Study On Mechanism Of The Continuous "Double Shell" Controlling Floor Heave In Deep Engineering Soft Rock Roadway

With the exhaustion of coal resources day by day, the depth of coal mining hasbeing increased year by year. As a result of high-stress, surrounding rock of deeproadway is characterized by engineering soft-rock and serious deformation anddestruction. Large floor heaving is a distinct characteristic of strata behaviors in deepengineering soft-rock roadway and its controlling is very difficult. Based on the theoryof continuous “double shell” supporting surrounding rock, according to analyzing themechanism of floor heave, the deformation and failure mechanism of surrounding rockand influence factors of floor heave, the effectiveness of continuous “double shell”controlling floor heave was revealed. According to theoretical analysis、numericalsimulation and similar material simulation test, the deformation features of engineeringsoft rock in deep mine and the mechanism of continuous “double shell” controllingfloor heave was analyzed, the specific conclusions are as follows:(1) The adjacent rock of roadway with deep mine was divides into several regions,aiming at the interaction relationship of different regions, the fact was ensured that floorheave is mainly caused by the deformation and failure of no.2area，the importance ofdeep grouting was verified.(2) It is assumed that the surrounding rock of roadway is homogeneous andisotropic and in a hydrostatic state (Lateral pressure coefficient is1), Analyzed andcalculated the stress of the rupture zone and elastic zone in no support state. The stressof surrounding rock after the support of the continuous double shell (put the shallowshell as a support system).(3) The mechanism types and influence factors of floor heave with deep mine wasdiscussed, adjacent rock of floor was firstly sheared by high stress, and then the brokenrock mass was in extrusion flowing because of bloat and break, the influence factors offloor heave with engineering soft rock roadway was mainly caused by high stress,support strength (ignore the bottom support), time effect (because of theologicalcharacteristic)(4) Outline the basic principle and coupling mechanism of continuous double shellcontrol of floor heave in deep soft engineering rock roadway:Shallow shell closes broken rock of shallow loose circle, increase the residual strengthof the rock. Deep shell is in a state of limit equilibrium. Which can separate the high deep stress damage to the shallow hell, then the floor rock can in a stable state, Thecoupling mechanism of continuous double shell support is” enhance support” and“moderate pressure”, support and surrounding rock can reach strength, stiffness andstructural coupling fundamentally.(5) Numerical simulation and similar material simulation analysis: The effect ofcontrolling floor heave and the stress-strain laws of adjacent rock with different burieddepth, different lateral pressure and different support pattern (without support,anchorage support, and continuous “double shell” support) were analyzed, and the factwas verified that the effectiveness and superiority of continuous “double shell”controlling floor heave; the convergence and deformation of surrounding rock with thesame shallow shell thickness, different shallow-deep shell gross thickness and the sameshallow-deep shell gross thickness, different shallow shell thickness were analyzed,Analysis of that should be first determine the overall reasonable thickness of shallowdeep shell by the specific depth, and then determine the reasonable shallow shellsupport thickness.