@article{Liu2022, 
author = {Zhaoxing Liu and Shuning Dong and Hao Wang},
title = {Analysis on Grout Selection and Control of Reformation Grouting Material in Advance Area of Ordovician Limestone Top},
year = {2022},
journal = {Chinese Journal of Underground Space and Engineering},
volume = {18},
number = {3},
pages = {910-924},
keywords = {advance area grouting, macro and micro characteristics of strata, orthogonal test, cement-based slurry, slurry selection and control},
url = {https://www.sciopen.com/article/10.20174/j.juse.2022.03.024},
doi = {10.20174/j.juse.2022.03.024},
abstract = {The cement-based slurry is widely used in the grouting reinforcement or transformation of coal mine floors. Due to the difference between grouting materials and slurry properties, there is a lack of reasonable selection of grouting materials and effective regulation of slurry type and ratio in grouting practice, so the effect of advanced grouting is difficult to achieve the expected goal. Given the above problems, this paper takes the grouting transformation of the top of Ordovician ash in the Hanxing mining area as background, analyzes the macro and meso development characteristics of the top of Ordovician ash, and reasonably selects the grouting materials in combination with the particle size distribution characteristics of cement, clay and fly ash used in local grouting; Considering the factors such as water-cement ratio, water glass content, Ordovician limestone hydrochemical type and solid ratio, orthogonal test is carried out on the physical and mechanical properties of cement-based slurry, and the physical and mechanical properties and main controlling factors of cement-based slurry are obtained. Research results: the water yield and permeability of the seventh member of Fengfeng formation at the top of Ordovician limestone are greater than those of the eighth member of Fengfeng formation at the top. The number of meso voids is mainly closed fractures and micro tensile fractures, with an average of 120 μm and 420 μm respectively. Wide tension fracture and medium tension fracture account for the main proportion in the fracture area and have good ductility; In the process of grouting transformation at the top of Ordovician limestone, cement fly ash or cement clay slurry can be used for "bottom filling grouting", then cement slurry can be used for booster grouting or splitting grouting for micro cracks and closed cracks; The setting time of cement slurry, cement fly ash slurry and cement clay slurry is mainly controlled by the content of water glass, the viscosity of cement slurry is mainly controlled by the content of water glass, the viscosity of cement fly ash slurry and cement clay slurry is mainly controlled by the water cement ratio, the stone rate of cement slurry and cement fly ash slurry is mainly controlled by the water cement ratio, and the setting rate of cement clay slurry is mainly controlled by the content of water glass, and the main controlling factor of compressive strength and flexural strength of three kinds of grout is water cement ratio; Based on the factors such as grouting process, hydrostatic pressure of confined aquifer and characteristics of injected stratum, the proportioning slurry and regulation process meeting the applicability of Ordovician ash top with hydrostatic pressure of 10MPa are obtained, which can provide reference and reference for the selection of grouting materials and slurry regulation in the transformation of advance area of Ordovician ash top.}
}