To address the lack of field data regarding the internal properties of landslide dams and to support the development of sophisticated stability indices, multidisciplinary investigations were performed on the Cuejdel Lake landslide dam in the Eastern Carpathians. The combination of electrical resistivity tomography, sedimentary facies mapping, infiltration tests, and geotechnical sampling revealed blocks of preserved stratigraphy embedded in a relatively impermeable sedimentary matrix containing sands and clayey-silt components. Although the eroded dam face shows a heterogenous distribution of sedimentary facies, the hydraulic properties are dominated by a mixture of sand, silt, and clay resulting in a uniformly saturated phreatic zone with permeability values between 1 × 10−7 <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10346_2025_2564_Article_IEq1.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="13" /> </InlineMediaObject> <EquationSource Format="TEX">$\frac{m}{s}$</EquationSource> <EquationSource Format="MATHML"><math> <mfrac> <mi>m</mi> <mi>s</mi> </mfrac> </math></EquationSource> </InlineEquation>. and 1 × 10−8 <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10346_2025_2564_Article_IEq1.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="13" /> </InlineMediaObject> <EquationSource Format="TEX">$\frac{m}{s}$</EquationSource> <EquationSource Format="MATHML"><math> <mfrac> <mi>m</mi> <mi>s</mi> </mfrac> </math></EquationSource> </InlineEquation>. Analyses of a LiDAR survey clarify that the previously described single landslide is a pair of two landslides from which the northern Slide A dammed the Cuejdel Lake. An abandoned spillway path responding to the lowest point of the dam crest indicates erosion due to overtopping shortly after the dam formation. The low permeability resulting from the sedimentary matrix prevented a destruction of the dam by internal erosion during the early formation stages. Although overtopping occurred after the dam initiation, the failure progression towards a dam breach was guided by the seasonal variations of lake water levels. The seasonal decrease of the water level prohibited the advancement of the overtopping related erosion, while the increase of the lake water level in the consecutive wet season led to a stabilization through a spillway along the landslide toe. While valuable for rapid first order hazard assessment, current stability indices are not capable of reproducing the complex stabilization process of the Cuejdel Lake landslide dam, emphasizing the need for integrating facies-based geotechnical parameters and hydraulic variabilities in hazard assessments of individual cases.

Structural, geotechnical, and hydrogeological investigation of the Lake Cuejdel Landslide Dam, Eastern Carpathians: a facies-based characterization of internal dam properties

期刊论文
出版模式：

开放获取
发表日期：

2025年7月4日

查看全文

Thomas Wolfert,
Alin Mihu-Pintilie,
Anja Dufresne,
Cristian Constantin Stoleriu,
Cristian Trifanov,
Florian Amann

摘要

To address the lack of field data regarding the internal properties of landslide dams and to support the development of sophisticated stability indices, multidisciplinary investigations were performed on the Cuejdel Lake landslide dam in the Eastern Carpathians. The combination of electrical resistivity tomography, sedimentary facies mapping, infiltration tests, and geotechnical sampling revealed blocks of preserved stratigraphy embedded in a relatively impermeable sedimentary matrix containing sands and clayey-silt components. Although the eroded dam face shows a heterogenous distribution of sedimentary facies, the hydraulic properties are dominated by a mixture of sand, silt, and clay resulting in a uniformly saturated phreatic zone with permeability values between 1 × 10⁻⁷ $\frac{m}{s}$ $\frac{m}{s}$ . and 1 × 10⁻⁸ $\frac{m}{s}$ $\frac{m}{s}$ . Analyses of a LiDAR survey clarify that the previously described single landslide is a pair of two landslides from which the northern Slide A dammed the Cuejdel Lake. An abandoned spillway path responding to the lowest point of the dam crest indicates erosion due to overtopping shortly after the dam formation. The low permeability resulting from the sedimentary matrix prevented a destruction of the dam by internal erosion during the early formation stages. Although overtopping occurred after the dam initiation, the failure progression towards a dam breach was guided by the seasonal variations of lake water levels. The seasonal decrease of the water level prohibited the advancement of the overtopping related erosion, while the increase of the lake water level in the consecutive wet season led to a stabilization through a spillway along the landslide toe. While valuable for rapid first order hazard assessment, current stability indices are not capable of reproducing the complex stabilization process of the Cuejdel Lake landslide dam, emphasizing the need for integrating facies-based geotechnical parameters and hydraulic variabilities in hazard assessments of individual cases.