孔压静力触探试验（CPTU）是目前中国海上风电场工程勘察中应用最多的原位测试方法之一,其缺点在于土体参数无法直接获取,需要通过解译获得,而不同地区的解译参数存在场地特异性。该文依托黄海海域江苏某海上风电工程,开展室内三轴UU、固结快剪、三轴CU试验和原位CPTU,得到江苏海域的黏性土强度随深度的关系,可用于江苏海域黏性土强度的快速评估。基于修正剑桥模型和三轴CU试验得到江苏海域黏性土强度的理论计算公式。基于固结快剪和三轴试验结果得到江苏海域不同黏性土层强度的CPTU解译参数Nkt值的范围分别为11.93~19.99和8.45~16.68,建议采用固结快剪标定得到的Nkt总平均值14.44作为黏性土最优强度（中值）的解译参数。最终建立CPTU孔压比Bq和Nkt的关系,采用建立的Nkt与Bq的关系可较好解译黄海海域黏性土的不排水抗剪强度su,通过标定建立Nkt-Bq关系的方法也可应用于其他海洋岩土工程项目中。
Abstract
Piezocone penetration test （CPTU） is one of the most widely used in-situ geotechnical investigation methods for offshore wind farms in China. Its disadvantage is that the soil parameters cannot be obtained directly, but needs interpretation of the CPTU data, while the interpretation parameter is site specific. Based on an offshore wind power project in Yellow sea area located near Jiangsu province, triaxial UU, direct consolidated quick shear, triaxial CU tests and in-situ CPTU test are carried out. Then the relationship between undrained shear strength su of clayey soil and embedment depth has been proposed in this offshore area, which can be used for a quick evaluation of the undrained shear strength su of clayey soil. The theoretical calculation formula is proposed based on the Modified Cam-Clay model against the triaxial CU test results. The calibrated CPTU interpretation parameter Nkt for the strength of clayey soils ranges from 11.93 to 19.99 according to direct consolidated quick shear tests, and ranges from 8.45 to 16.68 according to triaxial test results. It is suggested that a mean value of 14.44 for Nkt is taken as the interpretation parameter for the best estimate of the undrained shear strength of clayey soil in Jiangsu offshore area, which is calibrated by the direct shear test results. Finally, the relationship between the pore pressure ratio Bq and interpretation parameter Nkt is established to give a better interpretation of the undrained shear strength su of clayey soil in this area. The proposed calibration methodology of establishing the correlation between Nkt and Bq can also be used for other offshore geotechnical engineering projects in the future.
关键词
海上风电场 /
岩土工程 /
黏土 /
孔压静力触探 /
Nkt
Key words
offshore wind farms /
geotechnical engineering /
clay /
piezocone penetration test /
Nkt
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基金
国家自然科学基金（52108356; 52101334）; 浙江省自然科学基金（LQ20E090001; LHZ20E090001）
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