船桥碰撞中桩土相互作用模拟方式的影响分析

为研究船桥碰撞模拟中的桩土相互作用问题,本文建立了单桩-土-船舶高精度碰撞有限元模型,采用桩底固结、土弹簧以及无反射边界模拟桩土相互作用,并计算了船舶撞击力以及船撞作用下桩基的位移响应。计算结果表明,当桩基固结深度大于5倍桩径时,船舶撞击力趋势与其他模拟方式计算结果区别较大,在撞击过程中撞击力出现卸载现象,说明船舶与桩基之间出现了一次逐渐脱离的状态。无反射边界条件模拟得出的撞击力与结构位移响应均最小,土弹簧计算结果居于固结模拟与无反射边界模拟计算结果之间。通过分析,结构动力响应不仅与最大船撞力、平均船撞力相关,且与船撞力时程持续时间有关,当无详细地质资料时,可采用3倍桩径固结深度对桩底固结,所得动力响应偏安全,可满足工程应用需要。

Impact Analysis of Pile-Soil Interaction Simulation Method aboutShip-Bridge Collision

: To study the pile-soil interaction in ship-bridge collision simulation, a high-precision finite element model of single pile-soil-ship collision is established in this paper, the pile-soil interaction is simulated by pile bottom fixed, soil spring and nonreflecting boundary, and the impact force and displacement response of pile foundation under ship collision is calculated. The calculation results show that the trend of impact force was quite different from the results of other simulation methods when the fixed depth of pile foundation is greater than 5 times of pile diameter. the reason is the impact force appears unloading phenomenon, which indicates that the ship and pile foundation have a gradual separation state. The response of ship collision force and structural displacement obtained from the non-reflecting boundary simulation is the smallest, and the simulation results of soil spring between the fixed simulation results and the non-reflecting boundary simulation results. Through the analysis, the dynamic response of the structure is not only related to the maximum ship collision force and the average ship collision force, but also related to the duration of the ship collision force. When there is no detailed geological data, the pier can be fixed at 3 times the pile diameter depth. The dynamic response obtained was relatively safe and can meet the needs of engineering application.