Mechanical performance analysis of two-prop shield caving hydraulic support

The bed rock of shallow-buried depth coal seam is relatively thinner and the loose layer is thicker, the working face is easy to appear step subsidence and other conditions, and mine rock pressure is severe. The two-prop shield caving hydraulic support used in the working face of shallow buried depth coal seam is prone to insufficient working resistance, poor support for the roof, so as to cause production safety problems. In view of the above problems, using space mechanics analysis and structural finite element analysis, stress state of ZFY12000/25/42D two-prop shield caving hydraulic support suitable for shallow-buried depth coal seams was analyzed under the three most dangerous working conditions of the top beam subjected to eccentric load and loaded on both ends of the base, the top beam subjected to torsional load and loaded on both ends of the base and the top beam subjected to eccentric load and the base subjected to torsional load. The analysis results show that under different working conditions, the stress of each structural member of the hydraulic support will be different, and the stress distribution will be different. From the overall stress distribution of the hydraulic support, the top beam and the base will be subjected to large stresses for interact of the top beam, the prop and the bottom plate, and the front and rear connecting rods and the shield beam as the connecting transition parts will be subjected to less stress; the largest stress of the support is at 712.69 MPa under the working condition of the top beam subjected to torsional load and loaded on both ends of the base; the displacement deformation trend of the support is basically the same, from the top beam to the base, the deformation is gradually reduced, but the overall deformation is good. Under the premise of ensuring structural reliability, high-strength plates are used in the stress concentration part or the thickness of the material is increased to improve the stress distribution of the support and enhance roof-controlling ability of the support, so as to ensure the reliability and stability of the support working.