竖向正方形锚板水平拉拔极限承载力三维统一理论解研究

针对竖向正方形锚板水平极限拉拔力学机理和承载力理论研究存在人为区分浅埋、深埋,但界定标准不统一的问题,对其开展了破坏机制分析和极限承载力三维统一理论解的研究。通过板前四棱锥土核在垂直于板平面的竖直面和水平面投影三角形的形状演化来分别反映竖向和水平向破坏机制随土性、埋深比等因素变化的对称性;构建了竖向正方形锚板水平极限拉拔的三维统一力学模型;依次取不同受力体进行极限力学平衡分析;推导了拉拔极限承载力三维统一理论解。与其他理论方法、试验数据的对比验证表明:新的力学模型很好地实现了一个模型来反映不同埋深比范围破坏机制的连续变化规律,无需再人为区分浅埋和深埋;统一理论解计算结果不仅与室内模型试验数据符合的很好,也和现场、大尺寸室内试验数据吻合;较3种国外方法计算结果更加接近于实测值,且具有更小的离散性,平均值总体上偏于安全,在4种方法中表现最好。

Three-dimensional unified theoretical researches on ultimate horizontal pullout capacity of vertical square anchors

The researches on mechanical mechanism and bearing capacity of horizontal pullout of vertical square anchor plates have the problem of artificially distinguishing shallow and deep buried types without uniform definition standards. This study is devoted to the researches on the three-dimensional unified theoretical solution of horizontal ultimate pullout capacity of a vertical square anchor plate based on deep analysis of failure mechanism. The symmetry of failure mechanism varying with soil properties and buried ratios in vertical and horizontal directions is reflected by the evolution of projected triangles of rectangular pyramid soil core before the anchor plate to the vertical plane and horizontal plane, respectively. A three- dimensional unified mechanical model is established for the horizontal ultimate pullout of the vertical square anchor plate. The ultimate mechanical equilibrium analysis method is used for different loaded bodies in turns to derive the three-dimensional unified theoretical solution. Comparison with other theoretical methods and test data indicates that the new model can reflect the continuous variation rules of the symmetry of failure mechanism very well in different ranges of depth ratio. The three-dimensional unified theoretical solution has extensive applicability to the model test and field test data. The new solution performs the best as its calculation result is more close to the measured value with smaller discreteness and the average is generally safe.