摘要
[目的]富水砂层由于渗透性强、含水率高等特点,在盾构掘进过程中易因渣土改良不善而导致螺旋输送机出现喷涌以及刀盘结泥饼等事故,从而影响盾构施工效率,因此需对富水砂层土压平衡盾构渣土改良试验进行研究。[方法]依托南昌地铁4号线七里站—民园路西站区间典型富水砂层工况,开展室内渣土改良试验。采用自制盾构土舱模型装置对不同改良渣土进行土舱模型试验,基于渣土压力传递特性建立不同改良渣土的坍落度、渗透系数及土压传递系数K_(0)之间的相关关系,研究不同K_(0)下的渣土改良效果。[结果及结论]单独采用泡沫对渣土改良时,渣土的K_(0)与坍落度呈正相关,而与渣土的渗透系数呈负相关,而当渣土的坍落度超过200 mm时,K_(0)会逐步减小。为达到富水砂层土压平衡盾构中理想的渣土改良要求,改良剂配合比建议为:泡沫注入率为25%,或添加的膨润土泥浆注入率为10%。室内试验和土舱模型试验表明:K_(0)越大,渣土改良效果越好;实际工程中单独采用泡沫进行渣土改良后改良渣土的理想的K_(0)为0.60~0.65;而泡沫与膨润土泥浆相结合对渣土改良时,改良渣土理想的K_(0)约为0.85。
[Objective]Due to the characteristics of strong permeability and high water content in water-rich sand layer,the poor muck improvement can easily cause accidents such as spout spilling of screw conveyor and mud cake formation on the cutter plate during shield tunneling,thus affecting shield construction efficiency.So it is necessary to study the muck improvement of earth pressure balance shied tunnel in water-rich sand layer.[Method]Based on the typical water-rich sand layer working conditions in Qili Station-Minyuan Road West Station interval on Nanchang Metro Line 4,an indoor muck improvement experiment is carried out.The self-made shield soil chamber model device is used to implement soil chamber model experiments on different improved mucks.Based on muck pressure transfer characteristics,the correlations among slump,permeability coefficient and earth pressure transfer coefficient K_(0) of different improved mucks are established,and the improvement effect of muck under different K_(0) is studied.[Result&Conclusion]When foam is used alone to improve the muck,the transfer coefficient K_(0) of muck is positively correlated with slump,but negatively correlated with permeability coefficient of the muck.When the slump of the muck exceeds 200 mm,K_(0) decreases gradually.In order to achieve the ideal requirements of muck improvement for earth pressure balance shield in water-rich sand layer,the matched ratio of conditioners is suggested as follows:25%of foam injection,or 10%injection rate of added bentonite mud.Laboratory and soil chamber model experiments show that the greater K_(0) is,the better the improvement effect of muck will be.In actual projects,the ideal K_(0) value of improved muck by using foam alone is 0.60-0.65.While foam and bentonite slurry are combined to improve the muck,the ideal K_(0) of improved muck is about 0.85.
作者
蒋亚龙
黄玉龙
余金
黄展军
朱碧堂
JIANG Yalong;HUANG Yulong;YU Jin;HUANG Zhanjun;ZHU Bitang(School of Civil Engineering and Architecture,East China Jiaotong University,330013,Nanchang,China;Department of Architectural Engineering,Jiangxi Water Resources Institute,330013,Nanchang,China;Nanchang Urban Rail Group Co.,Ltd.,330038,Nanchang,China)
出处
《城市轨道交通研究》
北大核心
2024年第8期227-233,共7页
Urban Mass Transit
基金
国家自然科学基金项目(42377169,42267022)
江西省教育厅基金项目(GJJ2200678)。
关键词
富水砂层
土压平衡盾构
渣土改良试验
压力传递特性
water-rich sand layer
earth pressure balance shield tunnel
muck improvement experiment
pressure transfer characteristics
作者简介
第一作者:蒋亚龙,副教授,yalongjiang@whu.edu.cn;通信作者:黄展军,正高级工程师,1038344178@qq.com。
