Study On Mechanical Properties And Applications Of High-water Roadside Filling Material

High-water filling material has been widely applied to the engineering of god-side entry retaining in coal mines,but its mechanical properties are not studied enough.In this paper,the deformation failure characteristics and the variation rules of mechanical parameters are studied under uniaxial,three axial compression and creep.The mechanical properties of high-water material are greatly affected by the water cement ratio,which is restricted by the lack of research on the basic mechanical properties of the water cement ratio.So the experimental study on the mechanical properties of highwater material is very significant for engineering practice.Firstly,the micro morphology of the high-water materials was analyzed by SEM.Then the uniaxial compression test of high-water material samples were conducted by the RMT-301 rock mechanics testing machine,and the water cement ratio of the samples were 1.3~2.5:1.The variation laws of deformation characteristic,strength characteristic,failure characteristic,energy characteristic with water cement ratio variation were analyzed.The uniaxial compression and short time staged loading uniaxial creep test based on the RLW-2000 rock rheological testing machine were carried out for the high-water material samples.The single step creep curves of every stress level were acquired according to the principle of Chen loading method.Finally,the god-side entry retaining engineering was analyzed and applied at 4311 panel in Chengzhuang coal mine,based on research results.The research results show that: the microstructure of high-water material is a porous sponge like structure composed of solid,liquid,gas;The elastic modulus,secant modulus and the peak strength decrease by exponential function with the increase of water cement ratio.The samples are gradually transition from brittle failure to ductile failure with the increase of water cement ratio.The total strain energy and the elastic strain energy which can be released are both decrease by exponential function with the increase of water cement ratio,whereas the dissipation energy changes little.Under the condition of three axial compression,the high-water materials show brittle characteristics under low confining pressure.With the increase of confining pressure,the peak stress strain curve gradually changes from brittle to perfect plastic state and presents constant resistance state.Under the effect of confining pressure,the specimen failure form is complete,resulting in plastic flow failure.Under the uniaxial compression creep experiment,creep strain is more sensitive to stress level,and the steady creep rate at all levels increases exponentially with the increase of stress level.The Burgers creep model could describe the creep law of high-water material.By selecting the appropriate construction scheme of high-water material filling body the god-side entry retaining engineering is successfully conducted at 4311 panel in Cheng zhuang coal mine.The deformations of rib and roof are 214.2mm,183.2mm,respectively.The deformations are very miniature and the results show that the effect of god-side entry retaining is ideal.