循环荷载下徐州饱和粉砂土孔隙水压力特征试验研究
Experimental study on pore water pressure characteristics of saturated silty sand in Xuzhou under cyclic loading
曹国旭 1张璞 1蔺云宏1
作者信息
- 1. 广州地铁设计研究院股份有限公司,广东 广州 510000
- 折叠
摘要
为研究徐州地区饱和粉砂土在地铁列车振动、地震等循环荷载作用下孔隙水压力的变化规律,采用GDS空心圆柱扭剪仪对徐州地铁 3 号线区间隧道底部的饱和粉砂土进行了动三轴试验,考虑了不同振动频率、有效围压、循环应力比和固结比对粉砂土孔隙水压力变化的影响.试验结果表明,徐州地区饱和粉砂土的孔隙水压力变化规律主要表现为S型曲线和双曲线.在较低动荷载比、较低固结比、较低频率时,孔隙水压力变化规律为S型曲线;在较高动荷载比、较高固结比、较高频率时,孔隙水压力变化规律为双曲线型.针对孔隙水压力变化规律,修正了孔隙水压力增长模型,对参数进行了拟合标定,为徐州市域范围内的地铁隧道饱和粉砂土地基孔隙水压力变化预测提供参考依据.
Abstract
In order to obtain the development of pore water pressure of saturated silty sand in Xuzhou area under cyclic loading such as subway train vibrations and earthquakes,a series of dynamic triaxial tests were conducted using the GDS hollow cylindrical torsion shear instrument.These tests focused on saturated silty sand from the bottom of the interval tunnel of Xuzhou Metro Line 3,considering the effects of different vibration frequencies,effective confining pressures,cyclic stress ratios and consolidation ratios on pore water pressure variations under dynamic loads.The experimental results indicate that the pore water pressure variation in Xuzhou's saturated silty sand primarily follows S-type curve and hyperbola.Under conditions of lower dynamic load ratios,lower consolidation ratios,and lower frequencies,the pore water pressure changes follow an S-type curve.In contrast,under higher dynamic load ratios,higher consolidation ratios,and higher frequencies,the changes follow a hyperbolic curve.Based on the observed pore water pressure variation patterns,the pore water pressure growth model was modified,and the model parameters were fitted and calibrated.This paper provides a valuable reference for predicting changes in pore water pressure in saturated silty sand foundations of subway tunnels in Xuzhou area.
关键词
粉砂土/动三轴试验/循环荷载/孔隙水压力/孔压模型Key words
silty sand/dynamic triaxial test/cyclic loading/pore water pressure/pore water pressure model引用本文复制引用
出版年
2024
NETL
NSTL
万方数据