竖向矩形锚板水平拉拔极限承载力统一计算方法研究

Unified calculation method research on ultimate horizontal pullout capacity of vertical rectangle anchor

在已有竖向条形锚板和正方形锚板水平拉拔统一力学模型的基础上,进一步构建了矩形锚板的三维模型。以板前四棱楔形体土核在4个方向挤压土体所形成的空间滑移体来描述拉拔破坏面。分别对4块滑体进行力学平衡分析,求解作用于楔形体土核4个面上的土压力合力,再根据土核竖向极限平衡条件确定其形状,根据水平极限平衡条件推导极限承载力统一计算方法。与大尺寸锚板试验和其他计算方法的对比表明:本研究方法对锚板尺寸效应不敏感,对不同埋深无明显的倾向性;与实测值比值的变化范围较窄,靠近于1∶1线,计算精度和离散程度指标均优于其他3种方法,整体表现良好。

A three-dimensional model of rectangular anchor plate was further constructed on the base of the existing unified mechanical models of horizontal drawing of vertical strip plate and square anchor plate.The spatial slip body was used to describe the drawing failure surface,which was formed by the wedge-shaped soil core in front of the plate squeezing the soil in four directions.A mechanical equilibrium analysis was carried out on the four parts of spatial slip body separately to calculate the resultant soil pressure acting on the four faces of the soil core.The shape of the soil core was determined in accordance with its vertical limit equilibrium conditions and the unified calculation method of the ultimate pullout capacity was then deduced from the horizontal limit equilibrium conditions.Comparison with the large-size anchor plate tests and other calculation methods showed that the method in this paper was insensitive to size effect of anchor plate and had no obvious tendency to different buried depth.Moreover,the variation range of the ratio of the calculated bearing capacity to the measured value,which was close to the 1∶1 line,was narrow.The calculation accuracy and dispersion degree indexes were superior to those of the other three methods,and had overall good performance.