中文摘要：

梯形沟谷设涵在山区公路和铁路建设中的应用非常广泛。然而，目前规范中尚无梯形沟谷设涵的设计方法。现有的研究主要针对上埋式和沟埋式涵洞，对天然梯形沟谷埋设涵洞时的涵洞受力性状的研究甚少。通过数值模拟得出梯形沟谷设涵时，钢筋混凝土箱型涵洞顶部填土内的应力状态和土拱的分布规律。在此基础上建立理论模型，推导涵洞土压力理论计算式，并验证理论方法的正确性。此外，对涵顶土压力的影响因素进行了参数研究。结果表明，梯形沟谷设涵时涵洞的受力状态不同于上埋式和沟埋式两种情况。当涵顶填土高度到达临界高度时，填土中会形成上、下两层土拱。下层土拱效应使涵顶产生土压力集中，上层土拱效应会减小涵顶的土压力集中。涵顶土压力的大小取决于涵顶的填土高度、沟谷坡角、沟谷宽度、涵洞的几何尺寸及填土的性质。

英文摘要：

Trapezoidal trench installing （TTI） culverts are widely used in highway and railway in mountainous area. However, there are currently no published standards for the design of the TTI culvert. The performances of embankment installation （EI） and trench installation （TI） culverts have been investigated by a number of researchers; but the study of performance of TTI culverts is less common. To understand the complex soil-structure interaction issues related to the design of TTI culverts, a numerical simulation is conducted to investigate the stress states and the soil arches in the backfill over the reinforced concrete box culvert installed in trapezoidal trenches. A theoretical model is established based on the numerical results; and the formula for calculating the vertical earth pressure acting on the culvert is deduced. The theoretical results are in reasonable agreement with the field test data and numerical results. Moreover, a parametric study is carried out to investigate the important influencing factors on the vertical earth pressure acting on the culvert. Research results show that the stress states on the TTI culvert is different from those of EI and TI culverts. Two layers of soil arches at different levels form in the backfill over the TTI culvert when the fill on the culvert reaches a certain height. The lower soil arches incur the vertical earth pressure concentrating on the top of the culvert. However, the upper soil arches covering the lower ones alleviate the concentration effect. The vertical earth pressure on the culvert is determined by the soil arching effect, which is affected by the height of backfill over the culvert, the slope angle and bottom width of the trench, the dimensions of the culvert and the properties of backfill.