锤击荷载作用下大直径钢管群桩的动力特性分析

发布时间：2018-08-31 11:23

【摘要】：上海某机械厂有一大直径钢管桩,用于所生产柴油打桩锤出厂前的试用。目前试桩已不满足新生产大吨位柴油打桩锤的试打要求,因此拟增加8根短桩与试桩组成群桩。由于锤击荷载作用下长短组合群桩中荷载的分配及沉降的研究较少,为得到合理的群桩加固型式,采用有限元方法研究锤击荷载作用下群桩的动力承载特性。首先建立单桩有限元模型,分析竖向静荷载作用下钢管桩的沉降,并将模拟结果与现场静荷载试验结果进行对比,验证有限元模型的准确性,再分析锤击荷载作用下单桩的动力响应;其次建立锤击荷载作用下的长短组合群桩有限元模型,分析承台质量、承台埋深、辅桩桩长对群桩桩顶荷载分布及沉降的影响。结果表明锤击荷载作用过程中,角桩、边桩桩顶最大压应力较大,主桩桩顶最大压应力较小;承台埋深越浅,群桩桩顶应力越大,沉降反而越小;承台质量、辅桩桩长对群桩动力特性影响不大。
[Abstract]:There is a large diameter steel pipe pile in a machinery factory in Shanghai. At present, the test pile can not meet the test requirement of the new large tonnage diesel pile hammer, so it is proposed to add 8 short piles and test piles to form a pile group. Due to the lack of research on load distribution and settlement of long-long composite piles under hammering load, in order to obtain a reasonable reinforcement type of pile group, finite element method is used to study the dynamic bearing characteristics of pile groups under hammer impact load. Firstly, the finite element model of single pile is established to analyze the settlement of steel pipe pile under vertical static load, and the simulation results are compared with the results of field static load test to verify the accuracy of the finite element model. Secondly, the finite element model of long-long composite pile under hammer load is established to analyze the influence of pile cap quality, cap depth and auxiliary pile length on the load distribution and settlement of pile top. The results show that the maximum compressive stress of corner pile and edge pile is greater than that of main pile, the shallower the pile cap is, the greater the stress of pile top is, the smaller the settlement of pile cap is. The length of auxiliary pile has little effect on the dynamic characteristics of pile group.
【作者单位】：同济大学地下建筑与工程系;同济大学岩土及地下工程教育部重点实验室;
【分类号】：TU473.1

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