富水砂层土压平衡盾构渣土改良试验研究  

Experimental Study on Muck Improvement when Using Earth Pressure Balance Shield Tunneling in Water Bearing Sandy Ground

作　　者：崔灿 CUI Can(China Railway 18^(th)Bureau Group No.3 Engineering Co.,Ltd.,Zhuozhou 072750,Hebei,China)

机构地区：[1]中铁十八局集团第三工程有限公司,河北涿州072750

出　　处：《路基工程》2023年第5期136-141,共6页Subgrade Engineering

摘　　要：富水砂层由于其高渗透性、高含水率及高摩擦角等特性,在盾构开挖时常面临喷涌、刀具磨损严重及掌子面压力不均等难题。依托南昌地铁4号线七里站至民园路西站高渗透富水砂层区间隧道工程,为确定最优膨润土泥浆改良参数,通过室内试验测试膨润土泥浆性能及渣土改良,确定合理膨润土泥浆黏度和盾构膨润土泥浆性能参数及高承压水砂层改良方案。研究结果表明:采用膨润土泥浆配比为1∶8,对应黏度约为22 mPa·s,改良效果较好;砂土中含水量可促进膨润土泥浆改善渣土流动性;对上述膨润土泥浆配比,当膨润土泥浆注入率为10%、聚合物注入比为1%时,改良后的渣土具有很好的流塑性和较低的渗透性。现场渣土改良结果也表明,采用上述渣土改良方案,可以有效降低刀盘扭矩和盾构机总推力、提高盾构掘进速度。Due to the high permeability,high water content,and high friction angle of the water bearing sandy ground,problems such as gushing accidents,severe tool wear,and uneven pressure on the face of the tunnel often occur when shield tunneling is used for excavation.Relying on the tunnel's engineering in water bearing sandy ground intervals with high permeability between Qili Station and Minyuan Road West Station of Nanchang Metro Line 4,in order to determine the optimal bentonite slurry improvement parameters,the performance of bentonite slurry was tested through indoor experiments.Moreover,reasonable viscosity of bentonite slurry,performance parameters of shield tunneling bentonite slurry and the improvement plan for high pressure water sand layer were determined through indoor muck improvement test.The research showed that when the ratio of bentonite and mud is 1:8 and the corresponding viscosity is about 22 mPa∙s,the improvement effect is better.The moisture content in sand can promote the bentonite mud to improve the slurry fluidity.For the above bentonite slurry ratio,when the bentonite slurry injection rate is 10%and the polymer injection ratio is 1%,the improved muck has good flow plasticity and low permeability.The results of on-site muck improvement also showed that the above-mentioned scheme can effectively reduce the torque of the cutter head and the total thrust of the shield machine,and increase the speed of shield tunneling.

关 键 词：渣土改良 土压平衡盾构 富水砂层 膨润土泥浆 渗透试验 

分 类 号：U455[建筑科学—桥梁与隧道工程]