减载条件下高填方涵洞垂直土压力研究

Vertical earth pressure on high fill culverts under load reduction condition

针对现有理论方法没有考虑涵侧的外土柱体所受附加压力对涵顶垂直土压力的影响的问题,根据涵洞和填土实际受力状态,改进现有的涵顶垂直土压力计算理论方法,推导出涵洞垂直土压力计算式.将改进理论方法的计算结果、数值模拟和现有的试验结果进行对比,验证了改进理论方法的正确性.研究结果表明:涵顶铺设柔性填料能明显减小涵顶垂直土压力,涵顶土压力集中系数随填土高度、涵顶和涵侧填土变形模量、柔性填料厚度的增大呈非线性减小,随柔性填料变形模量的增大呈非线性增加,但最终均趋于稳定.

The present theoretical methods do not consider the influencing of the extra earth pressure acting on the adjacent fill mass on the vertical earth pressure over culvert under load reduction condition.So the present theoretical method was revised based on the actual soil-culvert stress states,and a new formula for calculating the vertical earth pressure on culvert was deduced.The results of revised theoretical method were compared with the numerical results and field tests,and the validation demonstrated that the revised theoretical method was correct.Research results show that setting a soft layer over culvert can significantly reduce the vertical earth pressure on culvert.The vertical earth pressure coefficient on culvert nonlinearly decreases with the fill height,the fill modulus over the culvert,the fill modulus adjacent to the culvert and the thickness of the soft layer,increases with the modulus of the soft layer,and all approach to asymptotic values at higher variable values,respectively.