基于相似理论的复合地基弹性垫层模型试验研究  

Similarity Theory-based Model Experimental Study on Elastic Cushion Layer of Composite Foundation

作　　者：姚云龙 李积泉 刘鑫[1,4] 徐奋强[5] 洪宝宁[1,2] YAO Yunlong;LI Jiquan;LIU Xin;XU Fenqiang;HONG Baoning(Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing,Jiangsu 210098,China;Geotechnical Research Institute,Hohai University,Nanjing,Jiangsu 210098,China;Foshan Communications Investment Group Co.,Ltd.,Foshan,Guangdong 528000,China;Tunnel and Underground Engineering Institute,Hohai University,Nanjing,Jiangsu 210098,China;School of Civil Engineering and Architecture,Nanjing Institute of Technology,Nanjing,Jiangsu 211167,China)

机构地区：[1]河海大学岩土力学与堤坝工程教育部重点实验室,江苏南京210098 [2]河海大学岩土工程科学研究所,江苏南京210098 [3]佛山市交通投资集团有限公司,广东佛山528000 [4]河海大学隧道与地下工程研究所,江苏南京210098 [5]南京工程学院建筑工程学院,江苏南京211167

出　　处：《公路工程》2023年第6期84-93,共10页Highway Engineering

基　　金：国家自然科学基金青年基金项目(51609071)。

摘　　要：为了对比分析不同桩型(半刚性桩和柔性桩)、不同垫层材料(砂垫层、碎石垫层、弹性垫层)和垫层厚度对复合地基承载特性的影响,需要开展复合地基室内模型试验研究。在研制模型试验系统、建立符合模型试验要求的模化条件和相关准则的基础上,分析了复合地基的承载特性,引入了弹性垫层模拟实际工况的可行性。结果表明,随着垫层厚度的增大,桩土应力比有所减小,上刺入量会逐渐增大。柔性桩的桩顶面中心点沉降量明显小于半刚性桩,一般差值在10 mm左右;柔性桩的分级加载分界点在60 kPa左右,半刚性桩则在80 kPa左右。弹性垫层相比于砂垫层和碎石垫层,其整体性相对更好,可将原有的“100~200 mm砂垫层+荷载板”改为“小于100 mm的砂粒找平层+弹性垫层+荷载板”,以更好地发挥实际垫层在复合地基的作用。In order to compare and analyze the effects of different pile types(semi-rigid piles and flexible piles),different cushion layer(sand cushion layer,gravel cushion layer and elastic cushion layer)and cushion thickness on the bearing characteristics of composite foundation,an indoor model test study of composite foundation is required.Based on the development of the model test system and the establishment of the modelling conditions and relevant guidelines that meet the requirements of the model test,the bearing characteristics of composite foundation and the feasibility of introducing elastic cushion layer to simulate the actual working conditions are analyzed.The results show that with the increase of cushion layer thickness,the pile-soil stress ratio of composite foundation decreases and the pile impaling volume will gradually increase.The settlement at the center point of the top surface of flexible pile is significantly smaller than that of semi-rigid pile,and the general difference is about 10 mm;the graded loading cut-off point of flexible pile is about 60 kPa,while that of semi-rigid pile is about 80 kPa.Compared with sand cushion layer and gravel cushion layer,its integrity is relatively better,and the original"100~200 mm sand cushion layer and load plate"can be changed to"less than 100 mm sand leveling layer and elastic cushion layer and load plate",in order to better play the actual cushion layer in the role of composite foundation.

关 键 词：复合地基 弹性垫层 模型试验 相似理论 桩土应力比 

分 类 号：TU528.2[建筑科学—建筑技术科学]