盾构管片壁后新型同步双液浆开发及工程应用

Development and Engineering Application of Novel Synchronous Double-Component Grouting behind Shield Segment

针对盾构施工中管片易发生上浮、错台等不良现象,通过室内试验对促强干粉(A料)、液体激发剂(B料)不同掺比的同步双液浆进行物理特性测定,并基于此开发出一种新型可调节初凝时间的同步双液浆。研究结果表明:(1)合理调配A料、B料掺比,同步双液浆的初凝时间可控制在30~60 min;(2)新型双液浆的初凝时间、流动度主要由B料控制,随着B料掺比的增加,初凝时间、流动度显著减小,当B料掺比大于3%后趋于稳定;(3)新型双液浆结石体强度由A料、B料共同控制,当A料、B料掺比分别为1.5%、3.5%时,结石体强度基本达到最大值;(4)A料与B料的最优掺比分别为1.5%~3.71%、1%~2.2%。在广州市中心城区地下综合管廊工程采用该新型同步双液浆,管片拼装质量得到了大幅提高,表明开发的新型双液浆具有良好的充填性与泵送性,克服了单液浆和传统双液浆在全断面围岩地层同步注浆的施工难题。

Upward floating and dislocation often occur to shield segments during construction.Therefore,a physical property test is conducted on double-component grout with different mixing proportions of strength-promoting dry powder(material A)and liquid activator(material B).On this basis,a novel synchronous double-component grout with adjustable initial setting time is developed.The results indicate the following:(1)The initial setting time of synchronous double-component grout can be controlled within 30~60 min by a reasonable mixing ratio of materials A and B.(2)The initial setting time and fluidity of the novel double-component grout are principally controlled by material B.With the increase of the mixing proportion of material B,the initial setting time and fluidity decrease significantly and tend to be stable when the mixing proportion of material B is more than 3%.(3)The strength of the novel double-component grout stone body is controlled by materials A and B.When the mixing proportions of materials A and B are 1.5%and 3.5%,respectively,the strength of the stone body basically reaches the maximum value.(4)The optimum mixing proportions of materials A and B are 1.5%~3.71%and 1%~2.2%,respectively.The novel synchronous double-component grout has been applied in the underground utility tunnel project in the central urban area of Guangzhou,China,and the assembly quality of segments has been greatly improved.This indicates that the novel double-component grout has good filling and pumping performance,and it addresses the construction problem of synchronous grouting of single-component and traditional double-component grout in the full-section surrounding rock stratum.