Field investigation of unsaturated seepage process and its influence on soil behavior in land creation for loess plateau with fiber-optic technology

IF 6.5 1区工程技术 Q1 ENGINEERING, GEOLOGICAL

Acta Geotechnica Pub Date : 2026-03-31 DOI:10.1007/s11440-026-02963-1

Jie Liu, Bin Shi, Meng-Ya Sun, Kai Gu, Jun-Cheng Yao, Chao-Sheng Tang

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Abstract

Unsaturated seepage is a key factor in triggering geohazards in land constructed with compacted loess on the Loess Plateau. However, in situ monitoring of deep soil–water interactions remains challenging. In this study, a 77 m-deep fiber-optic monitoring borehole was established in Yan’an New District to investigate the unsaturated seepage process and its influence on soil behavior. Field studies indicated that the thick vadose zone can be divided into four parts, including two active zones interacting with atmospheric conditions. One of them is located at shallow ground, and the other one is positioned above the interface between compacted and natural loess. Piston flow and seasonal moisture changes dominate seepage in shallow active zone, leading to deformation governed by matric suction. In steady zones with slight water content variation, soil still experiences time-dependent deformation. The secondary consolidation coefficient (C_α) of compacted loess increases exponentially with depth, while natural loess shows lower and more stable values. In the deep active zone, preferential flow drives rapid water content increases and localized deformation. These findings support the development of deformation models considering different unsaturated seepage process.

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利用光纤技术对黄土高原造陆过程中非饱和渗流过程及其对土壤特性影响的实地研究

非饱和渗流是黄土高原压实性黄土路基引发地质灾害的关键因素。然而，深层土壤-水相互作用的原位监测仍然具有挑战性。本文在延安新区建立了77 m深的光纤监测钻孔，研究非饱和渗流过程及其对土体特性的影响。野外研究表明，厚气包带可分为四个部分，其中包括两个与大气条件相互作用的活动区。其中一个位于浅层，另一个位于压实黄土与天然黄土的界面上方。浅层活动区渗流主要受活塞流动和季节性水分变化的影响，变形主要受基质吸力控制。在含水量变化不大的稳定区，土体仍发生随时间变化的变形。压实黄土的次固结系数（Cα）随深度呈指数增长，自然黄土的次固结系数（Cα）较低且较为稳定。在深部活动区，优先流驱动含水率快速增加和局部变形。这些发现支持了考虑不同非饱和渗流过程的变形模型的发展。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Acta Geotechnica ENGINEERING, GEOLOGICAL-

CiteScore

9.90

自引率

17.50%

发文量

297

审稿时长

4 months

期刊介绍： Acta Geotechnica is an international journal devoted to the publication and dissemination of basic and applied research in geoengineering – an interdisciplinary field dealing with geomaterials such as soils and rocks. Coverage emphasizes the interplay between geomechanical models and their engineering applications. The journal presents original research papers on fundamental concepts in geomechanics and their novel applications in geoengineering based on experimental, analytical and/or numerical approaches. The main purpose of the journal is to foster understanding of the fundamental mechanisms behind the phenomena and processes in geomaterials, from kilometer-scale problems as they occur in geoscience, and down to the nano-scale, with their potential impact on geoengineering. The journal strives to report and archive progress in the field in a timely manner, presenting research papers, review articles, short notes and letters to the editors.