摘要
试验段为自重湿陷性Ⅳ级黄土场地,分3种不同地基处理措施试验分区,分区之间设地基不处理过渡段。柱锤冲扩桩段对22 m深湿陷性黄土层全部处理,水泥挤密桩段仅处理上部15 m深湿陷性黄土层,强夯段处理上部6 m深湿陷性黄土层。结果表明,处理深度范围内黄土的湿陷性已消除,地基承载力均大于标准值。柱锤冲扩桩与水泥土挤密桩复合地基沉降量小于15 mm,满足高速铁路对工后沉降量的要求,而强夯地基的沉降量不满足要求。柱锤冲扩桩区段,桩间土的最小和平均挤密系数不低于0.88和0.93的标准,但是桩身平均压实系数和压缩模量却分别低于0.97和100 MPa的标准。水泥挤密桩区段,桩间土的最小和平均挤密系数、桩身平均压实系数和压缩模量也低于同样的标准值。强夯地基的压缩模量小于15 MPa的标准。检测标准的合理取值有待深入研究。
The experimental section is located in the classⅣ dead-weight collapsible loess site and is composed of three different kinds of loess foundation treatment measures. The transition sections without foundation treatment exist between them. All 22 m depth of collapsible loess is treated in zone of piles with down hole dynamic compaction. The upper 15 m depth of collapsible loess is treated in zone of cement soil compaction piles. The upper 6 m depth of collapsible loess is treated in zone of dynamic compaction. The results show that the collapsibility of loess within treatment depth has been completely eliminated. Their bearing capacity is higher than the standard value. The composite foundation settlements of piles with down hole dynamic compaction and cement soil compaction piles are less than 15 mm after construction for high-speed railway;but the dynamic compaction foundation can not meet the same requirement. In zone of pile with down hole dynamic compaction, the minimum and average coefficients of compaction are respectively more than the standard values of 0.88 and 0.93;but the average coefficient of compaction and compression modulus of piles are respectively less than the standard values of 0.97 and 100 MPa. In zone of piles with cement-soil compaction piles, the minimum and average coefficients of compaction, or the average coefficient of compaction and compression modulus of piles are also less than the same standard values. Average compression modulus of dynamic foundation is less than the standard value of 15 MPa. The reasonable values of test standard need further study.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2013年第S2期318-324,362,共8页
Rock and Soil Mechanics
基金
铁道部科技研究开发计划项目(No.2005K001-B-2)
宁波市自然科学基金项目(No.2010A610085)
宁波市社会发展科研项目(No.2011C50051)
宁波市科技创新团队项目(No.2011B81005)
宁波市重大(重点)科技攻关计划项目(No.2011C51011)
关键词
铁路客运专线
湿陷性黄土
路堤地基
处理效果
现场试验
railway passenger dedicated line
collapsible loess
embankment foundation
treatment effect
field test
