为了探究不同海砂掺量和振动频率对海砂复合固化淤泥动应力-动应变(σd-εd)关系、动弹性模量及阻尼比的影响,以海砂复合固化淤泥为研究对象,利用GDS动三轴仪在不同频率下进行分级加卸载试验。试验结果表明:动应力较小时,σd-εd曲线呈线性关系,逐级增大动应力,动应变增长迅速直至破坏;同一频率下,应力-应变曲线随海砂掺量的增加先上升后下移,掺量为15%的固化淤泥曲线位于最上方;同一海砂掺量,高频下的动变形小于低频、动强度高于低频;不同海砂掺量、不同频率下固化淤泥动弹性模量Ed均随动应力σd的增大而先增大后减小,阻尼比λ随动应力σd的增大先略有减小后逐渐增大;滞回耗能ΔW随动应力σd的增加呈现出非线性增大的趋势,相同动应力下对应的滞回耗能ΔW随频率的增加而减小;增大频率和掺入适量海砂可以提高固化淤泥的动弹性模量,有效降低固化淤泥的阻尼比。研究成果可供探讨海砂复合固化淤泥的动力特性和设计提供试验和理论参考。
Abstract
Graded loading and unloading test was conducted with different frequencies by using GDS dynamic triaxial instrument to explore the influences of sea sand content and vibration frequency on the dynamic stress-dynamic strain (σd-εd) relationship, dynamic elastic modulus and damping ratio of sea sand composite solidified silt. Test results show that the σd-εd curve is linear at small dynamic stress; when dynamic stress is increased stepwise, dynamic strain increases rapidly until failure. At a given frequency, the stress-strain curve first rises and then moves down with the increase of sea sand content; the stress-strain curve of solidified silt with 15% dosage of sea sand is at the top. At a given sea sand content, the dynamic deformation under high frequency is smaller than that at low frequency, and the dynamic strength is higher than that at low frequency. Under varying sea sand content and frequency and growing dynamic stress, the dynamic elastic modulus Ed of solidified silt first increases and then declines, the damping ratio λ decreases slightly and then gradually increases, and the hysteretic energy consumption ΔW increases nonlinearly. The corresponding ΔW under the same dynamic stress decreases with the increase of frequency. By increasing the frequency and mixing a proper amount of sea sand, the dynamic elastic modulus of solidified silt can be improved, and the damping ratio of the solidified silt can be effectively reduced.
关键词
海砂复合固化淤泥 /
GDS动三轴试验 /
动应力-动应变曲线 /
动弹性模量 /
阻尼比 /
滞回耗能
Key words
sea sand composite solidified silt /
GDS dynamic triaxial test /
dynamic stress-strain curve /
dynamic elastic modulus /
damping ratio /
hysteretic energy consumption
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基金
国家自然科学基金青年基金项目(51508283)
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