松砂中双叶片螺旋锚上拔承载及土体变形特性试验研究  

Experimental study on the uplift behavior and soil deformation characteristics of the double-blade screw anchor in loose sand

作　　者：史旦达 俞快 毛逸瑶 原媛 郝冬雪[2] 胡伟[3] SHI Dan-da;YU Kuail;MAO Yi-yao;YUAN Yuan;HAO Dong-xue;HU Wei(College of Ocean Science and Engineering,Shanghai Maritime University,Shanghai 201306,China;School of Civil Engineering and Architecture,Northeast Electric Power University,Jilin,Jilin132012,China;Key Laboratory of Geotechnical Engineering Stability Control and Health Monitoring of Hunan Province,Hunan University of Science and Technology,Xiangtan,Hunan 411201,China)

机构地区：[1]上海海事大学海洋科学与工程学院,上海201306 [2]东北电力大学建筑工程学院,吉林吉林132012 [3]湖南科技大学岩土工程稳定控制与健康监测湖南省重点实验室,湖南湘潭411201

出　　处：《岩土力学》2022年第11期3059-3072,3082,共15页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.41772273,No.11802172,No.52078108,No.52178332)。

摘　　要：基于室内1g模型试验,研究了松砂地基中双叶片螺旋锚的上拔承载性能,重点分析了埋深比和叶片间距的影响;在半模试验中融入数字图像相关技术(digital image correlation,简称DIC),分析了锚体上拔时锚周土体的变形和破坏规律;基于半模试验实测结果,提出了可用于松砂中双叶片螺旋锚上拔极限承载力预测的理论公式。研究结果表明,埋深比和叶片间距会影响螺旋锚的上拔极限承载力以及峰值上拔力出现时的位移水平;对于松砂中的双叶片螺旋锚上拔,埋深比H/D=3(H为上锚片的埋置深度,D为叶片直径)可视为浅埋和深埋的界限,当H/D>3后,上锚片上方土体的破坏模式由整体剪切破坏逐步转变为局部剪切破坏;间距比S/D=2.5(S为叶片间距)可视为两叶片之间的土体由圆柱剪切破坏向独立承载破坏转变的界限;经与全模试验及已有文献试验结果对比,上拔极限承载力理论公式的预测误差一般均在25%范围内,验证了理论公式的可靠性。Based on the 1g model tests, the uplift behavior of the double-blade screw anchor in loose sand was studied, where the influences of the embedment ratio and blade spacing were focused. Digital image correlation(DIC) was used in the half-model tests to analyze the deformation and failure mechanism of soils around the anchor during the uplift process. A theoretical formula for predicting the ultimate bearing capacity of double-blade screw anchors in loose sand was proposed based on the results of the half-model tests. The results show that the embedment ratio and blade spacing affect both the ultimate uplift bearing capacity and the displacement corresponding to the peak uplift force. For the double-blade screw anchors in loose sand, the embedment ratio H/D=3can be regarded as the demarcation between shallow and deep anchors, where H is the embedded depth of the upper anchor blade, D is the diameter of the blade. When embedment ratio H/D>3 is applied, the failure mode of soils above the upper blade gradually changes from overall shear failure to local shear failure. The spacing ratio S/D=2.5, where S is the blade spacing, can be regarded as the critical point that makes the failure of soils between two blades from the cylindrical shear failure to independent bearing failure.By comparing with the full-model tests and the experimental results in the literature, it is found that the prediction errors of the proposed theoretical formula for the ultimate uplift bearing capacity are generally within 25%. Thus, the reliability of the theoretical formula is verified.

关 键 词：松砂 双叶片螺旋锚 上拔承载力 土体变形 数字图像相关技术 

分 类 号：TU473[建筑科学—结构工程]