Experimental study on in-situ preparation of post-wall synchronous grouting materials for shield mud in Chengdu tunnel
Year: 2025
Type: article
Abstract: To mitigate the potential environmental and economic issues arising from the low resource utilization rate and extensive accumulation of shield waste mud during urban metro construction, in-situ post-wall grouting materials were developed. These materials were prepared using Chengdu Metro shield waste mud, supplemented by adding an appropriate amount of curing agent . The optimal ratio of grouting material containing different curing agent amounts was investigated, and the grouting performance, construction workability, durability indices, and microscopic cementation mechanism were analyzed for the material at this ratio. The results indicate that the new in-situ post-wall grouting material exhibits excellent cementation characteristics, high construction workability, stable performance, and superior filling capacity. The new in-situ post-wall grouting material exhibits outstanding early strength , achieving a compressive strength of 2.78 MPa at 7 days when using the optimal strength ratio. The best early compressive strength ratio comprises 60 % fly ash by mass, 15 % sodium silicate , 80 % silica fume , and a water-to-solid ratio of 0.8. For the optimal 28-day strength ratio, the mixture contains 40 % fly ash, 10 % sodium silicate , and 40 % silica fume by mass of cement, with a water-solid ratio of 0.85. This novel material surpasses traditional grouting materials in durability, offering a 28-day strength that exceeds that of on-site materials by 0.58 MPa and a 90-day strength of 0.6 MPa under water dissolution and erosion conditions. Additionally, the material's permeability coefficient reaches up to 10 −7 , and its 28-day dry shrinkage rate is less than 30 × 10 −6 , reflecting a reduction to nearly 1/2.73 of that found in conventional materials. Fly ash, sodium silicate, and silica powder can significantly reduce the plate-like and granular particle content in the slurry, thereby enhancing its stability, cementation strength, and seepage resistance. Through the resource treatment of Chengdu Metro shield slurry and the optimization of material ratios using a curing agent, a new type of in-situ post-wall grouting material has been successfully prepared. This development demonstrates its significant potential for application in metro construction.
Source: Materials Today Communications
Institution: Hainan University
Language: English
Subfield: Civil and Structural Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $2,830
OpenAlex ID: W4406561577