风化岩层岩渣配制的盾构同步注浆浆液性能及微观形貌分析

为探索泥水盾构穿越风化岩层时产生的大量岩渣的再利用问题,依托南京和燕路过江通道工程,采用岩渣代替部分商品砂配制同步注浆浆液,并测试了浆液流动度、稠度、凝结时间、泌水率及强度等指标,分析了岩渣配制同步注浆浆液的性能及微观结构。结果表明:随着岩渣替换商品砂比例的增大,浆液流动度、稠度和泌水率逐渐降低,而凝结时间呈缩短趋势,1.d抗压强度也逐渐增大；替换比例在50%~85%时,浆液各项性能均满足工程施工要求,当替换比例为85%时,浆液流动度、稠度与现场浆液接近,凝结时间从10.6.h缩短至7.3.h,1.d抗压强度增强了近1倍；岩渣中含有的高岭石相矿物在水中会电解出Al3+,促进了浆液中C-S-H凝胶的形成,是促使浆液凝结时间缩短和抗压强度增大的根本原因。

Analysis on performance and micro morphology of shield synchronous grouting slurry made of weathered rock slag

In order to solve the problem of reusing a large amount of rock slag when the slurry shield passes through the weathered rock stratum, relying on the Nanjing Heyan road crossing-river project, the rock slag is used to replace part of commercial sand to prepare the synchronous grouting slurry. The fluidity, consistency, setting time, bleeding rate and strength of the slurry are tested through laboratory tests, and the performance and micro morphology of shield synchronous grouting slurry made of weathered rock slag are analyzed. The results show that: with the increase of the proportion of rock slag replacing commercial sand (denote as the replacing ratio), the fluidity, consistency and bleeding rate of the slurry decrease, while the setting time shows a decreasing trend, and the compressive strength gradually increases after 1 day. When the replacing ratio is 50% to 85%, all properties of the slurry can meet the requirements of engineering construction; when the replacing ratio of rock slag is 85%, the fluidity and consistency of the slurry are close to those of the on-site slurry, the setting time is shortened from 10.6.h to 7.3.h, and the 1-day compressive strength is nearly doubled. Kaolinite phase minerals contained in the rock slag will electrolyze Al3+ in water, which promotes the formation of C-S-H gel in the slurry, and is the fundamental reason for shortening the setting time of the slurry and increasing the compressive strength of the slurry.