考虑桩体径竖向渗流的碎石桩复合地基固结解析解
Analytical solution for consolidation of stone column-reinforced foundations considering radical and vertical flows in columns
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摘要: 提出一种新的复合地基固结度求解方法及表达形式,推导得到了考虑桩体及土体的径竖向渗流,上部荷载分级逐渐施加,扰动区渗透系数呈线性变化等因素的一个较全面的散体材料桩复合地基固结解析解。通过退化、与已有解的比较等方法对解进行了分析验证。结果表明,现有的单级荷载及瞬时荷载下考虑桩体径竖向渗流的解、考虑桩体竖向渗流与变形协调的解、太沙基一维固结解等都是解的特例,这说明了解的正确合理性,发展和完善了现有复合地基固结理论。不考虑桩体径向渗流会高估地基固结速度;地基加载过程越缓,地基固结越慢。提出的求解方法,为复合地基固结度的求解提供了一种新的思路。Abstract: Based on the proposed new method for solving consolidation degree of composite foundation and its expression, an analytical solution is obtained for the consolidation of composite ground with granular columns considering both radical and vertical flows in piles under multi-stage loading. In addition, the disturbance effect of column construction on the surrounding soil is also considered by introducing a linear function for the horizontal permeability coefficient of soils in the disturbed zone. The solution was analyzed by the degradation method and the comparison with the existing solutions. The results show that the obtained solution can be reduced to the solution considering both radical and vertical flows in piles under single-stage or instantaneous loading, the solution considering the coordination of vertical seepage and deformation of pile body, and the Terzaghi's one-dimensional consolidation solution for natural foundation. Thus, the correction and reasonability of the solution obtained is confirmed, and the solution does contribute to the development and improvement of the consolidation theory of composite ground. No consideration of the radial seepage in piles will overestimate the consolidation rate of the ground; the slower the foundation loading process is, the slower the consolidation of the foundation is. The proposed method provides a new idea for solving the consolidation degree of composite foundation.