振动与冲击
振動與遲擊
진동여충격
JOURNAL OF VIBRATION AND SHOCK
2014年
19期
40-47,73
,共9页
李克冰%张楠%方翔宇%田园%夏禾
李剋冰%張楠%方翔宇%田園%夏禾
리극빙%장남%방상우%전완%하화
冲刷%等效刚度%动力响应%行车安全%群桩基础
遲刷%等效剛度%動力響應%行車安全%群樁基礎
충쇄%등효강도%동력향응%행차안전%군장기출
scouring%equivalent stiffness%dynamic responses%running safety%pile group foundation
桥墩周围受到河流冲刷后,基础埋深减小,使得基础刚度降低,从而影响桥梁的服役状态。为研究河流冲刷对车桥响应的影响,计算了群桩承台基础的冲刷深度,并利用m法在承台底施加弹簧约束模拟群桩基础等效刚度,进而基于全过程迭代求解车桥耦合动力方程。作为算例,对比了某跨江特大桥桥墩冲刷前后的车桥动力响应与列车运行安全性。对比分析表明:铁路桥梁桥墩位于水流或潮水中时应采用考虑河流冲刷作用的有限元模型进行车桥动力仿真分析。受到河流冲刷之后,全部桥墩承台底面均高于冲刷线,各墩基础等效刚度在冲刷之后都减小,其中水平方向的平移刚度与竖向的抗扭刚度减小最显著;车辆动力响应普遍增大,车体横向加速度变化最显著,部分工况车辆轮重减载率超出规范容许限值,受冲刷之后简支梁跨中横向位移与横向加速度明显增大,影响行车安全。
橋墩週圍受到河流遲刷後,基礎埋深減小,使得基礎剛度降低,從而影響橋樑的服役狀態。為研究河流遲刷對車橋響應的影響,計算瞭群樁承檯基礎的遲刷深度,併利用m法在承檯底施加彈簧約束模擬群樁基礎等效剛度,進而基于全過程迭代求解車橋耦閤動力方程。作為算例,對比瞭某跨江特大橋橋墩遲刷前後的車橋動力響應與列車運行安全性。對比分析錶明:鐵路橋樑橋墩位于水流或潮水中時應採用攷慮河流遲刷作用的有限元模型進行車橋動力倣真分析。受到河流遲刷之後,全部橋墩承檯底麵均高于遲刷線,各墩基礎等效剛度在遲刷之後都減小,其中水平方嚮的平移剛度與豎嚮的抗扭剛度減小最顯著;車輛動力響應普遍增大,車體橫嚮加速度變化最顯著,部分工況車輛輪重減載率超齣規範容許限值,受遲刷之後簡支樑跨中橫嚮位移與橫嚮加速度明顯增大,影響行車安全。
교돈주위수도하류충쇄후,기출매심감소,사득기출강도강저,종이영향교량적복역상태。위연구하류충쇄대차교향응적영향,계산료군장승태기출적충쇄심도,병이용m법재승태저시가탄황약속모의군장기출등효강도,진이기우전과정질대구해차교우합동력방정。작위산례,대비료모과강특대교교돈충쇄전후적차교동력향응여열차운행안전성。대비분석표명:철로교량교돈위우수류혹조수중시응채용고필하류충쇄작용적유한원모형진행차교동력방진분석。수도하류충쇄지후,전부교돈승태저면균고우충쇄선,각돈기출등효강도재충쇄지후도감소,기중수평방향적평이강도여수향적항뉴강도감소최현저;차량동력향응보편증대,차체횡향가속도변화최현저,부분공황차량륜중감재솔초출규범용허한치,수충쇄지후간지량과중횡향위이여횡향가속도명현증대,영향행차안전。
Dynamic performance of a bridge is influenced by river scouring.In order to study the effect of river scouring on vehicle-bridge interacted vibration,the erosion depth of pile group foundation was calculated.Considering the variation of equivalent stiffness of foundation induced by river scouring,a vehicle-bridge coupled dynamic model based on a full process iteration was established.In a case study,the dynamic response of the vehicle-bridge system and the running safety of trains before and after river scouring were contrasted.The results showed that for a railway bridge located in a river or tidewater,the vehicle-bridge model considering river scouring is proposed to analyze the vehicle-bridge interacted vibration;after river scouring,all bottom surfaces of pile caps are above the river bed,and the equivalent stiffness of the foundation decreases significantly,the lateral responses of both simply supported bridges and vehicles increase obviously,the running safety of trains may be influenced.