摘要
为研究硫酸盐盐渍土在冻融循环作用下的力学特性,结合京沈高速铁路朝阳段的工程实际,利用三轴不固结不排水试验对不同冻融循环次数(最多50次)、盐质量分数(0%、2%和5%)和围压(100 kPa、200 kPa、300 kPa和400 kPa)下的硫酸盐盐渍土进行研究,分析不同试验条件下硫酸盐盐渍土的抗剪强度特性及强度劣化机理。研究结果表明:随着冻融循环次数、盐质量分数和围压的逐渐增加,硫酸盐盐渍土的应力-应变曲线逐渐由应变软化向应变硬化转变;抗剪强度随冻融循环和盐质量分数的增加而逐渐降低;对于盐质量分数0%的试样,内摩擦角受冻融循环影响不明显,在30°~34°之间;在短期冻融循环(1~9次)作用下,黏聚力呈上升趋势,在冻融循环9~20次过程中,黏聚力急剧下降,当冻融循环大于20次后,黏聚力逐渐趋于稳定;对于盐质量分数2%和5%的试样,短期冻融循环(小于9次)对内摩擦角影响不显著,而在冻融循环20次后,内摩擦角急剧减小;在冻融循环1~20次过程中,试样的黏聚力逐渐减小,在冻融循环20次时,黏聚力达到最小值;土样在反复冻融循环作用后,土体颗粒大量分解,粒度逐渐变细,细颗粒占比逐渐增大。研究结果可为类似工程提供理论指导。
In order to study the mechanical properties of sulphate saline soil under freeze-thaw cycle,triaxial unconsolidated undrained test(UU)was used to study sulphate saline soils with different freeze-thaw cycles(up to 50),salt mass fraction(0%,2%and 5%),and confining pressures(100 kPa,200 kPa,300 kPa and 400 kPa)in conjunction with the engineering practice of the Chaoyang section of the Beijing-Shenyang high-speed Railway,.The analysis focused on the shear strength characteristics and strength deterioration mechanism of the sulphate saline soil under varying test conditions.The results show that the stress-strain curve of the sulfate saline soil gradually changes from strain softening to strain hardening with the increase of the number of freeze-thaw cycles,salt content fraction,and confining pressure.The shear strength decreases with increased freeze-thaw cycles and salt content.For samples with 0%salt content,the internal friction angle is not significantly affected by freeze-thaw cycle,and ranges from 30°to 34°.Under short-term freeze-thaw cycle(n=1~9),cohesion showed an upward trend,while during the 9~20 freeze-thaw cycles,cohesion decreased sharply and gradually stabilized after 20 cycles.For samples with 2%and 5%salt content,the influence of short-term freeze-thaw cycle(n<9)on the internal friction angle is not significant,but the internal friction angle decreases sharply after 20 cycles.In the process of 1~20 freeze-thaw cycles,the cohesion of the sample decreases gradually,reaching the minimum value at 20 cycles.Following repeated freeze-thaw cycles,soil particles decompose in large quantities,leading to a gradual decrease in particle size and an increase in the proportion of fine particles.The research results can provide theoretical guidance for similar projects.
作者
何野
HE Ye(China Railway 19th Bureau Group Third Co.,Ltd.,Shenyang 110136,Liaoning,China)
出处
《资源信息与工程》
2024年第1期96-100,104,共6页
Resource Information and Engineering
关键词
硫酸盐盐渍土
三轴试验
冻融循环
含盐量
抗剪强度参数
sulfate saline soil
triaxial test
freeze-thaw cycle
salt content
shear strength parameters
