摘要
为了研究海洋地基土具体的土层划分及其工程力学特性,对大型自升式海工平台桩靴地基土开展静力触探试验、室内基本物性试验及不固结不排水三轴剪切试验(UU)。通过静力触探试验CPT得到的锥尖阻力qc、侧摩阻力fa与摩阻比Rf这些参数来精确划分海洋土层,并解译不排水抗剪强度Su、超固结比OCR及灵敏度St。与室内试验进行对比,评价其吻合度以确定锥尖系数Nkt、无量纲系数k等参数的取值。试验发现,土体的黏聚力c随着深度呈现递增的趋势;使用CPT对海洋地基土的不固结不排水抗剪强度和固结比进行评价时发现,当参数分别选取Nkt为25,k取0.2时,CPT试验测得的不排水抗剪强度、超固结比OCR与室内试验吻合度较高,并发现Nkt的数值会随着深度的增加越为稳定。同时得到地基土的灵敏度,并揭示其变化规律。
In order to study the specific soil layer division and engineering mechanical characteristics of marine foundation soil,static cone penetration test,indoor basic physical property test and unconsolidated undrained triaxial shear test(UU)were carried out on the foundation soil of large jack-up offshore platform.The parameters of cone tip resistance qc,side friction resistance fa and friction ratio Rf obtained by CPT are used to accurately divide the marine soil layer.The undrained shear strength Su,overconsolidation ratio OCR and sensitivity St were interpreted by static cone penetration test.Compared with the indoor test,the coincidence degree is evaluated to determine the values of the parameters such as the tip coefficient Nkt and the dimensionless coefficient k.It is found that the cohesion c of the soil increases with the depth.When CPT is used to evaluate the undrained shear strength and consolidation ratio of marine foundation soil,it is found that when Nkt is 25 and k is 0.2,the undrained shear strength and overconsolidation ratio OCR measured by CPT test are in good agreement with those of laboratory test,and it is found that the value of Nkt will be more stable with the increase of depth.The sensitivity of foundation soil is obtained by CPT test,and the variation law of sensitivity of marine foundation soil is revealed.
作者
魏军
WEI Jun(Offshore and New Energy Research and Development Center,Nantong COSCO Shipping Engineering Co.,Ltd,Nantong Jiangsu 226001 China)
出处
《江苏建筑》
2024年第2期96-100,120,共6页
Jiangsu Construction
基金
江苏省工业和信息化厅“20MW/3200T级深水超大型自航自升式风电安装船研制”。
关键词
自升式海工平台
静力触探试验
三轴试验
海洋地基土分层
jack-up offshore platform
static cone penetration test
triaxial test
stratification of marine foundation soil
