摘要
为了研究列车加减速引起的饱和地基振动问题,基于两相介质Biot动力控制方程的简化u-p格式,开发二维饱和土体单元.通过引入饱和土体黏弹性人工边界,求解移动点荷载作用下的二维饱和地基动力响应,并与半解析解进行对比验证,说明饱和土体单元的正确性和黏弹性人工边界的适用性.结合E-B梁单元、弹簧-黏壶单元和集中质量单元对轨枕、道砟离散支承的轨道结构及饱和地基进行二维有限单元离散.将列车荷载简化为平面内的移动轴荷载,通过与列车匀速时对比研究列车加速和减速时饱和地基的孔压、位移响应及离散轨枕、道砟的加速度响应.结果表明列车减速将增大轨枕、道砟的水平及竖向加速度峰值;列车加速和减速在饱和地基中引起方向相反的土体水平向位移,且减速时土体水平位移峰值更大;列车加速和减速均增大土体竖向位移峰值.
Based on the simplified wp formulation of Biot＇s theory, a 2D saturated-soil element was devel- oped and used to discretize a saturated ground under plain-strain condition. At boundaries of the saturated ground model, artificial boundary conditions were applied to simulate the infinity of the ground. The rail, rail-pads, sleepers and ballasts of a 2D track were modeled by E-B beam elements, spring-damper elements and lumped mass elements, respectively. The train loads were simplified into a series of moving axle loads in plain. By comparing to the case of a train under uniform motion, the effects of train acceleration and de- celeration were investigated with respect to the track accelerations, the displacements and excess pore wa- ter pressures of the saturated ground. It is found that peak values of the horizontal and vertical accelera- tions of the sleeper and ballast are increased by train deceleration; train acceleration and deceleration cause horizontal ground displacements in opposite directions; the peak value of horizontal ground displacements caused by train deceleration is larger than that induced by train acceleration; both of train acceleration and deceleration slightly increase peak values of the vertical ground displacements.
出处
《浙江大学学报（工学版）》
EI
CAS
CSCD
北大核心
2013年第11期1932-1938,1944,共8页
Journal of Zhejiang University：Engineering Science
基金
国家杰出青年科学基金资助项目(51025827)
国家自然科学基金资助项目(50908212)
关键词
u-p格式
饱和地基
列车加减速
动力响应
u-p formulation
saturated ground~ train acceleration and deceleration~ dynamic responses
