Research On Control Mechanism And Application Of Weakly Cemented Soft Rock Roadway With Alkaline Water-enriched

The mining of weakly cemented coal strata in western China's mining areas has brought many technical problems,the most complicated of which is the surrounding rock control problem of weakly cemented soft rock roadway under water-rich conditions,especially under alkaline water conditions.The key to the solution lies in grasping the deformation characteristics and laws of the surrounding rock of the roadway under the action of water and rock,revealing the instability mechanism of surrounding rock under water chemical damage,and proposing a reasonable support scheme to realize the safety and stability of the roadway.Based on the hydrogeological investigation of weakly cemented strata in the western mining area,this paper focuses on the physical and mechanical damage mechanism and deformation control of weakly cemented surrounding rock under alkaline water.The laboratory experiments,theoretical analysis,numerical simulation and on-site measurement are used to carry out the rsearch on surrounding rock control technology of weakly cemented soft rock roadway with alkaline water-enriched.which has practical guiding significance and theoretical value for further enriching the surrounding rock control theory of soft rock roadway,guiding the mining practice of cemented strata under water-rich conditions and promoting the efficient use of coal resources in western China.The main research results are as follows:(1)Based on the investigation of the occurrence environment of weakly cemented strata in the mining area of western China,an experimental method of hydrochemical interaction between alkaline water and weakly cemented soft rock is proposed.The damage rules of mineral composition,microstructure and macroscopic mechanical properties of weakly cemented mudstone and weakly cemented siltstone under different alkaline water and different wetting time conditions were obtained.The variation law of the type and concentration of solution ions was mastered.(2)According to the variation law of mineral composition and immersion liquid ion concentration,the chemical equation of hydrorock action is deduced,and the nature of hydrorock action and the mechanism of rock physical and mechanical damage are revealed.According to the laboratory test data,the relationship between the variable factor and the damage factor is fitted,and the macroscopic mechanical damage evolution equation based on time effect,alkali degree and microscopic pore change is established,and the damage evolution constitutive relation is obtained.(3)The physical corrosion characteristics and the damage law of mechanical properties of the anchoring agent,the anchor rod body and the anchor cable steel strand in different alkaline water environments were analyzed and tested.The influence law of different surrounding rock,anchoring length,pH value and corrosion time on the anchorage body drawing performance was studied.The main failure modes and failure mechanism of anchorage body under the condition of rich alkaline water and weakly cemented soft rock are determined.(4)Based on the distribution of aquifer in roadway surrounding rock,the pH value of alkaline watert,and the anchorability of rock in the anchoring area under the action of water-rock,the roadway surrounding rock was divided into 5 categories,and the supporting forms were designed and given respectively.Taking the actual mining geological conditions of the Dananhu No.7 Mine as an example,the reasonable support parameters of different support forms were determined by numerical calculation,and the classified support technique scheme for weakly cemented soft rock roadway with alkaline water-enriched is formed.(5)The hydrogeological conditions of the surrounding rock of the roadway in the test area are evaluated and classified,and a classified support method is proposed.The industrial test of the classified support technique scheme for weakly cemented soft rock roadway with alkaline water-enriched was carried out,and the surrounding rock stability monitoring program was designed realizing the on-site monitoring of the surrounding rock deformation and the stress of the anchor cable in the roadway.This paper has 131 figures,30 tables and 139 references.