基于响应面法的泥水盾构同步注浆材料性能

泥水盾构隧道在富水高压地层掘进中,同步注浆浆液易逸散流失,为满足注浆要求,需研制出复掺外加剂的高性能注浆材料.以南昌地铁4号线过江盾构隧道工程为依托,在传统外加剂材料的基础上引入纳米材料,选用膨润土(BE)、羟乙基甲基纤维素(HEMC)与纳米二氧化硅(NS)为复合外加剂组分,采用响应面法,以外加剂掺量为配合比变量,探讨3种外加剂及其交互作用对注浆浆液性能的影响.研究表明:①在对凝结时间影响方面,NS＞ HEMC＞ BE,NS具有促凝作用,而HEMC起缓凝作用;在对抗压强度影响方面,HEMC＞ NS＞ BE,HEMC与BE不利于抗压强度发展,NS可以显著提高抗压强度;在对抗水分散性影响方面,HEMC＞ BE＞ NS,HEMC与BE有利于改善抗水分散性.②NS具有小尺寸、高活性等特点,可以加速水泥水化进程,缩短浆液初凝时间,提高浆体早期强度,对浆液性能起着积极作用.③通过响应面法建立的回归模型与响应曲面,可以很好地反映外加剂对浆液性能的影响,同时能对复掺外加剂的浆液配比进行优化,所制备的新型注浆材料能够满足在富水高压地层盾构隧道施工的注浆要求.

Study on Performance of Synchronous Grouting Material forSlurry Shield Based on Response Surface Method

In the process of slurry shield tunneling in water-rich and high-pressure stratum, the synchronous grouting slurry is easy to escape and lose. In order to meet the grouting requirements, it is necessary to develop high-performance grouting materials mixed with admixtures. based on the slurry shield crossing river tunnel project, in this paper, based on the traditional additive materials, nano materials are introduced, and bentonite (be), hydroxyethyl methylcellulose (HEMC) and nano silica (NS) are selected as composite additives. The response surface method is used to explore the influence of three additives and their interaction on the performance of grouting slurry. The results show that 1) In terms of the effect on the setting time, NS>HEMC>BE, has the effect of promoting coagulation, while HEMC has the effect of retarding coagulation; In terms of the impact of compressive strength, HEMC>NS>BE, HEMC and BE are not conducive to the development of compressive strength, NS can significantly improve the compressive strength; In terms of water dispersion resistant, HEMC>BE>NS, HEMC and BE help to improve water dispersibility. 2) NS has the characteristics of small size and high activity, which can accelerate the hydration process of cement, shorten the initial setting time of slurry, improve the early strength of slurry, and play a positive role in the performance of slurry. 3) The regression model and response surface established by response surface method can well reflect the influence of additives on slurry performance, and optimize the slurry ratio of compound additives. The new grouting material can meet the grouting requirements of shield tunnel construction in water-rich and high-pressure stratum.