【摘要】 为探求软土地基在循环荷载作用下的微观结构变形机理，研究宏观动力响应和微观结构之间的相互关系，对杭州市地铁2号线附近土层的原状海相软土进行动力固结压缩试验和核磁共振试验，获取不同固结围压（p₀）、不同循环动应力比（ζ）和不同超固结比(α_OCR)下的软土动力响应和孔隙微观结构特性。根据试验结果，应用广义加性模型（GAMs）建立微观孔隙结构参数和最终累积应变（ε）的耦合关系。研究结果表明：原状海相软土T₂谱分布主要包含2个峰，主峰面积占全峰总面积的99%以上，表明孔径小于1μm的小孔隙占99%以上；随着p₀,ζ和α_OCR不断增大，孔隙水弛豫强度显著降低，软土中大孔隙消失，部分小孔隙变化较小，平均孔径减小，孔隙率下降。更多还原

【Abstract】 To explore the mechanism of microstructure deformation in soft soil under cyclic loading,and to study the relationship between macro dynamic response and microstructure,the undisturbed soft marine soil near Hangzhou Metro Line 2 was subjected to dynamic consolidation compression tests and nuclear magnetic resonance tests.The soft soil dynamic response and pore microstructure characteristics under different consolidation confining pressures（p₀）,at different cyclic dynamic stress ratio（ζ） and different over-consolidation ratios(α_OCR) were obtained.According to the test results,generalized additive models（GAMs） were used to establish the coupling relationship between the microscopic pore structure parameters and the final cumulative strain（ε）.The results show that the T₂ spectrum distribution of the undisturbed soft marine soil mainly contains two peaks.The area of the main peak accounts for more than 99%of the total area of the peak,indicating that the small pores with a pore diameter less than 1μm account for more than 99%.With the continuous increase of p₀,ζ and α_OCR,the relaxation strength of pore water decreases significantly,the large pores in the soft soil disappear,some small pores have small changes,the average pore size decreases,and the porosity decreases.更多还原