减载条件下刚性涵洞土压力计算方法

Earth Pressure Calculation Method of Rigid Culverts Under Load Reduction Condition

目前减载条件下刚性涵洞的土压力计算理论未能关注侧墙摩擦力的作用和涵洞基底的受力状态,针对这一问题提出了减载条件下涵-土体系荷载传递模型,以曾国熙的填埋式结构物土压力计算方法为出发点推得减载条件下涵洞土压力的计算式,利用模型试验和数值模拟对该计算方法的正确性进行了验证,并将基底压力与非减载条件下基底压力的数值模拟结果进行了对比分析。研究结果表明:本文提出的计算方法能较为准确地计算减载条件下刚性涵洞的土压力,侧墙摩擦力对涵洞结构起加载作用,减载措施增大了侧墙摩擦力,基底压力并未因减载措施而减小;减载条件下涵洞设计中若不考虑涵侧摩擦作用,得出的基底压力将远小于实际值,给涵洞结构带来很大的安全隐患。

The present theories of earth pressure calculation for rigid culverts under load reduction condition fail to focus on the effect of the side wall friction and the stress state of the culvert base.Thus,a mechanic model of load transfer in the culvert soil system under load reduction condition was proposed and the formulas for calculating the earth pressure based on Zeng Guoxi’s landfill structure earth pressure calculation method were also deduced.The correctness of the calculation method was verified by model test and numerical simulation,and the numerical simulation results of the base pressure and the base pressure without load reduction were compared and analyzed.The results show that the calculation method proposed in this paper can accurately calculate the earth pressure of rigid culverts under load reduction condition,the friction force of side wall increases the load on the culvert structure,the load reduction measure increases the friction force of the side walls,and the base pressure do not decrease due to the load reduction measure.If the side friction is not considered in the culvert design under the condition of load reduction,the calculated base pressure will be far less than the actual value,which will bring great safety hazards to the culvert structure.