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Liu J.-Z.,Hebei United University | Guo L.-W.,Hebei United University | Li J.-M.,Kailuan Mining Group Ltd Company | Geng Q.-Y.,Kailuan Mining Group Ltd Company
Meitan Xuebao/Journal of the China Coal Society | Year: 2015

The pre-tightening force is a key index in bolting and anchoring engineering, because of its important influence on surrounding rock structures' rigidity and anchorage group effect. The mechanism using ANSYS simulation and the cable's pre-tightening course with mechanical analysis was investigated. According to its installation and pre-tighten process, a series drag springs model was put forward for mechanical analysis, which includes surrounding rock, cable, anchor cup, and anchor wedge. The difference and connection of installing tension load and pre-tightening force were analyzed in detail. Some formulas for pre-tightening force were deduced and demonstrated by a calculation example. The studies show that the bigger installing tension load, the softer rock, the longer free cable section and the better following performance of wedges, would lead to the bigger pre-tightening force and the smaller converting loss rate. In the engineering application, the super-tension, replenish-tension, optimal length of free section, improved restriction mode and lag resin bolt, could be applied to realize high pre-tightening force anchoring and better support efficiency. ©, 2015, China Coal Society. All right reserved.

Chai H.-B.,Henan Polytechnic University | Chai H.-B.,Kailuan Mining Group Ltd Company | Zhang R.-X.,Kailuan Mining Group Ltd Company | Zou Y.-F.,Henan Polytechnic University | Lu Z.-X.,Kailuan Mining Group Ltd Company
Dongbei Daxue Xuebao/Journal of Northeastern University | Year: 2013

To reduce the mining damage of the surface, and realize safe coal mining under buildings, the mining scheme of the 9th coal layer was designed according to the specific geological mining conditions and surface status in Jinggezhuang's coal mine. Observation results of Jinggezhuang's coal mine indicated that probability-integral method could suitably predict the surface subsidence. Based on similarity criterion, the maximum membership function is applied to determine the predicting parameters of the probability-integral method. The surface movement and deformation of the 2092ed, 2094th and 2096th working face of the 9th coal layer were calculated. The damage extent of the buildings is accurately analyzed and evaluated based on the predicted result.

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