摘要
台华高速公路采用干振碎石桩进行软土地基处理,在路堤填筑过程中发生了地基失稳滑移。通过数值方法对路堤填筑过程中地基沉降、超静孔隙水压力及地基塑性区的发展变化进行了模拟计算,并结合现场补勘数据,分析了引起路堤失稳滑移的原因。在此基础上,提出刚性桩地基处理加固方案。数值计算及现场勘查结果表明,在强度较低的软土中采用干振碎石桩进行地基处理是不成功的,施工不仅没有形成完整的碎石桩体,还因扰动降低了原状地基土强度,路堤填筑速度过快则直接导致了地基滑移破坏;当采用刚性桩加固软基时,桩间土仅承担小部分路堤荷载,而大部分路堤荷载由桩承担并传递给深层承载力较高的土层,因此路堤的稳定性高、沉降小,可实现快速填筑。数值分析及现场刚性桩试验段测试结果均表明:刚性桩方案可以满足路堤填筑要求。
Numerical method combined with field investigation is employed to explore the sliding failure mechanism of Taihua highway embankment during construction,which is built on soft soils and the soft soils are improved with stone columns.The analytical results show that the original design using stone columns to improve soft soils is not acceptable because the undrained shear strength of the soft soils is too low to confine the stone columns efficiently.As a result,no completed stone columns are formed in the soft soils,with which the high rate of embankment filling causes the sliding failure of the embankment slope.In addition,a treatment method by using rigid concrete tube-pile is presented.For the compression stiffness of pile is greater than those of soft soils,most of the embankment loads are borne by piles,and the remaining load is carried by the soft soils,which allow the embankment to be built in a single stage without further endangering of undrained failure of soft soils and the settlement of embankment can be reduced.Numerical analysis and field monitoring results both demonstrate that the soft soils treated by using rigid concrete tube-pile is successful.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2007年第7期1504-1510,共7页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(50308026)
关键词
土力学
软土
高速公路
地基处理
碎石桩
钢筋混凝土管桩
soil mechanics
soft soils
highway
soil improvement
stone column
reinforced concrete tube-pile
