的方法。在定流量和注浆时间的条件下注浆,对于改性水玻璃以及水灰比小于1的TGRM超细水泥浆液可应用宾汉姆流体渗透扩散理论公式计算浆液的扩散半径以及单孔的理论注浆量,根据注浆施工记录,单孔的实际注浆量是比较符合理论值的。(3)对饱和粉细砂地层进行注浆后,粉细砂土体的稳定性和强度都得到了提高,加固后的粉细砂土体中有明显的粗、细相交的网状浆脉,整个注浆堵水、加固作用过程是充填渗透、挤密、劈裂复合注浆作用的结果。本文通过理论研究、现场试验、实验室试验等方法分析得出的结论对今后类似工程的施工具有一定的借鉴意义。更多还原

【Abstract】 Quaternary soft stratum is common in urban underground space, among which fine silt, specially saturated fine silt, is normally unconsolidated, without cohesion, and relatively weak stability. To build urban subway tunnels by shallow tunnel construction in fine silt stratum being rich in underground water will easily cause construction accidents, such as water gushing, sand boiling and ground subsidence, etc. To ensure the stability of tunnelling working face and control land subsidence, and the successful progress of the construction, it’s an indispensable important part to grout for water-blocking and consolidation in fine silt stratum rich in underground water in construction process.With the combination of shallow depth excavation grouting construction for Yizhuang training station rear line of Beijing subway Yizhuang line, this thesis has analyzed and researched saturated sand grouting mechanism and effect by theoretical analysis, field test, and laboratory test, etc., and a conclusion is reached as follows:(1) Retreating grouting process in sections for horizontal sleeve valve tubes applies internal stop-grouting plug to stop grout in sections. The stop-grouting effect is good, with repeated fine grouting with fixed area, pressure, and amount. The application of horizontal sleeve valve tubes by retreating grouting in sections on saturated sand stratum for pre-grouting water blocking and reinforcement will achieve good water-plug and reinforcement purpose and effect.(2) For water plugging and reinforcement on saturated fine silt stratum, modified water glass mix and TGRM microfine cement slurry can be applied with repeated grouting method. To grout under constant flow and set grouting period, Bingham fluid permeability and diffusion format could be applied to calculate extent radius of grout and theoretical grouting volume for single pore of modified water glass mix and TGRM microfine cement slurry with the water cement ratio as less than 1. In accordance with grouting construction record, actual grouting volume for single pore relatively conforms to theoretical values.(3) After grouting in saturated fine silt stratum, the stability and strength of find silt are both enhanced. After reinforcement, find silt stratum is with obvious netted grout veins. The whole grouting, water blocking and reinforcement process is the effect of complex grouting with the combination of filling infiltration, compaction and hydrofracture.The conclusion reached in this thesis by theoretical analysis, field test, and laboratory test, etc. is with definite practical guidance to similar constructions.更多还原