饱和击实黄土的动力特性研究
|
摘要
通过进行不同固结条件下饱和击实黄土的动三轴试验,研究了饱和击实黄土的动模量、阻尼比、动强度、动孔压及抗液化特性。研究结果表明:饱和击实黄土的动应力-应变关系符合双曲线模型,模型中参数起始动剪切模量和最大动应力与轴向固结应力间均有良好的幂函数关系,且可以对不同固结应力状态归一,固结围压和固结比对阻尼比的影响较小。动剪应力比随固结围压的增大而减小,随固结比的增大而增大。固结围压、固结比以及动应力皆对动孔压比(u/σm)与振次比关系有显著的影响,而动孔压与破坏时动孔压之比与振次比关系只受固结围压变化的影响,基本上不受固结比和动应力变化的影响,可以用幂函数关系来模拟;在均压固结条件下,当破坏振次小于等于30时,饱和击实黄土不会产生液化,而当破坏振次较大(动应力较小)时可以产生液化;在偏压固结条件下不会产生液化。
Some dynamic characteristics such as shear modulus,damping,strength,pore water pressure and liquefaction are studies by dynamic triaxial tests on saturated compacted loess under different consolidation stress conditions.It is indicated that from test results,the relation between dynamic stress and strain can be fitted with hyperbola,power correlations between its two parameters containing the maximum dynamic shear modulus and the maximum dynamic shear stress and consolidation axial stress are obtained and normalized under different consolidation stress conditions.Damping ratio is almost independent of consolidation confining stress and consolidation ratio.Dynamic shear stress ratio increases with the increase of consolidation ratio,it decreases with the increase of consolidation confining stress.Relation between dynamic pore water pressure ratio u /σ m and cyclic number ratio is dependent on consolidation confining pressure and consolidation ratio as well as dynamic stress.Relation between ratio of dynamic pore water pressure and cyclic number ratio at vibrating process and failure is only dependent on consolidation confining stress,which is independent on consolidation confining stress and dynamic stress,and can be fitted by power function.The saturated compacted loess can produce liquefaction when failure cyclic number is larger than 30 under isotropic consolidation stress condition and can not produce liquefaction under anisotropic consolidation stress condition.
Some dynamic characteristics such as shear modulus,damping,strength,pore water pressure and liquefaction are studies by dynamic triaxial tests on saturated compacted loess under different consolidation stress conditions.It is indicated that from test results,the relation between dynamic stress and strain can be fitted with hyperbola,power correlations between its two parameters containing the maximum dynamic shear modulus and the maximum dynamic shear stress and consolidation axial stress are obtained and normalized under different consolidation stress conditions.Damping ratio is almost independent of consolidation confining stress and consolidation ratio.Dynamic shear stress ratio increases with the increase of consolidation ratio,it decreases with the increase of consolidation confining stress.Relation between dynamic pore water pressure ratio u /σ m and cyclic number ratio is dependent on consolidation confining pressure and consolidation ratio as well as dynamic stress.Relation between ratio of dynamic pore water pressure and cyclic number ratio at vibrating process and failure is only dependent on consolidation confining stress,which is independent on consolidation confining stress and dynamic stress,and can be fitted by power function.The saturated compacted loess can produce liquefaction when failure cyclic number is larger than 30 under isotropic consolidation stress condition and can not produce liquefaction under anisotropic consolidation stress condition.
引文
[1]谢定义.试论我国黄土力学研究中的若干新趋向[J].岩土工程学报,2001,23(1):3―13.XIE Ding-yi.Exploration of some new tendencies in research of loess soil mechanics[J].Chinese Journal of Geotechnical Engineering,2001,23(1):3―13.
[2]巫志辉,谢定义,余雄飞.洛川黄土动变形强度特性的研究[J].水利学报,1994,(12):67―71.WU Zhi-hui,XIE Ding-yi,YU Xiong-fei.Study on dynamic deformation and density characteristics of Luochuan loess[J].Journal of Hydraulic Engineering,1994,(12):67―71.
[3]佘跃心,刘汉龙,高玉峰.饱和黄土孔压增长模式与液化机理试验研究[J].岩土力学,2002,23(4):395―399.SHE Yue-xin,LIU Han-long,GAO Yu-feng.Study on liquefaction mechanism and pore-water pressure mode of saturated original loess[J].Rock and Soil Mechanics,2002,23(4):395―399.
[4]骆亚生,田勘良.非饱和黄土的动剪模量与阻尼比[J].水利学报,2005,36(7):830―834.LUO Ya-sheng,TIAN Kan-liang.Dynamic shear modulus and damping ratio of unsaturated loess[J].Journal of Hydraulic Engineering,2005,36(7):830―834.
[5]王兰民,刘红玫,李兰,等.饱和黄土液化机理与特性的试验研究[J].岩土工程学报,2000,22(1):31―36.WANG Lan-min,LIU Hong-mei,LI Lan,et al.Laboratory study on the mechanism and behaviors of saturated loess liquefaxtion[J].Chinese Journal of Geotechnical Engineering,2000,22(1):31―36.
[6]佘跃心,刘汉龙,高玉峰,等.击实黄土孔压增长及循环软化特性试验研究[J].西北地震学报,2002,24(2):123―128.SHE Yue-xin,LIU Han-long,GAO Yu-feng,et al.Study on pore pressure mode and cyclic softening of saturated compacted loess[J].Northwest Seismological Journal,2002,24(2):123―128.
[7]杨振茂,赵成刚,王兰民.饱和黄土液化的试验研究[J].岩石力学与工程学报,2005,24(5):864―871.YANG Zhen-mao,ZHAO Cheng-gang,WANG Lan-min.Testing study on saturated loess liquefaction[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(5):864―871.
[8]Seed H B,et al.Powerwater pressure changes during soil liquefaction[J].Journal of Geotechnical Engineering Division,ASCE,1976,102(GT4):327―346.
[9]张建民,谢定义.饱和砂土振动孔隙水压力增长的实用算法[J].水利学报,1991,(8):45―51.ZHANG Jian-min,XIE Ding-yi.Practical calculation of dynamic pore water pressure in saturated sand[J].Journal of Hydraulic Engineering,1991,(8):45―51.
[10]于濂洪,王波.饱和粉土振动孔隙水压力的试验研究[J].大连大学学报,1999,20(4):59―62.YU Lian-hong,WANG Bo.Study on pore water pressure of saturated and disturbed sandy loam during cyclic loading[J].Journal of Dalian University,1999,20(4):59―62.
[11]SL237―1999,土工试验规程[S].
[2]巫志辉,谢定义,余雄飞.洛川黄土动变形强度特性的研究[J].水利学报,1994,(12):67―71.WU Zhi-hui,XIE Ding-yi,YU Xiong-fei.Study on dynamic deformation and density characteristics of Luochuan loess[J].Journal of Hydraulic Engineering,1994,(12):67―71.
[3]佘跃心,刘汉龙,高玉峰.饱和黄土孔压增长模式与液化机理试验研究[J].岩土力学,2002,23(4):395―399.SHE Yue-xin,LIU Han-long,GAO Yu-feng.Study on liquefaction mechanism and pore-water pressure mode of saturated original loess[J].Rock and Soil Mechanics,2002,23(4):395―399.
[4]骆亚生,田勘良.非饱和黄土的动剪模量与阻尼比[J].水利学报,2005,36(7):830―834.LUO Ya-sheng,TIAN Kan-liang.Dynamic shear modulus and damping ratio of unsaturated loess[J].Journal of Hydraulic Engineering,2005,36(7):830―834.
[5]王兰民,刘红玫,李兰,等.饱和黄土液化机理与特性的试验研究[J].岩土工程学报,2000,22(1):31―36.WANG Lan-min,LIU Hong-mei,LI Lan,et al.Laboratory study on the mechanism and behaviors of saturated loess liquefaxtion[J].Chinese Journal of Geotechnical Engineering,2000,22(1):31―36.
[6]佘跃心,刘汉龙,高玉峰,等.击实黄土孔压增长及循环软化特性试验研究[J].西北地震学报,2002,24(2):123―128.SHE Yue-xin,LIU Han-long,GAO Yu-feng,et al.Study on pore pressure mode and cyclic softening of saturated compacted loess[J].Northwest Seismological Journal,2002,24(2):123―128.
[7]杨振茂,赵成刚,王兰民.饱和黄土液化的试验研究[J].岩石力学与工程学报,2005,24(5):864―871.YANG Zhen-mao,ZHAO Cheng-gang,WANG Lan-min.Testing study on saturated loess liquefaction[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(5):864―871.
[8]Seed H B,et al.Powerwater pressure changes during soil liquefaction[J].Journal of Geotechnical Engineering Division,ASCE,1976,102(GT4):327―346.
[9]张建民,谢定义.饱和砂土振动孔隙水压力增长的实用算法[J].水利学报,1991,(8):45―51.ZHANG Jian-min,XIE Ding-yi.Practical calculation of dynamic pore water pressure in saturated sand[J].Journal of Hydraulic Engineering,1991,(8):45―51.
[10]于濂洪,王波.饱和粉土振动孔隙水压力的试验研究[J].大连大学学报,1999,20(4):59―62.YU Lian-hong,WANG Bo.Study on pore water pressure of saturated and disturbed sandy loam during cyclic loading[J].Journal of Dalian University,1999,20(4):59―62.
[11]SL237―1999,土工试验规程[S].
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心