原位十字板试验评价上海软黏土灵敏性的可靠性
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摘要
详细分析了上海某工程勘察数据以及相关文献资料,发现FVT试验得到的灵敏度要明显小于UCT试验结果,因而会不同程度地低估上海地区各软黏土层的灵敏度。进一步研究表明,十字板重塑方式(而不是手工重塑)是造成FVT试验得到重塑土强度过高因而灵敏度偏低的主要原因,而这两种试验采用的试验方法以及原位应力对灵敏度测试结果的影响并不大。这种现象应引起工程界的重视以便正确评价我国沿海地区广泛分布的海相沉积软黏土的结构性和灵敏性。
The geotechnical investigation data from a real project in Shanghai as well as other relevant published data are analyzed. It is found that the sensitivity obtained by the FVT test is significantly smaller than the results of the unconfined compression test(UCT). Thus the sensitivity of soft clay will be underestimated by FVT. The vane-shear remolding method(not the artifical remolding method) makes the FVT obtain much higher remolded strength and therefore the lower sensitivity than UCT. The influences of test methods and in-situ stress state can be neglected. It is pointed out that much attention should be paid to this phenomenon in order to properly evaluate the sensitivity of the marine soft clay distributed in the coastal areas of China.
The geotechnical investigation data from a real project in Shanghai as well as other relevant published data are analyzed. It is found that the sensitivity obtained by the FVT test is significantly smaller than the results of the unconfined compression test(UCT). Thus the sensitivity of soft clay will be underestimated by FVT. The vane-shear remolding method(not the artifical remolding method) makes the FVT obtain much higher remolded strength and therefore the lower sensitivity than UCT. The influences of test methods and in-situ stress state can be neglected. It is pointed out that much attention should be paid to this phenomenon in order to properly evaluate the sensitivity of the marine soft clay distributed in the coastal areas of China.
引文
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[2]JGJ83—2011软土地区岩土工程勘察规程[S].北京:中国建筑工业出版社,2011.(JGJ83—2011 Specification for geotechnical investigation in soft clay area[S].Beijing:Chinese building industry press,2011.(in Chinese))
[3]SKEMPTON A W,NORTHEY R D.The sensitivity of clays[J].Geotechnical,1952,3(1):30–53.
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[7]李鹏娥.闽南地区软黏土灵敏度试验及分析[J].华侨大学学报(自然科学版),2006,27(1):61–63.(LI Peng-e.Test and analysis of the soft clay sensitivity in south Fujian Province[J].Journal of Huaqiao University:Natural Science,2006,27(1):61–63.(in Chinese))
[8]娄炎,何宁,娄斌.高速公路深厚软基工后沉降控制成套技术[M].北京:人民交通出版社,2011:1–329.(LOU Yan,HE Ning,LOU Bin.Monitor and control method of settlement and deformation for soft foundation in expressway[M].Beijing:China Communications Press,2011:1–329.(in Chinese))
[9]DGJ08—37—2012上海市工程建设规范岩土工程勘察规范[S].2012.(GJ08—37—2012 Code for investigation of geotechnical engineering[S].2012.(in Chinese))
[10]GB/T50123—1999土工试验方法标准[S].1999.(GB/T50123—1999 Standard for soil test method[S].1999.(in Chinese))
[11]高彦斌,鲍文鹏,楼康明.上海地区第4层淤泥质黏土灵敏性试验与分析[J].同济大学学报(自然科学版),2015,43(1):140–145.(GAO Yan-bin,BAO Wen-peng,LOU Kang-ming.Sensitive test and analysis of the No.4 Muddy Silty Clay in Shanghai[J].Journal of Tongji university(Natural Science),2015,43(1):140–145.(in Chinese))
[12]CHANEY R C,RICHARDSON G N.Measurement of residual/remolded vane shear strength of marine sediments[C]//International Symposium on Laboratory and Field Vane Shear Strength Testing,Tampa,Fla.1987:166–181.
[13]TANAKA Hiroyuki,HIRABAYASHI Hiroshi,MATSUOKA Tatsuya,et al.Use of fall cone test as measurement of shear strength for soft clay materials[J].Soils and Foundations,2012,52(4):590–599.
[2]JGJ83—2011软土地区岩土工程勘察规程[S].北京:中国建筑工业出版社,2011.(JGJ83—2011 Specification for geotechnical investigation in soft clay area[S].Beijing:Chinese building industry press,2011.(in Chinese))
[3]SKEMPTON A W,NORTHEY R D.The sensitivity of clays[J].Geotechnical,1952,3(1):30–53.
[4]钱征.天津新港软土的一些工程特性.天津软土地基[M].天津:天津科学技术出版社,1987.(QIAN Zheng.Engineering properties of soft soils in Tianjin new port[M].Tianjin:Tianjin Science and Technology Press,1987.(in Chinese))
[5]樊向阳,顾国荣,黄宏伟.上海地区土体灵敏度的研究[J].岩土工程技术,2004,18(3):130–132.(FAN Xiang-yang,GU Guo-rong,HUANG Hong-wei.Study on soil sensitivity in shanghai region[J].Geotechnical Engineering Technique,2004,18(3):130–132.(in Chinese))
[6]缪林昌,经绯.江苏海相灵敏性软土特征研究[J].岩土力学,2006,27(8):1283–1286.(MIAO Lin-chang,JING Fei.Features research of Jiangsu marine sensitive soft soils[J].Rock and Soil Mechanics,2006,27(8):1283–1286.(in Chinese))
[7]李鹏娥.闽南地区软黏土灵敏度试验及分析[J].华侨大学学报(自然科学版),2006,27(1):61–63.(LI Peng-e.Test and analysis of the soft clay sensitivity in south Fujian Province[J].Journal of Huaqiao University:Natural Science,2006,27(1):61–63.(in Chinese))
[8]娄炎,何宁,娄斌.高速公路深厚软基工后沉降控制成套技术[M].北京:人民交通出版社,2011:1–329.(LOU Yan,HE Ning,LOU Bin.Monitor and control method of settlement and deformation for soft foundation in expressway[M].Beijing:China Communications Press,2011:1–329.(in Chinese))
[9]DGJ08—37—2012上海市工程建设规范岩土工程勘察规范[S].2012.(GJ08—37—2012 Code for investigation of geotechnical engineering[S].2012.(in Chinese))
[10]GB/T50123—1999土工试验方法标准[S].1999.(GB/T50123—1999 Standard for soil test method[S].1999.(in Chinese))
[11]高彦斌,鲍文鹏,楼康明.上海地区第4层淤泥质黏土灵敏性试验与分析[J].同济大学学报(自然科学版),2015,43(1):140–145.(GAO Yan-bin,BAO Wen-peng,LOU Kang-ming.Sensitive test and analysis of the No.4 Muddy Silty Clay in Shanghai[J].Journal of Tongji university(Natural Science),2015,43(1):140–145.(in Chinese))
[12]CHANEY R C,RICHARDSON G N.Measurement of residual/remolded vane shear strength of marine sediments[C]//International Symposium on Laboratory and Field Vane Shear Strength Testing,Tampa,Fla.1987:166–181.
[13]TANAKA Hiroyuki,HIRABAYASHI Hiroshi,MATSUOKA Tatsuya,et al.Use of fall cone test as measurement of shear strength for soft clay materials[J].Soils and Foundations,2012,52(4):590–599.