高强格室和格栅格室加筋地基的试验对比  

Experimental comparative study of new lock enhanced integral geocell and geogrid mesh elements reinforced foundation

作　　者：戴治恒 张孟喜[1] 侯娟[2] 李家正 DAI Zhiheng;ZHANG Mengxi;HOU Juan;LI Jiazheng(Department of Civil Engineering,Shanghai University,Shanghai 200444,China;College of Sciences,Shanghai University,Shanghai 200444,China;Shanghai Institute of Applied Mathematics and Mechanics,Shanghai University,Shanghai 200072,China)

机构地区：[1]上海大学土木工程系,上海200444 [2]上海大学理学院,上海200444 [3]上海大学上海市应用数学和力学研究所,上海200072

出　　处：《上海大学学报（自然科学版）》2019年第5期796-806,共11页Journal of Shanghai University:Natural Science Edition

基　　金：国家自然科学基金资助项目(41202215,41372280)

摘　　要：分别对纯砂地基、整体插接式高强土工格室加筋地基和格栅格室加筋地基进行了室内模型试验.通过对比荷载-沉降曲线、地表位移曲线、格室变形以及破裂面的滑移等,研究了整体插接式高强土工格室和格栅格室对加筋地基受力性能的影响,初步分析了2种格室加筋地基的加固机理和破坏模式.试验结果表明,与纯砂地基相比,整体插接式高强土工格室和格栅格室均能有效提高加筋地基承载力,减小地表位移,均化地基中的应力分布,其中格室的最优加筋宽度约在4倍基础宽度.对整体插接式高强土工格室和格栅格室加筋地基进行对比发现,格栅格室组成的筋土复合结构的整体性更好,刚度更大,能更好地约束砂土的侧向滑移,延缓地基中破裂面的出现,进而能更好地提高地基承载力,减小沉降.虽然整体插接式高强土工格室条带的强度较大,但容易在节点处出现沿次要受力方向上的撕裂性破坏,因此需要进一步加强节点强度,改进节点形式.This paper presents results of laboratory model tests carried out on strip footings supported on geosynthetic reinforced sand beds. The relative performances of different forms of geosynthetic reinforcement (i.e. new lock enhanced integral geocell and geogrid mesh elements) foundation beds are compared using the same quantity of reinforcement in each test. Pressure-settlement curves, surface settlement and heave, deformation of two form geocells and glide planes are analyzed to understand the mechanism of different soil foundations. It is found that both form of geocells can decrease settlement and increase bearing capacity of the foundation. Vertical confinement of geocells is due to friction between the infill material and the geocell wall, which restrains soil from moving outside. The geocell-reinforced base can thus provide lateral and vertical confinement, tensioned membrane effect, and wider stress distribution, resulting in a better performance. The experiment also shows that geogrid mesh elements are more advantageous than new lock enhanced integral geocells. It is provided that there is no rupture of the material during loading. However, some ruptures can be found in joints of new lock enhanced integral geocells, which in turn principally decreased bearing capacity of the foundation. Meanwhile, significant observations on the difference in reinforcement mechanism for different forms of geocells are also presented.

关 键 词：格栅 高强格室 加筋地基 承载力 沉降 

分 类 号：TU443[建筑科学—岩土工程]