Floor Heave Mechanism of Soft Roadway in Mining of Underlying Coal Seam and Its Control Technology

In this paper,analysis was made on the deformation and failure characteristics of the surrounding rock of the soft roadway in the mining of underlying coal seam in Dengcao Mine by means of field measurement,numerical simulation and engineering practice,and based on this,the floor heave mechanism of the soft roadway were revealed:the floor stratas became extremely cracked due to the mining of underlying coal seam;the broken roadway floor moved towards the roadway under the combined action of the concentrated stress and strata stress,which caused the formation of floor heave.For this purpose,a control technology with the combination of reserving deformation,bolt-net-anchor-shotcrete support,bolt-grouting consolidation,bottom angle anchorage and consolidation by grouting was proposed.The effect of engineering application showed that the proposed control technology could effectively control the floor heave and deformation of the roadway and guarantee the stability of the surrounding rock and support structure of the roadway,so it can provide some theoretical basis and practical reference for support design and floor heave control of other soft roadways with underlying seam mining.