Engineering Geology最新文献

{"title":"Quantitative investigation of temperature-dependent bound water degeneration in bentonite clays","authors":"Nilufar Chowdhury,&nbsp;Omid Ghasemi-Fare","doi":"10.1016/j.enggeo.2024.107737","DOIUrl":"10.1016/j.enggeo.2024.107737","url":null,"abstract":"<div><div>Temperature increases in saturated clay alter the physicochemical clay-water interactions and may lead to the conversion of bound water into free water. These changes significantly influence the physical, chemical, and engineering properties of clays, which are critical for geotechnical and geological engineering and minimizing risks in areas with expansive clay soils. However, quantifying this phenomenon remains challenging in the literature. This study presents a robust experimental approach for quantifying the thermal-induced conversion of bound water in clays, providing valuable insights into the mechanisms governing their thermo-mechanical behavior. A novel experimental method is proposed to quantify the degenerated bound water content in a clay system subjected to temperatures ranging from 20 to 50 °C. The research employs the siphon principle to examine volume changes in a clay system at elevated temperatures, focusing on measuring the conversion of bound water to free water. This method accounts for thermal expansion of both the soil constituents and the confining glass cylinder, as well as potential evaporation losses. To validate the setup's accuracy, a calibration test using standard Ottawa sand with negligible bound water was performed. After measuring system error, the primary outcome was calibrated. Results showed that at 30 °C, 40 °C, and 50 °C, 3 %, 9 %, and 15 % of the initial bound water, respectively, converted to free water.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"342 ","pages":"Article 107737"},"PeriodicalIF":6.9,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427299","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":"Caprock sealing integrity and key indicators of CO2 geological storage considering the effect of hydraulic-mechanical coupling: X field in the Bohai Bay Basin, China","authors":"Bowen Chen ,&nbsp;Qi Li ,&nbsp;Yongsheng Tan ,&nbsp;Yao Zhang ,&nbsp;Tao Yu ,&nbsp;Jiyuan Ma ,&nbsp;Yiyan Zhong ,&nbsp;Xiaying Li","doi":"10.1016/j.enggeo.2024.107741","DOIUrl":"10.1016/j.enggeo.2024.107741","url":null,"abstract":"<div><div>Caprock sealing efficiency is an essential guarantee for the long-term safety and stability of CO₂ geological storage (CCS). However, the uncertainty in the physical and mechanical properties of deep formations poses challenges to accurately predict the risks of CO₂ leakage resulting in CO₂ breakthrough or caprock fracture. This study aims to address the issue of imperfect key indicators for caprock sealing by focusing on the CCS project in the Bohai Bay Basin, China. A hydraulic-mechanical (HM) coupling program without considering multiphase flow and the chemical reactions is secondary developed based on the finite element software ABAQUS. Furthermore, a three-dimensional finite element numerical model is established for the analysis of HM coupling, with pore pressure increment (∆<em>P</em>_P), Coulomb failure stress (∆CFS) and displacement (U) as evaluation criteria. The Tornado analysis and response surface analysis are employed to analyze the impact of 17 indicators on the caprock sealing, including caprock thickness, burial depth, reservoir and caprock permeability parameters, and mechanical parameters. Subsequently, key performance indicators for caprock sealing are determined. The research results indicate that the reservoir permeability, injection rate, caprock permeability, caprock Young's modulus, caprock internal friction angle, caprock Poisson's ratio, and caprock burial depth are key indicators of caprock sealing capability. The reservoir permeability has a greater impact sensitivity compared to the caprock permeability. Pore pressure and displacement increase with increasing in reservoir permeability. The caprock's resistance to deformation and fracturing increases with increasing in Young's modulus and Poisson's ratio of caprock. This study provides valuable insights for evaluating caprock sealing during CO₂ storage in saline aquifers.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"342 ","pages":"Article 107741"},"PeriodicalIF":6.9,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427303","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":"DEM simulations of particle dissolution effects on the passive earth pressure of retaining walls","authors":"Kai Cui ,&nbsp;Wei Ci ,&nbsp;Shangchuan Yang","doi":"10.1016/j.enggeo.2024.107742","DOIUrl":"10.1016/j.enggeo.2024.107742","url":null,"abstract":"<div><div>Assessing passive earth pressure is fundamental in geotechnical engineering practice. Mineral dissolution in the soil can reduce the soil strength, causing an overestimation of passive earth pressure in design. In this study, the effect of dissolution on passive earth pressure on retaining walls is investigated by using discrete element method, taking into account three modes of motion: translation (mode <em>T</em>), rotation around the wall bottom (mode <em>RB</em>), and rotation around the wall top (mode <em>RT</em>). The simulations show that the particle dissolution results in a significant reduction in the passive earth pressure on retaining walls. The largest reductions of resultant force are about 73.5 % and 78.5 % in modes <em>T</em> and <em>RT</em> when wall displacement is minor. Nevertheless, when the wall displacement is large, the largest reduction in resultant force is approximately 74.7 % in mode <em>RB</em>. A detailed analysis is provided to explain this phenomenon. Dissolution also leads to weak force chains and an increase in soil porosity, thereby weakening wall-soil interactions. Dissolution has a significant effect on passive earth pressure of lower part's soil. This study suggests that reinforcing the lower part's soil and preventing seepage in this area can help mitigate the effects of dissolution on retaining walls.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"342 ","pages":"Article 107742"},"PeriodicalIF":6.9,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357475","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":"Shear strength characteristics of unsaturated compacted GMZ bentonite considering anisotropy","authors":"Yu Lu ,&nbsp;Wei-min Ye ,&nbsp;Qiong Wang ,&nbsp;Yonggui Chen","doi":"10.1016/j.enggeo.2024.107743","DOIUrl":"10.1016/j.enggeo.2024.107743","url":null,"abstract":"<div><div>Anisotropic microstructure would be generated in the bentonite block during unidirectional compactions. Working as buffer materials, the compacted bentonite will inevitably experience shearing processes during the long-term operation of geological repositories. In this paper, high-pressure triaxial tests were conducted on unsaturated compacted GMZ bentonite specimens with different water contents, dry densities and confining stresses, with the compaction surface of the specimens oriented in both horizontally (H-type) and vertically (V-type) configurations. Results demonstrate that an increase in water content leads to a reduction in both peak strength and residual strength, while higher confining stresses enhance these strength parameters. Normally consolidated and lightly over-consolidated bentonite specimens display substantial shear deformation, whereas heavily over-consolidated specimens tend to experience brittle failure. Water content plays a significant role in shaping both the critical state line (CSL) and the Hvorslev surface (HS), with increasing water content resulting in decreased slope parameters for both and an increased intercept parameter for the HS. Generally, V-type specimens demonstrate a steeper CSL and an outwardly extended HS in contrast to that of H-type specimens. The critical state ratio for V-type specimens is about 10 % higher, and the friction angle is 2.8° greater, than that of the H-type ones. Moreover, this difference appears to increase with increasing water content. The difference of the HS slope parameter between the two specimens is minor, while the intercept parameter is higher for the V-type specimens.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"342 ","pages":"Article 107743"},"PeriodicalIF":6.9,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427238","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":"Investigating soil properties and their effects on freeze-thaw processes in a thermokarst lake region of Qinghai-Tibet Plateau, China","authors":"Xianmin Ke ,&nbsp;Wei Wang ,&nbsp;Fujun Niu ,&nbsp;Zeyong Gao","doi":"10.1016/j.enggeo.2024.107734","DOIUrl":"10.1016/j.enggeo.2024.107734","url":null,"abstract":"<div><div>Soil parameters form the foundation of hydrogeological research and are crucial for studying engineering construction and maintenance, climate change, and ecological environment effects in cold regions. However, the soil properties in the permafrost region of the Qinghai–Tibet Plateau (QTP) remain unclear. Hence, in this study, soil temperature (T_s), volumetric specific heat capacity (C), thermal conductivity (K), thermal diffusivity (D), soil water content (SWC), electric conductivity (EC), vertical (<em>K</em>_<em>v</em>) and horizontal (<em>K</em>_<em>h</em>) saturated hydraulic conductivity, bulk density (ρ_b), and soil texture near the Qinghai-Tibet Railway were measured, and their effects on the freeze-thaw process were evaluated. The results revealed a predominantly sandy loam soil texture, with <em>K</em>_<em>h</em> and <em>K</em>_<em>v</em> showing strong spatial variability, while the other parameters presented moderate spatial variability. Thermokarst lake had a limited influence on D, C, K, and ρ_b but significantly reduced <em>K</em>_<em>h</em> and <em>K</em>_<em>v</em>. Groundwater affected SWC, T_s, and EC. The model results showed that all parameters indicated small sensitivities to the maximum thawing depth (MTD), with MTD positively responding to all parameters except for <em>K</em>_<em>v</em> and porosity (ρ_p). Except for <em>K</em>_<em>h</em> and <em>K</em>_<em>v</em>, all parameters showed high sensitivities to the time from starting to complete freezing (TSCF). TSCF responded positively to C, ρ_p, and density (ρ_d) and negatively to K and <em>K</em>_<em>h</em>. This study expanded the quantification of soil properties in the QTP, which can help improve the accuracy of cryohydrogeologic models, thus guiding the construction and maintenance of infrastructure engineering.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"342 ","pages":"Article 107734"},"PeriodicalIF":6.9,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427306","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":"Numerical investigation of the fast shear behaviour of granular materials and its significance for rapid landslides","authors":"Chenhui Du ,&nbsp;Jianqi Zhuang ,&nbsp;Jianbing Peng ,&nbsp;Jiaxu Kong ,&nbsp;Wei Hu","doi":"10.1016/j.enggeo.2024.107733","DOIUrl":"10.1016/j.enggeo.2024.107733","url":null,"abstract":"<div><div>The shear behaviour of granular materials at high velocities is crucial for understanding the high mobility of rapid landslides and the low-friction mechanisms behind them. Here, a numerical ring shear model driven by granular shear platens was developed, and this model was validated in terms of the kinematics and mechanics of the granular material. The granular material was then accelerated at different accelerations to high shear velocities (ranging from 0.001 m/s to a maximum of 5.0 m/s). The results indicate that with increasing shear velocity, the shear behaviour of granular materials transitions from a single behaviour to a composite behaviour. The composite shear behaviour is important for both the shear flow state and the frictional characteristics. The velocity profile reveals the transition of granular materials from uniform shear flow to composite shear flow consisting of locally high-shear-rate layers and slow creep layers; the volume of granular materials transitions from global expansion at the onset of shearing to local expansion; and particle velocity fluctuations and contact force fluctuations change from being uniformly distributed and relatively small at the beginning of shearing to rapid growth in local areas. Furthermore, with increasing shear velocity, the frictional characteristics become nonuniform. Local areas exhibit positive velocity-related friction effects, whereas the friction of the particles in other regions slightly decreases. Particle fluctuations represent an important factor that leads to the composite shear behaviour of granular materials. This study provides valuable insights into the shear behaviour of particles in rapid landslides.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"342 ","pages":"Article 107733"},"PeriodicalIF":6.9,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427239","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":"Assessment of seabed trench formation based on marine sediment properties and chain-bar penetration tests","authors":"Shengjie Rui ,&nbsp;Hans Petter Jostad ,&nbsp;Zefeng Zhou ,&nbsp;Lizhong Wang ,&nbsp;Svein Sævik ,&nbsp;Yufei Wang ,&nbsp;Zhen Guo","doi":"10.1016/j.enggeo.2024.107746","DOIUrl":"10.1016/j.enggeo.2024.107746","url":null,"abstract":"<div><div>Seabed trenches, as a geological hazard, adversely influence the safety of adjacent anchors. Seabed trenches predominantly appear in the Gulf of Guinea, where the seabed soils exhibit some features, e.g., high plasticity, high water content and low shear strength. However, the marine engineering geology where seabed trenches appear is not well understood, as well as the trenching process related to soil erosion. In this paper, the information about seabed trenches was summarized, and marine engineering geology where seabed trenches appear was analyzed in detail. It was found that the marine clay with high plasticity index, high organic content, higher sensitivity, low effective unit weight and shear strength is easier to form seabed trenches. Then, penetration tests of a chain-bar penetrometer were conducted to investigate the soil deformation and erosion near the surface. Experimental observations reveal that the normalized soil resistances from both penetrometers exhibited similar trends, despite different soil deformation mechanisms. In the cyclic tests, the soil resistance was degraded significantly in the first 20 cycles, and water flow induced by chain motion eroded the soil particles near the chain links. This study provides insights into the marine engineering geology and development process of seabed trenches.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"342 ","pages":"Article 107746"},"PeriodicalIF":6.9,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142426754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coupling stress and transmissivity to define equivalent directional hydraulic conductivity of fractured rocks","authors":"C. Darcel ,&nbsp;R. Le Goc ,&nbsp;E. Lavoine ,&nbsp;P. Davy ,&nbsp;D. Mas Ivars ,&nbsp;E. Sykes ,&nbsp;H.A. Kasani","doi":"10.1016/j.enggeo.2024.107739","DOIUrl":"10.1016/j.enggeo.2024.107739","url":null,"abstract":"<div><div>A DFN (Discrete Fracture Network) modelling approach is developed to couple stresses with fracture transmissivities and to evaluate large scale rock mass hydraulic conductivity. The transmissivity-stress coupling relies on a negative exponential correlation between normal stress acting on a fracture and fracture transmissivity, bounded by residual and maximal apertures. The remote stresses and the local stress fluctuations induced by the fractures themselves are combined in a semi-analytical approach to compute the normal stress acting on each fracture of a DFN. Directional equivalent hydraulic conductivities are numerically computed in all directions from a spherical permeameter setup. The resulting properties are first a cloud of points, where each point defines a direction and an equivalent hydraulic conductivity. The distribution of equivalent hydraulic conductivities is analyzed to define mean values, preferential directions and anisotropy ratio. The entire workflow is developed in the numerical platform DFN.lab. The capacity of the method to investigate the impact of the in-situ stresses on the rock mass hydraulic conductivity is illustrated for fracturing and in-situ stress conditions similar to the conditions at the Forsmark site in Sweden. We find that the stress fluctuations induced by the fractures have a significant impact on the resulting hydraulic conductivity field. They limit the anisotropy ratio to values close to a factor of 3 while the transmissivity distribution is correlated to orientations and spans several orders of magnitude. Sensitivity analyses, performed by changing the parameters of the transmissivity-stress law, show quantitatively how the directional hydraulic conductivities are rather controlled by the orientations of the in-situ stresses or by the underlying connectivity structure of the DFN.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"342 ","pages":"Article 107739"},"PeriodicalIF":6.9,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427240","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":"Characterization of the active fault deformation zone of the Chegualin Fault in the alluvial plain of southwestern Taiwan","authors":"Chuan Ding ,&nbsp;Jia-Jyun Dong ,&nbsp;Maryline Le Béon ,&nbsp;Cheng-Chao Lee ,&nbsp;Shu-Ken Ho ,&nbsp;Sheng-Tsung Wang","doi":"10.1016/j.enggeo.2024.107740","DOIUrl":"10.1016/j.enggeo.2024.107740","url":null,"abstract":"<div><div>The activity of a creeping active fault poses significant challenges to engineering structures due to surface deformation. Therefore, quantifying the strain concentration caused by an active fault, delineating the extent and location of the Active Fault Deformation Zone (AFDZ), estimating long-term deformation trends, and predicting future deformations are crucial in the field of engineering geology.</div><div>This study comprehensively integrates multi-timescale analytical methods by incorporating detailed geodetic data, rupture surveys, morphotectonic analysis, geological borehole data, biochronological data, radiocarbon dating, and Holocene uplift rate analysis to identify or confirm the locations of active faults and the long-term evolution trends of active deformation zones. Based on our findings, three active fault planes are identified, with one possibly being the main fault with the highest activity. Furthermore, by comparing long-term deformation rates derived from isochrone lines with short-term deformation rates obtained from leveling, we observe a risk of slip rate deficit. These findings have significant implications for engineering geology. As a general contribution, our study can serve as a site screening strategy for similar locations. Regarding the infrastructure we targeted, we provide critical input parameters for further numerical models (such as the trishear model) to simulate surface deformation, and offer essential design parameters for structures. Considering potential coseismic deformation on the investigated fault, these results are fundamental for future investigations or mitigation plans.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"342 ","pages":"Article 107740"},"PeriodicalIF":6.9,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sediment stacking pattern effect on sand liquefaction inferred from full-scale experiments in the Emilia alluvial plain (Italy)","authors":"Luca Minarelli ,&nbsp;Daniela Fontana ,&nbsp;Stefano Lugli ,&nbsp;Kyle M. Rollins ,&nbsp;Marco Stefani ,&nbsp;Laura Tonni ,&nbsp;Sara Amoroso","doi":"10.1016/j.enggeo.2024.107735","DOIUrl":"10.1016/j.enggeo.2024.107735","url":null,"abstract":"<div><div>The geometry and the depositional configuration of sand bodies affected by the 2012 Emilia earthquakes (Bondeno site, northern Italy) were reconstructed and the role of the sediment stacking pattern was tested using data from full-scale blast experiments. The research integrates remote sensing and surface geological mapping, subsurface investigations including stratigraphic coring and cone penetration tests, grain-size and petrography of sands, geotechnical and geophysical monitoring. Data are compared with the Mirabello blast test site, also in the epicentral area. The results highlight the preeminent role of sediment heterogeneity and their mechanical and compositional properties in modulating liquefaction in alluvial settings. The lateral confinement of the buried sandy bodies, their thickness, and the occurrence of a thick non-liquefiable crust influence the dissipation of the excess pore water pressure, as indicated by the blast monitoring, and therefore the duration of liquefaction phenomena, according to the local stratigraphic architecture.</div></div>","PeriodicalId":11567,"journal":{"name":"Engineering Geology","volume":"341 ","pages":"Article 107735"},"PeriodicalIF":6.9,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}