富水粉细砂层盾构同步注浆复合浆液配比试验

Experimental Study on Composite Slurry Ratio for Synchronous Grouting of Shield Tunneling in Rich Water Powder Fine Sand Layer

为提高富水粉细砂地层盾构同步注浆的效率和质量,精准控制管片上浮位移,进行配比试验以期得到对富水地层具有良好适应性的浆液。基于常规惰性浆液通过单因素试验,确定出高分子材料羟乙基纤维素(HEC)和聚羧酸(PC)两种外加剂的掺量范围,然后采用正交试验,对水胶比、水玻璃、羟乙基纤维素和聚羧酸4因素3水平的试验结果进行极差分析,得到流动性好、凝胶时间可控、结石率高的复合浆液配合比。结果表明,针对富水粉细砂地层的复合浆液最佳配比为:水胶比0.8(A2),水玻璃掺量30%(B2),PC掺量0.1%(C1),HEC掺量0.2%(D2),这一配比在保证流动性(稠度10~12 cm)、凝胶时间(90~150 s)、结石率(97.53%)和抗压强度(2.63 MPa)的同时,优化了浆液的抗水分散性和经济性。采用推荐浆液配比进行同步注浆,管片的上浮位移可以控制在20 mm以内,满足规范要求。

In order to improve the efficiency and quality of synchronous grouting for shield tunneling in water rich fine sand formations,accurately control the upward displacement of pipe segments,and conduct proportioning tests in order to obtain a slurry with good adaptability to water rich formations.Based on the conventional inert slurry,the dosage range of two additives,hydroxyethyl cellulose(HEC)and polycarboxylic acid(PC),is determined by single factor test.Then,the range of test results of water binder ratio,water glass,hydroxyethyl cellulose and polycarboxylic acid in four factors and three levels is analyzed by orthogonal test,and the composite slurry mix ratio with good fluidity,controllable gel time and high stone rate is obtained.The results show that the optimal ratio of composite slurry for water rich silty fine sand formation is 0.8(A2),30%(B2),0.1%(C1)and 0.2%(D2)of PC,PC,HEC.This ratio optimizes the water resistance dispersion and economy of the slury while ensuring the fluidity(consistency 10~12 cm),gel time(90~150s),stonerate(97.53%)and compressive strength(2.63 MPa).Adopting the recommended slurry ratio for synchronous grouting,the upward displacement of the pipe segment can be controlled within 20 mm,meeting the regulatory requirements.