非均等固结下饱和砂土孔压增量简化计算公式
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摘要
通过动三轴液化试验,提出了一个新的适用于非均等固结下饱和砂土孔压的增量型简化计算公式。首先,试验和分析表明,描述非均等固结对饱和砂土液化影响较为合适的方式是以kc-1的幂函数模式,建立非均等固结下孔压变化的相对增量?U/U 0与固结比的增量kc-1之间的关系,即?U/U 0=1,bC1,a(kc?1)C。系数C1,b是一个远小于1的数,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,而若采用kc幂函数,在1正弦荷载作用时不同固结比下饱和砂土的孔压增长,而且也能较好地描述随机地震荷载作用时非均等固结下饱和砂土的孔压增长过程。
A new simplified incremental formula for evaluating the pore pressure of the saturated sands under the anisotropic consolidation was presented by using the dynamic triaxial tests.First,the test results indicated that the suitable form for describing the variation of the pore pressure due to the anisotropic consolidation was to use the power function of kc-1 to establish the relation between the relative increment of the pore pressure,?U/U 0,and the increment of the consolidation ratio,kc-1,i.e.,?U/U 0 =1,bC1,a(kc ?1)C.The coefficient C1,b was far away from 1,meaning that the pore pressure increment decreased rapidly when kc was near 1 and then decreased slowly.The power function of kc could not simulate the situation because in this case,the pore pressure increment was in nearly direct proportion to kc within 1
A new simplified incremental formula for evaluating the pore pressure of the saturated sands under the anisotropic consolidation was presented by using the dynamic triaxial tests.First,the test results indicated that the suitable form for describing the variation of the pore pressure due to the anisotropic consolidation was to use the power function of kc-1 to establish the relation between the relative increment of the pore pressure,?U/U 0,and the increment of the consolidation ratio,kc-1,i.e.,?U/U 0 =1,bC1,a(kc ?1)C.The coefficient C1,b was far away from 1,meaning that the pore pressure increment decreased rapidly when kc was near 1 and then decreased slowly.The power function of kc could not simulate the situation because in this case,the pore pressure increment was in nearly direct proportion to kc within 1
引文
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[5]Finn,W D L,Bnatia S K.Prediction of seismic pore water pressures[A].Proc,10th Int.Conf on Soil Mech and Found Eng[C].1981:213–219.
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[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]Sherif M A et,al.Pore-pressure prediction during earthquake loadings[J].Soil and Foundations.1978,18(4):19–30.
[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.
[10]孙锐,袁晓铭,韩俊伟,赵惠,张尚盈.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,(3):100–105.
[11]谢定义.土动力学[M].西安:西安交通大学出版社,1988:251-289.
[12]袁晓铭,孟上九,孙锐.随机地震荷载下粘性土残余应变的半经验计算公式[J].水利学报,2004,(11):59–65.
[2]Ishibashi I,Sherif M A,Tsuchiya C.Pore-pressure rise mechanism 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:南京水利科学研究所,1978.
[4]何广讷.砂土振动孔隙水压力的研究[R].大连:大连工学院学报,1983.
[5]Finn,W D L,Bnatia S K.Prediction of seismic pore water pressures[A].Proc,10th Int.Conf on Soil Mech and Found Eng[C].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]Sherif M A et,al.Pore-pressure prediction during earthquake loadings[J].Soil and Foundations.1978,18(4):19–30.
[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.
[10]孙锐,袁晓铭,韩俊伟,赵惠,张尚盈.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,(3):100–105.
[11]谢定义.土动力学[M].西安:西安交通大学出版社,1988:251-289.
[12]袁晓铭,孟上九,孙锐.随机地震荷载下粘性土残余应变的半经验计算公式[J].水利学报,2004,(11):59–65.
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