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随着地下空间的开发和利用,地下建筑结构埋深不断增加。当地下水位较高时,地下结构就会受到较大的浮力,因此需要在结构底板下设置抗拔桩。为了研究后张部分粘结预应力抗拔灌注桩的受力机理,首先通过试验测试了预应力钢绞线和水泥净浆的粘结强度。然后,运用ABAQUS有限元分析软件进行数值模拟,得出了粘结强度参数。在此基础上对后张部分粘结预应力抗拔桩进行数值分析,研究其受力机理,为工程应用提供理论依据。研究表明,后张部分粘结预应力抗拔灌注桩侧摩阻力由桩顶至桩底逐渐增加,持力点主要在桩底部,而预应力的施加不仅可以避免裂缝的产生,还可以抵抗“泊松效应”而产生的“颈缩现象”的影响,对提高桩体的抗拔性能十分有利。
With the development and utilization of underground space, the depth of underground structures is constantly increasing. When the local water table is high, the underground structure will be buoyant, so it is necessary to set up anti-pile under the structural floor. In order to study the mechanical mechanism of post-tensioned partially prestressed piles, the bond strength between prestressed steel strand and cement paste was first tested. Then, using ABAQUS finite element analysis software for numerical simulation, the bond strength parameters were obtained. On the basis of this, the numerical analysis of post-tensioned prestressed straightening pile is carried out to study the mechanism of its stress and provide a theoretical basis for engineering application. The results show that the lateral friction of prestressed anti-pull grouting pile is increased gradually from pile top to pile bottom, and the holding point is mainly at the bottom of the pile. The application of prestress can not only prevent the crack but also resist the “ Poisson effect ”and the resulting “ neck phenomenon ”, to improve the pull-out performance of the pile is very favorable.