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Numerical analysis of geosynthetic-reinforced embankment performance under moving loads

Journal of Rock Mechanics and Geotechnical engineering 2024年第2期16卷 682-696页

作者： Xuanming Ding Jinqiao Zhao Qiang Ou Jianfei Liu College of Civil Engineering Chongqing UniversityChongqing400045China Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityChongqing400045China China United Engineering Corporation Limited Hangzhou310052China

The performance of geosynthetic-reinforced embankments under traffic moving loads is always a hotspot in the geotechnical engineering field.A three-dimensional(3D)model of a geosynthetic-reinforced embankment without drainage consolidation was established using the finite element software *** this model,the traffic loads were simulated by two moving loads of rectangular pattern,and their amplitude,range,and moving speed were realized by a Fortran *** embankment fill was simulated by an equivalent linear viscoelastic model,which can reflect its *** geogrid was simulated by the truss element,and the geocell was simulated by the membrane *** elements were utilized to weaken the boundary effect caused by the model geometry at the *** of the established numerical model was conducted by comparing the predicted deformations in the cross-section of the geosynthetic-reinforced embankment with those from the existing *** this basis,the dynamic stress and strain distribution in the pavement structure layer of the geosynthetic-reinforced embankment under a moving load was also ***,a parametric study was conducted to examine the influences of the different types of reinforcement,overload,and the moving load velocity on the geosynthetic-reinforced embankment.

关键词： Geosynthetic-reinforced layer Numerical model Moving load Embankment Deformation Stress

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Expansion Performance and Microstructure of High-performance Concrete using Differently Scaled MgO Agents and Mineral Powder

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Journal of Wuhan University of technology(Materials Science) 2023年第6期38卷 1335-1347页

作者： TIAN Changjin WANG Youzhi QIU Kai YANG Qilin School of Civil Engineering Shandong UniversityJinan 250002China China Construction Infrastructure Co. LtdBeijing 100089China School of Transportation Science and Engineering Harbin Institute of TechnologyHarbin 150090China

To investigate the assumptions proposed in this paper,the evolution law governing the strength and expansion performance of MgO and nano-MgO micro-expansive concrete in the environment of mineral powder was firstly observed in this ***,SEM,XRD,and TG-DSC microscopic tests were conducted to reveal the effects of the active mineral-powder admixture on the hydration degree and expansion performance of MgO and nano-MgO in *** experimental results successfully verified our hypothesis,which indicated that the expansion performance of macro-MgO and nano-MgO was indeed depressed by the addition of active mineral power admixtures,even though the mechanical property of concrete composites was effectively ***,the hydration test also demonstrated the negative interference on the mineral powders,which was induced by the expansion *** is found the amounts of hydrates tend to decrease because the mineral powder ratio reaches and exceeds 40%.Moreover,it is also concluded the effect of expansion agents is governed by the alkalinity cement paste,especially for the *** other words,the expansion performance of nano-MgO will vary more obviously with the hydration process,than *** results of this study provide that effective experimental and theoretical data support the hydration-inhibition mechanism of magnesium expansive agents.

关键词： MgO Nano-MgO mineral powders high-performance concrete expansive agents microstructures

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The Influence of Oblique Tunnel Portals and Blockage Ratio on the Aerodynamic Performance of Urban Rapid Rail Tunnels

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Journal of Fluids engineering 2025年第8期147卷 081301页

作者： Weng, Miaocheng Zhang, Yu Xiong, Kang Liu, Fang Zhu, Xinyi Zou, Zhenbo Key Laboratory of New Technology for Construction of Cities in Mountain Area Ministry of Education Chongqing400045 China School of Civil Engineering Chongqing University Chongqing400045 China

The study aims to understand the differences in aerodynamic pressure between urban rapid rail (URR) transit and high-speed railway tunnels caused by different tunnel portal structures. In this paper, a three-dimensional compressible turbulent flow model is used to simulate trains entering tunnels with three portal forms. The effects of tunnel portal forms and blockage ratio on the aerodynamic interaction between trains and tunnels are analyzed. Using full-scale test data, the reliability of simulating train entry into the tunnel is verified. Based on validated simulations, peak values and maximum pressure gradients are investigated for the three scenarios mentioned above. As a result, the transient pressure caused by the three types of inclined portals does not differ significantly, but it affects a train’s surface pressure varies over time. The ring oblique and reversed ring oblique portals both reduce primary compression wave’s maximum pressure gradient, while reversed ring oblique portals exhibit better performance. In addition, the study also identifies a critical blockage ratio b*, which determines the opposing effects of the two portal types in mitigating the aerodynamic interaction. Copyright © 2025 by ASME.

关键词： Railroad tunnels

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Impact fracturing of rock-like material using carbon dioxide under different temperatures and pressures

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Journal of Rock Mechanics and Geotechnical engineering 2025年第1期17卷 370-384页

作者： Shaobin Hu Zhengyong Yan Chun Zhu Manchao He Shuogang Pang College of Civil and Transportation Engineering Hohai UniversityNanjing210098China Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing210098China School of Earth Sciences and Engineering Hohai UniversityNanjing210098China National Key Laboratory for Disaster Prevention Controland Intelligent Construction and Maintenance of Tunnel EngineeringChina University of Mining and Technology(Beijing)Beijing100083China School of Mechanics and Civil Engineering China University of Mining and TechnologyBeijing100083China

Unconventional resources (oil, gas, and geothermal) are often buried deep underground within dense rock strata and complex geological structures, making it increasingly difficult to create volumetric fractures through conventional hydraulic fracturing. This paper introduces a novel method of supercritical energetic fluid thermal shock fracturing. It pioneers a CO_(2) deflagration impact triaxial pneumatic fracturing experimental system, using high-strength similar materials to simulate deep, hard rock masses. The study investigates the rock-breaking process and crack propagation patterns under supercritical CO_(2) thermal shock, revealing and discussing the types of thermal shock-induced fractures, their formation conditions, and discrimination criteria. The research indicates that higher supercritical CO_(2) thermal shock pressures and faster pressure release rates facilitate the formation of radial branching fractures, circumferential cracks, and branch cracks. Typically, CO_(2) thermal shock generates 3–5 radial main cracks, which is significantly more than the single main crack formed by hydraulic fracturing. The formation of branched cracks is often caused by compression-shear failure and occurs under relatively harsh conditions, determined by the confining pressure, rock properties, peak thermal shock pressure, and the pressure sustained post-decompression. The findings are expected to offer a safe, efficient, and controllable shockwave method of supercritical fluid thermal shock fracturing for the exploitation of deep unconventional oil and gas resources.

关键词： Cracking mechanism Supercritical CO_(2) True triaxial experimental Impact fracturing

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Fractional viscoelastic solution of stratum displacement of a shallow tunnel under the surface slope condition

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Underground Space 2023年第3期10卷 233-247页

作者： Fanchao Kong Dechun Lu Chao Ma Chenpeng Shen Xiaodong Yang Xiuli Du Institute of Geotechnical and Underground Engineering Beijing University of TechnologyBeijing 100124China School of Civil and Transportation Engineering Beijing University of Civil Engineering and ArchitectureBeijing 102626China Beijing Urban Construction Design&Development Group Co. LimitedThe Third Design Institute of Railway InstituteBeijing 100034China College of Mechanical Engineering Beijing University of TechnologyBeijing 100124China

The unified displacement function(UDF)is presented to describe the deformation behaviours of the tunnel profile along with time under the surface slope *** on the discrete Fourier method,the third-order UDF in the physical plane is expanded to the Laurent series in the complex variable *** complex variable method is employed to derive the elastic analytical solution of stra-tum displacement,when the third-order UDF is taken as the displacement boundary condition of tunnel cross-section(DBCTC).The proposed elastic solution agrees well with the results of the finite element method for the consistent model,which verifies the correctness of the proposed analytical *** the corresponding principle and fractional Generalized Kelvin viscoelastic constitutive model,the fractional viscoelastic solution under the surface slope condition is *** time effect of stratum displacement is presented in two aspects:time-dependent DBCTC and time-dependent material *** parameter analysis is performed to investigate influences of deformation modes of the third-order UDF,slope angle,tunnel radius and fractional order on the time effect of stratum vertical and horizontal displacement.

关键词： Third-order unified displacement function Surface slope condition Fractional viscoelastic solution Complex variable method Discrete Fourier method

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Dynamic Response Analysis of Functionally Graded Stiffened Panels Subjected to Blast Loading 4th

Dynamic Response Analysis of Functionally Graded Stiffened P...

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4th International Conference on Recent Advancements in Mechanical engineering, ICRAME 2023

作者： Pal, Anwesha Roy, Anuja Sahu, Atanu Department of Civil Engineering National Institute of Technology Silchar Assam Silchar India Department of Construction Engineering Jadavpur University Kolkata India

ISBN: (纸本)9789819741663

A sudden explosion causes the generation of high temperature and pressure which hit the nearby structures subjecting them to an impulsive loading. This produces sudden unwanted vibrations in structures which often lead to structural failure. Functionally graded (FG) material could be an excellent choice for engineers to combat this situation due to its high thermal resistance and high stiffness. It is from this perspective that, a dynamic response analysis is carried out in this paper to investigate the vibration characteristics of stiffened FG panels due to a free air blast loading. The functionally graded panel is modelled following the finite element approach in the ANSYS platform to obtain its free vibration parameters. Subsequently, these parameters along with the geometry data of the panel are exported to the MATLAB platform where an in-house code is developed to perform the transient dynamic response due to the blast loading. The blast pressure is also calculated using an in-house developed MATLAB code following the Brode Model. Numerical simulations involving different types of unstiffened and stiffened FG panels have been carried out. The results reveal that the stiffened FG panels are quite effective to increase the sustainability of the structures due to a blast. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.

关键词： Dynamic response

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Evaluation of Empirical SPT N-Vs Correlations Using 1D Site Response Analysis for Shallow Bedrock Sites in Islamabad, Pakistan

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Iranian Journal of Science and technology - Transactions of civil engineering 2025年第3期49卷 2947-2963页

作者： Aaqib, Muhammad Nguyen, Van-Quang Javaid, Omer Khan, Ali Hamaiz Ashraf, Muhammad Aaliyan Bhusal, Bikram Department of Civil Engineering National University of Technology Islamabad Pakistan Department of Civil Engineering Vinh University Vinh Viet Nam College of Civil and Transportation Engineering Shenzhen University Shenzhen China Durham School of Architectural Engineering and Construction University of Nebraska-Lincoln Omaha NE United States

The use of standard penetration test blow count (SPT- N) to obtain shear wave velocity (Vs) profiles in the absence of geophysical field test data is a common practice. This study uses a set of SPT-N profiles from Islamabad, Pakistan, to develop Vs profiles using empirical SPT-N and Vs empirical correlations. A set of SPT-N and Vs correlations based on the frequency of their use for seismic site response studies in the region were selected. A suite of one-dimensional site response analyses is then performed on the generated Vs profiles. The 13 input ground motions were chosen to be compatible with the site class B of the newly enacted building code of Pakistan (BCP 2021). A set of 546 1D nonlinear site response analyses were carried out and site response outputs were compared with the corresponding design spectra of the building code of Pakistan. The site-specific comparisons revealed that the calculations of region-specific empirical correlations are more compatible with the code design spectrum for site class C, whereas the outputs using empirical correlations of other regions are more compatible with the code design spectrum for site class D. Based on a comparative analysis, suitable empirical correlations for engineering practices in Islamabad, Pakistan are recommended. © The Author(s), under exclusive licence to Shiraz University 2024.

关键词： BCP 2021 Design Spectrum One-dimensional Nonlinear site Response Analysis Shallow Bedrock Sites SPT N – Vs Correlation

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An optimization model for just-in-time (JIT) delivery of precast components considering 3D loading constraints, real-time road conditions and assembly time

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engineering, construction and Architectural Management 2025年第5期32卷 3259-3284页

作者： Mao, Wenqi Ran, Kexin Wang, Ting-Kwei Yu, Anyuan Lv, Hongyue Chen, Jieh-Haur Department of Management Science and Real Estate Chongqing University Chongqing China Department of Civil Engineering National Kaohsiung University of Science and Technology Kaohsiung Taiwan Hunan Post and Telecommunication College Changsha China Department of Civil Engineering National Central University Taoyuan Taiwan Department of Civil Engineering Research Center of Smart Construction National Central University Taoyuan Taiwan

Purpose: Although extensive research has been conducted on precast production, irregular component loading constraints have received little attention, resulting in limitations for transportation cost optimization. Traditional irregular component loading methods are based on past performance, which frequently wastes vehicle space. Additionally, real-time road conditions, precast component assembly times, and delivery vehicle waiting times due to equipment constraints at the construction site affect transportation time and overall transportation costs. Therefore, this paper aims to provide an optimization model for Just-In-Time (JIT) delivery of precast components considering 3D loading constraints, real-time road conditions and assembly time. Design/methodology/approach: In order to propose a JIT (just-in-time) delivery optimization model, the effects of the sizes of irregular precast components, the assembly time, and the loading methods are considered in the 3D loading constraint model. In addition, for JIT delivery, incorporating real-time road conditions in the transportation process is essential to mitigate delays in the delivery of precast components. The 3D precast component loading problem is solved by using a hybrid genetic algorithm which mixes the genetic algorithm and the simulated annealing algorithm. Findings: A real case study was used to validate the JIT delivery optimization model. The results indicated this study contributes to the optimization of strategies for loading irregular precast components and the reduction of transportation costs by 5.38%. Originality/value: This study establishes a JIT delivery optimization model with the aim of reducing transportation costs by considering 3D loading constraints, real-time road conditions and assembly time. The irregular precast component is simplified into 3D bounding box and loaded with three-space division heuristic packing algorithm. In addition, the hybrid algorithm mixing the genetic algorithm and t

关键词： Simulated annealing

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Workability and Strength of Ceramsite Self-Compacting Concrete with Steel Slag Sand

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Journal of Renewable Materials 2023年第2期11卷 881-904页

作者： Suiwei Pan Anqi Ren Yongli Peng Min Wu Wanguo Dong Chunlin Liu Depeng Chen School of Construction Engineering Ma’anshan UniversityMa’anshan243100China School of Architectural and Civil Engineering Anhui University of TechnologyMa’anshan243032China School of Management Science and Engineering Anhui University of TechnologyMa’anshan243032China

This study focuses on the workability and compressive strength of ceramsite self-compacting concrete with fine aggregate partially substituted by steel slag sand(CSLSCC)to prevent the pollution of steel slag in the *** SF,J-ring,visual stability index,and sieve analysis tests are primarily employed in this research to investigate the workability of freshly mixed self-compacting concrete containing steel slag at various steel slag sand replacement *** experiment results indicate that CSLSCC with the 20%volume percentage of steel slag(VPS)performs better workability,higher strength,and higher specific *** 7-day compressive strength of CSLSCC with the 0.4 of the water-binder ratio(W/B),decreases with the increase of steel slag content,while the 28-day compressive strength increases *** ceramsite self-compacting concrete with good comprehensive performance can be obtained when the substitution rate of steel slag sand for fine aggregate is less than 20%(volume percentage).

关键词： Steel slag ceramsite self-compacting concrete workability compressive strength

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Study on influence of key blasthole parameters on tunnel overbreak

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Underground Space 2023年第2期9卷 76-90页

作者： Zi-qiang Li Zheng Li Wei-wei Huang Xuan-ming Ding Hang Zhang School of Civil Engineering and Architecture Chongqing University of Science&TechnologyChongqing 401331China Key Laboratory of New Technology for Construction of Cities in Mountain Area Ministry of EducationChongqing UniversityChongqing 400045China Chongqing City Construction Investment(Group)Co. Ltd.Chongqing 400023China School of Civil Engineering Chongqing University400045China

To determine the influence of key blasthole parameters on tunnel overbreak during blasting construction,an intelligent detection sys-tem for tunnel blasting construction is independently *** the key blasthole parameters and overbreak of a typical section of a single line tunnel under the condition of Class V surrounding rock are analyzed and *** actual data obtained is compared with the results of numerical simulations and theoretical *** results are as follows:(1)Quantitative analysis is performed based on the blasthole angle,opening position,and charge mass by the self-developed intelligent detection equipment for blasthole parameters,which can be used to guide the drilling *** scanning equipment for outline excavation can be used to image the actual excavation section in real-time and has the advantages of high precision and fast speed;(2)Tunnel overbreak can be regarded as consisting of two parts:the surrounding rock damage caused by the blasting load,and the collapse of the surrounding rock caused by the blasthole opening *** parameter of the peripheral hole will affect the tunnel overbreak;however,the key parameter is the blasthole opening position;(3)The distributions of the tunnel overbreak volume obtained with the theoretical analysis,finite element simulation,and measurements are basically *** the condition of Class V surrounding rock,the overbreak of this single line tunnel can reach 14.1–78.2 *** meet the specification requirements,the opening position and construction accuracy of the peripheral hole should be strictly controlled.

关键词： Tunnel blasting Blasthole parameters Tunnel overbreak Surrounding rock damage Smooth surface blasting

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