The authors have invented a unique counter-rotating type tidal stream power unit, which is composed of tandem propellers and a double rotational armature type generator without a stator. The front and the rear propell...The authors have invented a unique counter-rotating type tidal stream power unit, which is composed of tandem propellers and a double rotational armature type generator without a stator. The front and the rear propellers drive, as for an upstream type, the inner and the outer rotational armatures in the counter-rotating directions respectively, which keep the rotational torques counter-balanced between both propellers and armatures. This paper investigates experimentally the output and forces acting on a pile in a water channel, to get design materials of the mono-pile type tidal stream power unit. The output is maximal at the moderate rotational speed, as the same as a wind turbine. The force acting on the pile is affected by the drag, the Karman vortex and the dynamic balances of the tandem propellers, and has dominant frequencies due to not only the individual but also the interacting rotation of the front and the rear propellers.展开更多
新建津石高速公路与既有铁路线路交汇,采用2×65 m T形刚构大节段现浇转体上跨既有铁路。考虑桥墩下部承台桩基距离既有铁路较近,通过施作防护桩、拉森钢板桩、回灌井及调整施工顺序等手段最大限度的减小对既有铁路的影响;采用水泥...新建津石高速公路与既有铁路线路交汇,采用2×65 m T形刚构大节段现浇转体上跨既有铁路。考虑桥墩下部承台桩基距离既有铁路较近,通过施作防护桩、拉森钢板桩、回灌井及调整施工顺序等手段最大限度的减小对既有铁路的影响;采用水泥搅拌桩加固地基,满足现浇梁支架地基承载要求;转体施工加强防护与监测。采用PLAXIS完成相关模拟运算,顺利完成上跨铁路转体施工,对后续类似工程有较大的参考价值。展开更多
Based on the upper bound of limit analysis, the plane-strain analysis of the slopes reinforced with a row of piles to the 3D case was extended. A 3D rotational failure mechanism was adopted to yield the upper bound of...Based on the upper bound of limit analysis, the plane-strain analysis of the slopes reinforced with a row of piles to the 3D case was extended. A 3D rotational failure mechanism was adopted to yield the upper bound of the factor of safety. Parametric studies were carried out to explore the end effects of the slope failures and the effects of the pile location and diameter on the safety of the reinforced slopes. The results demonstrate that the end effects nearly have no effects on the most suitable location of the installed piles but have significant influence on the safety of the slopes. For a slope constrained to a narrow width, the slope becomes more stable owing to the contribution of the end effects. When the slope is reinforced with a row of piles in small space between piles, the effects of group piles are significant for evaluating the safety of slopes. The presented method is more appropriate for assessing the stability of slopes reinforced with piles and can be also utilized in the design of plies stabilizing the unstable slopes.展开更多
目的:总结应用“打孔栽桩”技术解决股骨近端防旋髓内钉(Proximal femoral nail antirotation,PFNA)螺旋刀片取出滑丝时的临床效果。方法:回顾性分析2015年1月—2023年1月于定西市人民医院骨科行股骨粗隆间骨折PFNA内固定取出术258例患...目的:总结应用“打孔栽桩”技术解决股骨近端防旋髓内钉(Proximal femoral nail antirotation,PFNA)螺旋刀片取出滑丝时的临床效果。方法:回顾性分析2015年1月—2023年1月于定西市人民医院骨科行股骨粗隆间骨折PFNA内固定取出术258例患者临床资料,其中发生螺旋刀片滑丝采用“打孔栽桩”技术取出者35例,设为打孔组。选取以常规术式取出螺旋刀片滑丝者35例,设为常规组。比较两组手术时间、打磨时间、术中出血量等指标。结果:打孔组手术时间[(65.12±7.16)min]、打磨时间[(26.25±5.12)min]短于常规组[(115.51±16.09)min、(70.91±6.95)min],差异有统计学意义(t=-16.96,P<0.05;t=-30.56,P<0.05);术中出血量[(71.23±9.97)mL]少于对照组[(116.08±18.81)mL](t=-12.47,P<0.05);两组术中均无医源性骨折、血管及神经损伤发生。常规组术后切口感染2例,后经换药后愈合,4例患者存在伤口周围少量金属碎屑残留,两组术后X线片复查内固定物全部取出。结论:PFNA螺旋刀片尾端出现滑丝时可选择“打孔栽桩”技术取出,是一种方便、快捷、安全的取出方法。展开更多
文摘The authors have invented a unique counter-rotating type tidal stream power unit, which is composed of tandem propellers and a double rotational armature type generator without a stator. The front and the rear propellers drive, as for an upstream type, the inner and the outer rotational armatures in the counter-rotating directions respectively, which keep the rotational torques counter-balanced between both propellers and armatures. This paper investigates experimentally the output and forces acting on a pile in a water channel, to get design materials of the mono-pile type tidal stream power unit. The output is maximal at the moderate rotational speed, as the same as a wind turbine. The force acting on the pile is affected by the drag, the Karman vortex and the dynamic balances of the tandem propellers, and has dominant frequencies due to not only the individual but also the interacting rotation of the front and the rear propellers.
文摘新建津石高速公路与既有铁路线路交汇,采用2×65 m T形刚构大节段现浇转体上跨既有铁路。考虑桥墩下部承台桩基距离既有铁路较近,通过施作防护桩、拉森钢板桩、回灌井及调整施工顺序等手段最大限度的减小对既有铁路的影响;采用水泥搅拌桩加固地基,满足现浇梁支架地基承载要求;转体施工加强防护与监测。采用PLAXIS完成相关模拟运算,顺利完成上跨铁路转体施工,对后续类似工程有较大的参考价值。
基金Projects(51278382,51479050)supported by the National Natural Science Foundation of ChinaProject(2015CB057901)supported by the National Key Basic Research Program of China+3 种基金Project(201501035-03)supported by the Public Service Sector R&D Project of Ministry of Water Resource of ChinaProject(2014B06814)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(B13024)supported by the"111"ProjectProject(YK913004)supported by the Open Foundation of Key Laboratory of Failure Mechanism and Safety Control Techniques of Earthrock Dam of the Ministry of Water Resources,China
文摘Based on the upper bound of limit analysis, the plane-strain analysis of the slopes reinforced with a row of piles to the 3D case was extended. A 3D rotational failure mechanism was adopted to yield the upper bound of the factor of safety. Parametric studies were carried out to explore the end effects of the slope failures and the effects of the pile location and diameter on the safety of the reinforced slopes. The results demonstrate that the end effects nearly have no effects on the most suitable location of the installed piles but have significant influence on the safety of the slopes. For a slope constrained to a narrow width, the slope becomes more stable owing to the contribution of the end effects. When the slope is reinforced with a row of piles in small space between piles, the effects of group piles are significant for evaluating the safety of slopes. The presented method is more appropriate for assessing the stability of slopes reinforced with piles and can be also utilized in the design of plies stabilizing the unstable slopes.
文摘目的:总结应用“打孔栽桩”技术解决股骨近端防旋髓内钉(Proximal femoral nail antirotation,PFNA)螺旋刀片取出滑丝时的临床效果。方法:回顾性分析2015年1月—2023年1月于定西市人民医院骨科行股骨粗隆间骨折PFNA内固定取出术258例患者临床资料,其中发生螺旋刀片滑丝采用“打孔栽桩”技术取出者35例,设为打孔组。选取以常规术式取出螺旋刀片滑丝者35例,设为常规组。比较两组手术时间、打磨时间、术中出血量等指标。结果:打孔组手术时间[(65.12±7.16)min]、打磨时间[(26.25±5.12)min]短于常规组[(115.51±16.09)min、(70.91±6.95)min],差异有统计学意义(t=-16.96,P<0.05;t=-30.56,P<0.05);术中出血量[(71.23±9.97)mL]少于对照组[(116.08±18.81)mL](t=-12.47,P<0.05);两组术中均无医源性骨折、血管及神经损伤发生。常规组术后切口感染2例,后经换药后愈合,4例患者存在伤口周围少量金属碎屑残留,两组术后X线片复查内固定物全部取出。结论:PFNA螺旋刀片尾端出现滑丝时可选择“打孔栽桩”技术取出,是一种方便、快捷、安全的取出方法。
