摘要
我国广泛分布有黏土矿物含量较高的土层和风化程度不均的岩层,盾构穿越时易出现结泥饼,盾构结泥饼已成为制约盾构安全高效施工的行业痛点问题。针对广州地铁12号线某区间隧道中粗砂-泥质粉砂岩复合地层盾构结泥饼问题,分析双模盾构泥水模式下刀盘泥饼形成过程及掘进参数变化规律,研究模式切换后土压平衡下基于盾构渣土调控的泥饼预防方法,并提出粗-细颗粒混合黏性地层理想渣土状态。研究表明:(1)双模盾构泥水模式在中粗砂-泥质粉砂岩复合地层掘进易形成泥饼,造成盾构总推力增大、推进速度降低,掘进参数波动性增强;(2)粗-细颗粒混合黏性地层理想渣土黏稠指数:扣除粒径大于0.15 mm且吸水完全的颗粒后,当残余渣土黏稠指数I_(c)始终小于0.5时,盾构无结泥饼风险,因此工程实践中可通过测定渣土中大于0.15 mm颗粒的吸水率来间接判定盾构是否存在结泥饼风险;(3)中粗砂-泥质粉砂岩复合地层宜选用土压平衡掘进模式,辅助采用分散型泡沫改良剂来调控盾构渣土,泡沫改良剂类型、泡沫半衰期、发泡率等指标需基于渣土中小于0.15 mm土样液限指标加以确定。
There are soil layers with high clay mineral content and unevenly weathered rock layers widely distributed in China.When shield tunelling passes through these soils,mud cake formation is prone to occur,which has become an industry pain point restricting the safe and efficient construction of shield tunnelling.In response to the problem of mud cake formation in the shield tunnelling of Guangzhou Metro Line 12 with coarse sand and argillaceous siltstone composite formation,this paper analyzes the formation process of cutterhead mud cake and the variation law of excavation parameters under the slury mode of dual-mode shield tunelling.The paper studies the mud cake prevention method based on shield tunnelling muck control under earth pressure balance after mode switching,and proposes the ideal muck state of coarse fine particle mixed viscous formation.Research has shown that:(1)the dual-mode shield tunelling under slurry mode is prone to forming mud cakes during excavation in medium coarse sand and argillaceous siltstone composite formations,resulting in an increase in the total thrust of the shield tunnelling,a decrease in the advance speed,and an increase in the fuctuation of excavation parameters;(2)Ideal viscosity index of mixed coarse fine particles in cohesive strata:After deducting paricles with a diameter greater than 0.15 mm and complete water absorption,when the residual viscosity index I_(c)of the excavated soil is always less than 0.5,there is no risk of mud cake formation in the shield tunelling.Therefore,in engineering practice,the water absorption rate of particles larger than 0.15 mm in the excavated soil can be measured to indirectly determine whether there is a risk of mud cake formation in the shield tunnelling;(3)For medium coarse sand and argillaceous siltstone composite stratum,the earth pressure balance tunnelling mode should be selected to assist the dispersed foam modifier to control the shield muck.The foam modifier type,foam half-life,foaming rate and other indicators should be determined based on the liquid limit indicators of soil samples less than 0.15 mm in the muck.
作者
陈令强
游关军
宋相帅
杨志勇
余俊
刘朋飞
CHEN Lingqiang;YU Guanjun;SONG Xiangshuai;YANG Zhiyong;YU Jun;LIU Pengfei(Guangzhou Metro Group Co.,Ltd.,Guangzhou 510220;China Communications(Guangzhou)Construction Co.,Ltd.,Guangzhou 511400;CCCC Second Navigation Engineering Co.,Ltd.,Wuhan 430040)
出处
《现代隧道技术》
CSCD
北大核心
2024年第S01期967-975,共9页
Modern Tunnelling Technology
关键词
隧道工程
泥水-土压双模盾构
刀盘泥饼
泥饼预防
渣土改良
Tunnel engineering
Slurry-earth pressure dual-mode shield machine
Mud cake on cutterhead
Mud cake prevention
Improvement of soil muck
作者简介
陈令强(1983-),男,学士,高级工程师,主要从事城市轨道交通相关施工、研究工作,E-mail:2532175916@qq.com;通讯作者:宋相帅(1993-),男,硕土,工程师,主要从事城市轨道交通相关施工、研究工作,E-mail:songxiangshai@163.com.
