Research On Study On Diffusion Mechanism Of Seepage Grouting In Deep Fractured Rock Mass With Random Opening

The development of underground space will continue to develop to the deep,so it is very important to solve the safe utilization of underground space.Grouting technology is an important means to solve the stability control of underground engineering.Due to the complexity of slurry diffusion space,the invisibility of grouting engineering and the time-varying viscosity of slurry,the research on the temporal and spatial characteristics of slurry viscosity,the diffusion mechanism and engineering application of seepage grouting in randomly fractured rock mass has become a key engineering technical problem.Therefore,the diffusion mechanism of seepage grouting in deep fractured rock mass with random opening is taken as the research object.Through the self-developed three-dimensional stress state single fractured rock mass stress seepage coupling seepage grouting test device,the grouting test of fractured rock mass is carried out to obtain the variation law of permeability coefficient of single fractured rock mass under the action of three-dimensional principal stress.Then,two seepage grouting diffusion models considering the temporal and spatial characteristics of slurry viscosity in rock mass with random fracture opening are established to deduce the temporal and spatial distribution equation of pressure in the slurry diffusion zone.In engineering,the three-dimensional stress distribution parameters of roadway fractured surrounding rock are substituted into the expression of permeability coefficient to obtain the fracture opening distribution of fractured surrounding rock.Finally,the space-time distribution equation of pressure in the slurry diffusion zone is used to determine the grouting parameters.The key construction control parameters of deep and shallow hole high and low pressure coupling grouting technology have been optimized to obtain a better stable control effect.The thesis obtained the following innovative research results:(1)A set of three-dimensional stress single fracture rock mass stress seepage coupling seepage grouting test device has been independently developed.Experiments on the diffusion characteristics of single fracture penetration grouting slurry under different stress paths and fracture dip angles were carried out to obtain the fluid flow,injection pressure and stress-strain data of single fracture rock mass.The variation law of permeability coefficient of single fractured rock mass under three-dimensional stress state is calculated.(2)Based on the evolution of temporal and spatial characteristics of slurry viscosity,the theoretical models of "rectangular" and "trapezoidal" grouting slurry infiltration and diffusion in randomly fractured rock mass are established.The temporal and spatial distribution equations of pressure in the "rectangular" and "trapezoidal" grouting slurry diffusion zone of randomly fractured rock mass are derived.The pressure distribution in the slurry diffusion zone is calculated by extracting the random fracture opening data of W-M function.The local and overall interactions of the distribution of crack opening,slurry viscosity,fractal dimension of crack curve,horizontal moving distance of the lower end face of the crack and grouting rate on the slurry infiltration and diffusion process are discussed respectively to reflect the influence law of the change of the temporal and spatial characteristics of slurry viscosity on the infiltration and diffusion flow of grouting slurry.(3)Single fracture and plane fracture rock mass models with random fracture opening are constructed.The N-S equation is used as the Bingham fluid flow control equation.Moreover,the spatial distribution function of slurry viscosity is predefined for simulation calculation.Through numerical simulation,the diffusion mechanism of seepage grouting slurry in random single fracture and plane fracture rock mass considering the temporal and spatial characteristics of slurry viscosity is studied.The effects of slurry viscosity,grouting pressure and slurry shear rate on the process of slurry infiltration and diffusion are analyzed.The accuracy of "rectangular" and "trapezoidal" theoretical models of penetration grouting slurry diffusion has been verified.(4)The three-dimensional stress distribution parameters of roadway surrounding rock are substituted into the expression of permeability coefficient of single fractured rock mass to calculate the distribution law of fracture opening in random fractured rock mass.The accuracy of crack opening distribution parameters is verified by drilling detection method.Furthermore,the space-time distribution equation of pressure in the "rectangular" and "trapezoidal" grouting slurry diffusion zone of random fractured rock mass is adopted to determine the grouting parameters.The key construction control parameters of deep and shallow hole high and low pressure coupling grouting technology are optimized.The engineering practice and monitoring results show that the optimized grouting reinforcement project has achieved good stability control effect.