【摘要】 受全球气候变化和人类活动影响，海水入侵和地面沉降正逐渐成为沿海地区重要环境问题。为了研究海水入侵对地面沉降的潜在影响，本文开展了高纯石英砂一维侧限固结试验，研究了盐水环境、浸泡环境和固结环境等对砂土蠕变的影响，并从细观角度定性和定量分析其破碎过程和机制。结果表明：盐水环境能促进砂土的蠕变变形，相对于浸泡过程，其促进作用更能体现在固结过程中；盐溶液浓度越大，对砂样蠕变的促进作用越明显，即海水入侵可加剧地面沉降。细观结构图像的定量化分析结果显示，盐水环境下砂样的孔隙面积更小、颗粒破碎率及裂纹密度更高，颗粒的平均形状系数也更大，破碎程度更高。弱碱性的海水中存在的OH~-和Na~+等会促进石英颗粒尖端硅氧键的水解，加速砂颗粒裂纹的发育，进一步加剧颗粒的破碎。本文揭示了盐水环境下砂土蠕变的宏观变形规律和主要细观机制，阐明了海水入侵可能是一个影响沿海地区地面沉降不可忽视的因素。更多还原

【Abstract】 Influenced by global climate change and human activities, seawater intrusion and land subsidence have been important environmental problems in coastal areas. To study the potential effect of seawater intrusion on land subsidence, this paper conducted a series of one-dimensional lateral limit consolidation tests using high-purity quartz sand. The effects of the saline environment, the immersion environment and the consolidation environment on the creep of sand were investigated. Also, we qualitatively and quantitatively analyzed the breakage process and mechanism of the sand from a mesoscopic perspective. The results show that the saline environment can promote creep deformation of sand, and the promotion effect is more reflected in the consolidation process than in the immersion process. A higher concentration of salt solution usually leads to a significant promotion on sand creep. That is, seawater intrusion could potentially intensify land subsidence. The quantitative analysis of the mesoscopic structure images shows that, compared to non-saline environment, the saline environment may induce smaller pore areas, higher particle breakage rates and crack densities. Also, there are greater average shape factors of the particles and higher degrees of particle breakage. The presence of OH~- and Na~+in weakly alkaline seawater promotes the hydrolysis of silica-oxygen bonds at the tips of quartz grains, which accelerates the development of sand particle cracks and further intensifies the breakage of sand particles. This paper reveals the macroscopic deformation law and the main mesoscopic mechanism of sand creep under saline environment, and elucidates that seawater intrusion may be a non-negligible factor affecting land subsidence in coastal areas.更多还原