The Study On Instability Mechanism And Support Of Steep Coal Roadway With Soft Floor In Deep Of Da’anshan Coal Mine

The surrounding rock of roadway controlling has been one of the most technical problems which affect the safety and efficient production of coal mines, the soft rock roadway supporting is more and more serious, especially in the deep high stress environment. The developed folded structure, complex geological conditions in Da’anshan mine field, exists low intensity, high expansibility strata of sandstone of mud quality in the bottom of steep seam zone, brings great difficulties in roadway supporting, therefore, aiming at the high stress condition of steeply inclined coal and rock structural characteristics of soft bottom hard top, to reveal the mechanism of instability, the establishment has important theoretical significance and practical application value of scientific and effective support system.The expansion characteristic has carried on the test to the mine stress distribution, coal and rock physics mechanics parameters, soft bottom rock mineral composition, determined the distribution law of stress field, has been clear about the composition and strong soft bottom of expansive rock characteristics; Obtained the soft bottom of steep seam roadway surrounding rock stress field and the displacement field of evolution, the maximum amount of floor heave of roadway surrounding rock with the increasing exponentially increasing stress level, and with the increasing of lateral pressure coefficient logarithm relationship; surrounding rock of roadway wall part of the maximum displacement and stress level was leaping increase, with the increase of lateral pressure coefficient, increase the degree of concentration logarithm relationship; the horizontal stress with stress the increase of stress level and lateral pressure coefficient of the linear relationship between growth; The Da’anshan coal mine steep zone of coal rock experiments were conducted to study the creep, selection can reflect the rock viscoelastic plastic cvisc model reflect the creep deformation behavior of soft rock, soft rock creep stress level and confining pressure conditions in the different evolution rules are obtained, based on MATLAB platform, compiling the program model parameter Identification Search and nonlinear least square algorithm based on the creep model parameters were determined, and established the dynamic model of creep parameters considering confining pressure and stress level; Given the cvisc creep FLAC3D numerical platform based on difference scheme, the roadway in soft rock creep control effect are studied by numerical simulation, to determine the surrounding rock of roadway and reasonable support resistance and the best two supporting time;Aimed at the monoclinic groove in Da’anshan coal mine 2 coal occurrence characteristics, revealed that under the conditions of high stress soft bottom of steep seam roadway instability mechanism, established the technical system of control of roadway surrounding rock. In order to determine the overall control, the key part of roadway surrounding rock beam reinforcement as the core technology of the first support scheme to control the structure, soft rock creep instability as the core of the two supporting scheme, and the rationality of the solution is verified through industrial experiment site.