Mechanics Analysis And Treatment Of Floor Heave In Deep Soft Rock Roadway

For a long time,the floor heave of soft rock roadway has been a difficult problem in coal mine safety production.Soft rock roadway has the characteristics of quick pressure,fragile roof and floor,large deformation,difficult maintenance and easy repairing.It is particularly important to find effective control methods.The main ways and conclusions of this paper are as follows:?1?Through uniaxial compression test on press,the basic rock mechanics parameters such as average uniaxial compressive strength,general coefficient,elastic modulus and total stress-strain curve of different rock samples?floor siltstone and direct floor silty mudstone?are obtained.?2?Based on the study and analysis of the influencing factors of floor heave by combining with the actual situation of roadway,the related influencing factors of floor heave are the nature of floor rock,stress state of rock stratum,abutment pressure,water rationality,support strength of roadway surrounding rock and cross-section shape of roadway.Among them,the dominant factor is the stress condition of roadway after excavation.The type of floor heave is determined by the way of bulge and the size of floor heave.?3?Through the analysis of the stress on the floor of roadway,it is found that when the maximum stress on the floor is more than the maximum Bearing capacity of the floor,the floor can not maintain its original state under the action of the force,and the floor is damaged.At this time,in a certain range of roadway floor,three regions are formed,namely,active failure zone,extrusion transition zone and extrusion passive zone.The floor is simplified as a four-sided fixed-supported model,and the deflection caused by the model deformation is taken as the floor heave quantity in the calculation.The estimation formula of the floor heave quantity is deduced.The formula is verified by an engineering example.?4?The FLAC^3Dmodel is validated by using the derived formula for estimating the floor heave.The floor anchor method,groove pressure relief method and joint method which can control floor heave are simulated.By comparing the simulation results,it is found that the floor bolt method has a certain effect on improving the floor heave of roadway.Different length,spacing and inclination angle of the bolt have different effects on the floor.Slot pressure relief method has certain effect on improving floor heave of roadway,and the effect of different width and depth of groove is different.The combined method can give full play to their respective advantages,the strength and stability of the floor have been significantly improved,and the floor heave has been well controlled,which is the best of all the schemes.?5?Through on-site industrial verification of the final treatment scheme,the combined method has been proved to be effective,feasible in technology and economical,which has guiding significance for engineering practice.