Hasil untuk "Engineering geology. Rock mechanics. Soil mechanics. Underground construction"

SUN Junyuan 1, ZHOU Shilong 2, LUO Jiugang 3, CUI Min 3, CHENG Xuesong 2, LI Qinghan 2

Long-term operation of recharge wells leads to progressive decline in recharge efficiency, that is, the phenomenon of well clogging. As the most critical factor constraining recharge technology application, the mechanisms underlying recharge well clogging remain inadequately understood, with insufficient research on clogging causes and influencing factors during recharge operations. This study investigates the influence mechanisms of soil particle size distribution on recharge well clogging through laboratory model tests. Results indicate that fine particle migration during recharge induces hydraulic conductivity variations in different zones. When the proportion of the coarse particles is high, fine soil particles fail to completely fill soil voids. While no significant clogging occurs, this process alters local permeability characteristics, and particle size distribution will still change.

Ashis Kumar Mandal, Md Nadim, Chanchal K. Roy et al.

Research in software engineering is essential for improving development practices, leading to reliable and secure software. Leveraging the principles of quantum physics, quantum computing has emerged as a new computational paradigm that offers significant advantages over classical computing. As quantum computing progresses rapidly, its potential applications across various fields are becoming apparent. In software engineering, many tasks involve complex computations where quantum computers can greatly speed up the development process, leading to faster and more efficient solutions. With the growing use of quantum-based applications in different fields, quantum software engineering (QSE) has emerged as a discipline focused on designing, developing, and optimizing quantum software for diverse applications. This paper aims to review the role of quantum computing in software engineering research and the latest developments in QSE. To our knowledge, this is the first comprehensive review on this topic. We begin by introducing quantum computing, exploring its fundamental concepts, and discussing its potential applications in software engineering. We also examine various QSE techniques that expedite software development. Finally, we discuss the opportunities and challenges in quantum-driven software engineering and QSE. Our study reveals that quantum machine learning (QML) and quantum optimization have substantial potential to address classical software engineering tasks, though this area is still limited. Current QSE tools and techniques lack robustness and maturity, indicating a need for more focus. One of the main challenges is that quantum computing has yet to reach its full potential.

Xuyang Sun, Wenchang Tan, Yi Man

The acoustofluidic method holds great promise for manipulating microorganisms. When exposed to the steady vortex structures of acoustic streaming flow, these microorganisms exhibit intriguing dynamic behaviors, such as hydrodynamic trapping and aggregation. To uncover the mechanisms behind these behaviors, we investigate the swimming dynamics of both passive and active particles within a two-dimensional acoustic streaming flow. By employing a theoretically calculated streaming flow field, we demonstrate the existence of stable bounded orbits for particles. Additionally, we introduce rotational diffusion and examine the distribution of particles under varying flow strengths. Our findings reveal that active particles can laterally migrate across streamlines and become trapped in stable bounded orbits closer to the vortex center, whereas passive particles are confined to movement along the streamlines. We emphasize the influence of the flow field on the distribution and trapping of active particles, identifying a flow configuration that maximizes their aggregation. These insights contribute to the manipulation of microswimmers and the development of innovative biological microfluidic chips.

Simon Ghyselincks, Valeriia Okhmak, Stefano Zampini et al.

Reconstructing the structural geology and mineral composition of the first few kilometers of the Earth's subsurface from sparse or indirect surface observations remains a long-standing challenge with critical applications in mineral exploration, geohazard assessment, and geotechnical engineering. This inherently ill-posed problem is often addressed by classical geophysical inversion methods, which typically yield a single maximum-likelihood model that fails to capture the full range of plausible geology. The adoption of modern deep learning methods has been limited by the lack of large 3D training datasets. We address this gap with \textit{StructuralGeo}, a geological simulation engine that mimics eons of tectonic, magmatic, and sedimentary processes to generate a virtually limitless supply of realistic synthetic 3D lithological models. Using this dataset, we train both unconditional and conditional generative flow-matching models with a 3D attention U-Net architecture. The resulting foundation model can reconstruct multiple plausible 3D scenarios from surface topography and sparse borehole data, depicting structures such as layers, faults, folds, and dikes. By sampling many reconstructions from the same observations, we introduce a probabilistic framework for estimating the size and extent of subsurface features. While the realism of the output is bounded by the fidelity of the training data to true geology, this combination of simulation and generative AI functions offers a flexible prior for probabilistic modeling, regional fine-tuning, and use as an AI-based regularizer in traditional geophysical inversion workflows.

WANG Liye 1, ZHOU Fengxi 1, 2, ZHOU Lizeng 3, LIANG Yuwang 1

To reveal the impact of physicochemical effects on the compressive behaviors of unsaturated clay containing salt solution and its dependence properties on stress level, one-dimensional compression tests are performed on the specimens with pores containing distilled water, sodium chloride solution, sodium sulfate solution and controlled matric suction conditions. Then, the compression index, secondary compression coefficient and yield stress of clay under different conditions are measured according to the test results, and their variation laws with the matric suction and osmotic suction are calibrated. Furthermore, the stress-dependent characteristics of physicochemical action are clarified through an in-depth analysis of the primary and secondary consolidation behaviors of unsaturated saline clay under different matric suctions and osmotic suctions, and the LC yielding behaviors of unsaturated saline clay are explored. The results show that the ratio of the secondary compression coefficient to the compression index Ca/Cc and the yield stress of unsaturated saline clay at different physicochemical forces can be described uniformly using the osmotic suction and matric suction. From the slope of compression curve in the plastic loading zone and the correlation between characteristic parameter, Ca/Cc and the vertical stress, it is noted that the physicochemical action of unsaturated saline clay is closely related to the stress level. Moreover, the LC yield curve of unsaturated saline clay is a smooth curve composed of MLC yield curve and OLC yield curve under chemo- hydro-mechanical coupling.

Mauricio Ehrlich, Seyed Hamed Mirmoradi, Gustavo Fonseca Silva et al.

This study analytically and numerically investigates the impact of constant and non-constant Poisson’s ratio on the mobilized maximum load in the reinforcements, Tmax, of reinforced soil walls with vertical facing under working stress conditions. This assessment is carried out considering different controlling factors including reinforcement stiffness, wall height, backfill friction angle, and compaction-induced stress. The analytical procedure and the numerical model are validated against data from an instrumented, large-scale, geosynthetic-reinforced soil wall under working stress conditions. Considering the key factors evaluated in the current study, the results show that the impact of the reinforcement stiffness is dominant over the approach used to consider Poisson’s ratio. A maximum difference of about 20% was obtained between the values of Tmax calculated using constant and variable Poisson’s ratios. This implies that, from a practical standpoint, it may be appropriate to adopt a simpler approach that utilizes a constant Poisson's ratio for the determination of Tmax under operational conditions.

Jianjun Zi, Tao Liu, Wei Zhang et al.

The influences of biological, chemical, and flow processes on soil structure through microbially induced carbonate precipitation (MICP) are not yet fully understood. In this study, we use a multi-level thresholding segmentation algorithm, genetic algorithm (GA) enhanced Kapur entropy (KE) (GAE-KE), to accomplish quantitative characterization of sandy soil structure altered by MICP cementation. A sandy soil sample was treated using MICP method and scanned by the synchrotron radiation (SR) micro-CT with a resolution of 6.5 μm. After validation, tri-level thresholding segmentation using GAE-KE successfully separated the precipitated calcium carbonate crystals from sand particles and pores. The spatial distributions of porosity, pore structure parameters, and flow characteristics were calculated for quantitative characterization. The results offer pore-scale insights into the MICP treatment effect, and the quantitative understanding confirms the feasibility of the GAE-KE multi-level thresholding segmentation algorithm.

CUI Feilong 1, YANG Junchao 2, WANG Jinshang 1, ZHANG Yatao 3, LI Lihua 4

Seasonal temperature changes in the seasonal frozen areas have a significant impact on the engineering application performance of the underground pipe galleries. To study the effects of ambient temperature in the seasonal frozen areas on the temperature field and mechanical behaviors of the underground pipe galleries, the change laws of temperature field and earth pressure of the underground pipeline galleries under seasonal ambient temperature are studied by conducting the ABAQUS finite element numerical simulation. The numerical analysis results indicate that the occurent moment of the maximum freezing depth of the vertical section inside the pipe gallery is lagged behind that of the lowest ambient temperature. During the process of heating and cooling, the temperature fields inside the upper and nearby areas of the pipe gallery successively exhibit the special phenomena such as "cold core zone" and "hot core zone". These phenomena gradually disappear with the continuous effects of heating and cooling. During the cooling and heating processes, the earth pressure on the roof of the pipe gallery shows an increasing and decreasing tendency. After the influences of seasonal temperature, the earth pressure on the roof is significantly greater than that at the initial state.

Ahad M. Rauf, Sean Follmer

Electroadhesive clutches are electrically controllable switchable adhesives commonly used in soft robots and haptic user interfaces. They can form strong bonds to a wide variety of surfaces at low power consumption. However, electroadhesive clutches in the literature engage to and release from substrates several orders of magnitude slower than a traditional electrostatic model would predict. Large release times, in particular, can limit electroadhesion's usefulness in high-bandwidth applications. We develop a novel electromechanical model for electroadhesion, factoring in polarization dynamics, the drive circuitry's rise and fall times, and contact mechanics between the dielectric and substrate. We show in simulation and experimentally how different design parameters affect the engagement and release times of centimeter-scale electroadhesive clutches to metallic substrates, and we find that the model accurately captures the magnitude and trends of our experimental results. In particular, we find that higher drive frequencies, narrower substrate aspect ratios, and faster drive circuitry output stages enable significantly faster release times. The fastest clutches have engagement times less than 15 us and release times less than 875 us, which are 10x and 17.1x faster, respectively, than the best times found in prior literature on centimeter-scale electroadhesive clutches.

Hermínio T. Honório, Maartje Houben, Kevin Bisdom et al.

Renewable hydrogen storage in salt caverns requires fast injection and production rates to cope with the imbalance between energy production and consumption. Such operational conditions raise concerns about the mechanical stability of salt caverns. Choosing an appropriate constitutive model for salt mechanics is an important step in investigating this issue, and many constitutive models with several parameters have been presented in the literature. However, a robust calibration strategy to reliably determine which model and which parameter set represent the given rock, based on stress-strain data, remains an unsolved challenge. For the first time in the community, we present a multi-step strategy to determine a single parameter set based on many deformation datasets for salt rocks. Towards this end, we first develop a comprehensive constitutive model able to capture all relevant nonlinear deformation physics of transient, reverse, and steady-state creep. The determination of the single set of representative material parameters is achieved by framing the calibration process as an optimization problem, for which the global PSO algorithm is employed. Dynamic data integration is achieved by a multi-step calibration strategy for a situation where experiments are included one at a time, as they become available. Additionally, our calibration strategy is made flexible to account for mild heterogeneity between rock samples, resulting in a single set of parameters that is representative of the deformation datasets. As a rigorous mathematical analysis and the lack of relevant experimental datasets, we consider a wide range of synthetic experimental data, inspired by the existing sparse relevant data in the literature. The results of our performance analyses show that the proposed calibration strategy is robust and accuracy is improved as more experiments are included for calibration.

Premika S. Thasu, Gaurav Kumar, Subrahmanyam Duvvuri

Recent experimental studies reveal that the near-wake region of a circular cylinder at hypersonic Mach numbers exhibits self-sustained flow oscillations. The oscillation frequency was found to have a universal behavior. Experimental observations suggest an aeroacoustic feedback loop to be the driving mechanism of oscillations. An analytical aeroacoustic model which predicts the experimentally observed frequencies and explains the universal behavior is presented here. The model provides physical insights and informs of flow regimes where deviations from universal behavior are to be expected.

Ana Ramos, António Gomes Correia, Rui Calçada

A previsão da deformação permanente na fundação e respetiva fiabilidade é uma das principais preocupações dos gestores das Infraestruturas Ferroviárias, pois pode influenciar os custos de manutenção da via em serviço. Este artigo propõe uma nova metodologia relativa à previsão da deformação permanente com base num estudo paramétrico realizado usando uma abordagem híbrida e que inclui o desempenho a curto e longo prazo. O estudo realizado permitiu a construção de uma base de dados robusta que foi utilizada neste estudo para prever a deformação permanente. A base de dados alimenta um modelo da rede neuronal, cujo desempenho foi avaliado com base em diferentes métricas: MAE, MSE, RMSE, desvio padrão e coeficiente de regressão. O modelo foi testado e validado com base em resultados experimentais.  Os resultados obtidos mostram que o modelo desenvolvido é rápido e eficiente para prever com precisão a deformação permanente induzida pela passagem dos comboios. O modelo tem o potencial para ser implementado num sistema computacional de apoio de decisão para manutenção e gestão de linhas ferroviárias.

Nafis Bin Masud, Kam W. Ng, Shaun S. Wulff

Piles driven in Intermediate GeoMaterials (IGM) pose multiple design and construction challenges because of the high uncertainty in IGM properties, lacking knowledge pertaining to pile responses in IGM, and absence of classification, static analysis (SA) methods, and design recommendations. A classification criterion is established for coarse grained soil based intermediate geomaterials (CG-IGM) using test pile data from bridge projects completed in four U.S. states. This study improves our understanding of pile resistance responses in CG-IGM and results in pile design recommendations. Unit shaft resistance (qs) of CG-IGM increases with the ratio of effective vertical stress (σv′) to the ratio of corrected N-value, (N1)60. Unit end bearing (qb) increases with the ratio of. corrected N-value, (N1)60 to the effective vertical stress (σv′). New SA methods are developed for predicting qs and qb. The proposed SA methods are compared against existing β-method developed for coarse grained soil and validated using an independent pile load test dataset. Pile setup is observed in qs of piles driven in CG-IGMs, and pile relaxation is mostly observed in qb. Statistical assessment concludes that the proposed SA methods provide more accurate and consistent qs and qb predictions than that by the β-method.

Chang Liu, Dingli Zhang, Sulei Zhang et al.

Rock load on lining structures increases over time for tunnels buried in rheological rock, and in addition deterioration of primary lining is common due to its structural characteristics and service environment attack, where these delayed features affect the mechanical response of tunnels. However, accounting for these delayed features in long-term stability assessment of tunnel structures is complex and has not attracted enough attention. In this paper, an analytical approach is proposed for investigating long-term mechanical response of tunnel structures in rheological rock influenced by degradation of primary lining. For this purpose, degradation of primary lining, characterized by decreasing concrete stiffness over time, is quantitatively described by an exponential model. The rheological characteristic of surrounding rock is simulated by the Burgers model. The time-varying solutions for rock deformation and support pressure are obtained by considering the coordinated interaction between surrounding rock and linings, and their correctness is verified by comparing them with numerical results. The results revealed that the pressure imposed on linings due to the rheological behavior of surrounding rock increases over time. As the primary lining degrades, the rheological load is transferred from primary lining to secondary lining, leading to increasing pressure on secondary lining; and a faster degradation rate of primary lining leads to greater pressure on secondary lining. Therefore, the primary lining should not be overlooked in long-term safety assessment of operation tunnels because of its role in bearing and transmitting load. Finally, the tunnel's design and operational maintenance strategy are discussed when the delay effects of surrounding rock and lining are taken into account.

Ravi Prakash, Sara Abedi

Creep deformation in shale rocks is an important factor in many applications, such as the sustainability of geostructures, wellbore stability, evaluation of land subsidence, CO2 storage, toxic waste containment, and hydraulic fracturing. One mechanism leading to this time-dependent deformation under a constant load is the dissolution/formation processes accompanied by chemo-mechanical interactions with a reactive environment. When dissolution/formation processes occur within the material phases, the distribution of stress and strain within the material microstructure changes. In the case of the dissolution process, the stress carried by the dissolving phase is distributed into neighboring voxels, which leads to further deformation of the material. The aim of this study was to explore the relationship between the microstructural evolution and time-dependent creep behavior of rocks subjected to chemo-mechanical loading. This work uses the experimentally characterized microstructural and mechanical evolution of a shale rock induced by interactions with a reactive brine (CO2-rich brine) and a non-reactive brine (N2-rich brine) under high-pressure and high-temperature conditions to compute the resulting time-dependent deformation using a time-stepping finite-element-based modeling approach. Sample microstructure snapshots were obtained using segmented micro-CT images of the rock samples before and after the reactions. Coupled nanoindentation/EDS provided spatial alteration of the mechanical properties of individual material phases due to the dissolution and precipitation processes as a result of the chemo-mechanical loading of the samples. The time-dependent mechanically informed microstructures were then incorporated into a mechanical model to calculate the creep behavior caused by the dissolution/precipitation processes independent of the inherent viscous properties of the mineral phases.

WANG Gang 1, 2, XIAO Zhi-yong 1, WANG Chang-sheng 1, JIANG Yu-jing 2, YU Jun-hong 1

During extraction of coalbed methane, the reservoir will be in a non-equilibrium dynamic adjustment phase for a long period of time due to the high variability of fracture and matrix permeability properties. However, most of the current tests and permeability models only consider the effects of a certain fixed gas pressure, which greatly limits the study of reservoir gas flow under non-equilibrium condition. Therefore, based on the concept that the reservoir is a dual porous medium, and considering the effects of different pore pressures, desorption deformation and mechanical effects of matrix-fracture on the evolution of fracture aperture during the extraction process, a model is proposed to predict the reservoir permeability under variable stress states and validated through the field data. Then the model is substituted into the gas flow equation, and the pore pressure of matrix–fracture and the evolution of core permeability in time and space are studied separately by using the finite element software. The results show that during the core desorption: (1) The fracture gas pressure in the core is disturbed to a greater extent than the matrix gas pressure. (2) The gas pressure and permeability of matrix–fracture exhibit non-linear distribution along the core length. (3) The permeability of matrix–fracture varies in the same trend.

Markus Jesswein, Jinyuan Liu

A genetic algorithm (GA) was used in this study to develop a standard penetration test (SPT)-based design method for the axial capacity of driven piles. A total of 72 pile load tests was collected from literature and divided into two groups based on their measurements. The first group had the load-transfer distribution measurements for extracting both the unit side and tip resistances. These unit resistances were correlated by the GA with soil measurements and pile properties to develop the design method. The second group, where only the total capacity measurements were available, were used to validate the new design method and compare its performance with three existing SPT-based design methods. The new GA-derived design method considers nonlinear relationships with the effective stress and pile length and provides an unbiased prediction with a low coefficient of variation (COV) of 40.0 %, while the three existing methods overestimate the capacity by a factor of 1.62 to 1.65 with a high COV of 40.3 % to 52.8 %, which could result in an under design of pile foundations. This study shows that the GA was able to obtain complex relationships with great accuracy and the new design method can be applied to new cases reasonably well.

ZHANG Qi-hua 1, HU Hui-hua 2, ZHANG Yu 3, ZHAO Xue-lian 4

The stereographic projection used in engineering geological analysis is a hemispherical projection: a plane or a straight line in 3-D space is projected to be an arc or a point inside the equatorial circle. This kind of projection is widely used to judge the unstable blocks cut by discontinuities by analyzing the relationship of locations between the intersection of arcs projected by multiple sets of discontinuities and the arc projected by the free surface. Nevertheless, this kind of judgement lacks a rigous theoretical basis. The whole-space stereographic projection proposed in the block theory projects a whole plane and both its upper-half and lower-half space onto the equatorial plane. The removability and failure mode of blocks can be determined by analyzing the location relationship between the joint pyramid projected by multiple sets of discontinuities and the circle projected by the free surface. This approach is complete and accurate in theory. In this study, the shortcomings of the traditional stereographic projection used for slope stability analysis in "Geological engineering handbook" and "Design code for engineering slopes of water resources and hydropower projects" are pointed out by analyzing some specially designed examples, and the reasons for these shortcomings are released. Through the whole-space stereographic projection, the continuous variation of morphology of joint pyramid is exposed, the characteristics of the shape of projection zone projected by flat or sharp blocks are analyzed, and the significance of these issues is explored. Finally, the advantages of the whole-space stereographic projection are summarized, and the simplicity in using and the feasibility for popularization are pointed out.

Yang Baogui, Yang Haigang

In order to study the energy evolution characteristics of high concentration cemented backfill in coal mine, conventional triaxial compression tests of high-concentration cemented backfill under different confining pressures were carried out with the help of RTR-2000 triaxial dynamic test system for high pressure rocks.This paper analyzed the evolution law of the strain energy and the confining pressure effect during the deformation and failure of the specimens.The results show that: (1) for the specimen whose confining pressure is not 0, the ratio of dissipated strain energy corresponding to peak strength to absorbed strain energy is more than 70 %. Before the specimens reached the peak strength, they have undergone severe plastic deformation and failure.(2) in the process of deformation and failure of specimens, the absorbed strain energy increases rapidly, the elastic strain energy accumulates first and then releases, reaching the energy storage limit at peak strength, and the dissipated strain energy begins to increase rapidly from the stage of yield deformation.(3) under the condition of the same axial strain, the larger the confining pressure is, the larger the absorbed strain energy and elastic strain energy of the specimens are.The dissipated strain energy of the specimen with high confining pressure will exceed that of the specimen with low confining pressure as the axial strain increases.The confining pressure can greatly improve the stress level of the specimens, limit the radial deformation of the specimens, improve the energy storage capacity of the specimens, and restrain the deformation and failure of the specimens.

Chun-lei Liu, Chen-ming Lu, Ya-song Li et al.

The geothermal resources in Fujian Province are mainly hydrothermal resources of medium-low temperature. To better understand the whole process and conditions of heat control in the middle and deep crust, this study focuses on the analysis of heat accumulation model in Hongtang Area of Xiamen, and the main conditions of the model such as faults and sags are explored and interpreted in detail by using gravity and wide-field electromagnetic methods. 4 main faults (F33, F2, F12 and HT-F1) and 10 secondary faults (HT-F2, HT-F3, HT-F4, HT-F5, HT-F6, HT-F7, HT-F8, HT-F9, HT-F10 and HT-F11) were inferred, and the distribution range of sags was delineated. The convective geothermal system is composed of four components: Heat source, geothermal reservoir, heat-conductive fault and heat retaining cover, which form a quaternary heat accumulation model. According to the model, the intersection of the main faults F12, HT-F1 and F33 can be delineated as the primary target area of geothermal exploration, while the intersection of the secondary faults (F12 and HT-F6; F12 and HT-F2; HT-F9, HT-F10 and F12; F12 and HT-F11; F33 and HT-F3; HT-F8 and HT-F3; HT-F2, HT-F10 and HT-F1) can be delineated as the secondary target area. Borehole DR01, which is located in the primary target area, shows that the water temperature increases from fast to slow in the depth range of 0–500 m, and stays at 36℃ below 500 m. The reliability of the heat accumulation model and the target area was tested via geothermal boreholes, which is of great significance to the exploitation and utilization of geothermal resources in Hongtang Area of Xiamen.