1.长安大学建筑工程学院,陕西 西安 710064
2.中国科学院武汉岩土力学研究所 / 岩土力学与工程国家重点实验室,湖北 武汉 430071
3.中铁大桥勘测设计院集团有限公司,湖北 武汉 430050
4.武汉轻工大学土木工程与建筑学院,湖北 武汉 430023
5.中国科学院大学,北京 100049
刘帅(1996年生),男;研究方向:土体动力特性;E-mail:ls128057@163.com
黄珏皓(1991年生),男;研究方向:软土动力特性和本构关系;E-mail:jhhuang@whrsm.ac.cn
纸质出版日期:2023-07-25,
网络出版日期:2023-05-06,
收稿日期:2022-11-01,
录用日期:2022-12-08
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刘帅,高志华,胡波等.变围压循环荷载作用下珠江三角洲软土动力特性试验研究[J].中山大学学报(自然科学版),2023,62(04):131-138.
LIU Shuai,GAO Zhihua,HU Bo,et al.Experimental study on dynamic characteristics of soft soil in Pearl River Delta under cyclic confining pressure[J].Acta Scientiarum Naturalium Universitatis Sunyatseni,2023,62(04):131-138.
刘帅,高志华,胡波等.变围压循环荷载作用下珠江三角洲软土动力特性试验研究[J].中山大学学报(自然科学版),2023,62(04):131-138. DOI: 10.13471/j.cnki.acta.snus.2022D082.
LIU Shuai,GAO Zhihua,HU Bo,et al.Experimental study on dynamic characteristics of soft soil in Pearl River Delta under cyclic confining pressure[J].Acta Scientiarum Naturalium Universitatis Sunyatseni,2023,62(04):131-138. DOI: 10.13471/j.cnki.acta.snus.2022D082.
列车循环荷载作用下软土地基产生较大沉降。以往动三轴试验模拟列车循环荷载时主要分析循环偏应力对软土动力特性的影响,而较少考虑循环围压的作用。基于此,采用GDS动三轴试验系统对珠江入海口饱和软土开展了一系列不排水变围压循环三轴试验,分析循环偏应力和循环围压耦合效应对饱和软土累积轴向应变、孔压以及阻尼比的影响。结果表明:累积轴向应变和归一化阻尼比随循环围压的增大而减小,最大孔压和最小孔压均随循环围压的增大而增大。当循环加载次数
N
=1 000,应力路径斜率
η
=0.33增长至
η
=1.00、2.00时,累积轴向应变
ε
p
=4.04%下降至
ε
p
=3.52%、2.45%,归一化阻尼比
λ
N
/
λ
1
=0.253相应变化为
λ
N
/
λ
1
=0.269、0.217,最大孔压由
u
max
= 60.55 kPa分别增长至
u
max
=79.25和104.51 kPa,最小孔压由
u
min
= 58.69 kPa分别增长至
u
min
=71.12 和80.90 kPa。在此基础上,建立了饱和软土累积轴向应变计算模型,并进行了验证。
Large settlements of soft soil foundation occur under cyclic loading. The influence of cyclic deviatoric stress on the dynamic characteristics of soft soil has been previously analyzed using dynamic triaxial tests, while the effect of cyclic confining pressure has rarely been considered. In this study, a series of undrained dynamic triaxial tests with variable confining pressure were conducted for saturated soft soil from the Pearl River Delta using GDS dynamic triaxial test system. The coupling effects of cyclic deviatoric stress and confining pressure on the cumulative axial strain, pore pressure, and damping ratio were analyzed. The results show that the cumulative axial strain and normalized damping ratio decrease with the increase of the cyclic confining pressure, while the maximum and minimum pore pressures increase with the increase of the cyclic confining pressure. When the number of cycles
N
=1 000 and the stress path
η
increased from 0.33 to 1.00 and 2.00, the accumulated axial strain
ε
p
decreased from 4.04% to 3.52% and 2.45%, the normalized damping ratio
λ
N
/
λ
1
from 0.253 to 0.269 and 0.217, the maximum pore pressure
u
max
increased from 60.55 kPa to 79.25 kPa and 104.51 kPa, and the minimum pore pressure
u
min
increased from 58.69 kPa to 71.12 kPa and 80.90 kPa. Furthermore, a model for predicting the accumulated axial strain of saturated soft soil is established and verified. These results are helpful to deepen the understanding of the mechanical properties of soft clay under cyclic loading.
软土动三轴试验累积轴向应变孔压阻尼比珠江三角洲
soft soildynamic triaxial testaccumulated axial strainexcess pore water pressuredamping ratiothe Pearl River Delta
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