| With the development of my country’s land transportation,the gravity of road and bridge tunnel construction gradually shifts to remote mountainous areas in southwest and eastern coastal areas.The control of adverse geological disasters has become an important research topic in tunnel construction projects.Jointed rock mass are the typical bad geology in underground engineering.When connecting underground water or surface water body,the excavation of jointed rock masses is extremely easy to cause fracture-type water inrush disasters.Grouting is the most commonly used method to control the water inrush disaster,which can effectively block the groundwater and increase the impermeability of the rock mass.Quick-setting slurry has the advantages of short gel time,fast rise in early strength,and strong resistance to groundwater erosion.It can be effectively retained in jointed rock masses,as a result,quick-setting slurry becomes the main material for groundwater disaster management.In this paper,cement-water glass slurry is used as a typical quick-setting slurry,and a rheological model considering the characteristics of the flow-solid phase transition of the quicksetting slurry is studied through laboratory tests,theoretical analysis and simulation tests.A mathematical model of grout diffusion in fractured rock mass is established to quantitatively describe the time-variable model of slurry pressure field during the fracture grouting process,and describe the spatial distribution of viscosity and yield stress in grouting diffusion zone.The main results are as follows:(1)Considering the flow-solid phase transition characteristics of quick-setting slurry,the rheological properties of the quick-setting slurry is tested,and a rheological equation considering stream-solid phase changes is established.Quick-setting slurry of different water-cement ratio and proportion of cement to water glass were used to rheological performance test to get the slurry flow change curve.The slurry flow change curve is obtained and matched with the known rheology model,and the rheological curve at different time points is synthesized to obtain the velocity and yield stress change with time.Study shows that the viscosity and yield stress increase with grouting time.(2)Based on the rheological equation of quick-setting slurry,a mathematical model of the rough glue fracture grouting diffusion is established.The slurry diffusion region was discretized,and the slurry units represented by different time steps were analyzed.Viscosity and the yield stress and the slurry pressure of the slurry unit in different time periods was obtained.The math model is established by the step algorithm to describe the spatial distribution of pressure field changes and viscosity and yield stress during the slurry diffusion process.The model calculation can be seen that the slurry viscosity and the yield stress in the grouting process are constantly rising in the direction of diffusion direction.The slurry pressure of the constant current grout has gradually increased,and the grouting pressure increases with the grouting time and the increase in linearity is gradually increased;the constant pressure grout is far from the grouting mouth.The slurry pressure gradient gradually increases with time,and the grout flow is maintained after a certain value in the initial stage of the grout.(3)The simulation test is carried out to verify the change of slurry pressure of the crack grout.A set of test equipment for simulating fracture grouting has been developed independently,which includes flat fracture test bench,dual liquid grouting device,groundwater loader loading device and dynamic monitoring system.The test indicates that the pressure in the grouting process is non-linearly reduced along the diffusion direction,and the slurry pressure gradient near the grouting port is large,and the pressure gradient is low from the grouting mouth;C: S = 3: 1 set of tests showed that the pressure gradient of the slurry of the grouting mouth began to rise.The grouting pressure change during the grouting process conforms to the calculation trend of the mathematical model.Compared with the mathematical model results,the laxative simulation test is not shown that pressure gradient of slurry is high far from the grouting mouth and small at the grouting mouth. |
PDF Full Text Request