不同应力水平下结构性黏土动力特性试验研究
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摘要
对天津滨海地区典型结构性软黏土进行了压缩试验和不同固结应力下的循环三轴试验。结果表明:结构性软黏土的静力变形特性以先期固结应力和结构屈服应力为分界点可分为3个阶段;不同固结应力下的动应变-振次关系曲线上存在着一个临界动应力比,且该值随着围压的增大而降低;孔隙水压力的变化以结构屈服应力为转折点呈现出不同的变化规律;当振动频率为2Hz时固结应力的改变对轴向动应变的影响不明显。
A series of compression tests and cyclic triaxial shear tests under different consolidation stress are performed on the typical structural soft soil in Binhai region of Tianjin,which reveals the law of cyclic deformation under dynamic loading.The results show that the static deformation of structural soft clay can be divided into three parts by preconsolidation stress and structural yield stress.The relation curves of cyclic strain with cycle number under different consolidation stress has a critical dynamic stress ratio,which is not a fixed value,but reduces as the pressure increases.The changes of pore water pressure show different variation law taking the structural yield stress as a turning point.When vibrating frequency is 2 Hz,the influence of different consolidation stress on the dynamic strain is so little.
A series of compression tests and cyclic triaxial shear tests under different consolidation stress are performed on the typical structural soft soil in Binhai region of Tianjin,which reveals the law of cyclic deformation under dynamic loading.The results show that the static deformation of structural soft clay can be divided into three parts by preconsolidation stress and structural yield stress.The relation curves of cyclic strain with cycle number under different consolidation stress has a critical dynamic stress ratio,which is not a fixed value,but reduces as the pressure increases.The changes of pore water pressure show different variation law taking the structural yield stress as a turning point.When vibrating frequency is 2 Hz,the influence of different consolidation stress on the dynamic strain is so little.
引文
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[2]Behzadi G,Yandell W O.Determination of elastic and plasticsubgrade soil parameters for asphalt cracking and rutting pre-diction[J].Transportation Research Record,1996,1540:97-104.
[3]王建荣,张振中,王峻,等.振动频率对原状黄土动本构关系的影响[J].北地震学报,1999,21(3):310-314.
[4]周建.循环荷载作用下饱和软粘土的孔压模型[J].工程勘察,2000,(4):7-9.
[5]钟辉虹,黄茂松,吴世明,等.循环荷载作用下软黏土变形特性研究[J].土工程学报,2002,24(5):629-632.
[6]Sakai A,Samang L,Miura N.Partially-drained cyclic behav-ior and its application to the settlement of a low embankmentroad on silty-clay[J].Soils and Foundations,2003,43(1):33-46.
[7]顾中华,高广运.循环荷载下饱和粘土强度等效计算探讨[J].西北地震学报,2005,27(1):13-16.
[8]黄茂松,李进军,李兴照,等.饱和软粘土的不排水循环累积变形特性[J].岩土工程学报,2006,28(7):891-895.
[9]沈珠江.软土工程特性和软土地基设计[J].岩土工程学报,1998,20(1):100-111.
[10]何开胜,沈珠江.天然沉积粘土的结构性调查[J].东南大学学报(自然科学版),2002,32(5):818-822.
[11]刘恩龙,沈珠江.不同应力路径下结构性土的力学特性[J].岩石力学与工程学报,2006,25(10):2058-2064.
[12]郝玉龙,王立忠,陈云敏,等.深厚软土水泥搅拌桩复合地基沉降分析及控制[J].岩土工程学报,2001,23(3):345-349.
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