摘要
我国东部沿海地区沉积环境复杂多变,海上风电平台地基土性质软弱、复杂,与陆域土相比有较大差异。为系统研究海洋地基土工程力学特性,对江苏海域代表性扰动原状海洋土开展实验室基础土工试验、弯曲元试验及不排水三轴剪切试验,测定海域粉土及粉质黏土的物理力学性质,系统分析基本物理指标与扰动海洋原状土不排水剪切强度及剪切波速的相关性。试验发现:海洋粉土和粉质黏土的剪切波速V_(s)均随深度H的增大呈线性增大,但粉土V_(s)随H增大的增长速率明显大于粉质黏土;粉质黏土及粉土的呈现两种不同的应力-应变发展模式:应变硬化型和应变软化型,粉质黏土和粉土的不排水剪切强度S_(d)整体随H均增加呈增加趋势,但是没有表现出明显的单一相关性。孔隙比e的增大会促使两种土的S_(d)的降低,且S_(d)与e两者均有单一相关性;基于扰动原状土室内单元试验建立的S_(d)与V_(s)的关系,建立基于现场剪切波速的当前地层条件下未扰动原状土的不排水强度特性评价方法,但对于低含水率的粉质黏土,该方法略有保守。
Coastal beach zone in eastern China is rich in wind energy reserves with great development capabilities.However,the geographical conditions in the coastal area are complex and changeable,and the foundation soil of offshore wind power platform is weak and complex,which is quite different from land soil.In order to systematically study the mechanical properties of marine foundation soils along the coast of Jiangsu,basic laboratory geotechnical tests,bender element tests and undrained triaxial shear tests were carried out on representative disturbed marine soils.The physical and mechanical properties of marine silt and silty clay were measured,and the correlation between basic physical indexes and undrained shear strength S_(d) and shear wave velocity V_(s) of disturbed marine soil was systematically analyzed.The test results show that V_(s) of marine silt and silty clay increases linearly with the increase of depth H,however,the growth rate of V_(s) in silty clay with H is significantly higher than that in silty clay;the stress-strain relationship curves of silty clay and silt present two different development modes:strain hardening and strain softening.The S_(d) of silty clay and silty soil shows an increasing trend with the increase of H,but does not illustrate an obvious single correlation.The S_(d) of the two types of marine soils decreases with the increase of the void ratio e,and both show a good single correlation.Based on the relationship between S_(d) and V_(s) established by laboratory test of disturbed marine soils,an undrained strength evaluation method of undisturbed marine soils under the current stratum conditions incorporating in-situ shear wave velocity was established,it should be noted that for silty clay with low moisture content,this method is slightly conservative.
作者
吴奇
郭力嘉
张鑫磊
吴琪
WU Qi;GUO Lijia;ZHANG Xinlei;WU Qi(Wuxi Institute of Technology,Wuxi 214021,China;Institute of Geotechnical Engineering,Nanjing Tech University,Nanjing 210009,China)
出处
《防灾减灾工程学报》
CSCD
北大核心
2023年第4期666-673,共8页
Journal of Disaster Prevention and Mitigation Engineering
基金
国家重点研发计划项目(2018YFC1504301)
国家自然科学基金项目(52008206)资助。
关键词
海上风电平台
沉积条件
剪切波速
不排水剪切强度
评价方法
offshore wind power platforms
deposition conditions
shear wave volecity
undrained shear strength
evaluation method
