为确定涵侧填土对高填方涵洞地基承载力的提高作用,根据相似原理设计高填方涵洞模型试验,模拟不同涵侧填土高时涵洞地基受荷破坏的过程,绘制荷载-沉降曲线得到极限荷载;讨论使用经验公式和JTG D 63—2007《公路桥涵地基与基础设计规范》的计算结果与试验结果的差值;选取图们至珲春高速公路桩号为RK365+510处的高填方涵洞作为试验涵洞,在涵洞底部埋设沉降观测点测量基底沉降值和沉降差。结果表明:侧填荷载对地基承载力的提高十分显著,且提高幅度为非线性,先从18.4%增加到36.83%,然后减小到8.91%;计算承载力时不仅要考虑选取合适的计算公式,还应考虑不同试验方法所提供的计算参数的影响;现场测试的涵洞基底最大沉降值符合规范的要求。
In a semi-discretized Euler–Bernoulli beam equation, the non-nearest neighboring interaction and large span of temporal scales for wave propagations pose challenges to the effectiveness and stability for artificial boundary treatments. With the discrete equation regarded as an atomic lattice with a three-atom potential, two accurate artificial boundary conditions are first derived here. Reflection coefficient and numerical tests illustrate the capability of the proposed methods. In particular, the time history treatment gives an exact boundary condition, yet with sensitivity to numerical implementations. The ALEX(almost EXact) boundary condition is numerically more effective.
