| The main deposit in No.2 mine of Jin-chuan Group is lain in the poor strata with higher ground pressure, and its mining situation is extremely bad. Underhand drift cut-and-fill stoping has been adopted in the mine for decades. Thus, How to effectively enhance the whole stability of filling structure, consisting of filled drifts in mining slices, has been one of tough technical problems to be solved in the mine. According to the investigation contents of a project from the group, experimental studies on flexural test with three-point loading of beams, made of different filling material mortar, and on shearing test of slabs, manufactured by close assembling beams, were carried out so as to explore new and possible techniques for further enhancing the whole stability of filling structure. The main conclusions of this thesis are as following:(1) Flex experiment on four groups of filling materials mortar beams, namely plain beam of cemented high-density tailings mortar(SL), reinforced beam of cemented high-density tailing mortar(SJL), plain beam of graded tailing paste mortar(GL), and reinforced beam of graded tailing paste mortar(GJL), was carried out by flexural test with three-point loading. The research result showed that the flexural strength of reinforced and plain beams (GJL and GL), made of paste mortar, was more than those of reinforced and plain beams (SJL and SL), made of cemented tailing mortar, respectively. Under the same mortar, the flexural strength of reinforced beam was higher than that of plain beam, and it was indicated that reinforcement in filled drift is necessary for enhancing stability of the filled drift because the filled drift is used as artificial roof during under slice mining.(2) For different types of mortar, there was some difference in effect of reinforcement on the ratio of the flexural strength of its reinforced beam to its plain beam. The ratio of the flexural strength of SJL to SL was obviously more than that of GJL to GL.(3) Under six levels normal force separately exerting on any group's models, shearing experiment on four groups of differently structural slabs, namely SB, SJB, GB, and GJB, was carried put by RYL - 600 computer-controlled shear rheology machine. SB was manufactured by close assembling three reinforced beams of cemented high-density tailing mortar(SJL), and its early cast middle beam was naturally stuck with its side beams as they were cast late. The manufacture of SJB was similar to that of SB except adding shear resistant connection between its middle beam and its two side beams. GB and GJB were made from reinforced beams of graded tailing paste mortar(GJL), and their manufactures were similar to those of SB and SJB, respectively. The experimental result showed that, by comparison with SB and GB, the shear strength of SJB and GJB separately rose just as the shear resistant connection was installed in them. It was indicated that by installing shear resistant connection between two close filled drifts in a slice, to some degree, the whole stability of filling structure in the mined-out space was enhanced.(4) Without shear resistant connection in slabs, the shear strength of GB was more than that of SB. As installing shear resistant connection in slabs, the shear strength of GJB was close to that of SJB. Comparatively, the effect of installing shear resistant connection in the slab of cemented high-density tailing mortar on increase in shear strength was better.(5) By reinforcement in filled drift and installing shear resistant connection between two close filled drifts in a slice, the whole stability of filling structure in mined-out space was improved. It was good for the mine to effectively enhance the stability of drift stope and its surroundings. |
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