Foundation piles of the offshore oil platforms in the Bohai Bay are usually longer than 100 m with a diameter larger than 2 m. Driving such long and large-sized piles into the ground is a difficult task. It needs a co...Foundation piles of the offshore oil platforms in the Bohai Bay are usually longer than 100 m with a diameter larger than 2 m. Driving such long and large-sized piles into the ground is a difficult task. It needs a comprehensive consider ation of the pile dimensions, soil properties and the hammer energy. Thoughtful drivability analysis has to be performed in the design stage. It has been shown that judging whether the soil column inside the pile is fully plugged, which makes the pile behave as close-ended, strongly influences the accuracy of drivability analysis. Engineering practice repeatedly indicates that the current methods widely used for soil plug judgment often give incorrect results, leading the designers to make a wrong decision. It has been found that this problem is caused by the ignorance of the bearing capacity provided by the soil surrounding the pile. Based on the Terzaghi＇s bearing capacity calculation method for deep foundation, a new approach for judging soil plug status is put forward, in which the surcharge effect has been considered and the dynamic effect coefficient is included. This approach has been applied to some practical engineering projects successfully, which may give more reasonable results than the currently used method does.展开更多
Internal soliton forces on oil-platform piles in the ocean are estimated with the Morison Formula. Different from sur- face wave forces, which change only in magnitude along a pile, internal soliton forces can be dist...Internal soliton forces on oil-platform piles in the ocean are estimated with the Morison Formula. Different from sur- face wave forces, which change only in magnitude along a pile, internal soliton forces can be distributed over the entire pile in the water and they change not only in magnitude but also in direction with depth. Our calculations show that the maximum total force caused by a soliton with its associated current of 2.1 m s-1 is nearly equal to the maximum total force exerted by a surface wave with a wavelength of 300 m and a wave-height of 18 m. The total internal soliton force is large enough to affect the operations of marine oil platforms and other facilities. Therefore, the influence of internal solitons should not be neglected in the design of oil platforms.展开更多
高校教育教学改革中,仪器设备是专业升级与数字化改造的重要支撑,设备共享则是提高大型设备利用率、减少重复建设的重要手段。围绕设备共享存在的管理、维护、安全风险防范等问题,利用华为Ocean Connect平台设计一款由窄带物联网(Narrow...高校教育教学改革中,仪器设备是专业升级与数字化改造的重要支撑,设备共享则是提高大型设备利用率、减少重复建设的重要手段。围绕设备共享存在的管理、维护、安全风险防范等问题,利用华为Ocean Connect平台设计一款由窄带物联网(Narrow Band Internet of Things,NB-IoT)通信模块、电能测量芯片等组成的智能电源线,对仪器设备进行远程授权、控制、实时监控,同时还能分析设备使用数据,实现设备的维护提醒和安全风险评估。展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 50309009)
文摘Foundation piles of the offshore oil platforms in the Bohai Bay are usually longer than 100 m with a diameter larger than 2 m. Driving such long and large-sized piles into the ground is a difficult task. It needs a comprehensive consider ation of the pile dimensions, soil properties and the hammer energy. Thoughtful drivability analysis has to be performed in the design stage. It has been shown that judging whether the soil column inside the pile is fully plugged, which makes the pile behave as close-ended, strongly influences the accuracy of drivability analysis. Engineering practice repeatedly indicates that the current methods widely used for soil plug judgment often give incorrect results, leading the designers to make a wrong decision. It has been found that this problem is caused by the ignorance of the bearing capacity provided by the soil surrounding the pile. Based on the Terzaghi＇s bearing capacity calculation method for deep foundation, a new approach for judging soil plug status is put forward, in which the surcharge effect has been considered and the dynamic effect coefficient is included. This approach has been applied to some practical engineering projects successfully, which may give more reasonable results than the currently used method does.
基金This study is supported by the National Natural Science Foundation of China(Projects under contract Nos.40506007,49676275 and 49976002)the Natural Science Foundation of Shandong Province(No.Y2000E04)Microwave Imaging National Key Laboratory Foundation(No.51442020103JW1002).
文摘Internal soliton forces on oil-platform piles in the ocean are estimated with the Morison Formula. Different from sur- face wave forces, which change only in magnitude along a pile, internal soliton forces can be distributed over the entire pile in the water and they change not only in magnitude but also in direction with depth. Our calculations show that the maximum total force caused by a soliton with its associated current of 2.1 m s-1 is nearly equal to the maximum total force exerted by a surface wave with a wavelength of 300 m and a wave-height of 18 m. The total internal soliton force is large enough to affect the operations of marine oil platforms and other facilities. Therefore, the influence of internal solitons should not be neglected in the design of oil platforms.
文摘高校教育教学改革中,仪器设备是专业升级与数字化改造的重要支撑,设备共享则是提高大型设备利用率、减少重复建设的重要手段。围绕设备共享存在的管理、维护、安全风险防范等问题,利用华为Ocean Connect平台设计一款由窄带物联网(Narrow Band Internet of Things,NB-IoT)通信模块、电能测量芯片等组成的智能电源线,对仪器设备进行远程授权、控制、实时监控,同时还能分析设备使用数据,实现设备的维护提醒和安全风险评估。
