高填方涵洞减载的时间效应研究

Long-term behavior of load reduction culvrert under high fills

通过减载措施减小高填方涵洞涵顶垂直土压力,以减轻涵洞结构病害,在实际工程中已得到应用。目前对于高填方涵洞减载措施的研究较多,然而对采取减载措施后涵洞工作性状的时间效应研究很少。通过分析高填方涵洞减载措施的减载机理,根据减载材料、填土蠕变模型,建立了高填方涵洞工作性状时间效应的理论模型,分析了高填方减载涵洞工作性状的时间效应,并推得了能够考虑时间因素的涵顶垂直土压力计算式。此外,通过建立数值模型,得出了减载材料、填土、涵洞之间的位移特征和涵洞受力特征随时间的变化规律,针对不考虑材料蠕变性质、只考虑减载材料蠕变性质以及同时考虑减载材和填土蠕变性质三种情况分别进行了分析。将数值模拟结果与理论结果进行对比,验证了理论模型的正确性。

In order to release the structure disease of high fill culvert,load reduction measures have beengradually applied to reduce the vertical earth pressure on high fill culvert in the construction of express-ways and railways. The load reduction measures for high fill culvert have been investigated by a number ofresearchers recently. However,the study of the long-term beahavior of high fill culvert under the load re-duction condition is less common. Therefore,the theoretical model of long-term behavior for high fill cul-vert under the load reduction condition was eatablished based on the load shedding mechanism and creepmodels of the load-reducing material and fill. The time dependent effect of high fill culvert have been anal-ysed and the formula for calculating the vertical earth pressure acting on the culvert have been deduced.Moreover,the time dependent effect of soil-culvert deformation and stress have been discussed on threeconditions(i.e.,(a) without considering the creep characteristics of load-reducing material and fill;(b) on-ly considering the creep characteristic of load-reducing material;(c) considering the creep characteristicsof load-reducing material and fill) by numerical simulation. To verify the theoretical model,the theoreticalresults was compared with the numerical results and which were consistent with the numerical results.