偏压固结下饱和标准砂孔压增量分析
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摘要
通过对饱和福建标准砂动三轴液化试验现象的系统分析,提出了一个偏压固结下孔压增量计算公式。分析表明,固结比对饱和砂土液化有重要影响,孔压相对增量与固结比增量之间呈幂函数关系,即ΔU/U0=C1,a(kc-1)C1,b。C1,b是一个远小于1的数,平均为0.41,表明孔压增量在kc接近1时降低速度较快,在kc继续增大时降低速度变慢并趋于平缓。C1,a在0.20-0.35之间,平均为0.27,意味着kc=2时的孔压增量较kc=1时降低20%~35%,平均降低27%。
A new incremental formula for evaluating the pore pressure of the saturated sand under the deviatoric stress consolidation is presented by analyzing the dynamic triaxial tests of the Fujian standard sand.The test results indicate that the consolidation ratio has remarkable influence on the pore pressure rise and the relation between the relative increment of the pore pressure and the increment of the consolidation ratio is in the power function form,(i.e.,) ΔU/U_0=C_(1,a)(k_c-1)~(C_(1,b)),in which C_(1,b) is much less than 1 and equal to 0.41 on an average.It means that the pore pressure increment decreases rapidly in the beginning and then slows down.C_(1,a) is 0.25~0.35,and 0.27 on an average.This indicates that the pore pressure for k_(c)=2 is less by 20%~35% than that for k_(c)=1 and is by 27% reduction on an average.
A new incremental formula for evaluating the pore pressure of the saturated sand under the deviatoric stress consolidation is presented by analyzing the dynamic triaxial tests of the Fujian standard sand.The test results indicate that the consolidation ratio has remarkable influence on the pore pressure rise and the relation between the relative increment of the pore pressure and the increment of the consolidation ratio is in the power function form,(i.e.,) ΔU/U_0=C_(1,a)(k_c-1)~(C_(1,b)),in which C_(1,b) is much less than 1 and equal to 0.41 on an average.It means that the pore pressure increment decreases rapidly in the beginning and then slows down.C_(1,a) is 0.25~0.35,and 0.27 on an average.This indicates that the pore pressure for k_(c)=2 is less by 20%~35% than that for k_(c)=1 and is by 27% reduction on an average.
引文
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[8]孙锐,袁晓铭,韩俊伟,等.全自动地震波输入动三轴装置指标和功能测试[J].地震工程与工程振动,2002,22(3):100~105.
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[2]Ish ibash i I,SherifM A,Tsuch iya C.Pore-pressure rise m echan ism and soil liquefaction[J].Soils and Foundations,1977,17(2):17~27.
[3]魏汝龙.往复荷载下饱和砂土的抗液化强度和孔隙水压力[R].南京水利科学研究所,1978.1~6.
[4]何广讷.砂土振动孔隙水压力的研究[J].水利学报,1987,(3):58~63.
[5]F inn W D L,Bnatia S K.Pred iction of seism ic pore water pressures.Proc.10thint.Conf.on SoilM ech.and Found.Eng[C].Balkema,1981.213~219.
[6]徐志英,沈珠江.地震液化的有效应力二维动力分析方法[J].华东水利学院学报,1981,(3):1~13.
[7]王天颂,刘颖.饱和砂层抗震稳定分析的孔隙水压力方法[J].地震工程与工程振动,1987,7(3):73~83.
[8]孙锐,袁晓铭,韩俊伟,等.全自动地震波输入动三轴装置指标和功能测试[J].地震工程与工程振动,2002,22(3):100~105.
[9]丰万玲,石兆吉.判别水平土层液化势的孔隙水压力分析方法[J].工程抗震,1988,(4):30~33.
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