摘要
土压平衡盾构掘进是软土地区地铁隧道施工的主要方法之一,但是盾构在穿越塑流性差、含水量高、渗透系数大的砂性土层时,存在土体受扰动发生液化、流砂或由于螺旋出土器出土困难使工作面形成“干饼”等许多技术难题。为此,研究了盾构穿越砂性土层时采用合适的添加剂的施工工艺,并在盾构(工作面)原位对砂性土层掺入泡沫剂和肥皂水2种添加剂进行盾构推进对比试验,结合室内砂性土土样掺入泡沫剂和肥皂水试验数据,对比分析了掺入2种不同添加剂对减小盾构在砂性土层中的推进阻力及其对改善砂性土层特性的影响。在试验数据分析的基础上,对添加剂增加砂性土的塑流性、保水性以及工作面动态土压平衡机理作了较深入的探讨。研究结果表明,掺入添加剂易形成工作面动态土压平衡,有效控制地面沉降,并可加快螺旋出土器排土,减少刀盘扭矩、千斤顶推力及刀头磨损。
Earth pressure balanced (EPB) shield is one of the most important ways in tunneling. While there are still many troubles including disturbing soil liquefaction, quick sand, 'dry cake' at work-face due to the output difficulty of soil through screw during tunneling in sandy soil with low plasticity, high water content, and large penetration coefficient. The suitable additives (soapy water and foaming agent) are used to improve construction condition when tunnel passes through sandy strata. In-situ tests were conducted to compare shield driving force with different additives blended in sandy strata. Sandy soil mixed with additives is analyzed by laboratory tests. In addition, influences of two different additives on shield driving force in sandy strata for improving characteristic of sandy strata are compared. Based on the tested data, the effects of two additives in improving plasticity-fluid and capability of retaining water of sandy strata as well as the balance mechanics of shield work-face are discussed thoroughly. The research is valuable in improving characteristics of sandy strata to keep shield work normally while reducing construction deformation, controlling ground settlement efficiently, facilitating soil output through screw, decreasing torque and abrasion of cutter head, and decreasing driving force of jack and avoiding geological disaster.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2005年第1期52-56,共5页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(40372124)
上海市重点学科基金项目(沪教委科[2001]44 号)
关键词
土力学
土压平衡盾构
砂性土层
扰动液化
抗液化掺加剂
Additives
Liquefaction
Settlement of structures
Soil mechanics
Torque
Tunneling (excavation)
