Pub Date : 2026-01-18DOI: 10.1016/j.enggeo.2026.108567
Won-Taek Hong , Eun Sang Lee , Hyojung Ko , Wooseok Choi , Hyunwook Choo
In electrically conductive media such as marine clays, the strong attenuation of electromagnetic (EM) wave energy significantly complicates the determination of travel time, limiting the applicability of traditional time domain reflectometry (TDR) methods for estimating volumetric water content. This study presents an alternative approach that utilizes characteristic voltages in TDR waveforms—specifically, the normalized voltage ratio (Vf/V0)—to estimate the volumetric water content (θv) and electrical conductivity of marine clays; this approach can be applied even when travel time cannot be determined. Laboratory experiments were conducted on kaolin and bentonite clays with θv between 26.9 and 86.8%, saturated with a 0.5 M NaCl solution. The results show that, for both clay types, Vf/V0 was highly sensitive to changes in θv and strongly correlated with bulk electrical conductivity, regardless of their mineralogical differences. Empirical relationships were developed to estimate θv for each clay, and a generalized model applicable to tested clays with θv > 50% was proposed, achieving a mean absolute percentage error of 2.5%. This study demonstrates that waveform-based analysis using characteristic voltages can serve as a reliable alternative to traditional travel time-based TDR techniques, thereby expanding the applicability of TDR in highly conductive saline environments such as marine clays.
在海相粘土等导电介质中，电磁波（EM）能量的强烈衰减使走时的测定变得非常复杂，限制了传统时域反射法（TDR）估算体积含水量的适用性。本研究提出了一种替代方法，利用TDR波形中的特征电压-特别是归一化电压比（Vf/V0）来估计海洋粘土的体积含水量（θv）和电导率；这种方法即使在旅行时间不能确定的情况下也可以应用。以θv值为26.9 ~ 86.8%的高岭土和膨润土为实验材料，用0.5 M NaCl溶液饱和。结果表明，对于两种粘土类型，无论其矿物学差异如何，Vf/V0对θv的变化高度敏感，且与体电导率密切相关。建立了经验关系来估计每种粘土的θv，并提出了适用于θv >； 50%的测试粘土的广义模型，平均绝对百分比误差为2.5%。该研究表明，使用特征电压的基于波形的分析可以作为传统基于旅行时间的TDR技术的可靠替代方案，从而扩大了TDR在高导电性盐水环境（如海洋粘土）中的适用性。
{"title":"A simple TDR waveform analysis for estimating volumetric water content in marine clays","authors":"Won-Taek Hong , Eun Sang Lee , Hyojung Ko , Wooseok Choi , Hyunwook Choo","doi":"10.1016/j.enggeo.2026.108567","DOIUrl":"10.1016/j.enggeo.2026.108567","url":null,"abstract":"<div><div>In electrically conductive media such as marine clays, the strong attenuation of electromagnetic (EM) wave energy significantly complicates the determination of travel time, limiting the applicability of traditional time domain reflectometry (TDR) methods for estimating volumetric water content. This study presents an alternative approach that utilizes characteristic voltages in TDR waveforms—specifically, the normalized voltage ratio (<em>V</em><sub><em>f</em></sub>/<em>V</em><sub><em>0</em></sub>)—to estimate the volumetric water content (<em>θ</em><sub><em>v</em></sub>) and electrical conductivity of marine clays; this approach can be applied even when travel time cannot be determined. Laboratory experiments were conducted on kaolin and bentonite clays with <em>θ</em><sub><em>v</em></sub> between 26.9 and 86.8%, saturated with a 0.5 M NaCl solution. The results show that, for both clay types, <em>V</em><sub><em>f</em></sub>/<em>V</em><sub><em>0</em></sub> was highly sensitive to changes in <em>θ</em><sub><em>v</em></sub> and strongly correlated with bulk electrical conductivity, regardless of their mineralogical differences. Empirical relationships were developed to estimate <em>θ</em><sub><em>v</em></sub> for each clay, and a generalized model applicable to tested clays with <em>θ</em><sub><em>v</em></sub> > 50% was proposed, achieving a mean absolute percentage error of 2.5%. This study demonstrates that waveform-based analysis using characteristic voltages can serve as a reliable alternative to traditional travel time-based TDR techniques, thereby expanding the applicability of TDR in highly conductive saline environments such as marine clays.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"363 ","pages":"Article 108567"},"PeriodicalIF":8.4,"publicationDate":"2026-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-18DOI: 10.1016/j.enggeo.2026.108573
Makbule Ilgac , Joseph P. Vantassel , Adda Athanasopoulos-Zekkos
Leveraging a database of earthquake recordings and microtremor measurements collected at seismic stations in California, this research explores the influence of processing decisions on the site fundamental frequency (f0) obtained from the horizontal-to-vertical spectral ratio (HVSR) of earthquakes (eHVSR). The study systematically evaluates different approaches for processing eHVSR, including considering signal-to-noise ratio (SNR) to determine usable frequency range, the use of the Fourier amplitude spectrum (FAS) or pseudo-spectral acceleration (PSA), and the impact of using the full earthquake record or selecting the S-wave portion. The SESAME clearness and reliability checks on eHVSR reveal that an SNR-based frequency range outperforms a total frequency range, and FAS outperforms PSA. Across different eHVSR, f0 was determined to be consistent with microtremor HVSR (mHVSR) (Pearson correlation coefficient, r > 0.95) while revealing strong differences in amplitude (r ≈ 0.01–0.7), with 30–40% of the mHVSR-eHVSR pairs disagreeing regarding the occurrence of peaks and resultant median curves being flat. However, when peaks are identified, f0 from various eHVSR matches with mHVSR (r > 0.90), but their amplitudes do not (r < 0.6). eHVSR using the S-wave window resulted in clearer peaks, while the full earthquake records slightly outperformed using the S-wave window in matching f0 with mHVSR (r = 0.92 > r = 0.89). Lastly, while selecting the S-wave window manually versus automatically using existing machine-learning algorithms, they occasionally did not identify identical portions of the earthquake recordings; however, both methods produced very similar eHVSR. Therefore, while additional study is necessary to understand the source of these differences, existing machine algorithms for S-wave selection show promise for use as part of eHVSR processing. Hence, the FAS method employing the manually picked S-wave window and/or full earthquake, along with the calculation of SNR-based frequency range, may be favored for determining f0 from eHVSR curves. The source of inconsistency between mHVSR and eHVSR should be further investigated.
{"title":"Influence of processing technique on the agreement of site fundamental frequency (f0) from earthquake and microtremor horizontal-to-vertical spectral ratio","authors":"Makbule Ilgac , Joseph P. Vantassel , Adda Athanasopoulos-Zekkos","doi":"10.1016/j.enggeo.2026.108573","DOIUrl":"10.1016/j.enggeo.2026.108573","url":null,"abstract":"<div><div>Leveraging a database of earthquake recordings and microtremor measurements collected at seismic stations in California, this research explores the influence of processing decisions on the site fundamental frequency (f<sub>0</sub>) obtained from the horizontal-to-vertical spectral ratio (HVSR) of earthquakes (eHVSR). The study systematically evaluates different approaches for processing eHVSR, including considering signal-to-noise ratio (SNR) to determine usable frequency range, the use of the Fourier amplitude spectrum (FAS) or pseudo-spectral acceleration (PSA), and the impact of using the full earthquake record or selecting the S-wave portion. The SESAME clearness and reliability checks on eHVSR reveal that an SNR-based frequency range outperforms a total frequency range, and FAS outperforms PSA. Across different eHVSR, f<sub>0</sub> was determined to be consistent with microtremor HVSR (mHVSR) (Pearson correlation coefficient, <em>r</em> > 0.95) while revealing strong differences in amplitude (r ≈ 0.01–0.7), with 30–40% of the mHVSR-eHVSR pairs disagreeing regarding the occurrence of peaks and resultant median curves being flat. However, when peaks are identified, f<sub>0</sub> from various eHVSR matches with mHVSR (<em>r</em> > 0.90), but their amplitudes do not (<em>r</em> < 0.6). eHVSR using the S-wave window resulted in clearer peaks, while the full earthquake records slightly outperformed using the S-wave window in matching f<sub>0</sub> with mHVSR (<em>r</em> = 0.92 > <em>r</em> = 0.89). Lastly, while selecting the S-wave window manually versus automatically using existing machine-learning algorithms, they occasionally did not identify identical portions of the earthquake recordings; however, both methods produced very similar eHVSR. Therefore, while additional study is necessary to understand the source of these differences, existing machine algorithms for S-wave selection show promise for use as part of eHVSR processing. Hence, the FAS method employing the manually picked S-wave window and/or full earthquake, along with the calculation of SNR-based frequency range, may be favored for determining f<sub>0</sub> from eHVSR curves. The source of inconsistency between mHVSR and eHVSR should be further investigated.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"363 ","pages":"Article 108573"},"PeriodicalIF":8.4,"publicationDate":"2026-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-17DOI: 10.1016/j.enggeo.2026.108548
P. Sivasankar , K. Satish Kumar , K. Swapna Sri , P. Pavan Kishore , G.S. Srinivas , P. Shiva Shankar , Anand K. Pandey , D. Srinagesh , T. Seshunarayana
Shear wave velocity (Vs) of a medium depends on shear modulus, an essential parameter in geotechnical engineering applications that helps understand soil deformation under dynamic loading during earthquake shaking. We carried out Multichannel Analysis of Surface Waves (MASW) surveys to characterise geotechnical parameters of the shallow subsurface soil in Lucknow, Uttar Pradesh, a fast-growing urban city on the banks of Gomati and Sai rivers in the central Indo-Gangetic Plain (IGP), and lies to the south of the central seismic gap region in the Himalayan collision zone. The VS profiles are acquired at 191 locations across the Lucknow region, exploring up to ∼50 m depth in the thick alluvial soil. The analysis of 1D, 2D, and 3D shear wave velocity profiles suggests (i) average shear wave velocities (Vs30) vary from 226 m/s to 480 m/s throughout the study region. (ii) Long-range swapped 2D cross-sectional profiles reflect the geometry of the Gomati and Sai rivers up to a depth of 50 m. (iii) Very low VS values are observed along the Gomati and Sai river banks. (iv) Most of the soil in the study area is stiff soil of class C, accordingly to the Eurocode 8 classification, with stiffness varying from ∼100 KPa to 400 KPa. (v) The estimated soil predominant frequencies, amplifications, and Peak Ground Acceleration (PGA) vary from 1.9 Hz – 4.0 Hz, 1.4–3.7, and 0.04 g to 0.09 g, respectively.
{"title":"Soil characterization through shear wave velocity analysis of Lucknow city in the Indo-Gangetic plain of India","authors":"P. Sivasankar , K. Satish Kumar , K. Swapna Sri , P. Pavan Kishore , G.S. Srinivas , P. Shiva Shankar , Anand K. Pandey , D. Srinagesh , T. Seshunarayana","doi":"10.1016/j.enggeo.2026.108548","DOIUrl":"10.1016/j.enggeo.2026.108548","url":null,"abstract":"<div><div>Shear wave velocity (Vs) of a medium depends on shear modulus, an essential parameter in geotechnical engineering applications that helps understand soil deformation under dynamic loading during earthquake shaking. We carried out Multichannel Analysis of Surface Waves (MASW) surveys to characterise geotechnical parameters of the shallow subsurface soil in Lucknow, Uttar Pradesh, a fast-growing urban city on the banks of Gomati and Sai rivers in the central Indo-Gangetic Plain (IGP), and lies to the south of the central seismic gap region in the Himalayan collision zone. The V<sub>S</sub> profiles are acquired at 191 locations across the Lucknow region, exploring up to ∼50 m depth in the thick alluvial soil. The analysis of 1D, 2D, and 3D shear wave velocity profiles suggests (i) average shear wave velocities (Vs<sup>30</sup>) vary from 226 m/s to 480 m/s throughout the study region. (ii) Long-range swapped 2D cross-sectional profiles reflect the geometry of the Gomati and Sai rivers up to a depth of 50 m. (iii) Very low V<sub>S</sub> values are observed along the Gomati and Sai river banks. (iv) Most of the soil in the study area is stiff soil of class C, accordingly to the Eurocode 8 classification, with stiffness varying from ∼100 KPa to 400 KPa. (v) The estimated soil predominant frequencies, amplifications, and Peak Ground Acceleration (PGA) vary from 1.9 Hz – 4.0 Hz, 1.4–3.7, and 0.04 g to 0.09 g, respectively.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"363 ","pages":"Article 108548"},"PeriodicalIF":8.4,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-17DOI: 10.1016/j.enggeo.2026.108572
Xulei Guo , Yifan Chen , Jingwen Li , Mingming Luo , Junyi Yang , Benxin Jiang , Jingyi Xu , Yufei Zhang , Jiaqi You , Tiantong Zhou , Ye Kuang , Hong Zhou , Yanxin Wang
Water inrush is a common hazard in karst tunnels. Owing to the strong heterogeneity of subsurface media, accurately resolving the three-dimensional geometry of karst conduits and their spatial relationships with tunnel alignments remains challenging. Using the Badong Tunnel in central China as a case study, this research develops an aquitard-constrained, multi-source characterization framework that integrates geological survey, drilling, geophysical profiling, hydrodynamic monitoring, and tracer tests. This framework delineates the three-dimensional conduit architecture of the Wuyuandong (WYD) karst system and supports the development of a refined conceptual hydrogeological model. Results show that the WYD system is mainly hosted in Lower Triassic carbonate aquifers, with a maximum flood discharge of 34 m3/s. A thin laminated aquitard at the base of the second member of the Jialingjiang Formation controls conduit development depth and supports a modern subterranean river composed of three near-E–W conduits. The southern conduit, influenced by fault–syncline superposition, exhibits the highest tracer velocity (160 m/h), whereas karstification in the underlying Daye Formation is markedly weaker due to limited modern recharge. Conduit morphology is jointly governed by lithology, aquitard geometry, folding, and fault-guided flow. All tunnel alignments intersect the saturated zone, and eastern routes show smaller vertical separation from major conduits, implying higher inrush risk. Although A14 is comparatively favorable, the west-shifted D1 alignment lies beneath the aquitard when crossing the F3 Fault, resulting in reduced hydraulic connectivity and substantially lower inrush hazards. The proposed method greatly enhances conduit detection and supports hydrogeological investigation and risk mitigation in karst tunnels.
{"title":"Deciphering the architecture of complex karst conduit networks in mountainous tunneling areas and its implications for water inrush risk using aquitard-constrained multi-source data","authors":"Xulei Guo , Yifan Chen , Jingwen Li , Mingming Luo , Junyi Yang , Benxin Jiang , Jingyi Xu , Yufei Zhang , Jiaqi You , Tiantong Zhou , Ye Kuang , Hong Zhou , Yanxin Wang","doi":"10.1016/j.enggeo.2026.108572","DOIUrl":"10.1016/j.enggeo.2026.108572","url":null,"abstract":"<div><div>Water inrush is a common hazard in karst tunnels. Owing to the strong heterogeneity of subsurface media, accurately resolving the three-dimensional geometry of karst conduits and their spatial relationships with tunnel alignments remains challenging. Using the Badong Tunnel in central China as a case study, this research develops an aquitard-constrained, multi-source characterization framework that integrates geological survey, drilling, geophysical profiling, hydrodynamic monitoring, and tracer tests. This framework delineates the three-dimensional conduit architecture of the Wuyuandong (WYD) karst system and supports the development of a refined conceptual hydrogeological model. Results show that the WYD system is mainly hosted in Lower Triassic carbonate aquifers, with a maximum flood discharge of 34 m<sup>3</sup>/s. A thin laminated aquitard at the base of the second member of the Jialingjiang Formation controls conduit development depth and supports a modern subterranean river composed of three near-E–W conduits. The southern conduit, influenced by fault–syncline superposition, exhibits the highest tracer velocity (160 m/h), whereas karstification in the underlying Daye Formation is markedly weaker due to limited modern recharge. Conduit morphology is jointly governed by lithology, aquitard geometry, folding, and fault-guided flow. All tunnel alignments intersect the saturated zone, and eastern routes show smaller vertical separation from major conduits, implying higher inrush risk. Although A14 is comparatively favorable, the west-shifted D1 alignment lies beneath the aquitard when crossing the F3 Fault, resulting in reduced hydraulic connectivity and substantially lower inrush hazards. The proposed method greatly enhances conduit detection and supports hydrogeological investigation and risk mitigation in karst tunnels.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"363 ","pages":"Article 108572"},"PeriodicalIF":8.4,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-16DOI: 10.1016/j.enggeo.2025.108537
Teikeu Ngueveu Eric Donald, Kenfack Jean Victor, Njanko Théophile, Suffeu Talla Thiery Blondel, Tchomtchoua Tagne Stéphane
Soil assessment prior to construction is essential to ensure the durability and safety of structures. However, the geotechnical tests required to ensure soil stability are limited by certain factors, such as the spatial variability of soil properties and sporadic nature of data. This study aims to develop a multi-criteria equation model to predict the mechanical behavior of soils in the Fokoué subdivision using physical and geo-electrical parameters. The methods employed include electrical soundings, dynamic penetrometer soundings, and soil identification tests.A total of 92 vertical electrical soundings and dynamic penetrometer tests were carried out to assess the geoelectric and mechanical properties of the soil, and 30 samples were taken to identify the nature of the soil in situ. The soil layer of interest is the sub-layer beneath the arable topsoil, which varies in depth between 0.2 m and 2 m. For this section of soil, the true electrical resistivities obtained after 1D inversion vary between 180.68 and 383,105 Ω m, with an average of 15,696.68 Ω m. Mechanically, the permissible stresses for this layer range between 0.09 and 5.50 bar, with an average of 1.32 bar. Principal Component Analysis of the parameters revealed relationships between physico-mechanical properties and electrical resistivities, with correlation coefficients (rs) greater than 0.50 for some parameters and less than 0.50 for others. A multiple regression analysis was performed to establish the predictive equation model, using parameters with a strong correlation with electrical resistivity (rs > 0.80 and R2 > 0.70). The key parameters include water content (ω), permissible stress (σ), porosity (n), and fine particle percentage F80μm, with respective correlation coefficients of 0.91, 0.88, 0.90, and 0.87. The resulting model is:
. This multi-parametric model, with rM = 0.91, enables the estimation of permissible soil stress with an average absolute error of 0.23 bar. The validation criteria confirm the model's reliability for predicting permissible stress, crucial for designing shallow foundation structures in Fokoué soils.
{"title":"Predicting permissible soil stress from soil resistivities and physical parameters: case study of soils in Fokoué Urban Center, West-Cameroon","authors":"Teikeu Ngueveu Eric Donald, Kenfack Jean Victor, Njanko Théophile, Suffeu Talla Thiery Blondel, Tchomtchoua Tagne Stéphane","doi":"10.1016/j.enggeo.2025.108537","DOIUrl":"10.1016/j.enggeo.2025.108537","url":null,"abstract":"<div><div>Soil assessment prior to construction is essential to ensure the durability and safety of structures. However, the geotechnical tests required to ensure soil stability are limited by certain factors, such as the spatial variability of soil properties and sporadic nature of data. This study aims to develop a multi-criteria equation model to predict the mechanical behavior of soils in the Fokoué subdivision using physical and geo-electrical parameters. The methods employed include electrical soundings, dynamic penetrometer soundings, and soil identification tests.A total of 92 vertical electrical soundings and dynamic penetrometer tests were carried out to assess the geoelectric and mechanical properties of the soil, and 30 samples were taken to identify the nature of the soil in situ. The soil layer of interest is the sub-layer beneath the arable topsoil, which varies in depth between 0.2 m and 2 m. For this section of soil, the true electrical resistivities obtained after 1D inversion vary between 180.68 and 383,105 Ω m, with an average of 15,696.68 Ω m. Mechanically, the permissible stresses for this layer range between 0.09 and 5.50 bar, with an average of 1.32 bar. Principal Component Analysis of the parameters revealed relationships between physico-mechanical properties and electrical resistivities, with correlation coefficients (rs) greater than 0.50 for some parameters and less than 0.50 for others. A multiple regression analysis was performed to establish the predictive equation model, using parameters with a strong correlation with electrical resistivity (rs > 0.80 and R<sup>2</sup> > 0.70). The key parameters include water content (ω), permissible stress (σ), porosity (n), and fine particle percentage F80μm, with respective correlation coefficients of 0.91, 0.88, 0.90, and 0.87. The resulting model is:</div><div><span><math><msub><mi>σ</mi><mtext>perm</mtext></msub><mo>=</mo><mo>−</mo><mn>0.7495</mn><mo>+</mo><mn>0.00047355</mn><mi>ρ</mi><mo>−</mo><mn>0.01992502</mn><mi>ω</mi><mo>+</mo><mn>0.00047149</mn><mi>F</mi><mo>+</mo><mn>3.21765361</mn><mi>n</mi></math></span>. This multi-parametric model, with r<sub>M</sub> = 0.91, enables the estimation of permissible soil stress with an average absolute error of 0.23 bar. The validation criteria confirm the model's reliability for predicting permissible stress, crucial for designing shallow foundation structures in Fokoué soils.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"363 ","pages":"Article 108537"},"PeriodicalIF":8.4,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-15DOI: 10.1016/j.enggeo.2026.108569
Liguo Jin , Xiaoxiao Bai , Bingbing Jing , Kai Zhao , Xiaojun Li , Guoxing Chen
Modeling the cyclic behavior of saturated coral sand under non-proportional loading condition is still an challenging task in practice, due to the fabric anisotropy of coral sands. This paper presents an experimental studies on the drained shear-volume coupling behavior of saturated coral sand under wave-induced non-proportional loading. Through an automated hollow cylinder apparatus, the wave-induced stress path is inherent non-proportional characterized by simultaneous variations in magnitudes and directions of the principal stress. The results indicate that the drained shear-volume coupling behavior of coral sand is highly dependent on the imposed stress paths. A remarkable finding is that by defining equivalent cyclic stress ratio (ESR) as a new proxy, a unique shear-volume coupling equation can be established for the various stress paths studied. An explicit relationship is then proposed and implemented into Biot's equation as the source term for residual excess pore water pressure (EPWP) generation within an explicit time-matching finite difference platform. The proposed model is validated against the comparative undrained liquefaction test on saturated coral sand and siliceous Ottawa sand in the laboratory, as well as the data of siliceous fine sands in previous work. Finally, the potential of the proposed modeling framework is highlighted to capture the key mechanisms of wave-induced liquefaction of coral sand seabed through numerical examples. The proposed shear-volume coupling equation provides new insights into the physics of seabed liquefaction of coral sand under wave-induced non-proportional loading conditions.
{"title":"Excess pore water pressure generation of saturated uncemented coral sands under non-proportional loading","authors":"Liguo Jin , Xiaoxiao Bai , Bingbing Jing , Kai Zhao , Xiaojun Li , Guoxing Chen","doi":"10.1016/j.enggeo.2026.108569","DOIUrl":"10.1016/j.enggeo.2026.108569","url":null,"abstract":"<div><div>Modeling the cyclic behavior of saturated coral sand under non-proportional loading condition is still an challenging task in practice, due to the fabric anisotropy of coral sands. This paper presents an experimental studies on the drained shear-volume coupling behavior of saturated coral sand under wave-induced non-proportional loading. Through an automated hollow cylinder apparatus, the wave-induced stress path is inherent non-proportional characterized by simultaneous variations in magnitudes and directions of the principal stress. The results indicate that the drained shear-volume coupling behavior of coral sand is highly dependent on the imposed stress paths. A remarkable finding is that by defining equivalent cyclic stress ratio (ESR) as a new proxy, a unique shear-volume coupling equation can be established for the various stress paths studied. An explicit relationship is then proposed and implemented into Biot's equation as the source term for residual excess pore water pressure (EPWP) generation within an explicit time-matching finite difference platform. The proposed model is validated against the comparative undrained liquefaction test on saturated coral sand and siliceous Ottawa sand in the laboratory, as well as the data of siliceous fine sands in previous work. Finally, the potential of the proposed modeling framework is highlighted to capture the key mechanisms of wave-induced liquefaction of coral sand seabed through numerical examples. The proposed shear-volume coupling equation provides new insights into the physics of seabed liquefaction of coral sand under wave-induced non-proportional loading conditions.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"363 ","pages":"Article 108569"},"PeriodicalIF":8.4,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-14DOI: 10.1016/j.enggeo.2026.108566
Liyang Jiang, Xuanmei Fan, Junhan Du, Yu Deng, Zeyuan Xue
Rock-ice avalanches in cold regions exhibit formidable erosive power, posing severe threats to nearby communities and infrastructure. Yet, the role of ice content in erosion remains poorly understood largely due to the limited field and experimental data. Here, we present a series of temperature-controlled flume experiments to systematically investigate erosion dynamics in dry granular rock-ice mixtures of varying ice contents (0–100%). Through high-speed flow visualization of a specially designed erosion column, we record the full spatiotemporal progression of the erosion profiles. Further analysis identifies two coexisting erosion mechanisms: basal abrasion and impact erosion. Basal abrasion is produced by sustained shearing along the bed, whereas impact erosion arises from high-velocity particle collisions with the bed. Their respective contributions are also quantified. Notably, impact erosion shows a stronger correlation with erosion capacity than basal abrasion and contributes more to total erosion under high-mobility conditions. A dimensionless parameter RE = Ei/Ea is introduced to quantify the intensity of the impact erosion rate Ei relative to the basal abrasion rate Ea. RE first increases and then decreases with ice content, peaking at intermediate values. These findings advance the quantitative understanding of basal abrasion and impact erosion in rock-ice avalanches under dry granular conditions.
{"title":"Erosion processes in dry granular rock-ice avalanches with varying ice content: Insights from flume experiments","authors":"Liyang Jiang, Xuanmei Fan, Junhan Du, Yu Deng, Zeyuan Xue","doi":"10.1016/j.enggeo.2026.108566","DOIUrl":"10.1016/j.enggeo.2026.108566","url":null,"abstract":"<div><div>Rock-ice avalanches in cold regions exhibit formidable erosive power, posing severe threats to nearby communities and infrastructure. Yet, the role of ice content in erosion remains poorly understood largely due to the limited field and experimental data. Here, we present a series of temperature-controlled flume experiments to systematically investigate erosion dynamics in dry granular rock-ice mixtures of varying ice contents (0–100%). Through high-speed flow visualization of a specially designed erosion column, we record the full spatiotemporal progression of the erosion profiles. Further analysis identifies two coexisting erosion mechanisms: basal abrasion and impact erosion. Basal abrasion is produced by sustained shearing along the bed, whereas impact erosion arises from high-velocity particle collisions with the bed. Their respective contributions are also quantified. Notably, impact erosion shows a stronger correlation with erosion capacity than basal abrasion and contributes more to total erosion under high-mobility conditions. A dimensionless parameter <em>R</em><sub><em>E</em></sub> = <em>E</em><sub><em>i</em></sub>/<em>E</em><sub><em>a</em></sub> is introduced to quantify the intensity of the impact erosion rate <em>E</em><sub><em>i</em></sub> relative to the basal abrasion rate <em>E</em><sub><em>a</em></sub>. <em>R</em><sub><em>E</em></sub> first increases and then decreases with ice content, peaking at intermediate values. These findings advance the quantitative understanding of basal abrasion and impact erosion in rock-ice avalanches under dry granular conditions.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"363 ","pages":"Article 108566"},"PeriodicalIF":8.4,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-14DOI: 10.1016/j.enggeo.2026.108560
Yupeng Cao , Junxia Liu , Zhehao Qiu , Xiang Yong , Jie Yin
Large-scale dredging activities generate high-water-content sediments with poor engineering properties, which pose significant challenges to their reuse in construction and land reclamation. This paper proposes a combined treatment using superabsorbent polymer (SAP) flocculation and vacuum preloading to enhance consolidation and microstructural uniformity. Laboratory-scale model tests were conducted using both rectangular and cylindrical setups, and the treated specimens were examined using scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). In addition, digital image processing was applied to evaluate the microstructural evolution quantitatively. The results demonstrated that the SAP effectively improved soil flocculation, reduced pore connectivity, and mitigated clogging near prefabricated vertical drains, thereby enhancing radial drainage uniformity. EDS analysis revealed a more homogeneous elemental distribution, particularly of sodium ions, whereas XRD confirmed that the SAP acted via physical rather than chemical mechanisms. Quantitative metrics, such as reduced pore area ratio, increased roundness, and lower entropy, indicated a more stable and orderly soil fabric. From an engineering geological perspective, this study provides practical insights to improve the reliability, efficiency, and environmental sustainability of ground-treatment techniques in soft clayey terrains, particularly for infrastructure development in coastal and deltaic environments.
{"title":"Insights into the microstructural evolution of dredged clay treated by SAP flocculation and vacuum preloading","authors":"Yupeng Cao , Junxia Liu , Zhehao Qiu , Xiang Yong , Jie Yin","doi":"10.1016/j.enggeo.2026.108560","DOIUrl":"10.1016/j.enggeo.2026.108560","url":null,"abstract":"<div><div>Large-scale dredging activities generate high-water-content sediments with poor engineering properties, which pose significant challenges to their reuse in construction and land reclamation. This paper proposes a combined treatment using superabsorbent polymer (SAP) flocculation and vacuum preloading to enhance consolidation and microstructural uniformity. Laboratory-scale model tests were conducted using both rectangular and cylindrical setups, and the treated specimens were examined using scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). In addition, digital image processing was applied to evaluate the microstructural evolution quantitatively. The results demonstrated that the SAP effectively improved soil flocculation, reduced pore connectivity, and mitigated clogging near prefabricated vertical drains, thereby enhancing radial drainage uniformity. EDS analysis revealed a more homogeneous elemental distribution, particularly of sodium ions, whereas XRD confirmed that the SAP acted via physical rather than chemical mechanisms. Quantitative metrics, such as reduced pore area ratio, increased roundness, and lower entropy, indicated a more stable and orderly soil fabric. From an engineering geological perspective, this study provides practical insights to improve the reliability, efficiency, and environmental sustainability of ground-treatment techniques in soft clayey terrains, particularly for infrastructure development in coastal and deltaic environments.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"363 ","pages":"Article 108560"},"PeriodicalIF":8.4,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145962690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-14DOI: 10.1016/j.enggeo.2026.108565
Thanh-Tùng Nguyễn , Ivo Baroň , Rostislav Melichar , Jia-Cian Gao , Filip Hartvich , Cheng-Han Lin , Jan Klimeš , Martin Šutjak , Lenka Kociánová , Václav Dušek , František Bárta , Chia-Han Tseng , Jia-Jyun Dong
Paleoseismic methods frequently prove ineffective in stable continental interiors, where the rarity of surface-rupturing earthquakes can result in a significant underestimation of long-term seismic hazard. To address this limitation, an integrated approach was developed that transformed paleolandslides into quantitative paleoseismic indicators. This method combined detailed morphometric and structural analyses with dynamic back analysis, incorporating velocity-dependent friction laws from rotary shear experiments into Newmark displacement analysis. Results were validated using discrete element runout modeling (particle flow code in three dimensions). When applied to a well-preserved paleolandslide in the Outer Western Carpathians, a region traditionally considered as low hazard, this approach revealed a critical seismic triggering threshold. The analysis indicated that a magnitude of M7.1–7.3 earthquake at a short distance (∼1.2 km) was required for initiating catastrophic failure, consistent with the observed long runout and liquefaction features. The findings presented herein constitute the first physical evidence for M7+ paleoearthquakes in the region, challenging existing seismic hazard assessments for Central Europe and demonstrating that stable continental interiors can host large, although infrequent earthquakes.
{"title":"Paleo-landslide analysis reveals underestimated seismic hazards in the outer Western Carpathians","authors":"Thanh-Tùng Nguyễn , Ivo Baroň , Rostislav Melichar , Jia-Cian Gao , Filip Hartvich , Cheng-Han Lin , Jan Klimeš , Martin Šutjak , Lenka Kociánová , Václav Dušek , František Bárta , Chia-Han Tseng , Jia-Jyun Dong","doi":"10.1016/j.enggeo.2026.108565","DOIUrl":"10.1016/j.enggeo.2026.108565","url":null,"abstract":"<div><div>Paleoseismic methods frequently prove ineffective in stable continental interiors, where the rarity of surface-rupturing earthquakes can result in a significant underestimation of long-term seismic hazard. To address this limitation, an integrated approach was developed that transformed paleolandslides into quantitative paleoseismic indicators. This method combined detailed morphometric and structural analyses with dynamic back analysis, incorporating velocity-dependent friction laws from rotary shear experiments into Newmark displacement analysis. Results were validated using discrete element runout modeling (particle flow code in three dimensions). When applied to a well-preserved paleolandslide in the Outer Western Carpathians, a region traditionally considered as low hazard, this approach revealed a critical seismic triggering threshold. The analysis indicated that a magnitude of M7.1–7.3 earthquake at a short distance (∼1.2 km) was required for initiating catastrophic failure, consistent with the observed long runout and liquefaction features. The findings presented herein constitute the first physical evidence for M7+ paleoearthquakes in the region, challenging existing seismic hazard assessments for Central Europe and demonstrating that stable continental interiors can host large, although infrequent earthquakes.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"363 ","pages":"Article 108565"},"PeriodicalIF":8.4,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-14DOI: 10.1016/j.enggeo.2026.108564
Yuguo Su , Tiantian Ying , Qiaokan Wang , Xiaodong Pan
Soil spatial variability exhibits significant regional characteristics arising from various geological processes, weathering effects, and stress history during sedimentation. The spatial variability can influence the performance of geotechnical systems, and accurately capturing it is essential for effective reliability analysis. This study first compares the performance of the auto-correlation function and variance reduction function under different fitting strategies. Subsequently, the sampling strategies that yield the best performance in estimating the scale of fluctuation (SOF) are identified. After that, cone penetration test data are collected from sites along the Qiantang River to quantify the spatial variability parameters of the alluvial silt. Analysis reveals that the SOF and its associated uncertainty generally increase with expanding investigation domain length. The mean SOF rises from 0.691 m to 1.225 m across scales from 5 m to 15 m. The hole effect describes a spatial autocorrelation function that exhibits a non-monotonic, cyclical pattern as lag distance increases. A significant hole effect, identified in 75.6% of cases with SOF values ranging from 0.190 m to 1.135 m, may be associated with rhythmic tidal sedimentation processes. The cosine Whittle-Matérn model successfully captures the finer features of the spatial correlation structure, including the SOF, smoothness, and hole effect.
{"title":"Capturing the hole effect in Qiantang River alluvial silt by cone penetration test","authors":"Yuguo Su , Tiantian Ying , Qiaokan Wang , Xiaodong Pan","doi":"10.1016/j.enggeo.2026.108564","DOIUrl":"10.1016/j.enggeo.2026.108564","url":null,"abstract":"<div><div>Soil spatial variability exhibits significant regional characteristics arising from various geological processes, weathering effects, and stress history during sedimentation. The spatial variability can influence the performance of geotechnical systems, and accurately capturing it is essential for effective reliability analysis. This study first compares the performance of the auto-correlation function and variance reduction function under different fitting strategies. Subsequently, the sampling strategies that yield the best performance in estimating the scale of fluctuation (SOF) are identified. After that, cone penetration test data are collected from sites along the Qiantang River to quantify the spatial variability parameters of the alluvial silt. Analysis reveals that the SOF and its associated uncertainty generally increase with expanding investigation domain length. The mean SOF rises from 0.691 m to 1.225 m across scales from 5 m to 15 m. The hole effect describes a spatial autocorrelation function that exhibits a non-monotonic, cyclical pattern as lag distance increases. A significant hole effect, identified in 75.6% of cases with SOF values ranging from 0.190 m to 1.135 m, may be associated with rhythmic tidal sedimentation processes. The cosine Whittle-Matérn model successfully captures the finer features of the spatial correlation structure, including the SOF, smoothness, and hole effect.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"363 ","pages":"Article 108564"},"PeriodicalIF":8.4,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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