高填方土石混合体填料盖板涵垂直土压力计算新方法

涵洞在山区高填方高速公路中应用较为广泛，但由于涵洞上方填料组成复杂与填料—涵洞相对刚度差异大等问题引起涵顶垂直土压力集中，造成涵洞结构出现一系列病害。为探明涵顶土压力集中系数的影响因素，在室内模型试验和FLAC数值模拟的基础上，研究了涵洞顶部填料高度、盖板厚度、填料泊松比以及填料含石量对上埋式盖板涵顶部垂直土压力、侧墙水平土压力及土拱效应影响规律。结果表明：涵洞顶部填料高度、盖板厚度、填料泊松比以及填料含石量均会影响土压力集中系数值，涵顶土应力分布形式为抛物线，涵顶中心土压力集中系数值小于1，涵顶边缘土压力集中系数值大于1，涵顶与侧墙土压力呈非线性分布。将上述因素影响下的结果建立图表和方程，可用于评估同类型盖板涵的静止土压力和静弯矩设计。采用C#语言编写了《涵洞顶部竖向土压力值计算》程序，能快速准确的定位涵洞顶部垂直土压力，可为类似的高填方土石混合体填料—涵洞受力分析提供参考。

A new method for calculating vertical earth pressure of slab culvert with high filling soil-rock mixture

The Culverts are widely used in high fill expressways in mountainous areas. However, due to the complex composition of fillers above culverts and the large difference of relative stiffness between fillers and culverts, the vertical earth pressure on culvert top is concentrated, which causes a series of diseases in culvert structure. In order to find out the influencing factors of the earth pressure concentration factor on the top of culvert, based on the indoor model test and FLAC numerical simulation, the effects of the top filling height, cover thickness, Poisson''s ratio of the filling and the stone content of the filling on the vertical earth pressure on the top, horizontal earth pressure on the side wall and soil arching effect of the buried cover culvert were studied. The results show that the height of filling, the thickness of cover plate, Poisson''s ratio of filling and stone content of filling all affect the value of earth pressure concentration coefficient. The stress distribution form of culvert top soil is parabola, the center value of culvert top is less than 1, the edge value of culvert top is more than 1, and the earth pressure of culvert top and side wall is non-linear. The results of the above factors can be used to establish charts and equations for evaluating the static earth pressure and static bending moment design of the same type of cover culvert. The program of calculating the vertical earth pressure at the top of culvert is compiled in C# language. It can locate the vertical earth pressure at the top of culvert quickly and accurately. It can provide reference for similar high fill earth-rock mixture filling-culvert stress analysis.