高填方土石混合体填料盖板涵垂直土压力计算新方法

A New Method for Calculating Vertical Earth Pressure of Slab Culvert with High Filling Soil-rock Mixture

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会引起涵顶垂直土压力集中,造成涵洞结构出现了一系列病害。为探明涵顶土压力系数的影响因素,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、填料含石量、填料泊松比及盖板厚度等变量对上埋式盖板涵顶部垂直土压力,侧墙水平土压力及土压力系数的影响。结果表明:上述变量均会影响土压力系数值,涵顶垂直土压力分布形式为抛物线;土压力系数在涵顶中心小于1,在涵顶边缘大于1,涵顶与侧墙的土压力均呈非线性分布。对上述变量影响下的数值结果进行汇总,从而建立涵顶垂直土压力、剪力、弯矩的图表和方程,可用于评估同类型盖板涵的静止土压力数值,进行盖板涵顶部静弯矩设计。采用C#语言编写了《涵洞顶部垂直土压力值计算》程序,能快速准确地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。

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 may cause a series of diseases in culvert structure.To find out the influencing factors of the earth pressure concentration on the top of culvert,based on the indoor model test and FLAC(fast Lagrangian analysis of continua)numerical simulation,the relationships of factors,such as the top filling height,slab thickness,Poisson's ratio of the filling,and the stone content of the filling and the vertical earth pressure on the top,horizontal earth pressure on the side wall,and soil arching effect of the embankment slab culvert were studied.The results show that all the above-mentioned factors affect the 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.By summarizing the numerical results under the influence of the above factors,the charts and equations of vertical earth pressure,shear force and bending moment were established,which can be used to evaluate the static earth pressure of the same type of slab culvert and to design the static bending moment at the top of the slab culvert.In addition,the program of calculating the vertical earth pressure at the top of culvert was compiled in C#language,with which the vertical earth pressure at the top of culvert can be calculated quickly and accurately.The results of this study can provide a reference for similar high fill soil-rock mixture filling-culvert stress analysis.