压灌桩桩土接触面微观结构特性模型试验研究  

Model test study on microstructure characteristics of pile-soil interface of press-grouting pile

作　　者：高睿[1,2] 邓畅 蔡桦 石知政 GAO Rui;DENG Chang;CAI Hua;SHI Zhizheng(School of Civil Engineering,Wuhan University,Wuhan 430072,China;Hubei Provincial Key Laboratory of Safety for Geotechnical and Structural Engineering,Wuhan University,Wuhan 430072,China;Hubei Huajian Construction Engineering Design Examination Service Co.Ltd.,Wuhan 430000,China)

机构地区：[1]武汉大学土木建筑工程学院,湖北武汉430072 [2]武汉大学岩土与结构工程安全湖北省重点实验室,湖北武汉430072 [3]湖北华建建设工程设计审查事务有限公司,湖北武汉430000

出　　处：《华中科技大学学报（自然科学版）》2021年第5期67-73,共7页Journal of Huazhong University of Science and Technology(Natural Science Edition)

基　　金：国家自然科学基金资助项目(51878521)。

摘　　要：为探究钻孔压灌桩桩土接触面的微观结构特性,通过室内正交模型试验法,对不同水泥浆液压灌压力、水灰比、土体干密度和含水率下桩土接触面孔隙结构的扫描电镜(SEM)图像进行定性和定量分析,研究了桩土接触面的毛刺现象和孔隙微观结构参数随试验因素变化的规律.研究结果表明:毛刺现象客观存在且由桩土共同作用产生;压灌压力对试验影响最显著,干密度次之,水灰比和含水率影响较小;适当增大压灌压力和提高土体干密度可加强水泥浆液渗透及其三维网状水化产物的填充效果,降低桩土接触面土体孔隙率及孔隙数量,减弱孔隙定向性,并增加微观结构复杂程度,最终加强桩土相互作用效果及整体性,增大桩侧摩阻力.To explore the microstructure characteristics of the pile-soil interface of bored press-grouting pile, the laboratory orthogonal model test method was used to make qualitative and quantitative analysis on the scanning electron microscopy(SEM)images of the pore structure of the pile-soil interface under different grouting pressure, water-cement ratio, dry density and moisture content of soil. The burr phenomenon of pile-soil interface and the variation law of pore microstructure parameters with experimental factors were studied. Research results show that the burr phenomenon exists objectively and is caused by the interaction of pile and soil.The influence of grouting pressure on the test is the most significant,followed by the dry density,and the influence of water-cement ratio and moisture content is less.Properly increasing the pressure of grouting and the dry density of soil can enhance the filling effect of cement slurry and its three-dimensional network hydration products,which can also reduce the porosity and pore number of soil at the pile-soil interface, weaken the orientation of pores and increase the complexity of microstructure, strengthening the pile-soil interaction effect and integrity and increasing the pile shaft resistance finally.

关 键 词：钻孔压灌桩 微观结构 桩土接触面 孔隙 模型试验 

分 类 号：TU44[建筑科学—岩土工程]