摘要
为了研究嵌入石灰岩地基中大直径钻孔灌注桩的竖向承载性能和荷载传递特征,以济南某工程为依托,对现场6根大直径嵌岩钻孔灌注桩进行静载荷试验和桩身内力测试。试验结果表明,试桩P1—P3的Q-s曲线均呈缓降型,残余沉降占总沉降比例最大为52%,弹性工作特性比较明显,满足设计要求。试桩P4—P6在极限荷载下发生"刺入破坏",Q-s曲线出现陡降阶段,承载力未达到设计要求;在最大荷载作用下,在强风化石灰岩中试桩P4—P6侧摩阻力完全发挥,但极限侧摩阻力与JGJ 94-2008《建筑桩基技术规范》的最小推荐值相比偏低;在最大荷载作用下,试桩P1—P3的桩端阻力占桩顶荷载的23.7%～39.9%,试桩P4—P6的桩端阻力占桩顶荷载的38.4%～53.8%,均表现一定的端承摩擦桩特性。
In order to investigate the vertical bearing capacity and load transfer characteristics of large diameter bored piles embedded in limestone foundation,the static load test and the internal force test of 6 large diameter rock-socketed piles were conducted based on a project in Jinan.The test results show that the Q-s curves of the test piles P1-P3 were the slow type,the maximum percentage of residual sedimentation in the total sedimentation is 52%.There were obvious elastic working characteristics in the test results,which satisfied the design requirements.Additionally,the test piles P4-P6 occurred"piercing damage"under the ultimate load and the Q-s curve appears a steep descent stage,which means an unreached bearing capacity.Under the maximum load,the side friction of the piles P4-P6 in strong weathering limestone is completely exerted,but the ultimate side friction is lower than the minimum recommended value stipulated in the standard Technical code for building pile foundations(JGJ94-2008).Under the maximum load,the tip resistance of the piles P1-P3 accounts for 23.7%-39.9%of the total load,and the tip resistance of the piles P4-P6 accounts for 38.4%-53.8%of the total load,all piles test results show a portion of the characteristic of end-support friction pile.
作者
苗德滋
白晓宇
张明义
MIAO Dezi;BAI Xiaoyu;ZHANG Mingyi(School of Civil Engineering,Qingdao University of Technology,Qingdao,Shandong 266033,China;Collaborative Innovation Center of Engineering Construction and Safety in Shandong BlueEconomic Zone,Qingdao University of Technology,Qingdao,Shandong 266033,China)
出处
《中国科技论文》
CAS
北大核心
2018年第19期2270-2276,共7页
China Sciencepaper
基金
国家自然科学基金资助项目(51708316
51778312
51809146)
关键词
石灰岩
静载荷试验
桩身轴力
桩侧摩阻力
桩端阻力
limestone
static load test
pile axial force
pile side friction
tip resistance
