Acta Geotechnica最新文献

{"title":"Water retention behavior and microstructural evolution of GMZ bentonite granules upon wetting and drying for deep geological disposal","authors":"Fan Peng,&nbsp;Chen Bo,&nbsp;De’an Sun,&nbsp;You Gao","doi":"10.1007/s11440-024-02442-5","DOIUrl":"10.1007/s11440-024-02442-5","url":null,"abstract":"<div><p>Compared with compacted block, the bentonite granules (BG) were increasingly considered as feasible sealing materials for deep geological disposal, due to its superior operationality and installation efficiency. However, further studies are needed to assess the hydraulic response and microstructural evolution of BG. This work focused on the water retention behavior of BG specimens prepared with different grading curves and void ratios (0.6, 0.8 and 1.0), under confined/unconfined conditions following wetting and drying paths. The specimens’ pore structure and its evolution were studied using mercury intrusion porosimetry. Results indicated that the water retention capacity was generally unique at high suctions (&gt; about 10 MPa) due to adsorption mechanism, while it was related to pore structure at low suctions. Under confined condition, wetting caused macropore (i.e., inter-aggregate/pellet pores) compression and pore structure rearrangement, while the inter-particle pores kept almost unchanged. BG specimen with more and coarser granules initially exhibited more and bigger macropores, and its initial granular structure was progressively lost upon wetting. Meanwhile, the volume expansion was relatively limited upon wetting at high suctions, below which it gradually became obvious. Comparatively, wetting caused macropore enlargement and even cracks generation under unconfined condition. After saturation under confined condition, drying caused initially macropore contraction and the granular structure was somewhat recovered that could result in further opening of cracks. Besides, the shrinking rate gradually became slow at suction &gt; about 30 MPa. This study is conducive to comprehension and design of engineered barrier system for deep geological disposal.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"19 12","pages":"7821 - 7833"},"PeriodicalIF":5.6,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142754289","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":"Fault rupture propagation through stratified sand–clay deposits and engineered earth structures: a meshfree and critical-state modeling approach","authors":"Enrique M. del Castillo,&nbsp;Alomir H. Fávero Neto,&nbsp;Ronaldo I. Borja","doi":"10.1007/s11440-024-02421-w","DOIUrl":"10.1007/s11440-024-02421-w","url":null,"abstract":"<div><p>Permanent deformation and uplift caused by fault rupture is one of the most significant hazards posed by earthquakes on the built environment. In this paper, we use smoothed particle hydrodynamics (SPH) to explore the effects of soil layering or stratification on the trajectories and deformation patterns caused by rupturing reverse faults in bedrock, as well as in the foundations of engineered earth structures. SPH is a continuum meshfree numerical method highly adept at modeling large deformation problems in geotechnics. Through the use of constitutive models involving softening behavior as well as critical state type models, we isolate the effects of rigid body rotation from critical state behavior of soil in helping explain the frequently observed rotation of shear bands emanating from the bedrock fault. This analysis is facilitated by the fact that the SPH method allows us to track the propagation of shear bands over substantial amounts of vertical uplift (more than 50% of the total height of the soil deposit), far beyond many previous computational studies employing the finite element method (FEM). We observe and characterize various emergent features including fault bifurcations, stunted faults, and tension cracking, while providing insights into practical guidelines regarding the potential surface distortion width, and the critical amount of fault displacement required for surface rupture depending on the multilayered constitution of the soil deposit. Finally, we predict the expected amount of surface distortion and internal damage to earthen embankments depending on varying fault location and soil makeup.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"19 12","pages":"7767 - 7798"},"PeriodicalIF":5.6,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142754317","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":"Simulation of the failure and run-out processes of rotational–translational loess landslides using an SPH model considering strain softening","authors":"Zhitian Qiao,&nbsp;Wei Shen,&nbsp;Peng Xin,&nbsp;Tonglu Li,&nbsp;Ping Li,&nbsp;Hongcheng Jiao","doi":"10.1007/s11440-024-02427-4","DOIUrl":"10.1007/s11440-024-02427-4","url":null,"abstract":"<div><p>The rotational–translational loess landslides are widely distributed in northwest China, usually posing threats to the surrounding residents and infrastructure. These loess landslides are characterized by the formation of multiple slip surfaces during the run-out process, and the mechanisms of this phenomenon in loess landslides have not been sufficiently investigated. Therefore, in this paper, we integrated the elastic–plastic strain softening constitutive law into the original DualSPHysics code to extend its application in simulating rotational–translational loess landslides. Two benchmark cases are studied to validate the model, the failure process of a cohesive soil slope without strain softening and that of a sensitive clay slope with strain softening. The results illustrate that our model can effectively predict large deformation. Then, the run-out process of the Caijiapo landslide in northwest China is analyzed by the modified model to investigate its failure mechanism. The results illustrate that the failure pattern of the Caijiapo loess landslide is very different from the typical retrogressive failure of clay landslides. The main slip surface of the Caijiapo landslide is controlled by the pre-existing structural plane. The second and third slip surfaces of this landslide are formed inside the sliding mass due to stress redistribution during the run-out process. Three scarps are formed in the landslide deposit because of the formation of multiple slip surfaces. This deposition morphology can be well reproduced by the SPH model taking strain softening into account, while the results using an SPH model without considering strain softening cannot capture this essential deformation characteristic.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"19 12","pages":"7799 - 7820"},"PeriodicalIF":5.6,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142754256","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":"Experimental investigation of fracture permeability reduction process by MICP technology with Sporosarcina pasteurii cultured by different mediums","authors":"Lei Shi,&nbsp;Haiyang Qiao,&nbsp;Xiao Yang,&nbsp;Bin Zhang,&nbsp;Jianwei Zhang","doi":"10.1007/s11440-024-02425-6","DOIUrl":"10.1007/s11440-024-02425-6","url":null,"abstract":"<div><p>This study conducted a detailed investigation on the influence of the culture medium type on the permeability reduction effect through microbial-induced calcium carbonate precipitation (MICP) technology in a single rough fracture. The differences between the Sporosarcina pasteurii cultured by two mediums were compared in terms of bacterial growth properties, permeability treatment effects, distribution characteristics of induced CaCO₃, and microscopic crystal characteristics. The study revealed that the culture medium did indeed impact the permeability reduction effect when treated with MICP technology, primarily related to whether urea is added in the culture medium. Two distinct permeability reduction modes were proposed for the treatment process using Sporosarcina pasteurii cultured by different mediums through one-phase injection (mixing bacterial solution and cementing solution). The permeability decreased rapidly, and the distribution of induced CaCO₃ was uneven after treatment with Sporosarcina pasteurii cultured in medium containing urea, while the permeability decreased relatively slowly and the induced CaCO₃ distribution was relatively uniform when treated with Sporosarcina pasteurii cultured in medium without urea. Additionally, differences in crystal morphology were observed due to variations in seepage characteristics during the treatment process with the Sporosarcina pasteurii cultured by different mediums. Finally, some investigations were given to the treatment effect optimization for the treatment process of Sporosarcina pasteurii cultured in medium containing urea. This study gave an insight to the regulation mechanism of culture medium and treatment method for the process of permeability reduction by MICP technology in the rock fracture.</p><h3>Graphical abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"19 11","pages":"7349 - 7368"},"PeriodicalIF":5.6,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595312","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":"Visual experimental investigation on the performance of grouted gravel pile during construction process in clay","authors":"Lingzhi Zhang,&nbsp;Hanlong Liu,&nbsp;Xuanming Ding,&nbsp;Qiang Ou,&nbsp;Chunyan Wang","doi":"10.1007/s11440-024-02423-8","DOIUrl":"10.1007/s11440-024-02423-8","url":null,"abstract":"<div><p>The grouted gravel pile is a new method of pile foundation, which has been widely used in engineering fields in recent years. However, the grout diffusion characteristics and full-field displacement response of soil during grouting have not been fully revealed and systematically studied in previous publications. This paper employed a transparent soil model test system to explore the effects of the grouting pressure (GP), soil pre-consolidation pressure (SPCP), and initial viscosity of grout (GIV) on the grouting performances and load-bearing characteristics of grouted gravel piles. The development laws of the grouting duration, displacement field of the soil, and ultimate load-bearing capacity of the pile were analyzed. The results show that the total grouting duration decreases with a higher GP, increases with the increasing GIV, initially increases and then decreases as SPCP increases. Both the range of horizontal and vertical displacements of the soil around the pile and the distribution of vertical displacements of the soil at the pile end were obviously enlarged with GP as well as with GIV. However, with the increasing SPCP, they showed a decreasing tendency. The vertical ultimate load-bearing capacity of the grouted gravel pile increases with GP, SPCP, and GIV to varying degrees. The findings of this study contribute to the understanding of the pile-soil interaction during grouting process of the grouted gravel pile, which may improve the design of construction parameters.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"19 11","pages":"7369 - 7387"},"PeriodicalIF":5.6,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595475","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":"Experimental and 3D numerical analysis of embankment on soft soil improved with cement bottom ash columns","authors":"Arshad Ullah,&nbsp;Azman Kassim,&nbsp;Ahmad Safuan A. Rashid,&nbsp;Yu Huang,&nbsp;Muhammad Junaid,&nbsp;Mohammad Jawed Roshan","doi":"10.1007/s11440-024-02412-x","DOIUrl":"10.1007/s11440-024-02412-x","url":null,"abstract":"<div><p>Bottom ash (BA) is a byproduct produced during coal combustion and can be utilized in mortar as a column material to conserve natural resources and promote sustainable ground stabilization. In this paper, the load-carrying capacity performance of the embankment resting on cement bottom ash columns (CBAC) improved ground was examined. Physical model tests and numerical analysis were conducted for the soft soil improved with three columns spacing to diameter ratios (<i>s</i>/<i>d</i>) of 1.8, 2.4, and 3.6 and two columns length to diameter ratios (<i>L</i>/<i>d</i>) of 6 and 8. Three earth pressure transducers, load cell, and pore water pressure transducer were employed to measure the applied vertical stress on the bottom and top of the column and surrounding clay, embankment surface, and excess pore water pressure (<i>u′</i>), respectively. The findings obtained from both physical and numerical models demonstrated that ultimate bearing capacity (<i>q</i>_ult) increased by reducing the <i>s</i>/<i>d</i> and increasing the <i>L</i>/<i>d</i> values. The <i>q</i>_ult increased by almost 1.15, 1.39, 1.70 times and 1.18, 1.44, and 1.77 times as compared to the unimproved soil for the <i>s</i>/<i>d</i> of 3.6, 2.4, and 1.8 with <i>L</i>/<i>d</i> values of 6 and 8, respectively. The maximum improvement was achieved for the model with CBAC having <i>L</i>/<i>d</i> of 8 and <i>s</i>/<i>d</i> of 1.8. In addition, a mathematical equation with <i>R</i>² of 0.999 was established for the determination of the predicted <i>q</i>_ult. The results of this paper can lead to the usage of BA as a green material in the column for ground stabilization.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"19 11","pages":"7727 - 7745"},"PeriodicalIF":5.6,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595237","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":"Analysis of thixotropy of cement grout based on a virtual bond model","authors":"Haizhi Zang,&nbsp;Shanyong Wang,&nbsp;John P. Carter","doi":"10.1007/s11440-024-02417-6","DOIUrl":"10.1007/s11440-024-02417-6","url":null,"abstract":"<div><p>Thixotropy of cementitious materials is a crucial intrinsic property that determines the flowability and workability of cement-based grout. A novel virtual bond model of cement particles is developed in this paper to depict the thixotropy of cement grout. A particulate description of the reversible and erasable interparticle bonds is established based on experimental observations with a focus on the non-contact interactions mainly contributed in practice by calcium silicate hydrates (C–S–H). The structural breakdown of the cement network is realized through bonds breakage under applied motion, and the bonding network recovers with regeneration of interparticle connections that involve reversible hydrate reactions in the mixture. The balance between bond rupture and rebuilding can be tuned by assigning different strength limits for bond breakage. We have implemented this model in the open-source code Yade to carry out 3D discrete element method simulations of a rotational vane system filled with spherical particles, and the results show good agreement with experimental data. The modelling results reveal the transition from a solid-like structure to a fluid-like medium within cement suspensions caused by the evolution of broken interparticle bonds. The results also provide a distinct view of thixotropic variation upon disturbance. This model is extendable to other cohesive materials providing an explicit physical definition of the interparticle interactions. It also provides a theoretical explanation for the empirical estimations of thixotropy common in engineering industries and a potential means of measuring cementitious granular flow that may be useful in future studies.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"19 11","pages":"7427 - 7450"},"PeriodicalIF":5.6,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11440-024-02417-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595530","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":"Influence of bio-cementation on gas permeability of unsaturated soils in landfill cover system","authors":"Longjian Huang,&nbsp;Weiling Cai,&nbsp;Bogireddy Chandra,&nbsp;Ankit Garg,&nbsp;Yanning Wang","doi":"10.1007/s11440-024-02416-7","DOIUrl":"10.1007/s11440-024-02416-7","url":null,"abstract":"<div><p>Landfill cover systems should exhibit low gas permeability to minimize the overflow of greenhouse gases and subsequent air pollution. Microbially induced carbonate precipitation (MICP), a biocementation technique, has been applied for subsurface soil stabilization by improving the shear strength of the soil. However, the impact of MICP on the gas permeability of unsaturated soils remains unknown. Considering the role of biocementation in the modification of soil interpores, this study investigated the feasibility of using the MICP technique to reduce the gas permeability of granite residual soils in response to unsaturated conditions. The biocemented soil samples were prepared by mixing soils with MICP chemical solutions at different chemical concentrations. Water retention tests and measurements of gas permeability were performed, in which suction, volumetric water content and gas permeability were continuously monitored. Additionally, energy-dispersive X-ray spectroscopy and X-ray diffraction analyses were performed to investigate the formation of CaCO₃ precipitates; scanning electron microscopy was used to study the impact of MICP on the soil interpore structure, and the acid washing method was used to determine the CaCO₃ content. The results showed that soils treated with higher concentrations of MICP chemical solutions had higher air entry pressures and residual water contents. This indicates the improvement of water retention due to the presence of MICP, which increases the microstructural porosity and enhances the capillarity, as observed via microscopy. Furthermore, the results revealed that biocementation significantly reduced the gas permeability of the soil and that the change in the maximum gas permeability strongly correlated with the MICP chemical solution concentration and the CaCO₃ content. This study highlights the role of MICP in soil–water–air interface studies and the potential application of this biocementation technique to minimizing gas emission issues in landfill cover systems.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"19 11","pages":"7389 - 7405"},"PeriodicalIF":5.6,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595531","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":"Economic impact analysis for steel piles driven in intermediate geomaterials using machine learning algorithms","authors":"Nafis Bin Masud,&nbsp;Shaun S. Wulff,&nbsp;Kam Ng","doi":"10.1007/s11440-024-02406-9","DOIUrl":"10.1007/s11440-024-02406-9","url":null,"abstract":"<div><p>To mitigate the existing challenges with piles driven in intermediate geomaterial (IGM), this study presents an economic impact assessment for steel piles in IGMs based on the newly developed and existing static analysis (SA) methods using 149 test pile data from seven US states. The assessment determines the differences in the number of piles and the equivalent steel pile weight. The proposed SA methods yield, on average, a smaller difference in steel weight based on states, pile types, and bearing IGM layers. Three machine learning (ML) algorithms: random forest, support vector machine (SVM) and neural network are applied to predict the difference in steel weight. Three percentage-based variables are employed in the ML algorithms as inputs: total pile penetration, total shaft resistance and end bearing in IGM. Based upon 31 testing data, SVM with the lowest RMSE, MAD and highest pseudo-<i>R</i>² is identified as the best algorithm. The predicted difference in steel weight from SVM is optimized to zero using a novel application of the genetic algorithm, and various contour maps are generated. These contour maps can be used to predict the difference in steel weight graphically based on the three percentage-based variables for future driven steel piles in IGMs.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"19 11","pages":"7407 - 7425"},"PeriodicalIF":5.6,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595385","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 of the one-dimensional consolidation and creep of clays with different thicknesses using different hypotheses and three elastic visco-plastic models","authors":"Ze-jian Chen,&nbsp;Peng-lin Li,&nbsp;Pei-chen Wu,&nbsp;Jian-hua Yin,&nbsp;Ding-bao Song","doi":"10.1007/s11440-024-02405-w","DOIUrl":"10.1007/s11440-024-02405-w","url":null,"abstract":"<div><p>The one-dimensional consolidation analysis of clays considering creep compression is a classical issue in soil mechanics and geotechnical design. The major debate lies in how to predict the consolidation settlement for a thick layer in the field using parameters obtained from a thin specimen from the laboratory. Different hypotheses have been advocated, based on which various methods and constitutive models have been developed. However, there are still some questions unaddressed and concepts inconsistently used, which may mislead engineers in the selection of methods/models and may result in settlements underestimated on a risk design side. In this paper, a state-of-the-art review and a thorough comparison study are performed on the existing methods and models for the consolidation analysis of clays exhibiting creep, from theoretical derivations to numerical simulations in comparison with soil test data. An in-depth discussion is carried out on several key issues related to the thickness effects on the time-dependent compression behaviour of clays. The arguments of Hypothesis A and Hypothesis B are revisited based on the current development of constitutive theories. Three existing elastic visco-plastic (EVP) models that consider the creep compression implicitly during the whole consolidation process can perform well in predicting the settlement of clay layers with different thicknesses, and are in line with Hypothesis B. It is concluded that using existing EVP models based on porous-media continuum mechanics is a rigorous scientific method (also called “rigorous” Hypothesis B method), which is superior to the old Hypothesis A method which has logic errors and may result in unsafe underestimation of settlements.</p></div>","PeriodicalId":49308,"journal":{"name":"Acta Geotechnica","volume":"19 11","pages":"7329 - 7347"},"PeriodicalIF":5.6,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11440-024-02405-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595608","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}