溶洞回填黏土快速固化配方试验研究  

Experimental Study on Rapid Solidification Formula of Clay Backfill for Karst Cave

作　　者：倪嘉卿 李忠 朱帅[1] Ni Jiaqing;Li Zhong;Zhu Shuai(College of Urban Railway Transportation,Shanghai University of Engineering Science,201620,China;School of Civil Engineering,Lanzhou University of Technology,730050,China)

机构地区：[1]上海工程技术大学城市轨道交通学院,201620 [2]兰州理工大学土木工程学院,730050

出　　处：《特种结构》2022年第4期91-95,共5页Special Structures

摘　　要：为解决溶洞地层桩基成孔施工时传统片石黏土回填过程中存在漏浆、回填次数多、进度缓慢等问题,提出一种基于矿渣水泥快速固化回填黏土的方法,开展了以水泥与矿渣为基础,在单掺Na_(2)SO_(4)和复掺Na_(2)SO_(4)+CaO情况下不同配方与配比的回填黏土快速固化室内试验研究。结果表明:(1)水泥与矿渣用量比为5:5时为最快固化黏土的配比,水泥与矿渣用量比为3:7时为经济性与固化速度综合最优配比;(2)水泥与矿渣中单掺Na_(2)SO_(4)能加速固化,但作用很有限;(3)当复掺Na_(2)SO_(4)+CaO,且两者含量分别为矿渣质量的30%和20%时,固化效果最佳,所需固化时间仅为无Na_(2)SO_(4)和CaO情况下的1/10,自然养护7d黏聚力达到285.75kPa。试验揭示了不同配方及配比对回填黏土固化时间及强度指标的影响规律,得到了一种基于矿渣水泥的回填黏土快速固化的最优配方及配比。快速固化改良黏土用于回填施工时,不仅能加快施工进度、减少回填用料,而且能提高成孔质量。研究结果对同类工程施工具有重要的指导意义和参考价值。To solve the problems of slurry leakage,many backfilling times and slow progress in the backfilling process of traditional rock fragment clay in the construction of pile foundation in karst cave stratum,a clay backfilling method based on rapid solidification of slag and cement was proposed in this paper.Using cement and slag as base materials,the rapid solidification laboratory tests of clay backfilling with different formulas and proportions under the condition of single additive Na_(2)SO_(4)and compound additives Na_(2)SO_(4)+CaO were carried out.The results show that:(1)The cement-slag ratio of 55 is the ratio with shortest clay solidification time,and the cement-slag ratio of 37 is the comprehensive optimal ratio of economy and solidification speed;(2)The single additive of sodium sulfate in cement and slag can accelerate the solidification,but the effect is limited.(3)When Na_(2)SO_(4)+CaO is added and the contents of Na_(2)SO_(4)+CaO are 30%and 20%of the mass of slag respectively,the clay curing effect is the best,the curing time is about 1/10 of that of the condition with no additives,and the adhesive strength reaches 285.75kPa after 7 days of natural curing.The tests show the influence of different formulas and ratios on the curing time and strength index of clay backfilling,and an optimal formula and ratio for the rapid solidification of clay backfilling based on slag cement is obtained.When the modified rapid solidification clay is used in backfilling construction,it can not only speed up the construction progress,reduce the backfilling material,but also improve the pore-forming quality.This study provides important guidance and reference for similar engineering constructions.

关 键 词：岩溶地层 溶洞回填 桥梁桩基 黏土固化 

分 类 号：U445.55[建筑科学—桥梁与隧道工程]