Acta Geotechnica最新文献

{"title":"Sensitivity analysis on critical combinations of input parameters in DEM granular flow analysis","authors":"Junsen Xiao,&nbsp;Kenta Tozato,&nbsp;Reika Nomura,&nbsp;Yu Otake,&nbsp;Kenjiro Terada,&nbsp;Shuji Moriguchi","doi":"10.1007/s11440-024-02499-2","DOIUrl":"10.1007/s11440-024-02499-2","url":null,"abstract":"<div><p>Granular flow is a typical process that occurs in sediment disasters, including rockfalls, avalanches and landslides, etc. The runout distance in granular flow is closely associated with the ultimate impact range of these sediment disasters. However, this factor is often highly sensitive to various physical parameters and exhibits significant randomness. Hence the study of granular flow is crucial to elucidating the mechanism of such disasters and even to disaster prevention and mitigation. In recent years, a numerical simulation called discrete element method (DEM) that simulates at the particle level has been widely used in this field. Based on the above situation, this study aimed to capture the critical DEM input parameter combinations for risk assessment in a four-dimensional parameter space considering the particle size distribution. XGBoost feature importance is employed to decide the search priority, and its results indicate that the friction angle with bottom surface (FABS) and coefficient of restitution (COR) are the key parameters. The two key parameter spaces were then comprehensively explored using Gaussian process regression response surfaces. The correlation between the FABS and runout distance appeared as a convex function. The COR exhibited diverse degrees of approximately linear correlation with the runout distance throughout the granular flow. The particle size distribution indirectly led to inconsistencies between the bidisperse flow and other granular flows in the influence mechanisms of the key parameters. By clarifying this effect, we efficiently identified two critical parameter combinations for granular flow DEM simulation.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"20 1","pages":"387 - 412"},"PeriodicalIF":5.6,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11440-024-02499-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142963145","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":"Investigations on mechanical responses of frozen soil–rock mixture under cyclic loading: experiments and binary-medium-based multiscale constitutive model","authors":"Dan Wang,&nbsp;Enlong Liu,&nbsp;Qihao Yu,&nbsp;Chengsong Yang,&nbsp;Yunming Yang,&nbsp;Bingtang Song,&nbsp;Jian Kang,&nbsp;Ling Chen,&nbsp;Haotian Wei,&nbsp;Qiong Li","doi":"10.1007/s11440-024-02480-z","DOIUrl":"10.1007/s11440-024-02480-z","url":null,"abstract":"<div><p>In cold regions, the frozen soil–rock mixture (FSRM) is subjected to cyclic loading coupled with freeze–thaw cycles due to seismic loading and ambient temperature changes. In this study, in order to investigate the dynamic mechanical response of FSRM, a series of cyclic cryo-triaxial tests were performed at a temperature of −10 °C on FRSM with different coarse-grained contents under different loading conditions after freeze–thaw cycles. The experimental results show that the coarse-grained contents and freeze–thaw cycles have a significant influence on the deformation properties of FSRM under cyclic loading. Correspondingly, a novel binary-medium-based multiscale constitutive model is firstly proposed to describe the dynamic elastoplastic deformation of FSRM based on the coupling theoretical framework of breakage mechanics for geomaterials and homogenization theory. Considering the multiscale heterogeneities, ice-cementation differences, and the breakage process of FSRM under external loading, the relationship between the microscale compositions, the mesoscale deformation mechanism (including cementation breakage and frictional sliding), and the macroscopic mechanical response of the frozen soil is first established by two steps of homogenization on the proposed model. Meanwhile, a mixed hardening rule that combines the isotropic hardening rule and kinematic hardening is employed to properly evaluate the cyclic plastic behavior of FSRM. Finally, comparisons between the predicted results and experimental results show that the proposed multiscale model can simultaneously capture the main feature of stress–strain (nonlinearity, hysteresis, and plastic strain accumulation) and volumetric strain (contraction and dilatancy) of the studied material under cyclic loading.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"20 1","pages":"231 - 263"},"PeriodicalIF":5.6,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142963107","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":"Cosserat model incorporating anisotropy evolution and its application in numerical analysis of strain localization in clay","authors":"Wencheng Wei,&nbsp;Hongxiang Tang,&nbsp;Yang Liu,&nbsp;Haolong Chen","doi":"10.1007/s11440-024-02483-w","DOIUrl":"10.1007/s11440-024-02483-w","url":null,"abstract":"<div><p>This paper deeply couples the exponential-type nonlinear strain softening with the anisotropic method of microstructure tensor combined stress invariants, proposing an effective strength formula that reflects the anisotropy evolution of soil. Furthermore, an expression for the anisotropy ratio <i>k</i> of strength as an equivalent plastic strain-related variable is derived. For natural clay, this evolution of strength anisotropy is incorporated into the Mohr–Coulomb-matched Drucker–Prager (MC-matched DP) yield criterion within the Cosserat continuum framework, resulting in a more refined soil constitutive model. The main strength parameters required for this model can be conveniently obtained based on conventional soil tests, and the model functionality can be degraded through parameter adjustments. The detailed procedure of stress updating algorithm and the elastoplastic tangent modulus matrix are provided for the constitutive integration. Through the finite element implementation, the superiority of the model is demonstrated compared with existing literature. Also, a biaxial compression example is systematically analyzed to prove that the model can effectively reflect the sensitivity of soil to loading direction. Moreover, the evolution of the shear band morphology, particle rotation in the shear band, and the anisotropy degree presented by the model are consistent with previous experimental studies and discrete element method (DEM)-related literature results. Furthermore, the proposed model effectively addresses numerical convergence issues and mesh size dependence usually encountered in classical models during the simulation of strain localization occurred in the soil.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"20 1","pages":"365 - 385"},"PeriodicalIF":5.6,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142963102","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":"Final steady state of sloping capillary barriers under constant intensity rain: development and numerical validation of a simplified method of analysis","authors":"Simon J. Wheeler,&nbsp;Paverean Mudcharoen,&nbsp;Riccardo Scarfone","doi":"10.1007/s11440-024-02492-9","DOIUrl":"10.1007/s11440-024-02492-9","url":null,"abstract":"<div><p>A new simplified method of analysis is proposed for predicting the final steady state behaviour of sloping capillary barriers subjected to continuous rain of constant intensity. In contrast to an existing simplified method, the proposed new method assumes approximate final steady state suction profiles on vertical cross-sections of the finer layer that are appropriate for sloping capillary barriers, with flow parallel to the slope in the lower part of the finer layer. Numerical validation, performed by hydraulic FE modelling, shows that, in all cases studied, the final steady state profiles of suction, degree of saturation and horizontal seepage velocity predicted by the new simplified method are excellent matches to the corresponding results from FE simulations. As a consequence, values of water storage capacity and water transfer capacity are accurately predicted in all cases, together with the final steady state variation of water stored with horizontal coordinate. A parametric study shows the influence of key variables (slope angle, material of finer layer, thickness of finer layer and rainfall intensity) on water storage capacity and water transfer capacity of sloping capillary barriers.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"20 1","pages":"1 - 21"},"PeriodicalIF":5.6,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142963103","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":"New simplified stability analysis method of structuralized cemented slopes","authors":"Sujia Liu,&nbsp;Fangyue Luo,&nbsp;Ga Zhang","doi":"10.1007/s11440-024-02495-6","DOIUrl":"10.1007/s11440-024-02495-6","url":null,"abstract":"<div><p>In recent years, structuralized cementation method has become a novel and promising method for reinforcement of coarse-grained soil slope, which has been proved by practical application. Nevertheless, structuralized cemented slopes with gradient material properties cannot be analyzed using the current methods. The structuralized cemented slope is divided into pure soil zone, variation zone, and solidification zone. The constitutive models of cemented soil in the three zones are proposed, respectively. Slip surfaces of structuralized cemented slopes are all assumed as circular arc shape. It is proved that the displacement compatibility rule is valid for the structuralized cemented slope. A new simple approach is proposed through extension of simplified Bishop slice approach for analyzing structuralized cemented slope stability degree with different cement distribution under various conditions. Our proposed approach involves few parameters examined by element tests. Through analyzing structuralized cemented slopes based on vertical loading and excavation conditions, our proposed method is validated, showing agreement with centrifuge model test analysis. Application of this approach to an actual slope based on excavation conditions reveals that an expanded solidification zone enhances slope safety and reduces shear deformation. Stability remains relatively constant once the solidification zone reaches a certain size. This result underscores the practical value of the proposed method in predicting and optimizing the stability of structuralized cemented slopes.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"20 1","pages":"23 - 36"},"PeriodicalIF":5.6,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142963150","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":"On rotational hardening in soil elastic-plasticity","authors":"Giuseppe Mortara,&nbsp;Claudio di Prisco","doi":"10.1007/s11440-024-02458-x","DOIUrl":"10.1007/s11440-024-02458-x","url":null,"abstract":"<div><p>In this paper, a new approach for rotational hardening in elastic-plasticity is formulated. After discussing the standard yield criteria employed for geomaterials and the rotational hardening models proposed in the past, the authors introduce the concept of pure rotational hardening, that is a rigid rotation of the yield surface not implying any distortion of it. In the second part of the paper, a new approach for rotational hardening, based on Householder transformations, is proposed. The method, that allows to reflect vectors with respect to a given hyper-plane, is briefly described since not usually employed in geomechanics. Moreover, the authors clarify that any yield surface or plastic potential rotation, not being a rolling, is a transformation keeping unaltered first and second invariants, but not the third. As a consequence, when rotational hardening is introduced, the use of the third mixed invariant, for defining in the deviatoric plane the yield surface shape, is not appropriate. Finally, the application of the proposed approach in the formulation of anisotropic elastic–plastic strain hardening constitutive models is briefly discussed for the classes of <i>uncoupled</i> and <i>hybrid</i> yield criteria that include a dependence of the yield surface on Lode angle.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"20 1","pages":"197 - 210"},"PeriodicalIF":5.6,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142963053","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":"Undrained SHPB experiments on calcareous sand with different saturation degrees","authors":"Yuchen Su,&nbsp;Yuan Wang,&nbsp;Yaru Lv,&nbsp;Pengfei Li","doi":"10.1007/s11440-024-02478-7","DOIUrl":"10.1007/s11440-024-02478-7","url":null,"abstract":"<div><p>Extensive research has been conducted on the impact behavior of unsaturated sand at high strain rates. However, achieving the undrained boundary condition remains a persistent challenge, leading to an inconsistent understanding of the dynamic responses of sand with varying saturation degrees. In this study, a novel sleeve designed to conduct split Hopkinson pressure bar (SHPB) tests under undrained boundary conditions. Furthermore, drained SHPB tests were carried out by using the conventional steel sleeve as references. The absolute particle crushing distributions within various size ranges were investigated by utilization of dyed calcareous sand. Results revealed that, for the conventional drained sleeve, the locking-up phenomenon of full saturation sand was only observed at strain rate of 750 s⁻¹. However, locking-up occurs at all strain rates for undrained sleeve. The locking-up stiffness at strain rate of 1000 s⁻¹ was 1.6 times larger compared to that at strain rate of 500 s⁻¹ and 750 s⁻¹, respectively. It means that the locking-up stiffness increases with strain rates under the fully undrained boundary conditions. Furthermore, for the drained sleeve, negligible reductions up to 10.8% were observed in measured <i>B</i>_r if saturation degrees change from 0 to 100%. In contrast, for the undrained sleeve, the maximum reduction on <i>B</i>_r was 47.6% and increases rapidly with increasing strain rates. The particle crushing was more sensitive to saturation degree at higher loading strain rates under undrained boundary conditions. Meanwhile, the particle crushing probability <span>({P}_{text{c}})</span> of medium-sized (1.0–1.5 mm) particles decreases with decreasing saturation degrees and increasing strain rate. It leads that the probabilities of particle crushing across various size ranges become more uniformly distributed with lower saturation degree and higher strain rates.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"20 1","pages":"287 - 302"},"PeriodicalIF":5.6,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142963034","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":"Lateral capacity and failure mechanisms of skirted foundation resting on slopes","authors":"Khalid Bashir,&nbsp;Ravi S. Jakka","doi":"10.1007/s11440-024-02486-7","DOIUrl":"10.1007/s11440-024-02486-7","url":null,"abstract":"<div><p>While the effect of combined loading on the load carrying capacity of skirted foundations on horizontal ground surfaces is well documented in the literature, comprehensive studies for skirted footings situated on or near slopes remain lacking. This study aims to investigate the influence of various factors, including slope angle (<i>β</i>), angle of internal friction (<i>ϕ</i>), setback distance (<i>B′</i>/<i>B</i>), and skirt length (<i>L</i>/<i>B</i>), on failure loads and capacity envelopes for skirted foundations. The performance of a skirted footing system under combined vertical and lateral loadings in cohesionless soils was analysed using finite-element limit analysis (FELA) and small-scale experimental tests. The results indicate that the optimal skirt length depends on the specific conditions of the slope and setback distances. As the setback distance increases, the optimal skirt length tends to decrease, while an increase in slope steepness corresponds to an increase in the optimal skirt length. Furthermore, this study presents integrated capacity envelopes that incorporate a wide range of realistic soil slopes. The calculated capacity envelopes are subsequently compared to those on flat ground, highlighting that the unique characteristics of these envelopes are based on different combinations of vertical load (<i>V</i>) and combined vertical and lateral load (VH). Skirted footings on slopes exhibit distinct behaviour compared to those on level ground, with multiple factors influencing their capacity envelopes. Specifically, skirted foundations demonstrate lower capacity than equivalent block foundations, particularly when placed near steep slopes due to the formation of an inverted circular scoop failure surface for larger <i>L</i>/<i>B</i> ratios. In contrast, the formation of an inverted circular scoop is less pronounced for moderate slopes and footings with a smaller <i>L</i>/<i>B</i> ratio. The numerical study provides a comprehensive explanation of the failure mechanisms associated with the design of skirted footings located in close proximity to slopes, especially when subjected to lateral loads. Based on the results obtained, capacity envelope diagrams are proposed for estimating the capacity of skirted footings on slopes. Small-scale experiments were also conducted to explore the effects of varying skirt lengths placed on both level and sloping ground within a testing tank. The outcomes of this study yield valuable insights into the behaviour of skirted foundations on slopes, as well as their overall response to both vertical and lateral loadings.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"20 1","pages":"89 - 117"},"PeriodicalIF":5.6,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142963054","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":"Machine learning-aided selection of CPT-based transformation models using field monitoring data from a specific project","authors":"Hua-Ming Tian,&nbsp;Yu Wang,&nbsp;Chao Shi","doi":"10.1007/s11440-024-02475-w","DOIUrl":"10.1007/s11440-024-02475-w","url":null,"abstract":"<div><p>Transformation models have been widely used in geotechnical engineering to relate data from lab or field tests (e.g., cone penetration tests, CPT) to design parameters required in geotechnical analysis and design. Proper selection of transformation models is crucial but challenging for accurate prediction of geotechnical responses (e.g., reclamation-induced settlement) in practice. This study proposes a general machine learning framework that accommodates a wide variety of existing CPT-based transformation models and uses field monitoring data (e.g., settlement data observed from a specific project) to select suitable transformation models for improving prediction of spatiotemporally varying reclamation-induced settlement. The proposed approach takes advantage of sparse dictionary learning (SDL) and achieves prediction of settlement by a linear weighted sum of dictionary atoms that are constructed using outputs from finite element models (FEM) of reclamation-induced consolidation. Input parameters of the FEM models are determined using existing transformation models in literature. A transformation model database that relates multiple soil consolidation parameters with CPT data is also compiled for consolidation analysis and dictionary construction in SDL. The proposed approach is illustrated using a real reclamation project in Hong Kong. Results show that the proposed approach provides an effective and transparent vehicle to leverage existing abundant transformation models, identify appropriate transformation models using field monitoring data, and improve prediction of spatiotemporally varying reclamation-induced settlement, with greatly reduced prediction uncertainty. The transformation model selection and settlement prediction are also improved continuously as more field monitoring data are obtained.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"20 1","pages":"439 - 459"},"PeriodicalIF":5.6,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11440-024-02475-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142962977","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":"A machine learning-based drag model for sand particles in transition flow aided by spherical harmonic analysis and resolved CFD-DEM","authors":"Gaoyang Hu,&nbsp;Bo Zhou,&nbsp;Wenbo Zheng,&nbsp;Changheng Li,&nbsp;Huabin Wang","doi":"10.1007/s11440-024-02472-z","DOIUrl":"10.1007/s11440-024-02472-z","url":null,"abstract":"<div><p>Given the importance of drag model in solving fluid–particle interactions in unresolved numerical methods, this study proposed a machine learning (ML)-based drag model for irregular sand particles in transition flow, aided by spherical harmonic (SH) analysis and a resolved computational fluid dynamics-discrete element method (CFD-DEM). Initially, realistic particle shapes were reconstructed by the SH function, and their multi-scale shape features were quantified by the energy spectrums of SH frequencies. A developed fictitious domain method, particularly for irregularly shaped clumps, was proposed to solve fluid–solid interactions within resolved CFD-DEM. Subsequently, the fluid flow past a fixed particle test was repetitively simulated by the resolved CFD-DEM for 270 realistic sand particles, and a dataset consisting of 4220 drag coefficients was finally established. A classic ML algorithm, namely the multi-layer perceptron (MLP) neural network, was then utilized to train a drag model associated with the multi-scale shape features, particle orientations, and flow conditions. Compared with the results from the resolved CFD-DEM, the trained MLP model demonstrates both efficiency and accuracy in predicting the drag coefficients of natural sand particles with irregular shapes. This work provides a more reliable drag model for granular soils and shows its potential for application in large-scale modeling using the unresolved CFD-DEM framework.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"20 1","pages":"461 - 474"},"PeriodicalIF":5.6,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142962976","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}