摘要：Aiming to resolve the technical problems of lower gas concentrations and a reduced effective drainage period caused by gas-drainage borehole fracture development, a flexible gel(FG) gas-drainage borehole sealing material was developed that adapts to borehole deformation. In this study, based on orthogonal tests, the effect of the ratio of material to water, stirring time and stirring speed on the viscosity, filtration property, water retention and pumpability of the FG were studied. The results indicate that the stirring speed, ratio of material to water and stirring time in turn increased the viscosity and the ratio of material to water, stirring time and stirring speed enhanced the filtration property and water retention. The FG pumps smoothly and achieves the optimal state of high water retention, low fluid loss and low viscosity when the ratio of material to water is 1:10, the stirring speed is 800 r/min, and the stirring time is 12 *** field test results indicate that, after using the FG, the average drainage gas concentration increases by25.9% and 27.6% and the average negative pressure of extraction increases by 2.7 k Pa and 3.5 k Pa compared with expansive cement and polyurethane, respectively.

摘要：To overcome the drawbacks of the conventional foam technology used for dust suppression,including large pressure loss,high water pressure and low driving pressure,a new pneumatic foaming system is *** an original design of foaming agent mixing device is proposed,and its performance is investigated and evaluated under different pressure *** results show that the maximum absorption amount increases by 2.9-6.7 times at a pressure compensation of 0.04-0.2 MPa compared with no pressure *** pressure loss and pressure fluctuation both reduce significantly with increasing pressure *** critical outlet pressure increases by30.4-240%.Field application indicates that the proposed mixing device ensures the reliable addition of foaming agent used for foam dust *** effect of foam on dust suppression is remarkable,and the economic cost of foam is ***,there is reason to believe that the new mixing device will greatly promote foam technology to be widely used for suppressing dust in underground coal mines.

摘要：This paper analyzed the deformation mechanism in lateral roof roadway of the Ding Wu-3 roadway which was disturbed by repeated mining of close coal seams Wu-8 and Wu-10 in Pingdingshan No. 1Mine. To determine the strata disturbance scope, the strata displacement angle was used to calculate the protection pillar width. A numerical model was built considering the field geological conditions. In simulation, the mining stress borderline was defined as the contour where the induced stress is 1.5 times of the original stress. Simulation results show the mining stress borderline of the lateral roadway extended 91.7 m outward after repeated mining. Then the original stress increased, deforming the roadway of interest. This deformation agreed with the in situ observations. Moreover, the strata displacement angle changed due to repeated mining. Therefore, reselection of the displacement angle was required to design the protective pillar width. Since a constant strata displacement angle was used in traditional design, the proposed method was beneficial in field cases.

摘要：Deep large span cut holes are difficult to stabilize. The 7801 cut hole in the Lu'an Wuyang Mine was used as this project's background. The main factors affecting large span cut hole stability are analyzed. Pre- stressed bolting theory was used to design a roof control method for a large span roadway. By reducing the span and applying equal strength coordinated supports the rock could be stabilized. The control prin- ciples and methods are given herein along with the analysis. A double micro arch cross section roadway is defined and its use in solving the current problem is described. Beam arch theory was used to build a model of the double micro arch cross section roadway. A support reverse force model for the arch foot intersection was also derived. A support method based upon reducing the width of the large span in the cut hole is presented. These results show that the reduced span of the roadway roof plus the use of cable anchors and single supports gives an effective way to control the large span cut hole. On site monitoring showed that the reduced span support from the double micro arch cross section roadway design had a significant effect. The roadway surface displacement was small and harmful deformation of the cut hole was effectively controlled. This will ensure its long term stability.

摘要：进一步的理解煤自我加热被调查煤的不同等级的交叉的点温度(CPT ) 获得。测试为煤用一个自我设计的试验性的系统被执行自我加热。50 g (???

摘要：For further understanding of self-heating of coal,we tested the reactions of seven different ranks of coal under inert *** the test,50-gram of coal sample ranged from 0.18 mm to 0.38 mm was put into a special designed copper reaction vessel and let pure nitrogen to flow into the coal sample from the bottom at a rate of 100 mL/*** programmed temperature enclosure was run at a programmed rate of 0.8 °C/*** concentration of the carbon oxides and the coal temperature were *** results show that the coal reactions under inert atmosphere can generate CO and *** reactions under inert atmosphere are affected by coal ranks,initial pore structure of coal and sulfur *** low ranks of coal,the productions of carbon oxides are *** coal temperature is lower than the surrounding temperature throughout the reactions under inert atmosphere,but it rises quickly and reaches a crossing point temperature in the later stage under dry-air *** on the analysis,it indicates the self-reaction of initial active groups exists in the self-heating of coal besides the reactions in the two parallel reactions *** combustion of coal is due to both the oxidation heat accumulation and the chain reaction.A new reaction model of self-heating of coal was proposed.