长期荷载下减载式涵洞土压力求解

Theoretical Calculation of Earth Pressure in the Load-shedding Culvert under Long-term Load

减载式涵洞通过改变填土荷载传递路径减小涵顶土压力,然而长期荷载作用下填土与减载孔内的EPS板会随着时间发生蠕变,涵洞的受力机制发生变化,长期荷载下减载式涵洞土压力的理论计算方式也未知。为了探究短期荷载作用下以及长期荷载作用下减载式涵洞土压力的理论计算方法,在只考虑减载孔上方和涵侧上方形成的两个土柱体时,建立了减载式涵洞的受力机制模型,推导出减载式涵洞在短期荷载作用下的涵顶土压力计算公式。随后考虑到土体与EPS板的蠕变效应,进而推导出土体蠕变、EPS板蠕变以及土体和EPS板共同蠕变3种情况下的涵顶土压力计算方法,并将计算结果与数值模拟结果进行对比,验证了理论公式的正确性。

The load-shedding culvert reduces the earth pressure at the top of the culvert by changing the load transfer path of the fill.However,under the long-term load,the EPS plate in the fill and the load-shedding hole will creep with time,the stress mechanism of the culvert will change,and the theoretical calculation method of earth pressure under the long-term load is also unknown.In order to explore the theoretical calculation method of earth pressure under short-term and long-term load,the mechanical mechanism model of the load-shedding culvert was established when only two soil columns formed above the load-reducing hole and the culvert side were considered,and the calculation formula of earth pressure on the culvert top under short-term load was derived.Then,considering the creep effect of soil and EPS plate,the calculation methods of culvert top earth pressure under three cases of soil creep,EPS plate creep and soil and EPS plate both creep are deduced.The calculation results are compared with the numerical simulation results,and the correctness of the theoretical formula is verified.