Non-pillar mining technology with automatically formed roadway is a new mining method without coal pillar reservation and roadway excavation.The stability control of automatically formed roadway is the key to the succ...Non-pillar mining technology with automatically formed roadway is a new mining method without coal pillar reservation and roadway excavation.The stability control of automatically formed roadway is the key to the successful application of the new method.In order to realize the stability control of the roadway surrounding rock,the mechanical model of the roof and rib support structure is established,and the influence mechanism of the automatically formed roadway parameters on the compound force is revealed.On this basis,the roof and rib support structure technology of confined lightweight concrete is proposed,and its mechanical tests under different eccentricity are carried out.The results show that the bearing capacity of confined lightweight concrete specimens is basically the same as that of ordinary confined concrete specimens.The bearing capacity of confined lightweight concrete specimens under different eccentricities is 1.95 times higher than those of U-shaped steel specimens.By comparing the test results with the theoretical calculated results of the confined concrete,the calculation method of the bearing capacity for the confined lightweight concrete structure is selected.The design method of confined lightweight concrete support structure is established,and is successfully applied in the extra-large mine,Ningtiaota Coal Mine,China.展开更多
Researchers from the National Institute for Occupational Safety and Health(NIOSH)are developing a coal pillar rib rating(CPRR)technique to measure the integrity of coal ribs.The CPRR characterizes the rib composition ...Researchers from the National Institute for Occupational Safety and Health(NIOSH)are developing a coal pillar rib rating(CPRR)technique to measure the integrity of coal ribs.The CPRR characterizes the rib composition and evaluates its impact on the inherent stability of the coal ribs.The CPRR utilizes four parameters:rib homogeneity,bedding condition,face cleat orientation with respect to entry direction,and rib height.All these parameters are measurable in the field.A rib data collecting procedure and a simple sheet to calculate the CPRR were developed.The developed CPRR can be used as a rib quality mapping tool in underground coal mines and to determine the potential of local rib instabilities and support requirements associated with overburden depth.CPRR calculations were conducted for 22 surveyed solid coal ribs,mainly composed of coal units.Based on this study,the rib performance was classified into four categories.A preliminary minimum primary rib support density(PRSD)line was obtained from these surveyed cases.Two sample cases are presented that illustrate the data collection form and CPRR calculations.展开更多
In 2016, room-and-pillar mining provided nearly 40% of underground coal production in the United States.Over the past decade, rib falls have resulted in 12 fatalities, representing 28% of the ground fall fatalities in...In 2016, room-and-pillar mining provided nearly 40% of underground coal production in the United States.Over the past decade, rib falls have resulted in 12 fatalities, representing 28% of the ground fall fatalities in U.S.underground coal mines.Nine of these 12 fatalities(75%) have occurred in room-andpillar mines.The objective of this research is to study the geomechanics of bench room-and-pillar mining and the associated response of high pillar ribs at overburden depths greater than 300 m.This paper provides a definition of the bench technique, the pillar response due to loading, observational data for a case history, a calibrated numerical model of the observed rib response, and application of this calibrated model to a second site.展开更多
目的:探究并评价急诊多发肋骨骨折患者经高危预警与决策支持系统的护理干预效果。方法:选取2023年3月—2024年2月电子科技大学医学院附属绵阳医院·绵阳市中心医院急诊医学科收治的84例多发肋骨骨折患者作为研究对象,按照护理方法...目的:探究并评价急诊多发肋骨骨折患者经高危预警与决策支持系统的护理干预效果。方法:选取2023年3月—2024年2月电子科技大学医学院附属绵阳医院·绵阳市中心医院急诊医学科收治的84例多发肋骨骨折患者作为研究对象,按照护理方法不同分为A组与B组,各42例。A组实施常规急诊护理,B组在A组基础上实施高危预警与决策支持系统的护理干预。比较两组救治时间、生活质量[健康调查简表(the MOS item short form health survey,SF-36)]、干预期间不良事件发生情况及患者护理满意度。结果:B组急诊分诊时间、急诊停留时间、开始治疗时间较A组短,差异有统计学意义(t=6.358、5.408、7.802,P<0.05);转科当天,两组生理机能、躯体疼痛、一般健康状况评分高于干预前,且B组较A组高,差异有统计学意义(t=2.952、2.223、2.599,P<0.05);B组干预期间不良事件发生率为4.76%,较A组的21.43%低,差异有统计学意义(χ^(2)=5.126,P<0.05);B组转科当天护理满意度为97.62%,较A组的80.95%高,差异有统计学意义(χ^(2)=4.480,P<0.05)。结论:高危预警与决策支持系统的护理干预应用于急诊多发肋骨骨折患者,可缩短救治时间,提高生活质量,降低护理期间不良事件发生率,转科当天护理满意度较高。展开更多
基金Project(2023YFC2907600)supported by the National Key Research and Development Program of ChinaProjects(42077267,42277174,52074164)supported by the National Natural Science Foundation of ChinaProject(2024JCCXSB01)supported by the Fundamental Research Funds for the Central Universities,China。
文摘Non-pillar mining technology with automatically formed roadway is a new mining method without coal pillar reservation and roadway excavation.The stability control of automatically formed roadway is the key to the successful application of the new method.In order to realize the stability control of the roadway surrounding rock,the mechanical model of the roof and rib support structure is established,and the influence mechanism of the automatically formed roadway parameters on the compound force is revealed.On this basis,the roof and rib support structure technology of confined lightweight concrete is proposed,and its mechanical tests under different eccentricity are carried out.The results show that the bearing capacity of confined lightweight concrete specimens is basically the same as that of ordinary confined concrete specimens.The bearing capacity of confined lightweight concrete specimens under different eccentricities is 1.95 times higher than those of U-shaped steel specimens.By comparing the test results with the theoretical calculated results of the confined concrete,the calculation method of the bearing capacity for the confined lightweight concrete structure is selected.The design method of confined lightweight concrete support structure is established,and is successfully applied in the extra-large mine,Ningtiaota Coal Mine,China.
文摘Researchers from the National Institute for Occupational Safety and Health(NIOSH)are developing a coal pillar rib rating(CPRR)technique to measure the integrity of coal ribs.The CPRR characterizes the rib composition and evaluates its impact on the inherent stability of the coal ribs.The CPRR utilizes four parameters:rib homogeneity,bedding condition,face cleat orientation with respect to entry direction,and rib height.All these parameters are measurable in the field.A rib data collecting procedure and a simple sheet to calculate the CPRR were developed.The developed CPRR can be used as a rib quality mapping tool in underground coal mines and to determine the potential of local rib instabilities and support requirements associated with overburden depth.CPRR calculations were conducted for 22 surveyed solid coal ribs,mainly composed of coal units.Based on this study,the rib performance was classified into four categories.A preliminary minimum primary rib support density(PRSD)line was obtained from these surveyed cases.Two sample cases are presented that illustrate the data collection form and CPRR calculations.
文摘In 2016, room-and-pillar mining provided nearly 40% of underground coal production in the United States.Over the past decade, rib falls have resulted in 12 fatalities, representing 28% of the ground fall fatalities in U.S.underground coal mines.Nine of these 12 fatalities(75%) have occurred in room-andpillar mines.The objective of this research is to study the geomechanics of bench room-and-pillar mining and the associated response of high pillar ribs at overburden depths greater than 300 m.This paper provides a definition of the bench technique, the pillar response due to loading, observational data for a case history, a calibrated numerical model of the observed rib response, and application of this calibrated model to a second site.
文摘目的:探究并评价急诊多发肋骨骨折患者经高危预警与决策支持系统的护理干预效果。方法:选取2023年3月—2024年2月电子科技大学医学院附属绵阳医院·绵阳市中心医院急诊医学科收治的84例多发肋骨骨折患者作为研究对象,按照护理方法不同分为A组与B组,各42例。A组实施常规急诊护理,B组在A组基础上实施高危预警与决策支持系统的护理干预。比较两组救治时间、生活质量[健康调查简表(the MOS item short form health survey,SF-36)]、干预期间不良事件发生情况及患者护理满意度。结果:B组急诊分诊时间、急诊停留时间、开始治疗时间较A组短,差异有统计学意义(t=6.358、5.408、7.802,P<0.05);转科当天,两组生理机能、躯体疼痛、一般健康状况评分高于干预前,且B组较A组高,差异有统计学意义(t=2.952、2.223、2.599,P<0.05);B组干预期间不良事件发生率为4.76%,较A组的21.43%低,差异有统计学意义(χ^(2)=5.126,P<0.05);B组转科当天护理满意度为97.62%,较A组的80.95%高,差异有统计学意义(χ^(2)=4.480,P<0.05)。结论:高危预警与决策支持系统的护理干预应用于急诊多发肋骨骨折患者,可缩短救治时间,提高生活质量,降低护理期间不良事件发生率,转科当天护理满意度较高。
