基于微观孔隙特性的动力固结压缩条件下海相软土的变形分析  

Deformation analysis based on microscopic pore characteristics of soft marine soil under dynamic consolidation compressions

作　　者：夏唐代[1,2] 戴晨祥 何绍衡 丁智 朱黄鼎[1,2] 周盈 XIA Tangdai;DAI Chenxiang;HE Shaoheng;DING Zhi;ZHU Huangding;ZHOU Ying(School of Architectural Engineering,Zhejiang University,Hangzhou 310058,China;Engineering Research Center of Urban Underground Development of Zhejiang Province,Hangzhou 310058,China;Department of Civil Engineering,Zhejiang University City College,Hangzhou 310015,China)

机构地区：[1]浙江大学建筑工程学院,浙江杭州310058 [2]浙江省城市地下空间开发工程技术研究中心,浙江杭州310058 [3]浙江大学城市学院土木工程系,浙江杭州310015

出　　处：《中南大学学报（自然科学版）》2022年第11期4335-4347,共13页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51508506);浙江省自然科学基金联合基金重点资助项目(LHZ20E080001);浙江省重点研发计划项目(2020C01102);杭州市科学技术计划项目(20172016A06,20180533B06,20180533B12,20191203B44)。

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(αOCR)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αOCR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。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(αOCR) 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 T2spectrum 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 αOCR,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.

关 键 词：海相软土 累积应变 核磁共振 微观孔隙特性 

分 类 号：TU315[建筑科学—结构工程]