摘要
选取杭州城东地铁5号线隧道周边的典型饱和粉土进行不同卸荷应力路径下的静力三轴试验,研究在临近基坑施工情况下地铁隧道周边影响范围内该类土体静力特性的变化情况,并通过加装压电陶瓷弯曲元装置进行弯曲元试验,从而探寻不同卸荷应力路径对土体抗剪强度和变形的影响程度。研究结果表明:土体的抗剪强度指标会随着轴向及侧向卸荷强度的增大而呈现不同幅度的减小,在轴向卸荷应力路径下饱和粉土各静力特性指标变化幅度小于侧向卸荷应力路径下的变化幅度,但在卸荷再加荷应力路径下,轴向应力路径与侧向应力路径的变化对饱和粉土的抗剪强度的影响并不明显。同时,土体抗剪强度与剪切波速之间可以用模型拟合来建立关系,在实际的卸荷工程中对准确获取土体力学参数有实际意义。
The typical saturated silt surrounding the tunnel of Metro Line 5 in the east of Hangzhou is selected,the static triaxial tests under dfferent unloading stress path are carried out,the variation of the static characteristics of this kind of soil in the influence area around the subway tunnel under different excavation conditions near the foundation pit is studied.The bending element tests are carried out by adding piezoelectric ceramic bending element device to explore the influence of different unloading stress paths on the shear strength and deformation of soil.The study results show that the shear strength indexes of soil will differently decrease with the increases of the axial and lateral unloading strength,and the variation range of the static characteristics of saturated silt under the axial unloading stress path is less than that under the lateral unloading stress path,but the influences of the axial and lateral stress path on the shear strength of saturated silt are not obvious under the unloading and reloading stress path.At the same time,the relationship between the shear strength and shear wave velocity of the soil can be established by using model fitting,which has practical guiding significance to accurately obtain soil mechanical parameters in actual unloading engineering.
作者
孟凡丽
王逸晨
汤鄢
王小刀
Meng Fanli;Wang Yichen;Tang Yan;Wang Xiaodao(College of Civil Engineering,Zhejiang University of Technology,Hangzhou 310027,China;Zhejiang East China Construction Engineering Co.,Ltd,Hangzhou 310014,China)
出处
《工程勘察》
2023年第8期33-40,共8页
Geotechnical Investigation & Surveying
关键词
轴向卸荷
侧向卸荷
卸荷强度
应力路径
静力特性
axial unloading
lateral unloading
unloading strength
stress path
static characteristics
