Study On The Mechanism Of Fissure Visualization Grouting Diffusion And Magnetic-liquid Impermeability

In view of the lack of effective data support and shortage in the research of rock fracture visualization grouting stop seepage in underground engineering at present,based on the self-developed rock fracture visualization seepage flow-grouting device,the experimental research on the aspects of fracture grouting diffusion and magnetic fluid stop seepage is carried out.The area digital self-recognition technology is used to partition the test images and extract the relevant test parameters accurately.First proposed a way to use the combination of magnetic field intensity and magnetic slurry seepage plugging method,calibration and self-developed magnetic fissure seepage pressure test device,through the device under the effect of magnetic field and the fracture seepage research magnetic head,and for the first time put forward guiding type grouting check method,the magnetic slurry guide check permeability plugging mechanism,provide new thought for grouting plugging in practical engineering.The specific research results are as follows:1)Feasibility and function of rock fissure visual seepage-grouting deviceThe visual fracture seepage-grouting device(patent No.:CN201910655846.1)was independently developed to prepare visual transparent rock specimens by the accurate reprinting technology of double turning mold,providing technical support for the study of the seepage of fine fractures.A complete set of area digital self-identification technology is developed to provide technical means for accurately obtaining relevant parameters that can reflect specific characteristics of rock seepage.The feasibility and rationality of the device are demonstrated and analyzed,and the difference coefficient between the seepage test and the visual seepage test of the original rock fracture is obtained.Using the difference coefficient,the derivation formula of the relationship between the original rock and the visual seepage flow is obtained:q0=k0σs=k1fσs=fq12)Study on the water-free grouting diffusion mechanism in multi-angle spaceBased on the fracture visual percolation-grouting device,anhydrous grouting diffusion related tests at 0°,45° and 90° were carried out,and the relationships between normal stress,grouting pressure and slurry diffusion area at three different angles were obtained.By comparing the grouting experiments with three spatial dips of 0°,45° and 90°,it is found that with the increase of the crack dip Angle,the influence of factors such as the self-weight effect of grout and the pressure inside the crack becomes more obvious,leading to the failure of the slurry flow path to fill the entire crack through-passage and even the phenomenon of flow diameter shrinkage and migration.Therefore,grouting plugging works should be carried out at an inclination Angle≤0° to achieve the best filling effect.3)Study on the mechanism of dynamic water grouting diffusion under multiple spatial anglesBased on fracture seepage-grouting visualization device,carried out 0°,45°,90 °three different angles of dynamic water grouting diffusion test,study:space under the horizontal Angle stable grout diffusion form basic distribution is u-shaped,the stability of the dynamic water space of 45° Angle grout diffusion form the basic "arc",compared with the spatial dynamic water level Angle grouting,grout diffusion under 45° Angle space area shrank by 29%,the space under the vertical Angle grout diffusion area shrank by 39.7%;And f’ is defined as the difference coefficient of the diffusion area of dynamic water grouting in a space of 90° and 0° dip angles,and the semi-empirical formula between the diffusion area of slurry Ad,normal stress σf and grouting pressure σz is obtained:Ad’=f’Ad=t1·σft2σz+Bd’/Bd·t3e-t4σf.4)Study on the mechanism of crack magnetic fluid impermeabilityCalibration fissure seepage independent research and development of magnetic head device(patent no.:2019110469981.2),and based on the device was carried out by three different crack opening(3 mm,1 mm and 0.5 mm)test,calibration fissure seepage under the magnetic head and magnetic induction intensity and the relationship between water head:H=t1·et2B,and the relationship between the crack opening and head:H=t3·dt4,through the experiment illuminates the magnetic slurry under the effect of external magnetic field has the effect of water plugging.The method of guided magnetic grouting and anchoring to stop seepage was proposed for the first time,and a preliminary exploration was made.Experimental studies on magnetic adsorption,dynamic water resistance and CT scanning were carried out,which showed that the anchor solid added with magnetic grouting material was tighter and more dense than that of ordinary cement material.