Acta Geotechnica最新文献

{"title":"Study on particle loss-induced deformation of gap-graded soils: role of particle stress","authors":"Kuang Cheng,&nbsp;Xinyu Ping,&nbsp;Buyao Han,&nbsp;Hao Wu,&nbsp;Hongshuai Liu","doi":"10.1007/s11440-024-02377-x","DOIUrl":"10.1007/s11440-024-02377-x","url":null,"abstract":"<div><p>Deformation induced by finer particle loss is an important phenomenon during suffusion of gap-graded soils. This study focuses on the role of particle stress played in the particle loss-induced volumetric deformation. Discrete element simulations are performed to generate loss of finer particles with prescribed stress contribution, i.e. the contribution of particle stress to the macroscopic stress. Variations of volumetric strain, <i>ε</i>_<i>v</i>, with the stress contribution, <i>C</i>_<i>σ</i>^<i>e</i>, of eroded finer particles present two distinct patterns, that is, transition pattern, i.e. <i>ε</i>_<i>v</i> has extremely small values at relatively small <i>C</i>_<i>σ</i>^<i>e</i> and increases rapidly as <i>C</i>_<i>σ</i>^<i>e</i> exceeds the transition point near <i>C</i>_<i>σ</i>^<i>e</i> = 0.01%, and constant pattern, i.e. <i>ε</i>_<i>v</i> reaches a rather large value at extremely small <i>C</i>_<i>σ</i>^<i>e</i> and varies little with the increment of <i>C</i>_<i>σ</i>^<i>e</i>. A transformation from constant to transition pattern is observed for the <i>ε</i>_<i>v</i>–<i>C</i>_<i>σ</i>^<i>e</i> curves with the increment of the coordination number, <i>Z</i>_strong, of the load-carrying skeleton. The threshold of <i>Z</i>_strong for the transformation is around 3.71 for a relatively small eroded fraction (≤ 10%), while it is 3.96–4.09 for a relatively large eroded fraction (≥ 30%), in which the eroded fraction is the volume percentage of the eroded finer particles within the finer fraction.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"19 12","pages":"7865 - 7892"},"PeriodicalIF":5.6,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214251","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":"Cracking in compacted expansive soils under unidirectional wet-dry cycles: insights from X-ray computed tomography","authors":"Xun Zhu,&nbsp;Zheng Chen,&nbsp;Pengpeng Ni,&nbsp;Zheng-Yin Cai,&nbsp;Ying-Hao Huang,&nbsp;Chen Zhang","doi":"10.1007/s11440-024-02394-w","DOIUrl":"10.1007/s11440-024-02394-w","url":null,"abstract":"<div><p>Cracking of compacted clays during cyclic wetting–drying poses significant challenges to the stability of channel slopes. This study performed a series of unidirectional wet-dry tests to evaluate the cracking behavior of expansive soils collected from a channel slope in northern Xinjiang, China. Using computed tomography scanning and three-dimensional (3D) reconstruction, the internal crack characteristics of expansive soils were quantitatively described. The results indicate that the penetration depth of the cracks was stabilized after five cycles, reaching 31.4% of the initial specimen height. The morphologies of internal cracks revealed a transition in the cracking mode, form shallow and scattered cracks in the initial stage to deeper and more clustered cracks in the final stage. Centralized cracks were prominent in the first three wet-dry cycles, followed by a shift to crack deflection from the vertical plane in subsequent cycles. Four indices (i.e., slice crack ratio, crack length, branching number, and dead-end point) provided a satisfactory quantitative depiction of the evolution of the spatial distribution and connectivity of the cracks over the number of cycles. Additionally, the crack volume fraction and fractal dimension effectively evaluated the 3D cracking behavior of soil crack networks.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"19 12","pages":"7851 - 7864"},"PeriodicalIF":5.6,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214250","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":"Interaction between yielding tunnel support and strain-softening rock mass based on the three-dimensional strength criterion","authors":"Chen Xu,&nbsp;Caichu Xia","doi":"10.1007/s11440-024-02393-x","DOIUrl":"10.1007/s11440-024-02393-x","url":null,"abstract":"<div><p>The “yield-resist” combined support measure is a widely employed control measure in soft rock tunnels for controlling large deformation, particularly in high geostress conditions. For strain-softening rock masses, the strength parameters in the plastic zone are coupled with the support reaction. Due to the complexity of the interaction mechanism between yielding support and strain-softening surrounding rock, the majority of current solutions are based on the plane–strain model. However, the advancement of the tunnel is a three-dimensional problem. Therefore, the longitudinal effect is worthy of discussion when analyzing the mechanical behaviors of strain-softening rock and yielding support. A new two-stage method is proposed to describe the interaction between strain-softening rock mass and yielding support based on the generalized Zhang–Zhu (GZZ) strength criterion. Firstly, a simplified mechanical model of the yielding support structure is suggested to describe the mechanical response of the surrounding rock and support. Subsequently, a semi-analytical solution to three-dimensional ground–support interaction is proposed, taking into account the longitudinal effect. The results of the proposed solution are compared with those of a finite element simulation, and a high degree of agreement is observed. Finally, the mechanical behaviors of different yielding supports are discussed. The findings indicate that postponing the support timing by means of yielding technologies is essential, as otherwise the support would bear a very large load. The second stage of support reaction can be significantly reduced by implementing the “control-yield-resist” (CYR) support. The research offers novel insights and methodologies for investigating the three-dimensional interaction between the surrounding rock and various tunnel supports in high geostress conditions.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"19 12","pages":"7835 - 7850"},"PeriodicalIF":5.6,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214252","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":"Investigation on successive gas breakthroughs behavior of saturated GMZ bentonite under rigid boundary conditions","authors":"Lin-Yong Cui,&nbsp;Wei-Min Ye,&nbsp;Qiong Wang,&nbsp;Yong-Gui Chen,&nbsp;Yu-Jun Cui","doi":"10.1007/s11440-024-02391-z","DOIUrl":"10.1007/s11440-024-02391-z","url":null,"abstract":"<div><p>Understanding impacts of gas breakthrough processes on the sealing ability of the bentonite buffer/backfill materials is crucial for the safety evaluation of the nuclear waste geological repository. In this work, the residual capillary pressure method was utilized to conduct successive gas breakthrough tests on compacted Gaomiaozi bentonite specimens. During each gas breakthrough test, the upstream gas pressure was increased in a step-by-step way until the gas breakthrough was recorded. Water permeability tests were performed before each gas breakthrough to ensure that the bentonite specimen was fully saturated. Finally, after experienced five successive gas breakthrough processes, the bentonite specimen was submitted for the mercury intrusion porosimetry (MIP) test. For comparison, four other parallel specimens that experienced one to four gas breakthroughs, respectively, were also submitted for the MIP tests to examine the possible damage of the bentonite matrix resulted from gas breakthrough processes. Results show that, during the first three successive gas breakthrough tests, the gas breakthrough pressure and the snap-off pressure decreased rapidly from 4.46 to 3.66 MPa and from 0.51 to 0.26 MPa, respectively. An exponential decrease in the maximum effective gas permeability from 3.75 × 10^–18 to 3.17 × 10^–19 m² with gas breakthroughs experienced could also be observed. On contrary, both of the saturated water permeability and the pore size distribution show little difference as compared to its initial value. These results indicate that gas breakthrough process could induce a degradation of gas-tightness capacity of the bentonite specimen. Meanwhile, the gas injection pressure was reset to zero before conducting the water permeability test. Reducing the gas pressure will induce a contraction in the radius of the gas pathway, even leading to complete closure. Consequently, the water permeability and the pore size distribution remained almost unchanged.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"19 10","pages":"6773 - 6786"},"PeriodicalIF":5.6,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214263","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":"Discussion to the article Undrained shear strength prediction of clays using liquidity index, by Q. Wang, S. Qiu, H. Zheng, R. Zhang","authors":"Brendan C. O’Kelly, Stuart K. Haigh","doi":"10.1007/s11440-024-02385-x","DOIUrl":"https://doi.org/10.1007/s11440-024-02385-x","url":null,"abstract":"<p>This communication presents a critical discussion of the article “Undrained shear strength prediction of clays using liquidity index”, authored by Q. Wang, S. Qiu, H. Zheng, R. Zhang, and recently published in <i>Acta Geotechnica</i> (https://doi.org/10.1007/s11440-023-02107-9). Various inaccurate claims and flaws regarding the Authors’ newly developed three-parameter strength–liquidity index (<i>S</i>_<i>u</i>–<i>I</i>_<i>L</i>) models/correlations are highlighted and discussed herein. In particular, comparing existing two-parameter and their newly developed three-parameter <i>S</i>_<i>u</i>–<i>I</i>_<i>L</i> models, contrary to the Authors’ claims, no improvement in prediction accuracy is achieved over the two-parameter model by introducing a third model parameter. Rather, it is shown herein that the existing two-parameter and the Authors’ three-parameter <i>S</i>_<i>u</i>–<i>I</i>_<i>L</i> models are mathematically identical. Furthermore, two of the Authors’ newly developed <i>S</i>_<i>u</i>–<i>I</i>_<i>L</i> correlations, i.e., relating the triaxial-compression and shearbox derived strengths to the liquidity index, are shown to be inaccurate, forecasting gross under- and over-predictions of the measured strengths, respectively. This highlights the need for a reassessment of the proposed correlations, and emphasizes the importance of accurate and reliable correlations in geotechnical engineering.</p>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"38 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214268","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":"Discussion of “A 3D image-based method to measure soil stiffness in triaxial tests” by Wang et al. 2024 (DOI: /10.1007/s11440-023-01977-3)","authors":"Lin Li","doi":"10.1007/s11440-024-02379-9","DOIUrl":"10.1007/s11440-024-02379-9","url":null,"abstract":"<div><p>Wang et al. (2024) proposed a new method to measure soil stiffness through triaxial tests. This discussion illustrates some limitations of the proposed method and details several modifications on the post-image analysis process to enhance its capability. These modifications include the introduction of true stereophotogrammetry for camera and triaxial cell wall orientation, optical ray tracing technique for optical ray reconstruction, and three-dimensional digital image correlation (3D-DIC) for full-field two-dimensional (2D) point cloud generation. With these modifications, the capability of the new method can be significantly improved from only local strain to full-field deformation measurement at a higher accuracy and resolution.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"19 11","pages":"7759 - 7761"},"PeriodicalIF":5.6,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214265","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":"Comment on “Experimental study on the thixotropic mechanism of deep-sea clay from the perspective of microstructure and bound water” by Ren et al. (2023), Acta Geotechnica, https://doi.org/10.1007/s11440-023-01967-5","authors":"Wei Sun, Yucheng Li, Guoping Zhang","doi":"10.1007/s11440-024-02380-2","DOIUrl":"https://doi.org/10.1007/s11440-024-02380-2","url":null,"abstract":"<p>Ren et al. (Acta Geotech, 2023. https://doi.org/10.1007/s11440-023-01967-5) recently reported an interesting experimental investigation of the thixotropism, or thixotropy mechanism, of a deep-sea marine clay, conclusively claiming that the conversion of weakly and strongly bound waters to free water, in addition to microfabric change, contributes to the thixotropic hardening of the studied clay. While the microfabric evolution of the clay during the thixotropic hardening process was observed, in a speculative and qualitative fashion, using scanning electron microscopy, the interconversion of different types of waters (i.e., weakly bound water, strongly bound water, and free water) in the clay was quantitatively assessed using thermogravimetric analysis (TGA) and qualitatively judged by Fourier transform infrared spectroscopy (FTIR). However, some fundamental issues related to the viability and suitability of the employed experimental techniques and the interpretation of TGA and FTIR results arise and are worth re-examination and discussion. In this short communication, the TGA curves and FTIR spectra were re-interpreted, based on a mathematically more accurate and scientifically more rigorous analysis of the data, which appears to make the proposed model of evolution of different types of waters in clays invalid. Consequently, the attribution of thixotropy or one potential thixotropism to the conversion among different types of waters and the conclusions drawn based on the speculative interpretations are also worth further clarifying and commenting. Overall, the TGA and FTIR results probably fail to conclusively establish the conversion among the different types of waters occurring along with the thixotropic hardening process.</p>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"415 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214264","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":"Insight into nonlinear thermal consolidation of saturated clay under coupled thermo-mechanical loading: a unified one-dimensional model","authors":"Mengmeng Lu,&nbsp;Jinxin Sun,&nbsp;Minjie Wen,&nbsp;Kang Yang,&nbsp;Kuo Li","doi":"10.1007/s11440-024-02382-0","DOIUrl":"10.1007/s11440-024-02382-0","url":null,"abstract":"<div><p>The evaluation of thermo-hydro-mechanical (THM) coupling response of clayey soils has emerged as an imperative research focus within thermal-related geotechnical engineering. Clays will exhibit nonlinear physical and mechanical behavior when subjected to variations in effective stress and temperature. Additionally, temperature gradient within soils can induce additional pore water migration, thereby resulting in a significant thermo-osmosis effect. Indeed, thermal consolidation of clayey soils constitutes a complicated THM coupling issue, whereas the theoretical investigation into it currently remains insufficiently developed. In this context, a one-dimensional mathematical model for the nonlinear thermal consolidation of saturated clay is proposed, which comprehensively incorporates the crucial THM coupling characteristics under the combined effects of heating and mechanical loading. In current model, the interaction between nonlinear consolidation and heat transfer process is captured. Heat transfer within saturated clay is investigated by accounting for the conduction, advection, and thermomechanical dispersion. The resulting governing equations and numerical solutions are derived through assuming impeded drainage boundaries. Then, the reasonability of current model is validated by degradation and simulation analysis. Subsequently, an in-depth assessment is carried out to investigate the influence of crucial parameters on the nonlinear consolidation behavior. The results indicate that increasing the temperature can significantly promote the consolidation process of saturated clay, the dissipation rate of excess pore water pressure (EPWP) is accelerated by a maximum of approximately 15%. Moreover, the dissipation rate of EPWP also increases with the increment of pre-consolidation pressure, while the corresponding settlement decreases. Finally, the consolidation performance is remarkably impacted by thermo-osmosis and neglecting this process will generate a substantial departure from engineering practice.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"20 2","pages":"641 - 667"},"PeriodicalIF":5.6,"publicationDate":"2024-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214266","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 fabric anisotropy on the small-strain shear modulus of granular materials","authors":"Xiao-Tian Yang,&nbsp;Yan-Guo Zhou,&nbsp;Qiang Ma,&nbsp;Yun-Min Chen","doi":"10.1007/s11440-024-02381-1","DOIUrl":"10.1007/s11440-024-02381-1","url":null,"abstract":"<div><p>Granular soil generally exhibits an anisotropic stiffness in engineering but challenging to quantify in situ and laboratory condition, due to a lack of the appropriate factor and quantitative research. In this paper, discrete element method is employed to create two typical types of soil fabric and conduct shear wave measurement in double direction, with the microscopic parameters monitored to investigate the connection with macroscopic stiffness anisotropy. The results show that the reference fabric increases as fabric anisotropy increases first and then decreases with further increase in the <i>XZ</i> stress plane, while always decreases approximately linearly in the <i>XY</i> stress plane. The reference fabric is determined by the contact density in the direction of wave propagation and particle perturbation under microscale examination. The results also reveal a linear relationship between the macroscopic stiffness anisotropy and microscopic fabric anisotropy, which could be used as an effective method to reflect the degree of anisotropy in situ by wave measurement. And the applicability of the expression of small-strain shear modulus is also discussed.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"20 1","pages":"131 - 148"},"PeriodicalIF":5.6,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214267","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":"Landslide susceptibility mapping using physics-guided machine learning: a case study of a debris flow event in Colorado Front Range","authors":"Te Pei,&nbsp;Tong Qiu","doi":"10.1007/s11440-024-02384-y","DOIUrl":"10.1007/s11440-024-02384-y","url":null,"abstract":"<div><p>Landslides are common geohazards worldwide, resulting in significant losses to economies and human lives. Data-driven approaches, especially machine learning (ML) models, have been widely used recently for landslide susceptibility mapping (LSM) by extracting features from geospatial variables based on their contribution to landslide occurrences using known distributions of landslides as the training dataset. However, challenges remain in applying ML models for LSM models due to the scarcity and uneven spatial distribution of landslide data coupled with the spatial heterogeneity of hillslope conditions. Moreover, ML models developed with limited data often exhibit unexpected behaviors, resulting in poor interpretability and predictions that deviate from intuitive expectations and established domain knowledge. To overcome these challenges, this study proposes a physics-guided machine learning (PGML) framework that integrates landslide domain knowledge into ML models for LSM. The PGML framework was developed and assessed using a detailed debris flow inventory from a storm event in the Colorado Front Range. Based on the infinite slope model, the factor of safety for the study area was first determined and was subsequently used to constrain the prediction of ML models through a modified loss function and measure the physics consistency of model predictions. To evaluate the robustness and generalizability of the models, this study uses geographical sample selections for model performance evaluation, where ML models are trained and tested across heterogeneous ecoregions. The results of this study demonstrated the efficacy of both physics-based and data-driven methods in determining landslide susceptibility in the study area; however, pure data-driven ML models produced physically unrealistic results and poor generalization performance in new ecoregions. With the incorporation of physical constraints, the PGML model demonstrated notable enhancements in physics consistency and generalization capability, along with reduced model uncertainties across various ecoregions, surpassing the performance of benchmark ML models.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"19 10","pages":"6617 - 6641"},"PeriodicalIF":5.6,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214271","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}