摘要
基于离心模型试验,采用有限差分仿真法建立路桥过渡段三维数值分析模型。通过数值模拟计算结果和离心模型试验结果的对比分析,证明了所建立的模型可合理预测路、桥台变形耦合特性。数值分析结果表明:①距台背不同位置过渡段路基面沉降均随过渡段地基处理程度的加强而减小,离台背距离越近,路基面的沉降坡度越大;②桥台沉降稳定后再填筑路基有利于减小桥台自身的水平位移及台背处的差异沉降值。填筑时应注意填筑速率,重点关注桥台及过渡段路基的整体稳定性和过度的不均匀下沉,防止地基因填土堆载发生滑动破坏及路基层状几何形态的变坏所引起的路基刚度的急剧下降;③不同地基处理程度情况下路桥衔接处均存在差异沉降,因此,有必要在桥头设置搭板将路桥交界处的台阶式跳跃沉降变成斜坡式连续沉降;④过渡段路基收敛沉降值与桥台的水平位移和倾角成正相关性,在数值计算的基础上提出了台后20m处过渡段路基收敛沉降值这一控制指标,并将台后过渡段填料的容许剪应变引入到过渡段设计中。
Based on the results of centrifuge model test, a 3-D finite fifferencc model was established. By the comparison between the results of centrifuge model test and the results of numerical simulation, it is proved that the model can reasonably predict the features of deformation coupling of roads and bridges. Numerical analysis results indicate： ① The bridge-approach settlement increases gradually with the increase of the center to center spacing of the piles. The farther away from abutment, the smaller the approach slope is. ② In order to reduce abutment horizontal movement and bridge bump, bridge-approach should be constructed after the abutment settlement stabilized, and special attention should be paid to the loading rate and the global stability of abutment and embankment in order to eliminate the foundation sliding or road layers failure. ③ Due to the different center to center spacing of the piles, there exists differential settlement at the end of a bridge, so the placement of approach slab is essential to transform the stepped settlement into continuous sloped deformation. ④ The convergence settlement value of the transition zone subgrade is positively related to the horizontal displacement and angle of dip of abutment. Based on the numerical simulation, the convergent settlement of embankment at the distance of 20 meters from abutment is proposed, and the shear strain of embankment soil behind abutment is introduced into the design of bridge-approach.
出处
《土木工程学报》
EI
CSCD
北大核心
2012年第8期148-157,共10页
China Civil Engineering Journal
基金
铁道部科技计划开发计划(2008G031-D)
关键词
离心模型试验
数值模拟
路桥过渡段
变形耦合
收敛沉降
桥台倾斜
centrifuge model test
numerical simulation
bridge-approach
deformation coupling
convergent settlement
abutment tilting
