超细水泥-水玻璃双液浆性能及注浆止水效果试验研究

Experimental Study on Performance and Grouting Water Plugging Effect of Ultrafine Cement⁃Sodium Silicate Slurry

北京地铁14号线高家园站的站厅层和站台层采用暗挖通道连接,地层为富水粉细砂层。为解决暗挖通道采用普通水泥-水玻璃双液浆注浆止水效果差且地表隆起较大的问题,提出采用超细水泥-水玻璃双液浆注浆止水的方案。首先对浆液流动性、凝结时间和固结体强度进行测试,根据测试结果确定了超细水泥-水玻璃双液浆的配合比:A液为超细水泥净浆,水灰比为1.0;B液为水玻璃溶液,波美度为20°Bé;缓凝剂为磷酸氢二钠,掺量为2.5%。A液约占总注浆量的80%,B液与缓凝剂各占约10%。采用颗粒流数值模拟方法,研究了超细水泥浆液中颗粒在地层中的运移距离与注浆压力的关系。结合浆液性能测试和数值模拟结果,提出了注浆压力0.5 MPa,注浆孔直径5 cm,间距50 cm,梅花形布置的注浆方案。经在暗挖通道现场注浆试验,采用超细水泥-水玻璃双液浆注浆止水效果良好。

The station hall and platform of Gaojiayuan Station on Beijing Metro Line No.14 are connected by a underground channel,which passes through a water-rich silty and fine sand stratum.In order to solve the problem of poor water plugging effect and excessive surface uplift in the underground channel,the scheme of ultrafine cement-sodium silicate slurry grouting to plug water was proposed.Firstly,the fluidity,setting time and consolidated body strength of the slurry were tested,and the mix proportion of ultrafine cement-sodium silicate was determined according to the test results.Liquid A was ultrafine cement slurry with a water-cement ratio of 1.0,liquid B was a sodium silicate with a concentration of 20°Bé,and the retarder was disodium hydrogen phosphate with a dosage of 2.5%.Liquid A accounts for about 80%of the total grouting amount,and liquid B and retarder each account for about 10%.The relationship between the migration distance of particles of ultrafine cement slurry in the stratum and grouting pressure was studied by the PFC(Particle Flow Code)method.Combined with the results of slurry performance test and numerical simulation,a grouting scheme with a grouting pressure of 0.5 MPa,a grouting hole diameter of 5 cm,a spacing of 50 cm,and a plum blossom-shaped arrangement was proposed.The results of on-site grouting test in the underground channel show that the ultrafine cement-sodium silicate slurry grouting has a good effect on water plugging.