Influence of canopy ratio of powered roof support on longwall working stability – A case study
|نوع نگارش مقاله||
scopus – master journals – JCR
۴٫۲۷۶ در سال ۲۰۲۰
۲۶ در سال ۲۰۲۱
۰٫۹۰۱ در سال ۲۰۲۰
|شاخص Quartile (چارک)||
Q1 در سال ۲۰۲۰
خرید محصول توسط کلیه کارت های شتاب امکان پذیر است و بلافاصله پس از خرید، لینک دانلود محصول در اختیار شما قرار خواهد گرفت و هر گونه فروش در سایت های دیگر قابل پیگیری خواهد بود.
فهرست مطالب مقاله:
The case study describes longwall coal seam A in a hard coal mine, where longwall coal face stability loss and periodic roof fall occurrences had been registered. The authors have attempted to explain the situa- tion based on in-situ measurements and observations of the longwall working as well as numerical sim- ulation. The calculations included several parameters, such as powered roof support geometry in the form of the canopy ratio, which is a factor that influences load distribution along the canopy. Numerical simulations were realized based on a rock mass model representing realistic mining and geo- logical conditions at a depth of 600 m below surface for coal seam A. Numerical model assumptions are described, while the obtained results were compared with the in-situ measurements. The conclusions drawn from this work can complement engineering knowledge utilized at the stage of powered roof sup- port construction and selection in order to improve both personnel safety and longwall working stability, and to achieve better extraction.
|بخشی از متن مقاله:|
The safe and effective mining of coal seams is inseparably con- nected with maintaining the original mine working geometry despite the load applied by the rock mass. Adverse mining and geo- logical conditions while operating at great depths considerably contribute to the occurrence of damage events due to loss of stabil- ity [۱,۲]. Mine working stability is determined by several factors, which are dependent primarily on the natural and technical condi- tions of the conducted mining operations . Liu et al. found the internal factors between mining heights and shield resistance as well as surrounding rocks in order to determine the stability con- ditions of overburden based on the numerical simulation . Li el al. studied the stability of the roof structure and hydraulic supports with physical simulation and theoretical analysis . Prusek et al. analyzed and described typical damage to support of the workings, resulting from dynamic load, illustrated with numerical simula- tion, as well as determined the major factors influencing the stabil- ity of the roof in retreat longwall panels [3,6]. Also Prusek et al. studied the interaction between shield and roof strata in two long- wall panels with natural roof caving in the gob using the concept of ground reaction curves (GRCs) in order to determine shield
capacity . Hu et al. studied the effects of strike angle on support stability and analyzed influencing factors of support stability and the technical measures of controlling support and surrounding rock stability .
One of the significant technical factors influencing longwall working stability is the dimensions and geometrical parameters of the powered support. An unfavourable geometric configuration of the powered roof support, may result in a situation where the powered support does not sufficiently interact with surrounding mass rock. Important technical parameters ensuring that the bal- ance of mass forces originating from the surrounding rock mass is maintained include uniform distribution of pressure (active sup- port) along the entire length of the canopy . Load distribution can be achieved on condition that the position of the resultant force is within approximately 1/3 the length, L, from the end of the canopy, as shown in Fig. 1 .
Achieving a hydraulic leg socket distance (resultant force– Fig. 1) in relation to the end of the canopy at a proportion of max- imum of ۲٫۶:۱ constitutes the optimal powered support canopy ratio value [9–۱۱]. In order to demonstrate the importance of the powered support canopy ratio and its influence on the longwall working stability, a series of numerical simulations were per- formed. Various dimensions and geometrical parameters of the support were used for this purpose, one of which was character- ized by a favourable and unfavourable geometric configuration.
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