桩间距对矩形承台冲切承载力的影响分析  

Impact of Pile Spacing on Punching Shear Capacity of Rectangular Pile Caps

作　　者：李晓龙[1] 张建龙[1] 

机构地区：[1]广东工业大学土木与交通工程学院,广州510006

出　　处：《土工基础》2016年第3期337-340,共4页Soil Engineering and Foundation

摘　　要：讨论了桩间距对矩形桩基承台冲切承载力的影响,并运用上限解法和下限解法进行分析。结果表明:当承台尺寸满足一定条件时,冲切承载力随桩间距的增大而下降;规范计算中冲切承载力仅包含斜截面混凝土剪压区剪力,计算公式可以利用承台冲切名义剪应力的概念理解,冲切承载力下降是由于斜截面由剪压破坏向斜拉破坏发展;基于承台冲切破坏空间桁架理论,冲切承载力下降是由于位于冲切锥体内部的斜压杆承担的荷载比例增加,使得斜裂缝上下端的剪压区更容易破坏。In order to thoroughly understand the calculation of punching shear capacity of pile caps, the impact of pile spacing on punching shear capacity of the rectangular pile cap have been discussed based on mathematical method and the literatures. The upper bound solution and lower bound solution are used in the explanation. The results indicate that the punching shear ca- pacity decrease with the increase of pile spacing when the size of the pile cap meet a certain condition. In the calculation of code for design, punching shear capacity contains only the concrete shear of shear-compression zone of inclined section, and the cal- culation formula can understand by use of the concept of the nominal shear stress of the pile cap punching. The decline of punc- hing shear capacity is due to the change of the destruction pattern of inclined section form shear compression failure to diagonal tension failure. Based on the spatial strut-and-tie theory on punching failure of pile caps, the decline of punching shear capacity is due to the increase of the load carried by the strut within the punching shear cone, which make the shear-compression zone at the top and bottom of the inclined cracks failure more easily.

关 键 词：桩基承台 冲切承载力 桩间距 空间桁架模型 

分 类 号：TU473[建筑科学—结构工程]