There is a perpetual problem of partial or complete roof collapse within the Tamale Metropolis and other parts of Ghana.This has become an issue of grave public concern since this menace affects both public buildings ...There is a perpetual problem of partial or complete roof collapse within the Tamale Metropolis and other parts of Ghana.This has become an issue of grave public concern since this menace affects both public buildings of all kinds(schools,offices,churches,mosque etc.)as well as domestic buildings.This research sets out to conduct comprehensive investigations into the nature of roof failures,causes,and effects and then propose remedial actions towards stemming the tide.The study employed the use of roof construction affirmation surveys,questionnaires,interviews and focus group discussions.Relevant information synthesized indicates that the roof type,construction materials,building type and environmental conditions are crucial causative factors.Major consequences of roof failures include damage to personal belongings and exposure to inclement weather conditions,the psychological trauma victims are subjected and pressure on incomes and living conditions as a result of the cost of repair or replacement of the roofs.It is recommended that expert advice be sought in checking maintenance requirements of existing roofs in the study area and also during the design and construction of new roofs.Tree planting programmes for this heavily deforested region should be encouraged.The use of green timber for roof construction must be replaced with well-seasoned ones.Proper construction detailing and placement openings buildings should be done so that wind flow during a windstorm is optimized.展开更多
The damage process of fractured rock mass showed that the fracture in rocks induced roof collapse in Yangchangwan Coal Mine, China. The rock mass was particularly weak and fractured. There occurred 6 large-scale dynam...The damage process of fractured rock mass showed that the fracture in rocks induced roof collapse in Yangchangwan Coal Mine, China. The rock mass was particularly weak and fractured. There occurred 6 large-scale dynamical roof falls in the excavation disturbed zone （EDZ） with the collapsing volume of 216 m^3. First, the field detailed geological environment, regional seismic dynamics, and dynamic instability of roadways were generally investigated. Second, the field multiple-index monitoring measurements for detecting the deep delamination of the roof, convergence deformation, bolt-cable load, acoustic emission （AE） characteristic parameters, total AE events, AE energy-releasing rate, rock mass fracture, and damage were arranged. Finally, according to the time-space-strength relations, a quantitative assessment of the influence of rock-mass damage on the dynamic roof instability was accomplished.展开更多
文摘There is a perpetual problem of partial or complete roof collapse within the Tamale Metropolis and other parts of Ghana.This has become an issue of grave public concern since this menace affects both public buildings of all kinds(schools,offices,churches,mosque etc.)as well as domestic buildings.This research sets out to conduct comprehensive investigations into the nature of roof failures,causes,and effects and then propose remedial actions towards stemming the tide.The study employed the use of roof construction affirmation surveys,questionnaires,interviews and focus group discussions.Relevant information synthesized indicates that the roof type,construction materials,building type and environmental conditions are crucial causative factors.Major consequences of roof failures include damage to personal belongings and exposure to inclement weather conditions,the psychological trauma victims are subjected and pressure on incomes and living conditions as a result of the cost of repair or replacement of the roofs.It is recommended that expert advice be sought in checking maintenance requirements of existing roofs in the study area and also during the design and construction of new roofs.Tree planting programmes for this heavily deforested region should be encouraged.The use of green timber for roof construction must be replaced with well-seasoned ones.Proper construction detailing and placement openings buildings should be done so that wind flow during a windstorm is optimized.
基金supported by the National Natural Science Foundation of China (No.10402033 and No.10772144)
文摘The damage process of fractured rock mass showed that the fracture in rocks induced roof collapse in Yangchangwan Coal Mine, China. The rock mass was particularly weak and fractured. There occurred 6 large-scale dynamical roof falls in the excavation disturbed zone （EDZ） with the collapsing volume of 216 m^3. First, the field detailed geological environment, regional seismic dynamics, and dynamic instability of roadways were generally investigated. Second, the field multiple-index monitoring measurements for detecting the deep delamination of the roof, convergence deformation, bolt-cable load, acoustic emission （AE） characteristic parameters, total AE events, AE energy-releasing rate, rock mass fracture, and damage were arranged. Finally, according to the time-space-strength relations, a quantitative assessment of the influence of rock-mass damage on the dynamic roof instability was accomplished.
