During the period of caving coal mining,the coal tunnel pressure is greater with leaving narrow and small coal pillars,the support of driving tunnels along goaf is more difficult during the period of mining.

Numerical simulation of small pillar stress concentration areas borehole pressure relief effect

Under the condlition of medium-thick seam composite roof,the small pillars size and roadways support parameters are reasonably determined.

In view of the conditions tunneling small pillar along the goaf,introduces the situation of using anchor cable net and uity supporting and analyzes the application effect.

As a result, the structural models for both fore-wing of the beetle and trabecular structure were established: (1) the allomyrina dichotoma fore-wing is of sandwich plate structure with the central void layer of trabeculae, and this is one of the typical light-weight composite structures; (2) chitin fibers in trabeculae curved more than 90 degree to connect to .

Aimed at the severe deformation of surrounding rock of gob-side entry on insular face or the unstable of small coal pillar induced by dynamic pressure in mining,the stability of the gob-side entry with small coal pillar on insular face was studied by numerical calculation,physical simulation experiment and in-situ test.

This paper introduces dynamic information method under small coal pillar and large over-the-roadway roadway groups influnenced by full extraction and structure,building large model simulates diffierent reinforcing scheme and supporting parameter,the best scheme is obtained,through analyzing rock pressure,this method is rational and reliable.

This paper introduces new technology with minor diameter resin grouting combined anchor pretensional cable anchor under small coal pillar,structure and mining-induced in S520 main haulageway of Changcun coal mine,it analyzes reinforcing results of roadway and evaluates technical economical results.

Based on the analysis of the bolting with wire pillar supporting technology used in future small coal pillar along gob-side driving 8 228 wind entry of Taoyuan Coal Mine,consider that the supporting technology is workable,and has definite social and economic benefit.