大宽高比混凝土独立扩展基础承载性能室外试验研究

Site Experimental Research on Bearing Capacity of Concrete Independent Spread Foundation with Large Width-to-height Ratio

对8个常规配筋、1个改进配筋的大宽高比足尺混凝土独立扩展基础进行了现场试验,主要研究宽高比大于2.5的混凝土独立扩展基础在轴心与偏心荷载作用下的破坏模式和承载性能。首先对室外试验的基本信息进行简单描述,并阐述了基础破坏模式与试验现象,最后对试验结果进行分析,将基础承载力试验值与各规范计算值进行对比。试验结果表明,试件破坏时底板均未出现梯形塑性铰线,基础实际承载力普遍高于规范计算值,并且基础宽高比较大或偏心率较大时更易发生冲切破坏,配置箍筋能够有效提高基础抗冲切承载力。结果可为大宽高比混凝土独立扩展基础设计方法与相关研究提供参考。

In this paper, a series of site tests （including eight conventional reinforcement and one improved reinforcement） on full-scale concrete independent spread foundations with the width-to-height ratio greater than 2.5 were carried out to study the failure modes and bearing capacity of this type of foundation under axial compression or extremely eccentric compression. The basic information of tests was described first. Then the types of failure mode and experimental process were reported. Finally, the test results were shown and analyzed, and the test values of bearing capacity were compared with that calculated by Chinese codes. The results showed that there was no trapezoidal plastic hinge at the bottom of plate when the foundation was destroyed, the actual bearing capacity of the foundation was generally higher than that calculated by Chinese codes. The results also showed that the mode of punching failure was more likely to occur when the width-to- height ratio of foundation was larger or the eccentricity was larger, and the punching shear capacity of the foundation could be improved effectively with the allocation of hoops at the bottom of plate. This paper can be used for reference to further research work on design method of concrete independent spread foundation with a large width-to-height ratio.