Research And Application Of Soft Rock Roadway Supporting Technology In Dongsun Colliery

The research relies on the project of “Research support technology of soft rockroadway with Dongsun coal mine”. The combined support technology of side prestresstruss cable is proposed based on the failure mechanism of the original supporting andsurrounding rocks in repairing roadway of two coal three-stage belt with downhill fullanalyzed. The application of side prestress truss cable support in the field takes a goodeffect.By laboratory experiments and field analysis, it is concluded that the direct cause ofdamage of surrounding with soft rock roadway is the sides of roadway which are looseand weak surrounding rock. The low mechanical strength and the influence of externalenvironment lead to extend the zone of laneways loose, which is the failure of the boltsupport in the coal road. We reveal the path of mechanical effects with surrounding rocks.Firstly, after surrounding rock which is ore body with joint fissures and the lowerintensity is excavated, the rock mass with poor mechanical properties suffered from theexternal environment and disturbance appears obvious swelling deformation of broken,which develops the original joint fissures and weakens overall stability. Secondly, thedeformation pressure caused by bulking deformation not only extend the deformation ofroadway surrounding rock sides, but also roof and floor.By analyzing the deformation failure mechanism of soft rock roadway withDongsun coal mine, we proposed the combined support technology of side prestress trusscable. In order to verify its feasibility, the stress analysis of combined supporttechnology of side prestress truss cable is proposed, which combined the researchachievements of other scholars and engineering practice with Dongsun mine. To providea theoretical basis for the selection of support materials and parameter design, weconducted a simplified analysis of its results. In addition, a national utility model patentwhat was designed to develop the Steel beam of side truss cable prestress is developed,according to the characteristics of surrounding large deformation with soft rock roadwayin Dongsun coal mine.According to the actual deformation situation of Dongsun coal mine tunnel,numerical simulations of four different support programs are conducted by FLAC3Dsoftware. And the surface displacement of roadway surrounding rock and plastic areadistribution range are as analysis of indexes. It is concluded that the original supportscheme of2and the adjusted support scheme of3both can inhibit the development ofthe surface displacement and plastic with soft rock roadway, but the effect is very limited.The4scheme, which is combined support technology of side prestress truss cable, isable to pass a stable anchoring force in deep of the roadway shoulders to the walls ofsides. What’s more, it can not only increases the force area of the walls and improve the support stiffness, but also inhibit the development of the surface displacement and plasticwith soft rock roadway. So The4scheme effectively ensure roadway service life withinthe scope of normal using.Combined support technology of side prestress truss cable used in engineeringpractice and the surface and deep surrounding rock deformation of roadway aremonitored and analyzed. It is concluded that the supporting effect that it is thedeformation and deformation rate of sides or roof and floor in roadway of measuringpoints located within the test section are better than the points located within the originalsupport scheme and the adjusted support scheme. The practical effect of supportingverifications that combined support technology of side prestress truss cable caneffectively inhibit the development of the surface displacement and the closer of top andfloor. the support play a important role of “Fixed sides and Enhanced top and inhibitedfloor”.