Abstract：Wrapping the individual stone columns with vertical geosynthetics can effectively improve the load performance of stone columns and control the settlement of composite foundation. The quantitative improvement of loading capacity of geosynthetic-encased stone columns is investigated through two series of laboratory model tests conducted on stone columns installed in soft soils in a large scale testing tank. Bugling failure models and reinforcement mechanism are discussed, and the stress-strain characteristics of vertical encasement are analyzed. The results from the loading tests indicate significant improvement in loading capacity of the stone columns due to vertical encasement. The biggest bugling deformation occurs just below the encasement, and the bugling model involves the interaction between the stone column, vertical geosynthetic-encasement and surrounding soils. The column-soil stress ratio of composite foundation for the encased stone columns is much higher than that for the ordinary stone columns. The vertical geosynthetics greatly improve the stiffness of stone columns and help to transfer the upper load to the bottom layer of soils.
赵明华, 顾美湘, 张玲, 刘猛. 竖向土工加筋体对碎石桩承载变形影响的模型试验研究[J]. 岩土工程学报, 2014, 36(9): 1587-1593.
ZHAO Ming-hua, GU Mei-xiang, ZHANG Ling, LIU Meng. Model tests on influence of vertical geosynthetic-encasement on performance of stone columns. Chinese J. Geot. Eng., 2014, 36(9): 1587-1593.
[1] 赵明华, 俞 晓. 土力学与基础工程[M]. 武汉: 武汉理工大学出版社, 2003. (ZHAO Ming-hua, YU Xiao. Soil mechanics and foundation engineering[M]. Wuhan: Wuhan University of Technology Press, 2003. (in Chinese)) [2] 龚晓南. 复合地基理论及工程应用[M]. 北京: 中国建筑工业出版社, 2007. (GONG Xiao-nan. Theories and application of composite foundation[M]. Beijing: China Architecture and Building Press, 2007. (in Chinese)) [3] DHEERENDRA BABU M R, SITARAM Nayak, SHIVASHANKAR R. A critical review of construction, analysis and behaviour of stone columns[J]. Geotech Geol Eng, 2013, 31: 1-22. [4] RAITHEL M, KEMPFERT H G, KIRCHNER A. Gotextile-encased columns (GEC) for foundation of a dike on very soft soils[C]// Proc 7th Int Conf on Geosynthetics. Nice, 1025-1028. [5] VAN IMPE W F. Soil improvement techniques and their evolution[M]. Rotterdam: Balkema, 1989. [6] MURUGESAN S, RAJAGOPAL K. Studies on the behavior of single and group of geosynthetic encased stone columns[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2010, 136(1): 129-139. [7] MAHMOUD G, JAVAD NAZARI Afshar. Bearing capacity of geosynthetic encased stone columns[J]. Geotextiles and Geomembranes, 2013, 38: 26-36. [8] 徐 挺. 相似理论与模型试验[M]. 北京: 中国农业机械出版社, 1982. (XU Ting. Similarity theory and model test[M]. Beijing: Chinese Agricultural Machine Press, 1982. (in Chinese)) [9] 湖南大学. 散体材料桩鼓胀量测试仪:中国, ZL 200810143670.3[P]. 2008. (Hunan University. Ballooning tester of granular column: China, ZL 200810143670.3[P]. 2008. (in Chinese)) [10] GB/T 17689—2008 土工合成材料—塑料土工格栅[S]. 北京: 中国标准出版社, 2008. (GB/T 17689—2008 Geosynthetics—Plastic geogrids[S]. Beijing: Standard Press of China, 2008. (in Chinese))
