根式基础水平承载性能试验研究
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龚维明1，王磊1，殷永高2，童小东1(1 东南大学土木工程学院， 南京 210096； 2 安徽省高速公路总公司， 合肥 230051)［摘要］为了研究根式基础的水平承载性能，采用单向单循环慢速维持荷载法，在马鞍山长江大桥施工现场开展了两期根式基础水平静载试验。试验得到了普通沉井基础和根式基础的水平临界荷载、水平极限荷载、水平荷载与水平位移关系、变形特性等成果。试验结果表明：根式基础水平承载性能优于普通沉井基础。植入根键能显著提高普通沉井基础的水平承载力。与普通沉井基础相比，根式基础水平承载能力提高了近1倍；表层覆盖土层对根式基础水平承载能力影响较大，去除表层覆盖土层后，根式基础的水平临界荷载和水平极限荷载分别提高了150%和95%；根式基础自身结构的中上部是水平承载能力发挥的关键部位，当深度超过一定范围后，增加深度对提高水平承载力作用甚小。［关键词］根式基础; 水平静载试验; 水平承载力; 厚覆盖软土层图分类号：TU473 文献标识码：A 文章编号：1002-848X(2013)19-0090-05Experimental study on horizontal bearing capacity of root-caisson foundationGong Weiming1, Wang Lei1, Yin Yonggao2, Tong Xiaodong1(1 School of Civil Engineering, Southeast University, Nanjing 210096, China; 2 Expressway Corporations of Anhui Province, Hefei 230051, China)Abstract: In order to study the horizontal bearing capacity of root-caisson foundation, two-stage horizontal static load test of root-caisson foundation was carried out at the construction site of Maanshan Yangtze River Bridge, in which unidirectional-cyclic slow sustaining loading method was applied. Results of horizontal critical load, horizontal ultimate load, relationship between horizontal load and displacement, deformation mechanism were obtained of common caisson foundation and root-caisson foundation. Test results show that the value of horizontal bearing capacity of root-caisson foundation is one times larger than that of common caisson foundation. The existence of the rootstalks could improve the horizontal bearing capacity of common caisson foundation. Covering soil has great effect on horizontal bearing capacity of root-caisson foundation. The horizontal critical load and ultimate load could increase by 150% and 95% respectively without covering soil. The upper part of the root-caisson foundation structure is the key position to bear the horizontal loadings, so the effect is small to improve the horizontal bearing capacity through adding buried depth when the depth exceeds a certain range.Keywords: root-caisson foundation; horizontal static load test; horizontal bearing capacity; thick covering soft soil layer作者简介: 龚维明，博士，教授，博士生导师，Email: wmgong@seu.edu.cn。参考文献［1］殷永高. 根式基础及根式锚碇方案构思［J］.公路，2007，2(2)：46-49.［2］龚维明，胡丰，童小东，等. 根式基础竖向承载性能的试验研究［J］.岩土工程学报，2008，30（12）: 18-24.［3］张立奎，章征，殷永高. 根式沉井基础水平向荷载试验研究［J］.桥梁建设，2009（3）:33-36.［4］龚维明，有智慧，殷永高，等. 根式沉井基础群井效率系数现场水平试验研究［J］. 土木工程学报，2010，43(5):89-95.［5］殷永高，孙敦华. 悬索桥根式锚碇基础初步分析［J］. 土木工程学报，2010，43(11):102-113.［6］胡丰，龚维明，童小东，等. 含受弯根键的根式沉井承载性能分析［J］. 计算力学学报，2010，27(3):505-510.［7］木林隆，黄茂松，龚维明，等. 水平荷载作用下根式基础受力特性分析［J］. 岩土力学，2010，31(1):287-292.［8］胡丰，龚维明，童小东，等.刚性根式基础水平承载性能分析［J］. 力学与实践，2010，32(5):67-71.［9］JGJ 106—2003建筑基桩检测技术规范［S］. 北京：中国建筑工业出版社，2003.
