Study On Groutability And Numerical Simulation Of Grouting In Fractured Rock Mass

Toward the goal of the construction of hydraulic and geo-technical engineering of our country, the dissertation puts comparatively deep research on some difficult and hot points, of which in studying permeability, groutability and numerical simulation of grouting in random fractured rock masses. The following is the main research contents and the results in this dissertation.(1) The grouts rheological model is totally analyzed in this dissertation. The grouts are classified as cement-based coarse grouts and chemical-based fine grouts. Rheological characteristics and its influence factors are studied. Furthermore, some mechanics behavior and rheological characteristics of chemical-based grouts are preliminarily analyzed. It is found that the viscosity and shear strength of the cement-based coarse grouts keep nearly unchanged before some time. Subsequently, the viscosity and shear strength keep rapidly increased. Based on above observations, a rheological model for the cement-based grouts is put forward.(2) The specific definition of groutability is put forward. It is considered groutability includes not only the characteristic whether grouts can penetrate into soil, but the permeability of grouts in soil. It is commented on the domestic and international research on groutability and grouting criteria. Based on the others research, and combination with the groutability definition of the author of this dissertation, a grouting criteria is recommended.(3) The theoretical solution about cross-hole packer test, of which the aquifer is lamellar structure and the fractures are vertical, is put forward in the third bibliography. On the basis of the above solution, the theoretical solution about cross-hole packer test is gained in common fractured rock mass in this dissertation.(4) The expansion of grout bulb formed in soil medium is regarded as that of the spherical or columnar hole. According to the former solution of spherical or columnar hole about material strain-softening model, the model for grout bulb expansion is formed in compaction grouting. The fields of stress and displacement are got by the model when the spherical or columnar shape expansion of grout bulb. At last, the maximum radius of plastic area and the maximum expansion pressure of grout bulb are received in soil medium around borehole.(5) In accordance with the Navier-Stokes equation between planar plates, the equation of motion of the Binghamian grouts is deduced in smooth and inclined fissures. Combination with the planar and spatial network model for fissured rock masses, the respective grouting numerical model for fissured rock masses is put forward. Furthermore, the corresponding programs are compiled. Based on the programs, the flow behaviors of the grouts in fracturedrock masses are researched. It is verified that the grouting radius can't be used in fractured rock masses.(6) After making some computations about the flow behaviors of the typical Binghamian grouts and time-varying grouts, it is found that, in fissured rock masses grouting, the curve of the nodal pressure versus the grouting time is exponential function. Based on above discovery, the experiential equation is founded. In addition, it is found that the nodal pressures keep increased and stable in the end with the development of grouting time, when the viscosity of the grouts is small, then the absorption keeps increased and stable at last with the grouting time; when the viscosity is big, especially the grouts is time-varying, then the absorption keep decreased.(7) An unsteady seepage FEM model for grouts is built. The deformation of crack face acted by grouting pressure is considered in the model. Based on the model, a FEM procedure is developed. Furthermore, joint grouting in arch dams is simulated, and the characteristics of pressure distribution on crack faces are researched. Grouting in a crack above a checking gallery of a dam is numerically simulated.