Qingbin Meng

Analysis of rheology in deep high stress soft roadway

With the increase of mining depth, the mechanical feathers and mechanical behaviors could become more and more serious in the complex mechanical environment of “three-high and one-disturbance”. The solid rock in shallow mining shows nonlinear mechanical characteristics of soft rocks while entering deep mining, such as large deformation, high underground pressure, difficult to support, etc. The rheological behaviors of soft surrounding rocks are becoming increasingly conspicuous. Taken JiBei mining area for example, based on the basic geological features of deep high stress soft roadway and using the method combing theoretical viscoelastic analysis of soft surrounding rocks with the numerical analysis of FLAC3D, the deformation and failure characters of deep high stress soft roadway are thoroughly searched.

Experimental study of groutability of Super-Micro cement

Based on the similarity theory and the theory of model test, we simulate different opening rock fractures indoors. On account of Super-Micro cement with four different water cement ratios of 0.8, 1.0, 1.5, 2.0 under different water reducer and additive, the experiment is testing the passing rate of Super-Micro cement through the filter with diameters of 0.02mm, 0.05mm, 0.07mm. The test results indicate that the ultimate limit viscosities are 17.1mPa.s, 33.6mPa.s and 624.7mPa.s respectively when the superfine cement passes these three filtrations. After analyzing the influence of grout viscosity on passing rate, that is to say, the bigger the viscosity, the smaller the crack width.