Experimental Study On Coal Model Reinforced By New Polyurethane/water Glass Double Liquid Slurry Grouting

With the increase of coal mining depth,the soft coal seam often occurs coal wall collapse and roof falling accidents in the process of comprehensive mining.Usually,grouting is used to strengthen the soft coal seam and improve the mechanical properties of the coal body.Therefore,a new polyurethane/water glass double liquid grouting material is developed,which has small phase domain size,good compatibility,high strength of the consolidation body,improved antistatic,flame retardant and solidification time and heat storage temperature are more suitable for coal groutingThrough the physical and mechanical tests of the double liquid grouting material,it can be obtained that the gel time of the slurry changes under the influence of temperature.As the temperature inctreases,the gel time of the slurry decreases due to the temperature.When the initial temperature of the slurry is 7 "C,the solidification The glue time is 276s,and the gel time is 24s when the initial temperature of the slurry is 40?;the maximum reflected temperature of the slurry at room temperature is 85.2?;the average uniaxial compressive strength of pure slurry consolidation is 56.0MPa;when the slurry is different When the mixing ratio is consolidated with standard sand,the uniaxial compressive strength of the consolidated body increases as the proportion of slurry increases.A high-pressure double liquid grouting system was developed,and a model test of polyurethane/water glass double-liquid material grouting reinforcement coal was carried out to study the effect of double-liquid grouting material on coal reinforcement and the mechanical properties of solidification.Through the pressure sensors,thermocouples,strain gauges and other test elements in the grouting system,TDS-630 is used to monitor,record and analyze the changing trends of various parameters inside and outside the model during the grouting process.During the grouting process,the temperature and pressure peaks appear around 10 minutes,and the stress peaks appear around 15 minutes;the coal body reinforcement effect is good,and the samples obtained by core extraction are subjected to uniaxial compression,Brazilian splitting,and uniaxial creep Mechanical test to evaluate the effect of grouting.The uniaxial compressive strength is between 15.1-29.7MPa;the average tensile strength is 2.1 MPa.The slurry is non-uniformly diffused in the coal body,and the temperature,pressure,stress and compressive strength of the added solid gradually decrease with the distance from the grouting port.It can be seen from the electron microscope scanning test that the coal and slurry are tightly bonded at the junction,the slurry surface is dense and smooth,the slurry filling effect is good,and the consolidation strength is high.The diffusion method of slurry in coal body is permeation and diffusion,with good physical and mechanical properties,suitable for coal body grouting.The research results provide guidance for the application of new polyurethane/water glass double liquid grouting material in coal body grouting.Figure[39]table[19]reference[52]...