砂土地基中螺杆桩竖向承载特性的模型试验研究
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摘要
通过砂箱模型试验,采用应变片测试技术和PhotoInfor数字图像软件技术试验方法,比较分析螺杆桩和直杆桩在竖向荷载作用下轴力的变化和桩周土体的位移场,研究螺杆桩的竖向承载特性。研究结果表明:螺杆桩和等直径直杆桩的Q-s曲线均呈缓降型;在相同条件下,螺杆桩的极限承载力和桩侧阻力相比于直杆桩有较大的提高;极限状态下螺杆桩桩侧破坏面呈连续的拱形,而直杆桩桩侧破坏面可以近似看作平面;螺杆桩的侧阻主要表现为螺牙间土体与外侧土体的剪切力,而直杆桩的侧阻主要表现为桩体与土体的摩擦力。
Through sand box model test, strain gauge test technology and PhotoInfor digital image software test method are adopted to compare and analyze the change of axial force and the deformation of soil around the pile of screw pile and straight pile under vertical load, and to study the vertical bearing characteristics of screw pile.The results show that: the Q-s curves of the screw pile and the straight pile with the same diameter are of slow drop type; under the same conditions, the ultimate bearing capacity and lateral resistance of screw pile improve greatly compared with that of straight pile; in the limit state, the side failure surface of screw pile is continuous arch, while the side failure surface of straight pile can be approximately regarded as plane; the lateral resistance of the screw pile is mainly manifested as the shear force between the screw teeth and the lateral soil, while the lateral resistance of the straight pile is mainly manifested as the friction between the pile and the soil.
Through sand box model test, strain gauge test technology and PhotoInfor digital image software test method are adopted to compare and analyze the change of axial force and the deformation of soil around the pile of screw pile and straight pile under vertical load, and to study the vertical bearing characteristics of screw pile.The results show that: the Q-s curves of the screw pile and the straight pile with the same diameter are of slow drop type; under the same conditions, the ultimate bearing capacity and lateral resistance of screw pile improve greatly compared with that of straight pile; in the limit state, the side failure surface of screw pile is continuous arch, while the side failure surface of straight pile can be approximately regarded as plane; the lateral resistance of the screw pile is mainly manifested as the shear force between the screw teeth and the lateral soil, while the lateral resistance of the straight pile is mainly manifested as the friction between the pile and the soil.
引文
[1] 沈保汉.桩基础施工新技术专题讲座(二十七)旋转挤压灌注桩(上)[J].工程机械与维修,2013,(3):104-107
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[3] 徐学燕,于琳琳,刘复孝.滚压成型灌注螺纹桩承载性能研究[J].土木建筑与环境工程,2011,33(3):19-24
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[2] 方崇,张信贵,彭桂皎.对新型螺杆灌注桩的受力特征与破坏性状的探讨[J].岩土工程技术,2006,20(6):316-319
[3] 徐学燕,于琳琳,刘复孝.滚压成型灌注螺纹桩承载性能研究[J].土木建筑与环境工程,2011,33(3):19-24
[4] 董天文,梁力,王明恕,等.极限荷载条件下螺旋桩的螺距设计与承载力计算[J].岩土工程学报,2006,28(11):2031-2034
[5] 陈亚东,王安汀,蔡江东,等.竖向受荷螺杆桩承载变形特性模型试验[J].施工技术,2017,46(14):116-119
[6] 孟振,陈锦剑,王建华,等.砂土中螺纹桩承载特性的模型试验研究[J].岩土力学,2012,(S1):141-145
[7] 钱建固,陈宏伟,贾鹏,等.注浆成型螺纹桩接触面特性试验研究[J].岩石力学与工程学报,2013,(9):1744-1749
[8] 李元海,朱合华,上野胜利,等.基于图像相关分析的砂土模型试验变形场量测[J].岩土工程学报,2004,(1):36-41