沉井基础竖向承载力试验研究  

Experimental Study on Vertical Bearing Capacity of Open Caisson

作　　者：童小东[1] 殷永高 徐敏[1] 龚维明[1] 刘勇[1] 吴东红[3] 

机构地区：[1]东南大学混凝土及预应力混凝土结构教育部重点实验室,南京210096 [2]安徽省高等级公路工程建设指挥部,合肥230061 [3]长安大学理学院,西安710061

出　　处：《地下空间与工程学报》2009年第5期897-902,909,共7页Chinese Journal of Underground Space and Engineering

基　　金：江苏省自然科学基金资助项目(BK2008314);建设部研究开发项目资助项目(06-K7-37)

摘　　要：因沉井基础具有尺寸大、承载力高等特点,所以难以利用常规的方法对其竖向承载力进行测试。利用自平衡测试技术,通过两次试验对1个直径5.0m、长度12.0m的沉井进行了竖向静载试验,分别得到了沉井基础的极限侧阻力和端阻力,通过将两者叠加得到了沉井基础的竖向极限承载力,并对测试结果进行了等效转换。试验结果表明,沉井封底之下的土压力分布呈现由外向内逐渐减小的规律;预制下沉工艺造成沉井侧壁周围土体的结构遭到破坏,导致土体的极限侧摩阻力降低;实测得到的沉井基础的端部承载力大于按规范中钻(挖)孔灌注桩竖向承载力计算公式得到的估算值。The vertical bearing capacity of the open caisson is difficult to be measured by the routine methods for its large dimension and high capacity,etc.An open caisson with diameter of 5.0m and length of 12.0m was tested by the self-balanced measurement through two tests.The ultimate shaft resistance and tip resistance were determined separately.The ultimate vertical bearing capacity of the open caisson was obtained by adding the above two resistances.The test results were transformed equivalently.The tests results were transformed equivalently. The tests results show that the earth pressure under the sealed bottom of the open caisson is decreasing gradually through the boundary to the center. The ultimate shaft resistance is decreased by the prefab sinking technics. The measured tip resistance of the foundation is greater than the estimated value using the bearing capacity formula of cast - in - situ pile in the codes.

关 键 词：自平衡测试技术 沉井 竖向承载力 

分 类 号：TU476.9[建筑科学—结构工程]