Research On Broken Soft Rock Supporting And The Project Cost Control

A lot of mine in our country, cataclastic soft rock has seriously restricted the technology development and coal mine safety in production, and even caused great economic loss. Therefore, research on the cataclastic soft failure roadway support control and engineering cost has important theoretical significance and engineering practical value.This paper bases on mine roadway of Liuqiao, reaches on broken soft rock tunnel excavation by monitoring,numerical simulation and engineering cost method and so on. The main research results and related conclusions are as follows:1)Through the numerical simulation and theoretical analysis about the characteristics of the fracture deformation of soft rock tunnel excavation research, reveal the fracture failure mechanism of soft rock tunnel excavation, and its main features are:â‘ Displacement is larger,which induces caving roof and floor heave phenomenon, and has an serious impact on the stability of the roadway.During the role of secondary horizontal stress which is induced by the excavation disturbance, the side large displacement resultes in the tensile failure of roof strata or produce sliding failure along the crack surface.â‘¡Two sides displacement is large, and the distribution is symmetric. the resulting cracks on both sides of roadway, and constantly expands inside rock mass, and its bearing capacity is gradually reduced.â‘¢Initial stage of excavation, amount of displacement of surrounding rock of two sides is very large, then the increased displacement decreases.2)According to the damage characteristics of the fractured soft rock,the system simulates the four solutions of stress and its distribution characteristics of the plastic area,which are bolt-shotcrete support,Bolt-shotcrete+meshreinforcement+anchorrope, Bolt+shotcrete+mesh reinforcement+anchor rope and Disc anchor+Sprayed concrete+mesh reinforcement+anchor rope support.By contrast, rock mass deformation of disc spray++anchor reinforcement fabric+anchor cable support scheme is minimum, and supporting effect is best, so get the optimized design scheme.3)Through the analysis of four kinds design scheme of construction cost, the scheme one is the minimum, but dose not reach the supporting effect;Engineering cost of plan two, three and four has a little difference, the impact on cost is not big, but the supporting effect of scheme four is best, therefore, the final optimization is scheme4.