【研究背景】
滑坡滑动区/面的热-水-孔隙-力学特征是当前的研究热点，特别是考虑到近年来水库诱发滑坡对社会造成的巨大损失，这一问题的研究显得尤为迫切。关于关键的工程地质界面在滑坡渐进性破坏中的潜在作用还未得到足够的认识，这一缺口是当前研究的主要瓶颈。深入探索这些界面的作用不仅是基础理论发展的需要，也对防灾减灾工程实践具有重要的意义。
【研究内容】
为了解决上述问题，我们选择我国三峡库区中游的新铺滑坡作为案例研究，通过使用超弱光纤布拉格光栅（UWFBG）技术，我们在滑坡脚部的一个31米深的钻孔中垂直埋设了特殊的传感光缆，将其称为“大地神经元”，用于收集土壤温度、含水量、孔隙水压力和应变等数据。我们分析了2021-2022年期间的现场监测结果，并在整个钻孔中生成了多参量的时空剖面。 研究结果表明，湿年份比干年份更容易引发滑坡运动。滑坡的年度热活跃层大约在9米的深度，可能在较暖的年份向下移动。动态地下水位位于9-15米深度，应变峰值对年度水文气象周期表现出周期性的跳跃和回退响应。这些界面行为有助于我们了解水库调节及气候变化如何影响库岸边坡的稳定性。此外，本文还提出了一种渐进性库区滑坡的评估新方法，可基于滑坡界面力学行为构建一个可靠的监测预警系统。
【研究意义】
创新：这项研究的创新之处在于我们采用了高分辨率光纤传感技术，成功监测获得了水库诱发滑坡的多物理响应。通过分析滑坡内重要的工程地质界面，我们能够更好地理解滑坡的渐进性破坏机制。此外，我们的研究结果对于解释滑坡的形成机制、预测滑坡风险以及制定相应的防灾措施具有重要的意义。
总结：高分辨率光纤传感技术的应用为我们提供了深入了解水库诱发滑坡的多物理响应的机会。通过研究滑坡滑动区/面之外的界面行为，我们能够更好地理解滑坡的形成机制，并为滑坡监测和预警系统的建立提供了基础。这项研究的成果对于减少滑坡灾害对社会造成的损失具有重要意义，也为相关领域的进一步研究提供了借鉴。
Thermo-hydro-poro-mechanical responses of a reservoir-induced landslide tracked by high-resolution fiber optic sensing nerves
来源：Journal of Rock Mechanics and Geotechnical Engineering
作者：Ye X.; Zhu H.-H.; Cheng G.; Pei H.-F.; Shi B.; Schenato L.; Pasuto A.
作者单位：南京大学, 华北科技学院, 大连理工大学, 意大利国家研究委员会, 意大利帕多瓦大学
出版时间：2024-03-01
DOI：10.1016/j.jrmge.2023.04.004
Abstract: Thermo-poro-mechanical responses along sliding zone/surface have been extensively studied. However, it has not been recognized that the potential contribution of other crucial engineering geological interfaces beyond the slip surface to progressive failure. Here, we aim to investigate the subsurface multiphysics of reservoir landslides under two extreme hydrologic conditions (i.e. wet and dry), particularly within sliding masses. Based on ultra-weak fiber Bragg grating (UWFBG) technology, we employ special-purpose fiber optic sensing cables that can be implanted into boreholes as “nerves of the Earth” to collect data on soil temperature, water content, pore water pressure, and strain. The Xinpu landslide in the middle reach of the Three Gorges Reservoir Area in China was selected as a case study to establish a paradigm for in situ thermo-hydro-poro-mechanical monitoring. These UWFBG-based sensing cables were vertically buried in a 31 m-deep borehole at the foot of the landslide, with a resolution of 1 m except for the pressure sensor. We reported field measurements covering the period 2021 and 2022 and produced the spatiotemporal profiles throughout the borehole. Results show that wet years are more likely to motivate landslide motions than dry years. The annual thermally active layer of the landslide has a critical depth of roughly 9 m and might move downward in warmer years. The dynamic groundwater table is located at depths of 9e15 m, where the peaked strain undergoes a periodical response of leap and withdrawal to annual hydrometeorological cycles. These interface behaviors may support the interpretation of the contribution of reservoir regulation to slope stability, allowing us to correlate them to local damage events and potential global destabilization. This paper also offers a natural framework for interpreting thermo-hydro-poro-mechanical signatures from creeping reservoir bank slopes, which may form the basis for a landslide monitoring and early warning system.
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