It is challenging to assure safe and effective gas mining due the surrounding soft coal rock roads in deep high mines being extremely loose broken. One of ways arrange pre-stressed anchors a certain area roadway rocks form compression arch with joint action rocks, but lack in-depth systematic research on formation mechanism arch, effect difficult give full play. The typical microstructure was o...

We construct a four-parameter family of smooth, horizonless, stationary solutions of ungauged five-dimensional supergravity by using the four-dimensional Euclidean Schwarzschild metric as a base space and “magnetizing” its bolt. We then generalize this to a five-parameter family based upon the Euclidean Kerr-Taub-Bolt. These “running Bolt” solutions are necessarily non-static. They also have th...

This article deals with a static and quasi-static load using the maximum power of hydraulic pump. Additionally, coefficients for partially embedded rock bolts were determined. The laboratory tests included 2.2 m long bolts, which segmentally on lengths 0.05 m, 0.3 0.9 tested. To fix ribbed bolt rods in steel cylinders, resin cartridges length 0.45 used. main aim research was to determine load-d...

The extremely soft coal seam roadway has the problems of low surrounding rock strength and difficult support. Based on engineering background mining in Quandian mine, this paper adopts research method combining numerical simulation field measurement. stress field, displacement support force, loading arch structure characteristics under bolt-mesh-cable existing shed-cable are compared, control p...

Homes are increasingly filled with connected devices such as wireless door locks, remotely controllable thermostats, and security cameras. Home automation systems, which used to be prohibitively expensive to average consumers, are now offered at an affordable price, accelerating the adoption of “smart” devices in the home. The advances in devices also enable researchers and practitioners to dev...

In coal mining, as the mining depth increases, a complex mechanical environment of “high ground stress”, temperature”, karst water pressure”, and “mining disturbance”, namely “three highs one disturbance” appears. Many roadways have characteristics soft rock with large deformation, pressure, difficult support, high support cost, which brings severe challenges to safe efficient production mines....

The embedment length (EL) of full-grouting rock bolts is a core factor in bolt reinforcement. Therefore, understanding the influence EL on reinforcement performance benefits quality. To realise this purpose, paper adopted numerical modelling method. In method, structural elements modified piles were used. elastic debonding law was incorporated into pile to model behaviour surface between and gr...

In order to study the local deformation of an anchor bolt and improvement in shear strength a structural surface under misalignment anchorage structure surface, FLAC3D software was used simulate granite, sandstone, coal specimens with angles 90° analyze damage anchoring agent changes axial forces bolts surface. The results show that near had significant characteristics surface; is, length area ...

The gob-side entry driving is in low pressure area, which bears less support and easy to maintain, so it widely used. Taking the thick coal seam of Dongtan Coal Mine as an example, reasonable size pillar section roadway are numerically simulated by combining numerical with measurement, designed. According distribution lateral stress working face, eight pillars different sizes By simulating comp...