摘要
劲性复合桩是一种将预制芯桩与水泥土搅拌桩相结合的新型桩基,其中,水泥土厚度作为影响芯桩-水泥土界面剪切性能的关键参数,其作用机制尚未得到充分研究。鉴于相同外表面积下,外接方桩的劲性复合桩的水泥土最小厚度较小,且方桩角点处存在应力集中现象,其性能对水泥土厚度的变化更为敏感,因此,本研究特地选择方桩作为研究对象。通过三维桩-土界面剪切试验,以方形芯桩为研究对象,系统探究了水泥土最小厚度与水泥掺量对芯桩-水泥土界面剪切行为的影响机制。结果表明:界面峰值强度随水泥土最小厚度和水泥掺量的增加而升高,并与水泥土无侧限抗压强度呈线性正相关关系;随着水泥土最小厚度的增加,界面破坏模式由脆性转为延性,残余强度亦随之提高。基于试验数据,提出了界面峰值强度和残余强度的计算公式。通过厚壁圆筒理论,揭示了水泥土最小厚度与无侧限抗压强度对界面强度的影响机理。同时,构建了反映界面弹性-软化-残余三阶段力学行为的剪切本构模型,为劲性复合桩的优化设计提供了理论依据。
Strength composite piles are a novel type of pile foundation that integrate a prefabricated core pile with a cemented soil mixing pile,where the thickness of cemented soil as a key factor affecting the shear performance of the core pile-cemented soil interface has not been fully investigated.Given that square piles with the same outer surface area have smaller minimum cemented soil thickness in strength composite piles,and stress concentration occurs at the corners of square piles,making their performance more sensitive to changes in cemented soil thickness,this study specifically selected square piles for investigation.Through three-dimensional pile-soil interface shear tests with square-section core piles,this study systematically explored the influence mechanism of the minimum cemented soil thickness and cement content on the shear behavior of the core pile-cemented soil interface.Results show that the peak interface shear strength increases with the increase of the minimum cemented soil thickness and cement content,and exhibits a linear positive correlation with the unconfined compressive strength of the cemented soil.Furthermore,as the minimum cemented soil thickness increases,the interface failure mode transitions from brittle to ductile,with a corresponding increase in residual strength.Based on the test data,calculation formulas for the peak interface strength and residual strength were proposed.Through thick-walled cylinder theory,the influence mechanism of the minimum cemented soil thickness and unconfined compressive strength on the interface strength was revealed.Meanwhile,a shear constitutive model reflecting the threestage mechanical behavior(elastic-softening-residual)of the interface was established,providing a theoretical basis for the optimized design of strength composite piles.
作者
周建
陈家琛
刘翔
ZHOU Jian;CHEN Jiachen;LIU Xiang(Research Center of Coastal and Urban Geotechnical Engineering,Zhejiang University,Hangzhou 310058,Zhejiang,China;Engineering Research Center of Urban Underground Development of Zhejiang Province,Zhejiang University,Hangzhou 310058,Zhejiang,China;Yuhang Forestry and Water Resources Bureau of Zhejiang Province,Hangzhou 311100,Zhejiang,China)
出处
《地基处理》
2026年第2期107-117,127,共12页
Journal of Ground Improvement
基金
浙江省水利工程带科研揭榜挂帅项目(RA+202303)。
关键词
劲性复合桩
方桩
芯桩-水泥土界面
剪切特性
界面本构关系
strength composite pile
square pile
core pile-cemented soil interface
shear characteristics
interface constitutive relationship
