贵阳红黏土固结排水孔隙水压力消散归一化分析
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摘要
孔隙水压力的发展规律是应用有效应力原理研究土体变形和强度变化的重要因素。通过贵阳红黏土的固结试验和三轴试验,分析了所取土样的固结状态和该状态下固结过程中孔隙水压力的消散规律。试样结果表明:所取贵阳红黏土的超固结度OCR为5.8,属超固结土;三轴固结过程中,不同围压下的孔隙水压力均随时间的增加逐渐消散至零,消散速率逐渐减小。围压越大,消散速率越大,最后趋于平稳。引入消散度的概念对其进行归一化后,不同围压下U-t曲线几乎重合,用最小二乘法拟合后的函数表达式呈指数函数关系。
The law of development of pore water pressure is an important factor in the use of effective stress principle study soil deformation and intensity change. Through consolidation test and triaxial test on Guiyang red clay,consolidated state and dissipation of pore water pressure during consolidation was analyzed. The results show that OCR of taken Guiyang red clay are 5.8,belonging to over-consolidated earth. Pore water pressures under different confining pressures are gradually dissipate to zero with the time in triaxial consolidation process,disappearance rate were decreased. The bigger confining pressure,the greater dissipation rate are,and finally leveled off. With U-t curve under different confining pressures after normalized by introducing the concept of dissipation,the function expression are exponential coincided with a least squares.
The law of development of pore water pressure is an important factor in the use of effective stress principle study soil deformation and intensity change. Through consolidation test and triaxial test on Guiyang red clay,consolidated state and dissipation of pore water pressure during consolidation was analyzed. The results show that OCR of taken Guiyang red clay are 5.8,belonging to over-consolidated earth. Pore water pressures under different confining pressures are gradually dissipate to zero with the time in triaxial consolidation process,disappearance rate were decreased. The bigger confining pressure,the greater dissipation rate are,and finally leveled off. With U-t curve under different confining pressures after normalized by introducing the concept of dissipation,the function expression are exponential coincided with a least squares.
引文
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[2]Skempton.A.W.The Pore-pressures Coefficient A and B[J].Geotechnique,1954,14(4):143-147.
[3]Henkel.D.J..The Shear Strength of Saturated Remoulded Clays[C]//Colorado:Proc.Res.Conf.Shear Strength of Cohesive Soils,1960.
[4]Butterfield R.A nature compression law for soils[J].Geotechnique,1979,29(4):469-480.
[5]Hong Z,Onitsuka K.A method of correcting yield stress and compression index of Ariake clays for sample disturbance[J].Soils and Foundations,1998,38(2):211-222.
[6]SL237-1999,土工试验规程[S].北京:中国水利水电出版社,1999.
[7]李晓静,李术才,姚凯,等.黄泛区路基强夯时超孔隙水压力变化规律试验研究[J].岩土力学,2011,32(9):2815-2820.
[8]张民选,罗贤兵.数值分析[M].南京:南京大学出版社,2013.