Properties and Engineering Applications of a New Goaf Grouting Filling Material

Abstract

In the treatment of goafs in traffic engineering, technical problems such as those related to large-volume grouting and the precise control of material properties are often encountered. To address these issues, we developed a new composite material comprising cement-fly ash-modified sodium silicate (C-FA-MS). The setting time, fluidity, unconfined compressive strength, and microstructure were varied for different proportions of cement-sodium silicate (C-S) slurry, cement-fly ash-sodium silicate (C-FA-S) slurry, and C-FA-MS slurry, and their performances were compared and analysed. The experimental results showed that the initial setting time of the slurry was the shortest when both the original sodium silicate volume ratio ( V S ) and modified sodium silicate volume ratio ( V MS ) were 0.2. The final setting time of the C-S and C-FA-S slurries tended to decrease but then increased with decrease in V S , while that of the C-FA-MS slurry increased with lower V MS . The fluidity of the C-FA-S and C-FA-MS slurries decreased with decrease in V S or V MS at different fly ash admixture ratios. The consolidation compressive strength of C-S increased with decreasing V S , while that of C-FA-S showed a considerable increase only when V S decreased from 0.4 to 0.2. Meanwhile, the compressive strength of the C-FA-MS concretions first increased and then decreased with decrease in V MS . Microstructural analysis revealed that there were more cracks in the C-S agglomerate, the fly ash in the C-FA-S agglomerate reduced the relative density of the skeletal structure, and the stronger cross-linking in the C-FA-MS agglomerate improved the strength of the agglomerate. Under the condition of unit grouting volume, the cost of the C-FA-MS slurry was approximately 44.7% and 31.3% lower than that of the C-S and C-FA-S slurries, respectively. The new C-FA-MS material was applied for the treatment of the goaf in the Wu Sizhuang coal mine. Core drilling detection and audiofrequency magnetotelluric survey revealed that the goaf was sufficiently filled.

Study on Preparation and Performance of Foamed Lightweight Soil Grouting Material for Goaf Treatment

“…When selecting grouting materials for reinforcement projects, it is important to consider their impact on the reinforcement effect and cost [ 19 ]. Researchers from around the world have conducted extensive research on grouting materials, mainly focusing on cement–clay slurry, single-cement slurry, cement–fly ash slurry, cement–water glass slurry, and other materials [ 20 ]. Using conventional grouting materials to fill goaf areas makes it difficult for the slurry to quickly accumulate, results in significant loss of slurry, and leads to low stone formation rates, thereby increasing the cost of treatment.…”

Performance comparison of geopolymer and clay-cement grouting pastes and goaf effect evaluation of grouting backfilling method

“…For grouting reinforcement projects, the filling paste selection is a very essential issue, influencing consolidation cause and cost for grouting projects (Huang et al, 2022). Extensive research has been conducted by researchers both domestically and internationally on slip casting materials, with particular emphasis on cement-clay mud, single-cement mud, cementitious mud, some similar substances (Feng et al, 2022). Utilizing traditional slip casting materials for goaf regions filling presents challenges in terms of mud accumulation, leading to substantial mud loss and reduced stone formation rate.…”