Study on slurry diffusion law of grouting reinforcement for fractured surrounding rock in deep roadway

XIAO Tongqiang; YU Zihao; LI Huaizhen; XU Lei

doi:10.16186/j.cnki.1673-9787.2023020045

Abstract：Objective Under the action of high stress of deep depth,the weak surrounding rock shows the phenomenon of whole movement or the crack being compressed and closed,and the whole injectability is poor.Methods In order to solve the problem of grouting reinforcement of fractured surrounding rock in deep roadway,the failure characteristics of surrounding rock in deep roadway were studied by means of field mine pressure observation and numerical simulation.Results The results showed that the deep roadway presents a large deformation of"roof,sides and floor"full section,and the failure depth of surrounding rock in-creased significantly.The surrounding rock of deep roadway formed fracture development area,fracture ex-pansion area and primary fracture area from shallow to deep,and the fracture opening of the fracture expan-sion area was small and difficult to inject.Using numerical simulation methods,the influence of factors such as crack characteristics,grouting pressure,and slurry water cement ratio on slurry diffusion characteristics was analyzed.The results showed that:the influence of fracture aperture on slurry diffusion radius was sig-nificant,while the influence of fracture roughness was relatively small.For the fracture development area with large fracture opening,the conventional grouting pressure could be used,while for the fracture expan-sion area,the fracture opening was small(less than 0.10 mm),and the grouting pressure should be higher than 10 MPa;the slurry diffusion radius was proportional to the grouting pressure and water-cement ratio.However,for the deep surrounding rock with small fracture,the grouting pressure had a critical point,and the grouting pressure should not be blindly increased.When the water-cement ratio was selected,the slurry diffusion radius and the water precipitation effect of the slurry should be comprehensively considered.Con-clusion For grouting engineering,the development state of surrounding rock fracture opening after roadway excavation should be considered when selecting grout proportion and grouting pressure.