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圆孔扩张理论应用于静压桩沉桩、搅拌桩成桩过程周围土体的应力和变形分析,取得了一定的成果,但其理论分析结果和实验结果仍存在一定的偏差,主要原因在于理论推导时未考虑桩周一定范围内的土体受施工因素影响而产生的损伤.为更有效地发挥圆孔扩张理论在指导桩基施工中的作用,论文通过构造桩周土体粘聚力变化的表达式来考虑施工造成的土体损伤,基于连续介质力学的原理,依据边界条件确定了表达式中的土体损伤因子,得到了能够反映造成土体损伤主要因素的土体粘聚力变化表达式.基于圆孔扩张理论,并引入土体损伤因子,通过平衡微分方程的迭代计算,分析了成桩过程中的土体塑性区半径及应力分布,发现考虑土体损伤时,塑性区范围相对较大且应力的变化会相对较缓.通过不考虑损伤和考虑损伤的分析结果与既有理论的计算结果对比分析,表明论文提出的考虑土体损伤的分析方法简单合理,为精细化分析桩基施工对地基的影响提供了新方法.
The theory of circular hole expansion is applied to the stress and deformation analysis of the soil around the piles under static pressure pile driving and the mixing pile forming process. Some achievements have been obtained. However, there are still some deviations between the theoretical analysis results and the experimental results. The main reason is that the theory The deduction did not consider the damage caused by construction factors within a certain range of pile circumference.In order to make full use of the function of circular hole expansion theory in guiding the construction of pile foundation, Based on the principle of continuum mechanics, the damage factors of soil in the expression were determined according to the boundary conditions, and the change of cohesion of soil mass, which can reflect the main factors causing soil damage, was obtained. Based on the theory of circular hole expansion and the damage factor of soil, the iterative calculation of equilibrium differential equation is used to analyze the radius and stress distribution of soil plastic zone in pile forming process. It is found that the plastic zone radius Relatively large changes in stress will be relatively slow.By ignoring the injury and consider the damage analysis results compared with the existing theory of comparative analysis that the theory The analysis method proposed in this paper is simple and reasonable considering the soil damage, which provides a new method for the detailed analysis of the impact of pile foundation construction on the foundation.