Engineering Geology最新文献

{"title":"Model test study on the rainfall erosion mechanisms and reclamation potential of open-pit coal mine dump soil improved by fly ash and polyacrylamide","authors":"Shiyu Li, Shuhong Wang, Zhonghua Zhao, Natalia Telyatnikova, Marinichev Maxim","doi":"10.1016/j.enggeo.2024.107837","DOIUrl":"https://doi.org/10.1016/j.enggeo.2024.107837","url":null,"abstract":"Increasing the soil erosion resistance is one of the core issues in slope erosion control and ecological environmental restoration of open-pit coal mine (OPCM) dumps. In this study, fly ash (FA) and polyacrylamide (PAM) were used to improve the soil quality of an OPCM dump, and an indoor physical model was constructed to investigate the water and soil loss characteristics of the improved soil via simulated rainfall experiments. Scanning electron microscopy and Pore and Crack Analysis System software were employed to systematically investigate the erosion resistance mechanisms of the improved soil qualitatively and quantitatively. Finally, the improved technique for order preference by similarity to an ideal solution (TOPSIS) method was adopted to evaluate the reclamation potential of the improved soil. The results revealed that under the action of PAM (PAM and PAM–FA), the average erosion rate of the slope decreased by more than 90 %. Compared with that in the control group, when FA was applied alone, the slope erosion rate first decreased and then increased with increasing FA content. Upon PAM addition, the erosion pattern changed from the splash erosion stage, cave erosion stage, gully erosion stage, and tensile slip stage to the splash erosion stage and cave erosion stage. However, no obvious change in the runoff pattern. Erosion and runoff patterns are generally affected by the amendment type, addition concentration, porosity, pore shape, pore direction and hydrological environment. The erosion resistance mechanism of the improved soil entailed the formation of more stable soil aggregates via filling, cementation, skeleton support generation, and flocculation of FA and PAM. In addition, the optimal soil improvement was achieved when FA and PAM were added at levels of 16 % and 0.01 %, respectively. The obtained research results could be used for erosion control and ecological environmental protection of coarse-grained soil slopes in mining areas, highways and other fields and could be widely applied.","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"1 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142793508","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}

{"title":"Improving subsurface structural interpretation in complex geological settings through geophysical imaging and machine learning","authors":"Yonatan Garkebo Doyoro, Samuel Kebede Gelena, Chih-Ping Lin","doi":"10.1016/j.enggeo.2024.107839","DOIUrl":"https://doi.org/10.1016/j.enggeo.2024.107839","url":null,"abstract":"This study employs seismic refraction tomography (SRT) and electrical resistivity tomography (ERT) to assess subsurface geological conditions along the proposed Porsgrunn Highway in Norway. The primary objective is to analyze SRT and ERT tomograms to identify subsurface geological structures. However, interpreting tomograms is often limited by smoothed boundaries and reduced resolution. To address these challenges, we apply <ce:italic>k</ce:italic>-means clustering, a machine learning technique that groups data based on similarities in physical properties, to post-process the geophysical tomograms. This study pioneers the use of <ce:italic>k</ce:italic>-means clustering to interpret tomograms from SRT and ERT data in complex geological settings. We first evaluate the effectiveness of clustering techniques using numerical modeling for two geological scenarios: a horizontally layered case and a layered case with undulation and a fault structure. Utilizing automated methods (Elbow and Silhouette), we objectively determine the optimal number of clusters for each geophysical tomogram. Subsequently, we compare the performance of the <ce:italic>k</ce:italic>-means clustering algorithm with subjective expert interpretations and the Laplacian edge detection method. Borehole data validate the clustering results and confirm the effectiveness of optimal cluster selection techniques. The findings of this study demonstrate that <ce:italic>k</ce:italic>-means clustering significantly enhances the detection of geological structures by establishing clearer boundaries and minimizing noise interference, enabling more accurate fault zone delineation. Compared to traditional edge detection and subjective interpretation methods, <ce:italic>k</ce:italic>-means clustering offers a systematic and objective approach that improves consistency and reliability across diverse geological settings. Moreover, its automated classification of geophysical data into meaningful clusters enables efficient analysis of large datasets. This study underscores the value of integrating machine learning techniques with geophysical methods such as SRT and ERT to improve interpretability and accurately identify subsurface geological structures, particularly in fault zone identification.","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"5 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789953","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}

{"title":"Seepage and stability analysis of hydraulically anisotropic unsaturated infinite slopes under steady infiltration","authors":"Chuanjie Dai, Guo Hui Lei","doi":"10.1016/j.enggeo.2024.107838","DOIUrl":"https://doi.org/10.1016/j.enggeo.2024.107838","url":null,"abstract":"An analytical model is derived for predicting the flow field and stability of an unsaturated infinite slope subjected to steady infiltration. The proposed model is novel because it accounts for the hydraulic anisotropy of unsaturated soil. The governing equation for steady-state seepage in an infinite slope is established in terms of matric suction under a constant surface flux boundary condition. On the basis of the available experimental findings on the hydraulic anisotropy behavior of unsaturated soils, the relative hydraulic conductivity for a soil under unsaturated conditions with respect to the soil at saturation is postulated to be a direction-independent scalar. This postulation simplifies the governing equation to a form that is directly solvable via the relative hydraulic conductivity and the saturated hydraulic conductivity tensor. To enable sophisticated applications, an exponential law and a power law that are well established in the unsaturated soil literature are used to relate the relative hydraulic conductivity to the matric suction and the effective degree of saturation, respectively. Closed-form solutions are derived for the matric suction, the flow net (potential function and stream function), and the effective degree of saturation. Analytical solutions are also derived for the soil unit weight and overburden stress. These solutions are incorporated into the unsaturated infinite slope stability formula constructed on a suction stress-based effective stress failure criterion. Hydraulic anisotropy has been shown to directly affect the flow field and the change in matric suction, which, in turn, drastically affects the slope safety factor against shallow landslides. This finding demonstrates that neglecting hydraulic anisotropy can cause a considerable overestimation of the safety factor, resulting in an unsafe slope stability prediction. The proposed model is useful for preliminary evaluation of the long-term stability of unsaturated slopes during wet periods and the antecedent slope conditions for shallow landslide initiation under transient infiltration.","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"7 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789954","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}

{"title":"Determining a representative elementary area for soil desiccation cracking","authors":"C. Clay Goodman, Farshid Vahedifard","doi":"10.1016/j.enggeo.2024.107831","DOIUrl":"https://doi.org/10.1016/j.enggeo.2024.107831","url":null,"abstract":"Laboratory tests involving soil desiccation cracking are subjected to geometrical boundary constraints that are not always present in field conditions. To better understand the effects of sample geometry on desiccation cracks, several researchers have used controlled climatic conditions coupled with image analysis to accurately quantify the crack characteristics of soil samples subjected to laboratory studies. However, to date, no known studies in the literature present a simple method for determining the appropriate sample size for laboratory desiccation cracking testing that ensures the effects of boundary conditions are minimized. The primary objective of this research is to address this gap by proposing an experimental approach to determine a representative elementary area (REA) for soil desiccation cracking studies in the laboratory. To achieve this, we conducted four series of tests using an environmental chamber. One preliminary test series was carried out to identify the optimal sample preparation and REA testing techniques. Subsequently, three additional series of REA tests were conducted with sample thicknesses of 2.5, 5.0, and 7.5 mm to explore the impact of sample size on the REA. The REA for each sample thickness was determined by examining the surface area at which the surface crack ratio (R<ce:inf loc=\"post\">SC</ce:inf>) for the sample was unaffected by boundary constraints. The results indicate that as sample thickness increases, REA increases. Further research is needed to determine how the REA is affected by sample shape and soil type.","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"35 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789958","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}

{"title":"Physics-based time-of-failure determination of rainfall-induced instability in lateritic soil slopes","authors":"Sushant Rahul, Akanksha Tyagi","doi":"10.1016/j.enggeo.2024.107834","DOIUrl":"https://doi.org/10.1016/j.enggeo.2024.107834","url":null,"abstract":"Conventional time-of-failure estimated from slope surface displacement over time, ignores the crucial geotechnical and environmental causative factors that lead to slope instability. The instrumentation and monitoring are expensive, labour-intensive, and often not feasible for large number of hill slopes. This paper focuses on the physics-based determination of time-of-failure charts for laterite soil slopes prevalent in the Western Ghats of India, under rainfall infiltration. The finite element model was first validated by performing coupled flow deformation analysis of Kondavi soil cutting situated in the Ratnagiri district of Maharashtra, India. The soil samples were collected from the site for basic geotechnical characterisation in the laboratory. In addition, the soil water characteristics curve (SWCC) was determined using the filter paper method, and the unsaturated parameters were obtained using the van Genuchten model. Following the validation of numerical model with the failed Kondavi cutting, the factor of safety (FOS) and time-of-failure (TOF) were studied for varying rainfall intensity, and permeability of the soil. The FOS and TOF charts were then established for varying slope angles (30°, 45°, 60°), effective cohesion (10 kPa, 18 kPa, 25 kPa), effective friction angle (22°, 25°, 28°), water table depth (25 m, 28 m, 30 m, 35 m) and height of slope (15 m, 25 m, 35 m). Results indicate that if rainfall intensity is lower than soil permeability, TOF depends on both the intensity and duration of the rainfall. Higher rainfall intensity leads to a shorter time of failure, and vice versa. Conversely, when rainfall intensity exceeds soil permeability, TOF is determined by the duration of rainfall and the permeability of soil, as the rainfall infiltrates at the saturated permeability rate regardless of its intensity. It is also observed that friction is the dominant parameter for initial FOS, while cohesion is the dominant parameter for the TOF of a rainfall-induced landslide. Finally, charts are proposed that shall serve as a preliminary guide for the determination of the TOF for rainfall-induced instability in the lateritic soil slopes of India. The performance of the charts is further evaluated by comparing the observed and predicted TOF of two other failed laterite cuttings. The implications of these findings are profound, as the proposed TOF charts can be integrated into early warning systems, contributing towards improved disaster mitigation and preparedness with timely decision making for adequate management of landslide associated risks.","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"244 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142823146","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}

{"title":"Suffusion characteristics of a heterogeneous dam foundation with a cut-off wall of stochastic defects","authors":"Zezhi Deng, Gang Wang, Wei Jin, Liangjun Deng, Mingke Liao, Qiuyi Chen","doi":"10.1016/j.enggeo.2024.107829","DOIUrl":"https://doi.org/10.1016/j.enggeo.2024.107829","url":null,"abstract":"Natural alluvial foundations are inherently heterogeneous. To enhance seepage safety, a cut-off wall is commonly embedded in a dam foundation. However, walls can also have stochastic defects. The dual uncertainties arising from soil heterogeneity and wall defects pose significant challenges for seepage safety evaluation. In this study, systematic numerical simulations were conducted on an internally unstable dam foundation based on a four-constituent mixture framework. Soil heterogeneity was characterized by stochastic initial hydraulic conductivity and initial fines content. An erosion model, specifically incorporating the influence of overburden pressure, was employed to quantify suffusion. A probabilistic assessment utilizing Monte Carlo simulations revealed that suffusion in heterogeneous fields could be more severe than that in homogeneous fields. Various combinations of stochastic soil properties and defect locations can result in substantial disparities in seepage and erosion fields. The mean values of the total flux and the fines eroded ratio are insensitive to the spatial variation length, while their deviations increase with increasing spatial variation length, leading to larger uncertainties in the leakage channel morphology. For highly heterogeneous alluvial foundations with large spatial variations, conventional seepage and suffusion analyses that rely on homogeneous assumptions may considerably underestimate the internal erosion risk.","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"37 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142790042","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}

{"title":"Study on the deformation mechanism of chair-like bedding rock landslides under the coupling effect of geological and hydrological factors","authors":"Biao Wang, Qingjun Zuo, Maolin Deng, Qinglin Yi, Di Ruan, Zhikang Liang","doi":"10.1016/j.enggeo.2024.107832","DOIUrl":"https://doi.org/10.1016/j.enggeo.2024.107832","url":null,"abstract":"Chair-like bedding rock landslides are prevalent in the Three Gorges Reservoir area (TGRA), necessitating further investigation into their inducing mechanisms. This study focuses on the Muyubao and Tanjiahe landslides, conducting a comparative analysis of their deformation characteristics and mechanisms while comprehensively considering geological and hydrological factors. The findings indicate that the Muyubao landslide was primarily triggered by the combined effects of rainfall during the water storage period and the rise of the reservoir water levels (RWL), with a threshold of approximately 165 m. In contrast, the Tanjiahe landslide was influenced by a rapid drawdown in RWL, heavy rainfall, and a high RWL, with a threshold of around 175 m. Both landslides exhibited a clear response to the rise in groundwater levels in the steep sections, with significant deformation occurring when groundwater levels reached 175 m (Muyubao landslide QSK1) and 245 m (Tanjiahe landslide QSK2). Notably, variations in landslide morphology, permeability coefficients, and fluctuations in groundwater levels can facilitate the mutual conversion between different landslide types (seepage-driven and buoyancy-driven). To investigate the influence of chair-like slope morphology on landslides, eight landslide models were constructed, featuring a range of dip angles for the rock formation (15° to 30°) and varying length ratios of gentle to steep sections (2:8 to 5:5). The UDEC Code was employed to simulate and analyze the governing effects of slope morphology on landslide deformation and evolution. Through a comparative analysis of the Muyubao, Tanjiahe, Jiuxianping, and Qianjiangping landslide cases, we examined the significant influence of landslide morphology and permeability coefficients on landslide behavior. The results indicate that the length ratio of gentle to steep section is a crucial parameter. When this ratio exceeds 2:8, the landslide is characterized by pushing deformation; conversely, when the ratio is lower, it tends to exhibit overall movement. Additionally, geological factors affect groundwater seepage and water level variation under the influence of rainfall and reservoir water, resulting in distinct deformation characteristics and mechanisms across different landslide types. Factors such as slope angle and the length of the gentle section influence the extent of the submerged area, leading to varied landslide responses to rise of the RWL.","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"10 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789955","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}

{"title":"Flume investigation of debris flow entrained boulders with cylindrical baffles and a rigid barrier","authors":"Beom-Jun Kim, Chan-Young Yune","doi":"10.1016/j.enggeo.2024.107836","DOIUrl":"https://doi.org/10.1016/j.enggeo.2024.107836","url":null,"abstract":"Large boulders entrained by debris flow can generate destructive impact force and cause significant damage to a rigid barrier located downstream. Baffle arrays can be installed in front of the rigid barrier to reduce the potential damage from large boulders by dissipating flow energy with filtering boulders from the debris flows. In this study, to investigate the effect of baffle arrays on the flow behavior and the dynamic impact force of debris flows acting on the terminal barrier, small-scale flume experiments were performed with various baffle configurations. After the experiments, the dynamic flow behavior with boulders, impact forces, and travel distances of boulders, were analyzed with transverse blockage ratios and numbers of baffle rows. As a result, entrained boulders in debris flows significantly increased impact force about six times. With the installations of baffle arrays, however, peak impact force decreased by an average of 70 % and by up to 94 %. In addition, increasing the number of rows of baffles from one to two led to an average reduction of 50 % in impact force for each transverse blockage ratio. However, in the case of one row of baffles, the impact force reduction for high <ce:italic>s/δ</ce:italic> values proved to be less effective compared to the other baffle configurations. Finally, the results of this study can provide appropriate ranges for the baffle spacing and the number of baffle rows in the baffle design to estimate the load attenuation due to boulder filtration.","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"225 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789956","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}

{"title":"Energy-based method for the failure criterion and resistance evaluation of marine clay under cyclic loading","authors":"Xing Xiao, Xin Guan, Qi Wu, Dingfeng Zhao, Ruirong Zhou, Guoxing Chen","doi":"10.1016/j.enggeo.2024.107833","DOIUrl":"https://doi.org/10.1016/j.enggeo.2024.107833","url":null,"abstract":"Energy dissipation can macroscopically synthesize the evolutions in the microstructure of the marine clay during cyclic loading. Hence an energy-based method was employed to investigate the failure criterion and cyclic resistance of marine clay. A series of constant-volume cyclic direct simple shear tests was conducted on undisturbed saturated marine clay from the Yangtze Estuary considering the effects of the plasticity index (<ce:italic>I</ce:italic><ce:inf loc=\"post\">P</ce:inf>) and cyclic stress ratio (<ce:italic>CSR</ce:italic>). The results indicated that a threshold <ce:italic>CSR</ce:italic> (<ce:italic>CSR</ce:italic><ce:inf loc=\"post\">th</ce:inf>) exhibiting a power function relationship with <ce:italic>I</ce:italic><ce:inf loc=\"post\">P</ce:inf> exists in marine clay, which divides the cyclic response into non-failure and failure states. For failed specimens, the development of energy dissipation per cycle (<ce:italic>W</ce:italic><ce:inf loc=\"post\"><ce:italic>i</ce:italic></ce:inf>) with the number of cycles (<ce:italic>N</ce:italic>) exhibited an inflection point owing to the onset of serious damage to the soil structure. In this regard, the energy-based failure criterion was proposed by considering the inflection point as the failure point. Consequently, a model was proposed to quantify the relationships between failure energy dissipation per cycle (<ce:italic>W</ce:italic><ce:inf loc=\"post\">f</ce:inf>) [or failure accumulative energy dissipation (<ce:italic>W</ce:italic><ce:inf loc=\"post\">af</ce:inf>)], initial vertical effective stress, <ce:italic>I</ce:italic><ce:inf loc=\"post\">P</ce:inf>, and the number of cycles to failure (<ce:italic>N</ce:italic><ce:inf loc=\"post\">f,E</ce:inf>). An evaluation model capturing the correlation among <ce:italic>CSR</ce:italic>, <ce:italic>I</ce:italic><ce:inf loc=\"post\">P,</ce:inf> and <ce:italic>N</ce:italic><ce:inf loc=\"post\">f,E</ce:inf> was then established to predict the cyclic resistance, and its applicability was verified. Compared with the strain-based cyclic failure criterion, the energy-based failure criterion provides a more robust and rational approach. Finally, a failure double-amplitude shear strain (<ce:italic>γ</ce:italic><ce:inf loc=\"post\">DA,f</ce:inf>) evaluation method applicable to marine clay in different seas was presented for use in practical geotechnical engineering.","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"20 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789957","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}

{"title":"Effects of alkaline solution and aging time on thermal conductivity of MX80 powder-granule mixtures","authors":"Jiesheng Shao, De'an Sun, Xiangyun Zhou, Zhaotian Zeng, Zhen Liang","doi":"10.1016/j.enggeo.2024.107830","DOIUrl":"https://doi.org/10.1016/j.enggeo.2024.107830","url":null,"abstract":"In the design of high-level nuclear waste (HLW) repositories, granular bentonite is esteemed as an effective sealant for interfacing the spaces that exist between the bentonite blocks and adjacent geological bodies. When degraded cement dissolves in groundwater, it generates an alkaline solution with a high pH. Therefore, determining whether the thermal conductivity of granular bentonite changes under the long-term effect of alkaline solution is essential for the repository safety. In this study an experimental investigation was conducted on the changes in the thermal conductivity of granular bentonite with an alkaline solution (NaOH solution) over time, with the effects of aging time, particle size distribution, alkaline solution content and concentration being considered. X-ray diffraction (XRD) technique was applied for examining the variations in mineral composition, while the pores and cracks analysis system (PCAS) was utilized to process previous SEM images, revealing the change in porosity. The test results are as follows. Increasing the alkaline concentration, average particle size or aging time leads to a decline in thermal conductivity, whereas a higher alkaline solution content enhances it. In descending order of effect, the factors influencing thermal conductivity are ranked as the alkaline solution content, particle size distribution, alkaline concentration, and aging time. The interaction effects exist between these different factors. The decrease of thermal conductivity is not only related to the increase in porosity caused by the dissolution of montmorillonite, but also to the decrease in quartz content. The evolution of thermal performance can be a reference for the design and construction of HLW repositories.","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"10 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789959","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}