Experimental and theoretical study on hydraulic support in working face and its relationship with roof subsidence

In terms of the shortage of stiffness measurement data for hydraulic support, by using ZTN-1 hydraulic support test bed, four types of support line stiffness and anti-compression stiffness were analyzed. Also, based on the measurement results, by using elastic foundation plate mechanics, the relationship between support stiffness and the amount of roof subsidence was theoretically studied. The results show that support is compressible in increasing resistance process, the average line stiffnessrange of the four typesof supports is 138-538 kN/m, and the average anti-compression stiffness range is 20. 3-68. 5 MPa/m, so the current hydraulic support line stiffness range is about 100-600 kN/m, and the anti-compression stiffness range is about 10-80 MPa/m; the working resistance was bigger, support anti-compression stiffness was bigger. When the working resistance is the same, the anti-compression stiffness of four-leg hydraulic supports is bigger than that of two-leg supports. In each loading cycle, support stiffness is unique, and has little to do with the working resistance of support at the interval relationship; the support anti-compression stiffness is bigger, inhibitory effect on the roof subsidence is more obvious, when the anti-compression stiffness reaches a critical value, roof subsidence tends to be stable. ©, 2015, China Coal Society. All right reserved.