公路桥涵台背回填稳定性极限分析上限解

Highway-bridge abutment-backfill stability analysis based on plastic upper bound theorems

运用塑性力学极限分析的上限定理,分析公路桥涵台背回填的稳定性问题。首先,由模型试验和数值分析结果确定回填区和地基的滑动模式;其次,根据位移协调条件建立滑动体的速度场,并计算各滑动楔块的位移速度;最后,运用虚功原理和优化算法寻找最不利滑动面位置,计算不同回填材料的土压力或临界填筑高度。研究发现:地基与回填材料的强度、性能以及加筋条件对台背回填稳定性的影响都非常显著。结果表明:增加地基与回填材料的强度,采用轻质回填材料,减小加筋间距和增加筋材强度,都有利于提高台背回填材料的稳定性。

This paper studied highway-bridge abutment-backfill stability by the upper bound theorems of plasticity. Firstly, slip model of groundsill and backfill was decided according to centrifuge test and numerical calculation results. Secondly, the velocity field was determined based on the conditions of kinematic admissibility. Finally, to seek the least upper bound and calculate the soil pressure and the critic height, energy equilibrium theorems and programming resolutions were employed. It is pointed that groundsill and backfill material properties and reinforcement effect on abutment backfill stability markedly. The results indicate that increasing groundsill and backfill material strength, using light backfill material, dense and high strength reinforcing are propitious to backfill stability.