该研究开展原位和室内的CPT、十字板剪切（VST）试验,分析土体在不同深度下的抗剪峰值强度（Sup）、抗剪残余强度（Su）,以及相应的Nkp和Nkr的取值。依据原位和室内Nk系数结果计算得到上海黏土Su预测值。研究结果表明,原位试验浅层土体的Sup和Sur随深度增加而增大,而这两者在较深土层中差距较小。计算得到的Nkp波动范围较Nkr小。室内试验中,黏土固结所需时间较短,且在相同上覆应力下不同深度的土体抗剪强度差异较小。原位和室内试验单一土层Nkp、Nkr结果差异不大,使用Nkp可预测原位不同深度土体Su
Abstract
The cone factor （Nk） can be used to estimate the undrained shear strength （Su） of clay, which in turn enables the calculation of the bearing capacity of offshore wind turbine foundations based on empirical correlations. In this study, both in-situ and laboratory cone penetration tests （CPT）, together with vane shear tests （VST）, were conducted to analyze the peak shear strength （Sup） and residual shear strength （Sur） of soil at various depths, as well as the corresponding Nkp and Nkr values. Based on the obtained in-situ and laboratory Nk coefficients, the predicted Su values for Shanghai clay were calculated. The results indicate that both Sup and Sur in the shallow soil layers increase with depth, while their difference becomes less significant in deeper layers. The fluctuation range of Nkp was found to be smaller than that for Nkr. In the laboratory tests, the required consolidation time for the clay was short, and the variation in shear strength at different depths under the same overburden stress was not pronounced. Furthermore, the Nkp and Nkr values obtained from both in-situ and laboratory tests for a given soil layer showed little difference, suggesting that Su at various depths can be reliably predicted using Nkp.
关键词
海上风电场 /
静力触探 /
十字板 /
不排水抗剪强度 /
锥尖系数
Key words
offshore wind farm /
cone penetration test /
vane shear test /
undrained shear strength /
cone factor
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参考文献
[1] 张双益, 李熙晨. 气候变化背景下未来中国近海风能资源预估[J]. 太阳能学报, 2022, 43(1): 29-35.
ZHANG S Y, LI X C.Future projection of wind energy resources over China’s offshore areas under different climate change scenarios[J]. Acta energiae solaris sinica, 2022, 43(1): 29-35.
[2] 朱蓉, 徐红, 龚强, 等. 中国风能开发利用的风环境区划[J]. 太阳能学报, 2023, 44(3): 55-66.
ZHU R, XU H, GONG Q, et al.Wind environmental regionalization for development and utilization of wind energy in China[J]. Acta energiae solaris sinica, 2023, 44(3): 55-66.
[3] 林逸凡, 杨梓豪, 刘玉飞, 等. 中国沿海风电施工窗口期及功效分析[J]. 太阳能学报, 2023, 44(1): 273-280.
LIN Y F, YANG Z H, LIU Y F, et al.Analysis of weather window and construction efficiency for wind power development in offshore China[J]. Acta energiae solaris sinica, 2023, 44(1): 273-280.
[4] 宋二祥, 付浩, 林世杰, 等. 饱和黏性土不排水分析中总应力强度指标的选用[J]. 土木工程学报. 2021, 54(9): 88-95.
SONG E X, FU H, LIN S J, et al.Discussion on the choice of strength parameters for the analysis of saturated clay under undrained conditions[J]. China civil of engineering journal, 2021, 54(9): 88-95.
[5] ABDEL RAHMAN I.Correlation of cone resistance with undrained shear strength for clay soils[R]. Johor: Universiti Teknologi Malaysisa, 2007.
[6] GEBRESELASSIE B.Experimental, analytical and numerical investigations of excavations in normally consolidated soft soils[M]. Kassel: Kassel University. Press, 2003.
[7] CHEN C.Evaluating undrained shear strength of Klang clay from cone penetration test[C]//International Conference on In-situ Measurement of Soil Properties and Case Histories. Bali, Indonesia. 2001:141-148.
[8] ISMAIL H, ZEIN A.Prediction of undrained shear strength and SPT using the static CPT data[C]//Proceedings 9th regional African Conference on SMFE.Lagos, Nigeria. 1987: 185-192.
[9] OTOKO G R, MANUEL I, IGWAGU M, et al.Empirical cone factor for estimation of undrained shear strength[J]. Electronic journal of geotechnical engineering, 2016, 21: 6069-6076.
[10] HONG S, LEE M, KIM J, et al.Evaluation of undrained shear strength of Busan clay using CPT[C]//2nd Symposium on Cone Penetration Testing, CPT, Huntington Beach, USA, 2010.
[11] RÉMAI Z. Correlation of undrained shear strength and CPT resistance[J]. Periodica polytechnica civil engineering, 2013, 57: 39-44.
[12] SCHMERTMANN J H.Guidelines for cone penetration test: performance and design[M]. Washington: Federal Highway Administration, 1978.
[13] TERZAGHI K, PECK R B, MESRI G.Soil mechanics in engineering practice[M]. Hoboken: John wiley & sons, 1996:480-490.
[14] YI J T, GOH S H, LEE F H, et al.A numerical study of cone penetration in fine-grained soils allowing for consolidation effects[J]. Géotechnique, 2012, 62(8): 707-719.
[15] YU H S, HERRMANN L R, BOULANGER R W.Analysis of steady cone penetration in clay[J]. Journal of Geotechnical and geoenvironmental engineering, 2000, 126(7): 594-605.
[16] 林毅峰, 朱俊霖, 俞剑, 等. 考虑黏土非线性特性的锥尖系数小孔扩张计算方法[J]. 岩土工程学报, 2024, 46(S2): 67-71.
LIN Y F, ZHU J L, YU J, et al.Spherical cavity expansion-based method for cone factor considering nonlinear characteristics of clay[J]. Chinese journal of geotechnical engineering, 2024, 46(S2): 67-71.
[17] SHENG D C, CUI L, ANSARI Y.Interpretation of cone factor in undrained soils via full-penetration finite-element analysis[J]. International journal of geomechanics, 2013, 13(6): 745-753.
[18] HAUSER L, SCHWEIGER H F.Numerical study on undrained cone penetration in structured soil using G-PFEM[J]. Computers and Geotechnics, 2021, 133: 104061.
[19] 中华人民共和国住房和城乡建设部, 国家市场监督管理总局. 土工试验方法标准: GB/T 50123—2019[S]. 北京: 中国计划出版社, 2019.
Ministry of Housing and Urban-Rural Development of PRC, State Administration for Market Regulation. Standard for Geotechnical Testing Method: GB/T 50123—2019[S]. Beijing: China Planning Press, 2019.
基金
中国长江三峡集团有限公司科研项目（202103495）
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