粉喷桩复合地基大刚度垫层特性研究  

Study on large-stiffness cushion in dry jet mixing pile composite foundation

作　　者：尹检亮 张国祥[2] YIN Jianliang;ZHANG Guoxiang(Infrastructure Construction Department,Central South University,Changsha 410075,China;School of Civil Engineering,Central South University,Changsha 410075,China)

机构地区：[1]中南大学基建处,湖南长沙410075 [2]中南大学土木工程学院,湖南长沙410075

出　　处：《铁道科学与工程学报》2020年第2期341-348,共8页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(51578550)

摘　　要：复合地基承载力和刚度与垫层厚度和材质等密切相关,常规垫层的合理厚度和材质基本是靠经验选值,缺少理论依据。为此本文提出用大刚度块石垫层提高道路软土复合地基刚度的新方法,推导出新的垫层最小厚度理论公式。通过有限差分软件分析和现场试验结果对比,探讨道路粉喷桩复合地基大刚度垫层受力变形特点。数值分析结果表明:对于道路复合地基上大刚度垫层,垫层刚度提高明显降低路基表面弯沉值,以及存在合适的垫层刚度和厚度能让粉喷桩复合地基的力学性能效果达到最佳。现已成功地将大刚度块石垫层方法应用于常德安乡大道低液限粉土粉喷桩复合地基垫层处理,道路运行多年状况良好。This paper presented a new method to improve the stiffness of road soft soil composite foundation with block stone cushion of high stiffness and deduced a new theoretical formula for determining the minimum thickness of the cushion. The bearing capacity and stiffness of the composite foundation are closely related to the thickness and material quality of the cushion. Based on the analysis of finite difference software and the comparison of field test results, the stress and deformation characteristics of the high-stiffness cushion in the composite foundation of powder grouting piles were discussed. Numerical analysis shows that for the high-stiffness cushion layer on the composite road foundation, increasing cushion stiffness significantly reduces roadbed surface deflection, and there exists optimal pad stiffness and thickness that result in optimal mechanical performance of composite foundation with powder jet piles. This high-stiffness stone cushion technique has been successfully applied in the Changde-Anxiang road construction project to treat the low liquid limit silt by using the composite foundation with powder jet piles, which has helped to maintain satisfactory road serviceability for several years.

关 键 词：大刚度块石垫层 粉喷桩复合地基 垫层厚度 承载力特性 

分 类 号：TU411.7[建筑科学—岩土工程]