高填方钢波纹管涵垂直土压力计算

引入表征钢波纹管波形特性的惯性矩计算方法, 通过Spangler管-土相互作用模型, 得到了钢波纹管涵竖向收敛变形计算公式; 假设管涵顶部填土为半无限直线变形体, 将条形基础沉降倒置后比拟上埋式管涵的受力模型; 基于弹性力学推导的基础沉降计算公式, 着重考虑管涵侧向土体压缩变形与管涵自身的竖向收敛变形之差, 推导了管涵垂直土压力的计算公式; 以广巴广陕高速公路连接线吴家浩-张家湾段高填方钢波纹管涵工程为例, 对涵顶垂直土压力进行了现场测试, 将采用公式计算所得涵顶垂直土压力与现场试验结果和应用实测沉降差反算的垂直土压力进行了对比。研究结果表明: 涵顶垂直土压力随填方高度的增加而增大, 填土至设计标高后涵顶垂直土压力计算值、实测值和反算值分别为224.14、221.98、211.33kPa, 计算值与实测值的相对误差约为0.9%, 反算值分别比计算值和实测值小6.1%、5.0%, 且计算结果、反算结果均与实测涵顶垂直土压力变化规律一致, 填方越高, 误差越小。可见, 提出的高填方钢波纹管涵垂直土压力计算公式可行, 不仅考虑了涵侧土体的抗力系数和基床系数, 而且体现了钢波纹管的变形与受力特征。

Calulation of vertical earth pressure of high-fill steel corrugated pipe culvert

A method involving the inertia moment calculation for characterizing the wave characteristics of steel corrugated pipe was introduced. Through the Spangler pipe-soil interaction model, a computational formula of the vertical convergent deformation of steel corrugated pipe culvert was obtained. The top fill of the pipe culvert was deemed to be a semi-infinite straight line deformation body, and the settlement of the strip foundation was inverted to assimilate the stress model of buried pipe culvert. Based on the foundation settlement calculation formula derived from the elastic mechanics, the settlement difference between the compression deformation of the soil and the vertical convergent deformation of the pipe culvert was mainly considered and the calculating formula of the vertical earth pressure of the tube culvert was derived. Taking theproject of the high-fill steel corrugated pipe culvert at the Wujiahao to Zhangjiawan Section of the Guangba-Guangshan Highway as an example, the field test of vertical earth pressure on the top of steel corrugated pipe was performed. The vertical earth pressure computed by the formula was compared with the field test value and back-calculated result using the measured settlement difference value. Research result shows that the vertical earth pressure at the top of the culvert increases with the increase of filling height. The calculated values, measured values and inverse values of the vertical earth pressure at the top of the culvert after filling to design elevation are 224.14, 221.98 and 211.33 kPa, respectively, the relative error between the calculated value and the measured value is approximately 0.9%, and the inverse values are 6.1% and 5.0% less than the calculated and test values, respectively. The results of calculation and inverse calculation are consistent with the variation rule of the measured vertical earth pressure, and the higher the fill, the more consistent are the results. The proposed calculation formula of the vertical earth pressure of high-fill steel corrugated pipe culvert is feasible because it considers the resistance coefficient and the coefficient of the foundation bed, and reflects the deformation and stress characteristics of the steel corrugated pipe culvert.