Very Soft Rock Surrounding Rock Control Technology

Supporting technique in deep-seated soft rock roadway is always one of the puzzles in underground engineering field at home and abroad. With increasing of exploit depth, complexity of environment, the surrounding rock stress become more high, the rock properties of soft rock tunnel excavation, supporting and maintenance problems become very important.By means of theoretic analysis, numerical simulation, field observations and etc, surrounding rock support of extremely soft rock roadway is systematically researched. The achievements are as following:Through the literature summarized in the concept of soft rock, given the definition of soft rock and analysis the soft rock of the surrounding rock deformation and failure processes; to the basis of elasticity and plasticity are obtained mesh reinforcement combined support much higher than the ultimate strength of support provided by the general carrying capacity.-300 east roadway of Hunan Niumasi mining company are summarized: fractured surrounding rock-mass; high horizontal geo-stress; serious heaving of floor rock-mass, serious heaving of flank side of roadway,fractured roof of roadway. Through summarizing the conceptions of compound roof on field data and field investigation, study the high level of stress of the deformation mechanism of extremely soft rock roadway.Analysis of the -300 East roadway surrounding rock mineral composition, observed by borehole imaging device within the surrounding rock fracture distribution and damage conditions, proposed roadway deformation and damage mechanism.Through the numerical simulation of the surrounding nature, the level of stress and other factors on very soft rock roadway deformation, that is the role of horizontal stress of such a strong base drum major roadway.By numerical calculation and field testing, analysis of the surrounding rock crushing zone, plastic zone development law, to determine the scope of the tunnel grouting and support parameters, according to tunnel surrounding rock displacement - time (Ut) curve to determine the U shaped steel support Support in bolting after 32 hours by roadway surface displacement monitoring, to determine the time and Grouting Support U steel support 10 days later.The paper propose high resistance pressure allowing,large stiffness and high strength can effectively control extremely soft rock tunnel deformation and ensure the strong rock roadway stability. And he research results of thesis are successfully applied to -300 east roadway of Hunan Niumasi mining company.