摘要
考虑到西北地区阶地黄土的特殊工程地质条件,为了更好地契合当地工况,满足高铁路基的沉降控制指标,本文提出了一种变刚度组合桩复合地基,并进行了现场载荷试验,研究了其承载特性、桩土应力比与桩周土挤密系数变化特征;通过数值模拟,深入研究了变刚度组合桩桩体与桩周土体地应力变形分布特征。结果表明:相比于水泥土挤密桩,变刚度组合桩复合地基能够更有效地控制沉降;地表处桩土应力比特征更接近柔性桩,具备柔性桩复合地基的变形协调能力;变刚度组合桩复合地基能够产生土拱效应,从而更好地发挥桩体的端承作用,降低复合地基下层桩间土所受的荷载,以契合阶地黄土区特殊的工程地质条件。
Considering the special engineering geological conditions of terrace loess in Northwest China,in order to better fit the local conditions and meet the settlement control index of high-speed railway subgrade,a composite foundation with variable stiffness combination pile isproposed,and the field load tests are carried out,and bearing characteristics,pile-soil stress ratio and variation characteristics of soil compaction coefficient around pile are discussed.Through numerical simulation,the stress and deformation distribution characteristics of variable stiffness composite pile and soil around pile are deeply studied.The results show that,compared with the cement soil compaction pile,the composite foundation with variable stiffness composite pile can more effectively control the settlement,and the pile-soil stress ratio at the surface is closer to the flexible pile,which has the deformation coordination ability of the flexible pile composite foundation.The composite foundation with variable stiffness composite piles can produce soil arching effect,so as to give better play to the end bearing role of piles and reduce the load on the soil between piles in the lower layer of composite foundation,so as to meet the special engineering geological conditions of terrace loess area.
作者
吕擎峰
韩启亮
赵彦旭
郭连星
杲斐
LüQingfeng;Han Qiliang;Zhao Yanxu;Guo Lianxing;Gao Fei(College of Civil Engineering and Mechanics,Lanzhou University,Lanzhou 730000,P.R.China;China Railway 21st Bureau Group Co.,Ltd.,Lanzhou 730050,P.R.China)
出处
《地下空间与工程学报》
CSCD
北大核心
2023年第4期1289-1298,共10页
Chinese Journal of Underground Space and Engineering
基金
甘肃省科技重大专项(19ZD2FA001)
中国铁建科技研发计划项目(2019-B08)
国家自然科学基金(51878322)。
关键词
变刚度组合桩
复合地基
地基承载力
土拱效应
数值模拟
variable stiffness combination pile
composite foundation
foundation bearing capacity
soil arching effect
numerical simulation
