滚轴滚动摩擦系数研究与建筑物迁移工程水平动力计算

滚轴滚动摩擦系数是建筑物整体迁移工程水平动力计算的重要参数,在钢管混凝土滚轴与钢板的滚动摩擦试验中,测得滚动摩擦系数为0.002～0.004,它随滚轴受到的竖向压力增大而减小。现场实测值为0.04～0.067,表明现场条件对滚动摩擦系数影响很大。通过分析滚轴滚动摩擦时的赫兹接触模型,推导出滚动摩擦系数理论公式,式中滚动摩擦系数与竖向压力的平方根成正比(和试验值规律不同),和半径、有效支承长度、弹性模量的平方根成反比。在理论公式和几个实际工程现场测试基础上,进一步提出建筑物整体迁移工程中滚动摩擦系数与水平动力的实用计算公式,式中以实际工程状况系数K反应现场条件影响。钢管混凝土滚轴、实心钢滚轴、工程塑料滚轴启动时的实际工程状况系数K取值范围分别建议为1.15～1.35、0.7～1.0、0.6～0.7。

A study on the rolling friction coefficient and the horizontal driving-force calculation in building monolithic moving engineering

The rolling friction coefficient between roller and track is an important parameter in building monolithic moving engineering.A rolling friction experiment is conducted,and the results indicate that the rolling friction coefficient between the steel-tube concrete roller and the steel plate is 0.002~0.004,and decreases with the increases of vertical pressure.Because the field condition is complex and very different from the lab condition,the rolling friction coefficient from field test is 0.04~ 0.067.According to the Hertz contact model of rolling friction,a theoretical calculation formula for rolling friction coefficient is derived.The rolling friction coefficient is proportional to the square root of vertical pressure on the roller,and inversely proportional to the square roots of the roller radius,the effective supporting length,and the elastic modulus of the friction material.Based on the theoretical formula and field test results in several projects,the application formula of the horizontal driving-force is established.A coefficient is devised to take account of the influence of field conditions.The value of this coefficient is related to the style of the roller and field conditions,and with the horizontal driving-force for rolling initiation being calculated,it is equal to 1.15~1.35,0.7~1.0 and 0.6~ 0.7 for steel-tube concrete roller,solid steel roller and engineering plastics roller,respectively.