基于能量耗散的球孔扩张理论解答

发布时间：2018-01-12 18:02

本文关键词：基于能量耗散的球孔扩张理论解答　出处：《岩土力学》2016年07期 　论文类型：期刊论文

【摘要】：以空间准滑动面(SMP)准则为基础,推导了扩底桩扩孔压力的理论解。从能量耗散的角度分析球孔扩张的全过程,利用应力不变量推导了符合球孔扩张的屈服准则;化简微分方程得到了弹塑性区应力表达式,进而求出位移、应变表达式;分别利用体积守恒和能量守恒性推导出扩孔压力的表达式。该法考虑了塑性区弹性变形,并得到了扩孔压力p、塑性区半径R与扩孔半径a的关系。算例分析表明,该方法计算的扩孔压力与现场试验得出的结果较好地吻合,塑性区半径和扩孔压力均随扩孔半径的增加而增大,但增幅逐渐减小而趋于稳定值,剪胀角对塑性区半径和扩孔压力影响显著,随着剪胀角的增加,塑性区半径和扩孔压力明显增加。
[Abstract]:Based on the spatial quasi-sliding surface (SMP) criterion, the theoretical solution of the reaming pressure of the reamed pile is derived, and the whole process of the expansion of the spherical hole is analyzed from the point of view of energy dissipation. By using the stress invariant, the yield criterion which accords with the expansion of the spherical hole is derived. The stress expression of elastic-plastic zone is obtained by simplifying the differential equation, and the displacement and strain expressions are obtained. By using volume conservation and energy conservation, the expression of hole reaming pressure is derived. The elastic deformation in plastic zone is considered, and the hole reaming pressure p is obtained. The relationship between the radius of plastic zone R and the radius of expansion hole a. The analysis of example shows that the pressure calculated by this method is in good agreement with the result of field test. Both the radius of plastic zone and the pressure of expanding hole increase with the increase of radius of expansion hole, but the increase decreases gradually and tends to be stable. The influence of expansion angle on radius of plastic zone and pressure of reaming hole is significant, with the increase of expansion angle. The radius of plastic zone and the pressure of reaming holes are obviously increased.
【作者单位】：山东科技大学土木建筑学院;山东科技大学山东省土木工程防灾减灾重点实验室;新加坡国立大学土木与环境工程系;
【基金】：山东科技大学科研创新团队资助(No.2015KYTD104)~~
【分类号】：TU473.1
【正文快照】： 1引言圆孔扩张理论是计算桩成孔时的扩孔压力的有效方法,如,柱孔扩张理论模拟挤土桩与周围土体的相互作用;球孔扩张理论解答可用于初步估算扩底灌注桩扩大端部机械成孔时所需的扩孔压力等。自从圆孔扩张理论引入岩土工程领域以来,就不断地被推广和应用。Vesic[1]采用Mohr-Coul

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