洛阳铲因其操作方便、实用经济被广泛运用到岩土桩基工程中,而目前对于洛阳铲取土原理的研究尚不成熟.选取洛阳铲作为研究对象,测量铲子形状,并拟合出铲子的几何曲线.通过对铲中土的受力分析,推导出铲土接触面上平衡铲中土体自重的剪应力.另通过土拱效应原理求出铲土接触面上土体的抗剪强度,分析认为洛阳铲取土力学机理可以解释成:土拱作用增加了土体与铲面的法向接触应力,提高了土体与铲面的抗剪强度,使其克服土体重力所产生的剪应力,实现取土.另外,对洛阳铲取土效果的影响因素进行了分析,分析表明:洛阳铲取土后铲内土体的稳定性系数随土体粘聚力、土体内摩擦角及铲土深度的增大而增大,随土体容重和洛阳铲铲口尺寸的增大而减小.%Luoyang shovel has been widely applied to the pile foundation construction in geotechnical engineering because of its easily operated and economical. Luoyang shovel is Taken as the research object, by using the laser displacement sensor to measure the shape of Luoyang shovel, and then the shovel geometry is fitted out. After making stress analysis on the soil which is dug in the shovel, the shear stress is calculated which is used to counterbalance the body weight of soil on the sliding surface. Besides, the soil shear strength on the sliding surface is calculated by using the theory of soil arching effect. The mechanical mechanism of Luoyang shovel digging can be interpreted ; the soil arching effect increases the vertical stress on the sliding surface, so that the soil shear strength is improved on the surface , which is sufficient to overcome the shear stress caused by the body weight of the soil, and makes digging successfully. The analysis of the factors are given also which can effect the result of the dug of Luoyang shovel, and the results showed that the stability of the soil inside the shovel would be improved with the increase of soil cohesion, soil internal angle and the height of the soil inside the shovel when reduced with the increase of soil bulk density and the size of Luoyang shovel.
展开▼
