三角形周期荷载作用下软基路堤沉降研究

采用能够同时考虑主次固结变形的Yin-Graham一维弹黏塑性模型,对三角形周期荷载作用下软土路堤运行期间和运行期结束时的长期沉降进行了理论分析,获得三角形周期荷载作用下软基路堤运行期结束时的总沉降计算公式和工后沉降计算公式。分析了三角形周期荷载作用下软基不考虑流固耦合与考虑流固耦合时长期沉降之间的相互关系,证明了三角形周期荷载作用下当循环荷载次数趋向于无穷大时软基具有最终沉降量与应力随时间增长的模式无关的性质。按照文中提供的总沉降计算公式,针对具体工程的土工参数,对路堤运行期结束时的总沉降量进行了计算,并由此确定运行期开始时软基应发生的沉降量,为合理确定高速公路路面铺筑时机提供沉降标准。

Study of settlements of road embankment on soft clay under triangle periodic loading

Based on Yin-Graham’s 1D elasto-viscoplastic model which can predict both primary and secondary consolidations, the long term settlements caused by triangle periodic loading during road service period are theoretically studied. The expressions of total settlement and post-construction settlement of road embankment on soft clay produced by the triangle periodic loading during its service period are achieved. The relationship between the long term settlement considering fluid-solid coupling and that without considering fluid-solid coupling under the triangle periodic loading is analyzed. It is proved that the soft clay has the behavior of which the ultimate settlement when periodicity trend to infinite is not affected by the fashion that stress increases with time under the triangle periodic loading. Based on the expression of the total settlement proposed in the paper and the physical parameters of clay for a definite engineering, the total settlement of road embankment during its service period is numerically calculated. The critical settlement of road embankment at the start of its service period can further be determined from the total settlement at the end of its service period. From the above results, a required settlement standard is provided for rationally determining the start time of road pavement in the construction of expressways.