Experimental And Numerical Simulation Study On Mechanical Properties Of Grouting Reinforcement

Grouting is a kind of support method which widely used in tunnels,rock tunnels and other underground diverticulum.After grouting the fractured rock mass,the original voids in the rock mass are filled with slurry.The slurry continuously solidifies and solidifies,and gradually assumes the force between the rock masses.The stress state in the rock body is redistributed and the bond strength between the rock masses is continuously enhanced,and the stability is improved.However,the current researches on the influencing factors of grouting and solidification mechanical properties,as well as the related research that can be used to guide the design of on-site grouting scheme and quantitative evaluation of grouting reinforcement effect are not sufficient.In this paper,the effects of grouting amount,slurry solidification time,confining pressure and solidified body distribution on grouting and solid mechanical properties were studied by means of laboratory tests,theoretical analysis and numerical simulation.The main work is as follows:Firstly,the self-made mortar specimens were studied by means of indoor uniaxial compression.The mechanical parameters and the same porosity were not grouted under different grouting volumes(different pore sizes,different pore numbers),different solidification times and different degrees of damage.Compared with the degree of improvement of the test piece,the grouting amount-elastic modulus curve is drawn for on-site reference,and the difference of the damage form of the test piece under different working conditions is observed.Secondly,the grouting and solidification is regarded as the composite material composed of the parent rock and the grouting solidified body.The formula for calculating the mixing ratio of the three composite materials is corrected considering the solidification time of the grouting solidified body,and the calculation results and test results are compared.It is found that the modified Voigt model has the smallest error and can be used to predict the grouting plus solid mechanics parameters.Thirdly,the model parameters close to the indoor uniaxial compression test results were obtained by the trial and error method in the particle flow software.The following model was used to model the parameters:(1)diameter and number of grouting solidifications versus grouting plus solid mechanical properties and The effects of failure modes indicate that The injection of grouting solids can reduce the stress concentration around the upper hole and improve the ductility of the specimen.The specimen is damaged along the vertical connection of the small hole,and the more the number of small holes,the more obvious;(2)the effect of lateral pressure on the mechanical properties and failure modes of grouting plus solids;(3)the partial form of grouting solidification in parent rock for grouting plus solid mechanical properties influences.Finally,the viscoelastic-plastic creep model is established in FLAC3D with the background of the Shanghai Miao mine bottom yard.The full stress-strain curve of the grouting and solidification under the grouting volume is simplified into a three-line strain softening model.According to Hencky-?????? full quantity theory,the stress-strain relationship of uniaxial compression is generalized to the relationship between equivalent stress and equivalent strain of rock mass under complex stress state,and the strain softening trend of rock mass under various working conditions is further obtained.After excavation,the surrounding rock enters different strain ranges with rheological transformation,grouting according to the strain range of the surrounding rock,and corresponding softening tendency is given to the surrounding rock under different grouting quantities to simulate more close to the actual situation.Grouting effect.The variation trend of surrounding rock displacement after grouting was monitored,and the evaluation of grouting effect was proposed.