Study On Slurry Diffusion Of Stubble Surface Of Vertical Shaft Wall Based On Double Cavity Steel Structure Stubble Plate

During the construction of single-layer freezing ground shaft lining and single-row operation of short piecewise excavation,there are some problems such as low anti-seepage performance of shaft wall and high well water inflow caused by the uncompactness of new and old concrete stubble surface.The existing prevention and plugging technology is often difficult to be used to obtain good grouting water plugging effect.What`s more,controlling the wellborewater gushing needs a great deal of time and money.In order to solve this key technical problem,the invention patent"a waterproof stubble board and its construction technology for shaft lining steel structure"is put forward.The invention patent designs the stubble board with grouting technology,which improves the impermeability of interface by grouting the stubble slab-concrete interface.The paper studies the diffusion of superfine cement slurry in the boundary of stubble slab and concrete by laboratory test,numerical calculation and model test.According to the time-varying characteristics of the viscosity of superfine cement slurry,based on C language,the slurry viscosity module of the numerical calculation software is developed and the diffusion law of the superfine cement slurry in the bond interface is studied.The ultrafine cement slurry is developed through laboratory test.The effect of grouting pressure on the diffusion of superfine cement slurry at the bond interface is studied by physical model test.The microstructure observation and energy dispersive analysis of the bond interface between stubble slabs and concrete are carried out by scanning electron microscope.The relationship between setting time,stability,viscosity,swelling ratio of stone and physical and mechanical properties of superfine cement slurry and the content of each material is obtained by laboratory slurry performance test.The formula of superfine cement slurry for interfacial grouting of stubble slabs and concrete is determined.The time-varying curve of viscosity is obtained as follows:m?28?0.00869e<sup>0.000233t</sup>.Through numerical simulation,the greater the grouting pressure applied,the faster the permeation rate of the slurry in the interface between the stubble slab and the concrete bond.With the continuous grouting,the permeation rate in the interface decreases continuously.The influence of time-varying viscosity of slurry on the diffusion law of slurry in the interface can not be ignored.Also,the relationship between seepage field,grouting pressure and properties of bond surface in the interface between stubble slab and concrete is obtained.Through the physical model test,the unidirectional valve hole,the stubble plate and the slurry pouring device are developed.There are holes and pores in the interface between stubble slabs and concrete,and the existence of pores and pores reduces the compactness of the interface.What`s more,the distribution of pores and pores in the interface is not uniform.The permeable pores and pores form a water conduction channel in the interface,which reduces the impermeability of the interface.At the same time,the influence of grouting pressure on the diffusion rate of slurry at the interface between stubble slab and concrete is obtained.When the grouting pressure is 2MPa,the average seepage velocity of the bond surface is 5.44×10^-6m/s,and the average seepage velocity is 6.57×10^-6m/s when the grouting pressure is 3MPa.The results of scanning electron microscope show that there are a lot of holes and pores in the bonded interface between stubble slabs and concrete.The results of Image Pro Plus show that the pore diameter of some holes is 3500?m and the pore size of part is 10?m.The surface porosity of the local bonding interface is up to 25%or more,and the dispersion of the slurry at the interface between the stubble slabs and concrete is obtained by energy spectrum analysis.The feasibility of the invention patent"a waterproof stubble board and its construction technology for shaft lining steel structure"is verified in this paper.