Computers and Geotechnics最新文献

{"title":"Hyperspheric Integral Reliability Method for efficient reliability analysis of geotechnical ultimate limit states","authors":"Ivan Depina","doi":"10.1016/j.compgeo.2024.106861","DOIUrl":"10.1016/j.compgeo.2024.106861","url":null,"abstract":"<div><div>This paper introduces the Hyperspheric Integral Reliability Method (HINT) for efficient reliability analysis of geotechnical ultimate limit states. The method is motivated by the mechanism of the Shear Strength Reduction Method (SSRM), which is often employed to calculate the factor of safety for geotechnical ultimate limit states. HINT exploits the observation that a factor of safety, computed by the SSRM, is not only a pointwise estimate of safety, but also a measure of distance to the failure limit along a radial direction in the space of the shear strength parameters. This observation is utilized to transform the reliability integral in the hyperspheric coordinate system and develop an efficient estimator of failure probability for geotechnical ultimate limit states. HINT was examined on several benchmarking problems, demonstrating stable and highly efficient performance on low to medium dimensional reliability problems. HINT can be also applied to general reliability problems if a radial search mechanism is implemented as in the SSRM. Given that the SSRM is already available in most commercial geotechnical software packages, HINT is perfectly suited to advance geotechnical reliability analyses and make them accessible to a wider set of use-cases.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"177 ","pages":"Article 106861"},"PeriodicalIF":5.3,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660210","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":"Reliability analysis of slopes reinforced by frame-anchor structures under earthquake conditions","authors":"Zhengzhen Wang ,&nbsp;Zhentao Zhang ,&nbsp;Guoliang Dai ,&nbsp;Yong Zhou ,&nbsp;Chengming Cao ,&nbsp;Tiantao Su","doi":"10.1016/j.compgeo.2024.106885","DOIUrl":"10.1016/j.compgeo.2024.106885","url":null,"abstract":"<div><div>Earthquakes often cause slope collapse, which poses a serious threat to people’s lives and property. Therefore, it is important to study slope stability under earthquake conditions. The limit element upper bound method was improved and applied to the stability analysis of the slope reinforced by frame-anchor structures under earthquake action. The influences of anchor prestress and seismic force on the stability of slope were analysed comprehensively, and the soil was regarded as a heterogeneous material in its natural state under the action of weathering, deposition and historical stress. The rationality of the slope’s safety factor and failure mode obtained by this method was verified by an example. Based on the Monte Carlo method, considering the random distribution of soil parameters in space and the autocorrelation between any two points, the midpoint method based on Cholesky decomposition was used to simulate the relevant Gaussian random field. The solution program was compiled in MATLAB. The influence of several commonly used autocorrelation function types on the failure probability of slopes was analysed. The influence of the anchor rod prestress, anchor rod inclination angle and seismic force on the slope’s safety factor was discussed, and the failure mode of the slopes under a random field was studied. The results show that the velocity field boundary obtained by the reliability analysis method proposed in this paper is close to the sliding surface obtained by the traditional methods and the deviation of the slope’s safety factors between the proposed method and the traditional methods is small. The probability density functions of the slope’s safety factors under different autocorrelation functions are approximately normally distributed. Increasing the seismic force will increase the probability of slope failure, while the increase in anchor rod prestress and the decrease in anchor rod inclination angle have positive effects on the slope stability. The failure modes of slopes under different random distribution of soil parameters change significantly. The method proposed in this paper, which does not require to assume the failure model, can realistically and intuitively display the actual failure of slopes.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"177 ","pages":"Article 106885"},"PeriodicalIF":5.3,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660207","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":"Micro-fracture mechanism of microwave induced fracturing of basalt based on a novel Electromagnetic–Thermal–Mechanical coupling model","authors":"Jian Ma,&nbsp;Zheng-Wei Li,&nbsp;Wen-Feng Guo,&nbsp;Liang-Xiao Chen","doi":"10.1016/j.compgeo.2024.106874","DOIUrl":"10.1016/j.compgeo.2024.106874","url":null,"abstract":"<div><div>Microwave-assisted rock fracturing is recognized for its efficiency, energy savings, and environmental benefits. Investigating microscopic mechanisms of microwave-induced rock fracturing is essential for predicting the weakening effect on rock. A coupled Electromagnetic–Thermal–Mechanical model based on FEM–DEM was established to describe the response of rock under microwave irradiation. This model employs interpolation algorithms and mineral lattices randomization algorithms to establish a 2D cross-sectional representation of rock. A discrete element calculation method is proposed to synchronize computational time with the experimental time. The model can simulate the multi-physical field response of different rocks under various conditions, making it an effective tool for studying microwave-induced rock fracturing. The effectiveness of the numerical model was validated through open-end microwave-induced fracturing experiments on basalt. Additionally, the study elucidates the micro-fracture mechanism of basalt under microwave irradiation. The results indicate that the direction of crack propagation is influenced by microwave power and boundary effects. The patterns of fracture development between minerals are summarized as follows: Initial fractures primarily result from the rapid heating of microwave-absorbing minerals like enstatite,creating a significant temperature gradient. With increased heating time, heat transfers to highly expansive minerals such as olivine, causing fractures due to localized thermal expansion.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"177 ","pages":"Article 106874"},"PeriodicalIF":5.3,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660206","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":"Micro mechanism and analytical model of stress distribution in loosened soil zone above active trapdoor","authors":"Fan Chen ,&nbsp;Xiaohui Liu ,&nbsp;Junfeng Sun ,&nbsp;Hao Xiong ,&nbsp;Zhen-Yu Yin ,&nbsp;Xiangsheng Chen","doi":"10.1016/j.compgeo.2024.106841","DOIUrl":"10.1016/j.compgeo.2024.106841","url":null,"abstract":"<div><div>The formation of discontinuities within soil masses due to arching phenomena is a critical issue in geotechnical engineering, profoundly influencing the stability and integrity of underground structures. This study investigated the microscopic mechanisms and associated stress redistribution in the soil mass above an actively moving trapdoor. Utilizing the Discrete Element Method (DEM) model, the influence of varying initial soil packing densities on the induced arching phenomena is examined concerning the soil displacement mechanism and shearing configuration: transfer from inner triangular to vertical bands is observed in dense soil while only vertical shearing bands are observed in initially loose soil. To account for principal stress trajectories under differing initial density conditions, an analytical model was developed to quantify the variations in soil stress. The findings reveal a noteworthy impact of the initial soil void ratio <span><math><mi>e</mi></math></span>, on the pattern evolution and stress redistribution of soil arching, manifesting a passive stress limit coefficient, <span><math><msub><mrow><mi>K</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span>, in denser soils along the central line above the trapdoor. The analytical model demonstrates robust agreement with both numerical and experimental data in soil loosening stress distribution and the load–displacement response of the trapdoor.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"177 ","pages":"Article 106841"},"PeriodicalIF":5.3,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660213","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":"Finite-strain gradient-extended damage-plastic modeling of rock: Understanding catastrophe from material failure and structural instability","authors":"Xiaofeng Cheng ,&nbsp;Xianhui Feng ,&nbsp;Chun’an Tang","doi":"10.1016/j.compgeo.2024.106891","DOIUrl":"10.1016/j.compgeo.2024.106891","url":null,"abstract":"<div><div>Rock, a natural geological material, exhibits diverse collapse modes that make predicting catastrophic behavior challenging. Material failure and structural instability each provide independent mechanical explanations for rock catastrophes. However, isolated perspectives often obscure the distinctions and connections between these two critical mechanisms. Here, we propose a finite-strain gradient-extended damage-plastic scheme within a thermodynamically consistent framework to encapsulate the indispensable dual effects of failure and instability. The crack propagation and frictional dissipation of crack clusters in rock materials inspire coupled damage-plastic theory, whereas the large displacement, large rotation and large strain of rock structures motivate the application of finite strain theory. The proposed scheme incorporates nonlocal gradient-enhanced terms to mitigate mesh dependence and is immune to spurious energy dissipation under cyclic loading. Constitutive treatment at finite strain retains the easily achievable features of the small deformation case. The model is validated through laboratory- and engineering-scale simulations, offering insights into the mechanisms of rock catastrophes. Our findings highlight the dual role of material failure and structural instability as interconnected drivers of rock catastrophes, offering a more holistic understanding for effective prediction and mitigation strategies.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"177 ","pages":"Article 106891"},"PeriodicalIF":5.3,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660208","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":"Dynamic column collapse of dry granular materials with multi-scale shape characteristics","authors":"Haoran Jiang ,&nbsp;Jiayan Nie ,&nbsp;Opu Chandra Debanath ,&nbsp;Yang Li","doi":"10.1016/j.compgeo.2024.106873","DOIUrl":"10.1016/j.compgeo.2024.106873","url":null,"abstract":"<div><div>Understanding the fundamental principles governing granular flow dynamics has been a longstanding problem. The complexity is heightened when diverse particle shapes come into play, which thus necessitates a quantitative assessment of the impact of particle shape and especially, the interplay among multi-scale shape characteristics. In this study, we numerically study the combined effects of the particle’s overall form and surface asperity in dry granular columns, a simplified granular flow model, using spherical harmonics and the level-set discrete element method. Our results reveal that flow mobility for a given column aspect ratio decreases linearly with an adopted shape index known as the rotational resistance angle. This motivates us to propose a simple runout model incorporating shape effects for predicting flow mobility. Additionally, we analyze the energy evolution process and demonstrate that both the maximum kinetic energy and the final accumulated energy dissipation scale linearly with the shape index. Furthermore, column flow mobility is found to be correlated well with the front kinetic energy. Finally, we compare the static deposit angle from column collapse tests with the critical friction angle from triaxial compression tests, finding that they are approximately equal under short column conditions, which correspond to the quasi-static collapse regime. This provides potential alternative protocols to quickly measure the internal friction angle of dry granular materials.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"177 ","pages":"Article 106873"},"PeriodicalIF":5.3,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660205","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":"Coupled heat and moisture migration in unsaturated soils subjected to thermal gradients","authors":"Arvind Kumar ,&nbsp;Asal Bidarmaghz ,&nbsp;Arman Khoshghalb ,&nbsp;Kenichi Soga","doi":"10.1016/j.compgeo.2024.106893","DOIUrl":"10.1016/j.compgeo.2024.106893","url":null,"abstract":"<div><div>Various mathematical formulations have been proposed to model moisture migration coupled with heat transfer in unsaturated soils under non-isothermal conditions. These formulations adopt different assumptions and approaches to incorporating phase change phenomena. This has led to confusion when assessing the performance of ground heat exchangers in unsaturated soils. This research provides insights into the development of fully coupled hydro-thermal numerical models for partially saturated soils under thermal loading. The multiphysics phenomenon involved is clearly discussed, and the governing equations are presented for both the equilibrium phase change (EPC) and non-equilibrium phase change (NEPC) approaches. A parallel comparison is then made between the two approaches through the estimation of variation in the degree of saturation in unsaturated soils when subjected to thermal gradients. The suitability of the two approaches for numerical modeling of unsaturated soils in the context of ground heat exchangers is then discussed. Considering the uncertainties in parameter identification, the results indicate that the EPC approach is sufficiently accurate and is often preferred over the NEPC approach in hydro-thermal modeling of ground heat exchangers in unsaturated soils.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"177 ","pages":"Article 106893"},"PeriodicalIF":5.3,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660204","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":"Linear and nonlinear unified fluid flow in fractured porous media considering flow pattern adaptive conversions","authors":"Huidong Wang ,&nbsp;Zhen Qu ,&nbsp;Guowei Ma","doi":"10.1016/j.compgeo.2024.106856","DOIUrl":"10.1016/j.compgeo.2024.106856","url":null,"abstract":"<div><div>Linear and nonlinear fluid flow in fractured rock masses often co-occurs because of the hydraulic pressure gradient discrepancy and significant permeability difference between fractures and rock matrixes. In the current Darcy-Forchheimer coupled theory, the linear and nonlinear fluid flow is often artificially and strictly confined to rock matrixes and fractures, respectively. In this study, we conducted a numerical study on linear and nonlinear unified fluid flow in fractured porous media, considering flow pattern adaptive conversions instead of artificial constraints. The flow pattern adaptive conversion is realized by a conversion factor of linear and nonlinear fluid flow. A numerical linear and nonlinear unified fluid flow method was proposed using the unified pipe-network method. The accuracy and correctness of the proposed method were validated by comparing it with the result of both linear and nonlinear fluid flow. This method can effectively describe the linear and nonlinear mixed fluid flow and calculate the distributions of linear and nonlinear flow regions in fractured porous media. Characteristics of the unified fluid flow in fractured porous media were analyzed in detail by parametric discussions based on the developed numerical method.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"177 ","pages":"Article 106856"},"PeriodicalIF":5.3,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593778","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 homogenization behavior of compacted bentonite containing technological voids using modified penalty-based contact model","authors":"Rong-Sheng Deng ,&nbsp;Bao Chen ,&nbsp;Wei-Min Ye ,&nbsp;Yong-Gui Chen ,&nbsp;Qiong Wang","doi":"10.1016/j.compgeo.2024.106894","DOIUrl":"10.1016/j.compgeo.2024.106894","url":null,"abstract":"<div><div>Low-density zones generated during the bentonite blocks/voids homogenization process in the repository may serve as potentially preferential paths for radionuclide leakage. More importantly, void closure during homogenization process involves complex contact problems, where the stiffness at the contact interface typically undergoes significant fluctuations. In this work, with contact interface stiffness addressed through a step function approach, a modified penal.</div><div>ty-based contact model was proposed to simulate the contact behavior involved at the gap closure stage of the bentonite/gap assemblage homogenization process. Then, unsaturated infiltration swelling tests on bentonite block (1.7 Mg/m³)/gap (width: 2 mm) assemblages were performed, and the variation of dry density at different hydrated times (0, 24, 72, 168, and 720 h) in specific areas were measured. Based on the results, time-dependent swelling pressure profiles of the assemblage were acquired, while the homogenization process was evaluated. Results reveal that after approximately 40 h of hydration, the gap is completely closed, and the radial stress condition of the compacted bentonite transits progressively from the initial free swelling into a constant volume expansion state. The swelling pressure correspondingly develops quickly to a peak value at 1.8 MPa once the hydration starts, then decreases to a valley value of 1.4 MPa at the complete gap closure, and subsequently begins to increase to the final stable value of 1.8 MPa. Further examination reveals that as hydration advances, dry density of the assemblage converges to the expected final dry density with a maximum residual inhomogeneity of about 2 %. Finally, validations demonstrate that the proposed model can accurately reproduce deformations of the assemblage during the free swelling stage, and the swelling pressure profiles. A comparative analysis was made with the previous approach of identifying gaps as highly deformable materials, revealing that the proposed model overcomes the traditional limitations associated with the separation or penetration behavior occurring between the compacted bentonite and contact boundaries during the gap closure.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"177 ","pages":"Article 106894"},"PeriodicalIF":5.3,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593780","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":"Probabilistic bearing capacity of eccentrically loaded strip footing on spatially random rock mass using correlation-controlled LHS sampling","authors":"Shuvankar Das,&nbsp;Debarghya Chakraborty","doi":"10.1016/j.compgeo.2024.106859","DOIUrl":"10.1016/j.compgeo.2024.106859","url":null,"abstract":"<div><div>To examine the heterogeneous behavior of spatially random rock mass, the probabilistic bearing capacity of strip footing subjected to eccentric loading is computed in the present study. The lower bound finite element limit analysis in combination with the power conic optimization technique is employed by assuming the rock mass to follow the generalized Hoek-Brown (GHB) failure criterion at collapse. Geological Strength Index (<em>GSI</em>) is modeled as a spatially random variable. The rock mass material constant (<em>m_i</em>) and uniaxial compressive strength ratio (<em>σ_ci/γB</em>) are modeled as spatially random fields. Correlation-controlled Latin hypercube sampling (LHS) is implemented to create the spatially random discretized rock mass domain. With the help of the Monte Carlo simulation technique, the stochastic responses are determined. The obtained values of bearing capacity factor are found to follow the gamma distribution. The failure probability and mean bearing capacity factor for different ranges of practical cases of rock mass heterogeneity and loading eccentricity conditions are presented in design charts. With the increase in the eccentricity values, the mean bearing capacity factor reduces in all probabilistic cases. The target probability is expressed in terms of the desired factor of safety based on the acquired results for different rock mass and loading parameters.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"177 ","pages":"Article 106859"},"PeriodicalIF":5.3,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593777","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}