Institute of Applied Geosciences, Graz University of Technology, Rechbauerstraße 12, 8010 Graz, Austria.
Institute of Applied Geosciences, Graz University of Technology, Rechbauerstraße 12, 8010 Graz, Austria; Abteilung 5, Baudirektion, Amt der Burgenländischen Landesregierung, Europaplatz 1, 7000 Eisenstadt, Austria.
Sci Total Environ. 2021 Jul 15;778:146300. doi: 10.1016/j.scitotenv.2021.146300. Epub 2021 Mar 9.
Landslides can behave as dynamic processes, which emerge from the complex interplay of tectonics, erosion, weathering and gravitational influences, triggered by various hydrological, mineralogical, biological and geotechnical factors. Integral studies to assess the mechanisms underlying landslide initiation and progression are mainly focussed on specific cases with high geohazard potential. The landslide near Stadtschlaining (Austria) represents a key study site to elucidate the impacts of pelitic sediment composition, weathering regime, alteration patterns and hydrochemistry on recurrent damage progression in the local infrastructure. Based on field work, soil-mechanical logging (Atterberg limits, undrained strength, friction angles), water chemistry (ICP-OES, IC, hydrochemical modeling), solid-phase characterization (XRD, XRF, SEM) and sorption experiments we establish a conceptual model for initiating and progressing of landslides: Infiltration of low mineralized meteoric water (EC: <200 μS/cm) in permeable limonitic gravels triggers chemical weathering of greenschist-derived detritus and promotes its transformation into kaolinite and smectite. The clayey strata (>50 wt% of clay minerals) create zones of mechanical and chemical weakness in the underground (~4-6 m below ground level), which are characterized by particle disintegration/delamination, slip bedding and deformations, and development of porous layers depicting water flow paths. Subsequent Na exchange for bivalent ions in the smectite interlayer delivered by percolating, highly mineralized water (EC: 1600-5100 μS/cm) is caused by de-icing salt and fertilizer applications during winter and late summer, and yield in i) decohesion and physical breakdown of the particle aggregates and ii) swelling of the clay matrix in early spring and autumn. These processes reduce the shear strength of the pelitic sediments, resulting in failure and initiation of landslides (deformation: ~500 mm within a month) and subsequent steady creeping motion (deformation: ~100 mm in 6 months). Customized engineered solutions to prevent landslides in this area are presented, which can be conveyed to analogous landslide-affected areas worldwide.
滑坡可以表现为动态过程，这些过程是由构造、侵蚀、风化和重力影响的复杂相互作用产生的，由各种水文、矿物、生物和岩土工程因素触发。评估滑坡启动和演化机制的综合研究主要集中在具有高地质灾害潜力的特定案例上。施塔德施莱宁（奥地利）附近的滑坡是一个关键的研究地点，用于阐明泥质沉积物组成、风化制度、蚀变模式和水化学对当地基础设施中反复出现的破坏进展的影响。基于野外工作、土力学测井（界限含水量、不排水强度、摩擦角）、水化学（ICP-OES、IC、水化学模拟）、固相特征（XRD、XRF、SEM）和吸附实验，我们建立了一个滑坡启动和演化的概念模型：低矿化的大气水（电导率：<200μS/cm）在渗透性的针铁矿砾石中渗透，触发绿片岩衍生碎屑的化学风化，并促进其转化为高岭石和蒙脱石。含粘土的地层（粘土矿物含量>50wt%）在地下（地下 4-6m 处）形成机械和化学弱化带，其特征为颗粒崩解/分层、滑层理和变形以及多孔层的发育，这些层描绘了水流路径。随后，由冬季和夏末除冰盐和肥料应用引起的渗流、高矿化水（电导率：1600-5100μS/cm）中的二价离子对蒙脱石夹层中的钠离子的交换，导致 i）颗粒聚集体的解聚和物理破坏以及 ii）粘土基质在早春和秋季的膨胀。这些过程降低了泥质沉积物的剪切强度，导致滑坡的失稳和启动（变形：一个月内约 500mm），以及随后的稳定蠕动运动（变形：六个月内约 100mm）。提出了防止该地区滑坡的定制工程解决方案，可以将其推广到全球类似的受滑坡影响的地区。
