Consolidation behaviors of soft marine clay in Lianyungang under desalination environment of pore water
DENG Yong-feng1, 2, YUE Xi-bing1, 2, ZHANG Tong-wei1, 2, LIU Song-yu1, 2, YANG Zhong-chao3
1. Institute of Geotechnical Engineering, Transportation College, Southeast University, Nanjing 210096, China; 2. Key Laboratory of Urban Underground Engineering and Environmental Safety of Jiangsu Province, Nanjing 210096, China; 3. Key Laboratory of Hydraulic and Waterway Engineering of the Ministry of Education, Chongqing Jiaotong University, Chongqing 400074, China
Abstract：The marine soft clays, the quaternary sediments, are widely deposited in the sea transgression/regression environment in Lianyungang, Jiangsu Province, whose behaviors are focused recently with the implementation of the coastal development strategy. The salinity of pore water during deposition is relatively high, and with the erosion of the surface or underground freshwater, the desalination of pore water occurs, whilst its effect on soil behaviors of the natural soft clays is still unclear. The piezo-cone penetration tests (CPTu) and physical property experiments of the soft clays with salinity of pore water of 0.1% and 4.9% at two sites, e.g. Lianyungang-Linyi highway and Linhai highway, are conducted. The higher strength of the soils with more salinity at the same depth is observed, but they have the similar deposition environment, ratios of water content to liquid limit, particle-size distributions and mineral compositions. To further clarify the effect of pore water, the paralleled percolation and oedometer tests with the synthetic solution and deionized water are performed. The results show that the parameters of oedometer modulus EOed, consolidation coefficient Cv and hydraulic conductivity k with the synthetic solution are higher than those with deionized water, while the compression index Cc, swelling index Cs and secondary consolidation coefficient Cα are on the contrary. Those results will deepen the understanding of behaviors of Lianyungang marine clays and provide the reference for the offshore engineering.
邓永锋, 岳喜兵, 张彤炜, 刘松玉, 杨忠超. 连云港海相软土在孔隙水盐分溶脱环境下的固结特性[J]. 岩土工程学报, 2015, 37(1): 47-53.
DENG Yong-feng, YUE Xi-bing, ZHANG Tong-wei, LIU Song-yu, YANG Zhong-chao. Consolidation behaviors of soft marine clay in Lianyungang under desalination environment of pore water. Chinese J. Geot. Eng., 2015, 37(1): 47-53.
 任美锷. 江苏省海岸带与海涂资源综合考察报告[M]. 北京:海洋出版社, 1987: 517. (REN Mei-e. Investigation report of coastal zone and tideland resource in Jiangsu Province[M]. Beijing: Ocean Press, 1987: 517. (in Chinese))  魏汝龙. 我国沿海软黏土特性及其工程问题[J]. 水利水运科学研究, 1985(3): 109-121. (WEI Ru-long. The engineering behavior of coastal soft clay in China[J]. Journal of Nanjing Hydraulic Research Institute, 1985(3): 109-121. (in Chinese))  LIU S Y, CAI G J, TONG L Y, et al. Approach on the engineering properties of Lianyungang marine clay from piezocone penetration tests[J]. Marine Georesources and Geotechnology, 2008, 26(3): 189-210.  邓永锋, 吴燕开, 刘松玉, 等. 连云港浅层海相软土沉积环境及物理力学性质研究[J]. 工程地质学报, 2005, 13(1): 29-34. (DENG Yong-feng, WU Yan-kai, LIU Song-yu, et al. Sediment environment of shallow marine clays deposited in Lianyungang area and their physical and mechanical properties[J]. Engineering Geology, 2005, 13(1): 29-34. (in Chinese))  CHEN J, ANADARAJAH A. Influence of pore fluid composition on volume of sediments in kaolinite suspensions[J]. Clays and Clay Minerals, 1998, 46 (2): 145-152.  SRIDHARAN A, PRAKASH K. Influence of clay mineralogy and pore medium chemistry on clay sediment formation[J]. Canadian Geotechnical Journal, 1999, 36: 961-966.  KAYA A, ÖREN A H, YUKSELEN-AKSOY Y. Settling of kaolinite in different aqueous environment[J]. Marine Georesources and Geotechnology, 2006, 24(3): 203-218.  ABDULLAH W S, AL-ZOU'BI M S, ALSHIBLI K A. On the physicochemical aspects of compacted clay compressibility[J]. Canadian Geotechnical Journal, 1997, 34(4): 551-559.  KAYA A, FANG H Y. The effects of organic fluids on physicochemical parameters of fine-grained soils[J]. Canadian Geotechnical Journal, 2000, 37: 943-950.  SRIDHARAN A, EL-SHAFEI A, MIURA N. Mechanisms controlling the undrained strength behavior of remolded Ariake marine clays[J]. Marine Georesources and Geotechnology, 2002, 20: 21-50.  DI Maio C, SANTOLI L, SCHIAVONE P. Volume change behavior of clays: the influence of mineral composition, pore fluid composition and stress state[J]. Mechanics of Materials, 2004, 36: 435-451.  GAJO A, MAINES M. Mechanical effects of aqueous solutions of inorganic acids and bases on a natural active clay[J]. Géotechnique, 2007, 57(8): 687-699.  YUKSELEN-AKSOY Y, KAYA A, ÖREN A H. Seawater effect on consistency limits and compressibility characteristics of clays[J]. Engineering Geology, 2008, 102: 54-61.  ÖREN A H, KAYA A. Some engineering aspects of homoionized mixed clay minerals[J]. Environmental Monitoring and Assessment, 2003, 84: 85-98.  LUNNE T, ROBERTSON P K, POWELL J J M. Cone penetration testing in geotechnical practice[M]. London: Blankie Academic and Professional, 1997.  蔡国军. 现代数字式多功能CPTU技术理论与工程应用研究[D]. 南京: 东南大学, 2010. (CAI Guo-jun. Study on theory and engineering application of digital multifunctional piezocone penetration test (CPTU)[D]. Nanjing: Southeast University, 2010. (in Chinese))  HONG Z, LIU S, NEGAMI T. Strength sensitivity of marine Ariake clays[J]. Marine Georesources and Geotechnology, 2005, 23(3): 221-233.  GENS A. Soil-environment interactions in geo-technicalengineering[J]. Géotechnique, 2010, 60(1): 3-74.  MITCHELL J K, SOGA K. Fundamentals of soil behavior[M]. New York: Wiley, 1976.  TAVENAS F, JEAN P, LEBLOND J, et al. The permeability of natural soft clays Part II: permeability characteristics[J]. Canadian Geotechnical Journal, 1983, 20(4): 645-660.  CARMAN P C. Flow of gases through porous media[M]. London: Butterworths Scientific Publications, 1956.  KOZENY J. Ueber kapillare leitung des wassers im boden[J]. Sitzungsberichte der Akademie der Wissenschaften inWien, 1927, 136(2): 271-306. (KOZENY J. About capillary pipe of the water in the soil[J]. Proceedings of the Academy of Sciences in Vienna, 1927, 136(2): 271-306. (in German))  DENG Y F, TANG A M, CUI Y J, et al. Study on the hydraulic conductivity of Boom clay[J]. CanadianGeotechnical Journal, 2011, 48: 1461-1470.