破碎生产线在建设设计时选用熟料散装机进行放料,由于产品物料粒度为0~80 m m,在实际工作时经常发生钢丝绳错位、伸缩布套运作不灵敏等问题,降低了发料速度,增加了损耗。为解决这一系列问题,采取料仓下料处垂直压力分析法,校核所需推力...破碎生产线在建设设计时选用熟料散装机进行放料,由于产品物料粒度为0~80 m m,在实际工作时经常发生钢丝绳错位、伸缩布套运作不灵敏等问题,降低了发料速度,增加了损耗。为解决这一系列问题,采取料仓下料处垂直压力分析法,校核所需推力,选取合适的固定螺栓,并依据各项计算数据,选取以液压驱动的电液推杆平板阀,在实际运转中起到了良好的作用,对石灰石放料装置的选择具有一定的借鉴意义。展开更多
This study proposes a novel approach to study stress field distribution and overlying ground pressure behavior in shallow seam mining in gully terrain.This approach combines numerical simulations and field tests based...This study proposes a novel approach to study stress field distribution and overlying ground pressure behavior in shallow seam mining in gully terrain.This approach combines numerical simulations and field tests based on the conditions of gully terrain in the Chuancao Gedan Mine.The effects of gully terrain on the in situ stress field of coal beds can be identified by the ratio of self-weight stress to vertical stress(η) at the location corresponding to the maximum vertical stress.Based on the function η =j(h),the effect of gully terrain on the stress field of overlying strata of the entire field can be characterized as a significantly affected area,moderately affected area,or non-affected area.Working face 6106 in the Chuancao Gedan Mine had a coal bed Jepth <80 m and was located in what was identified as a significantly affected area.Hence,mining may cause sliding of the gully slope and increased loading(including significant dynamic loading) on the roof strata.Field tests suggest that significant dynamic pressures were observed at the body and foot of the gully slope,and that dynamic loadings were observed upslope of the working face expansion,provided that the expanding direction of the working face is parallel to the gully.展开更多
A new analytical study on stresses around a post-tensioned anchor in rocks with two perpendicular joint sets is presented. The assumptions of orthotropic elastic rock with plane strain conditions are made in derivatio...A new analytical study on stresses around a post-tensioned anchor in rocks with two perpendicular joint sets is presented. The assumptions of orthotropic elastic rock with plane strain conditions are made in derivation of the formulations. A tri-linear bond-slip constitutive law is used for modeling the tendon-grout interface behavior and debonding of this interface. The bearing plate width is also considered in the analysis. The obtained solutions are in the integral forms and numerical techniques that have been used for evaluation. In the illustrative example given, the major principal stress is compressive in the anchor free zone and compressive stress concentrations of 815 k Pa and 727 k Pa(for the anchor load of 300 k N) are observed under the bearing plate and the bond length proximal end, respectively. However, large values of tensile stresses with the maximum of-434 k Pa are formed at the bond length distal end. The results obtained using the proposed solution are compared very those of numerical method(FEM).展开更多
文摘破碎生产线在建设设计时选用熟料散装机进行放料,由于产品物料粒度为0~80 m m,在实际工作时经常发生钢丝绳错位、伸缩布套运作不灵敏等问题,降低了发料速度,增加了损耗。为解决这一系列问题,采取料仓下料处垂直压力分析法,校核所需推力,选取合适的固定螺栓,并依据各项计算数据,选取以液压驱动的电液推杆平板阀,在实际运转中起到了良好的作用,对石灰石放料装置的选择具有一定的借鉴意义。
基金supported by the Fundamental Research Funds for the Central Universities of China University of Mining and Technology(No.2014ZDPY21)
文摘This study proposes a novel approach to study stress field distribution and overlying ground pressure behavior in shallow seam mining in gully terrain.This approach combines numerical simulations and field tests based on the conditions of gully terrain in the Chuancao Gedan Mine.The effects of gully terrain on the in situ stress field of coal beds can be identified by the ratio of self-weight stress to vertical stress(η) at the location corresponding to the maximum vertical stress.Based on the function η =j(h),the effect of gully terrain on the stress field of overlying strata of the entire field can be characterized as a significantly affected area,moderately affected area,or non-affected area.Working face 6106 in the Chuancao Gedan Mine had a coal bed Jepth <80 m and was located in what was identified as a significantly affected area.Hence,mining may cause sliding of the gully slope and increased loading(including significant dynamic loading) on the roof strata.Field tests suggest that significant dynamic pressures were observed at the body and foot of the gully slope,and that dynamic loadings were observed upslope of the working face expansion,provided that the expanding direction of the working face is parallel to the gully.
文摘A new analytical study on stresses around a post-tensioned anchor in rocks with two perpendicular joint sets is presented. The assumptions of orthotropic elastic rock with plane strain conditions are made in derivation of the formulations. A tri-linear bond-slip constitutive law is used for modeling the tendon-grout interface behavior and debonding of this interface. The bearing plate width is also considered in the analysis. The obtained solutions are in the integral forms and numerical techniques that have been used for evaluation. In the illustrative example given, the major principal stress is compressive in the anchor free zone and compressive stress concentrations of 815 k Pa and 727 k Pa(for the anchor load of 300 k N) are observed under the bearing plate and the bond length proximal end, respectively. However, large values of tensile stresses with the maximum of-434 k Pa are formed at the bond length distal end. The results obtained using the proposed solution are compared very those of numerical method(FEM).
