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Wind-sand flow simulation and radius optimization of highway embankment under different vertical curve radius

Journal of Mountain Science 2024年第8期21卷 2533-2546页

作者： LI Liangying LI Qi WANG Xu XIN Guowei WANG Zhenqiang school of civil engineering Lanzhou Jiaotong UniversityLanzhou 730070China

It is of great practical value to explore the correlation between the vertical curve radius of desert highway and the increase of sand accumulation in local lines,and to select the appropriate vertical curve radius for reducing the risk of sand *** this study,three-dimensional models of desert highway embankments with different vertical curve radii were constructed,and Fluent software was used to simulate the wind-sand flow field and sand accumulation distribution of vertical curve *** results show that:(1)Along the direction of the road,the concave and the convex vertical curve embankments have the effect of collecting and diverging the wind-sand flow,*** the radius of the concave vertical curve is 3000 m,5000 m,8000 m,10000 m and 20000 m,the wind velocity in the middle of the vertical curve is 31.76%,22.58%,10.78%,10.53%and 10.44%,higher than that at both *** the radius of the convex vertical curve is 6500 m,8000 m,10000 m,20000 m and 30000 m,the wind velocity at both ends of the vertical curve is 14.06%,9.99%,6.14%,3.22%and 2.41%,higher than that in the *** diversion effect also decreases with the increase of the radius.(2)The conductivity of the concave and convex vertical curve embankments with different radii is greater than 1,which is the sediment transport *** conductivity increases with the increase of radius and gradually tends to be *** the radius of the concave and convex vertical curves reaches 8000 m and 20000 m respectively,the phenomenon of sand accumulation is no longer *** the same radius condition,the concave vertical curve embankment is more prone to sand accumulation than the convex one.(3)Considering the strength of the collection and diversion of the vertical curve embankment with different radii,and the sand accumulation of the vertical curve embankment in the desert section of Wuma Expressway,the radius of the concave vertical curve is not less than 8000 m,and the r

关键词： Highway engineering Vertical curve Numerical simulation Embankment wind-sand flow Radius optimization

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Impact resistance performance and optimization of the sand-EPE composite cushion in rock sheds

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Journal of Mountain Science 2024年第2期21卷 676-689页

作者： YU Bingxin ZHOU Xiaojun TANG Jianhui ZHANG Yujin ZHANG Yuefeng school of civil engineering Southwest Jiaotong UniversityChengdu 610031China

Rock sheds are widely used to prevent rockfall disasters along roads in mountainous *** improve the capacity of rock sheds for resisting rockfall impact,a sand and expandable polyethylene(EPE)composite cushion was proposed.A series of model experiments of rockfall impact on rock sheds were conducted,and the buried depth of the EPE foam board in the sand layer was *** impact load and dynamic response of the rock shed were *** results show that the maximum impact load and dynamic response of the rock shed roof are all significantly less than those of the sand ***,as the distance between the EPE foam board and rock shed roof decreases,the maximum rockfall impact force and impact pressure gradually decrease,and the maximum displacement,acceleration and strain of the rock shed first decrease and then change *** addition,the vibration acceleration and vertical displacement of the rock shed roof decrease from the centre to the edge and decrease faster along the longitudinal direction than that along the transverse *** conclusion,the buffering effect of the sand-EPE composite cushion is better than that of the pure sand cushion,and the EPE foam board at a depth of 1/3 the thickness of the sand layer is appropriate.

关键词： Rockfall Rock shed Impact Composite cushion Buffering effect Dynamic response

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Performance of Bacillus tropicus on Mechanical,Durable and Crack Remediation Properties in Sustainable Vermiculite Concrete

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Journal of Bionic engineering 2024年第4期21卷 1987-1999页

作者： Anbazhagan Rajesh Venkatesh Sri Hariny Arunachalam Sumathi school of civil engineering SASTRA Deemed to be UniversityThirumalaisamudramThanjavurTamilnadu613401India

Sustainable cement-based concrete materials are primarily used for construction,among which vermiculite as lightweight fine aggregate gains more future development ***,a bacterial solution was sprayed over vermiculite and wrapped using calcium sulphoaluminate(CSA)cement to replace with fine aggregate in ***,based on a preliminary test on compressive strength results,10%of Ground Granulated Blast Furnace Slag(GGBS)and a healing solution proportion of 9:1 was selected for preparing self-healing *** fine aggregate was replaced in concrete using vermiculite in 0%,5%,10%and 15%and the findings suggest that bacterial vermiculite replacement should be at most 5%to achieve better results in strength and durable *** strength enhancement observed for compressive strength,strength regain,split tensile strength,flexural strength,and ultrasonic pulse velocity were 29.22%,45.5%,34.02%,28.03%and 41.4%*** crack healing at 7,14 and 28 days of BIVC was 38.23%,58.82%and 79.41%,which is 3–4%lower than internal crack *** analysis by Scanning Electron Microscopy(SEM),X-Ray Diffractometer(XRD),and Energy Dispersive Spectroscopy(EDS)reveals the existence of calcite,and it was formed due to the bio-mineral action of bacteria with available nutrients in sustainable concrete.

关键词： Bacillus tropicus Vermiculite Ground granulated blast furnace slag Mechanical properties Durable properties Crack healing Microstructural characterization

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Frost heaving and crack initiation characteristics of tunnel rock mass in cold regions under low-temperature degradation

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Journal of Mountain Science 2024年第8期21卷 2844-2854页

作者： CHEN Wenhua XIANG Tian school of civil engineering Beijing Jiaotong UniversityBeijing 202303China

water freezing in rock fractures causes volumetric expansion and fracture development through frost *** study introduces a novel analytical model to investigate how uneven freezing force and surrounding rock pressure influence fracture initiation,based on mass conservation,elasticity,and water-ice phase transition principles.A model for rock fracture initiation considering freezing temperature,uneven freezing expansion,in-situ stress,and lateral pressure was proposed based on fracture *** for stress intensity factors were developed and validated using the phase field *** effects of rock elastic modulus anisotropy and critical fracture energy density on fracture initiation were also *** results show that the values of KI and KII exhibit an upward trend as the freezing temperature,uneven expansion,in-situ stress,and lateral pressure *** uneven freezing expansion has the most significant influence on KI and KII values among these *** the uneven freezing expansion coefficient increases to 0.5,the fracture initiation mode shifts from tensile fracture to shear *** the lateral pressure coefficient increases to 1,the fracture initiation mode shifts from tensile fracture to shear *** elastic modulus anisotropy causes fractures to propagate in a clockwise direction,forming a'butterfly'*** fracture energy density an isotropy causes counterclockwise deviation in propagation direction,resulting in branching paths and an'H'-shaped pattern.

关键词： Rock fractures Fracture water Uneven freezing expansion Phase field method Initiation angle Anisotropy

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Gravel hardness effect on compaction characteristics of gravelly soil

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Journal of Mountain Science 2024年第4期21卷 1432-1443页

作者： SHI Yunfang LI Shengang JIANG Chen LIU Jinning school of Resources and civil engineering Northeastern UniversityShenyang 110004China

The compaction characteristics of gravelly soil are affected by gravel *** investigate the evolution and influencing mechanism of different gravel hardness on the compaction characteristics of gravelly soil,heavy compaction tests and crushing tests were conducted on gravelly soils with gravels originated from hard,soft and extremely soft *** to orthogonal experiments and variance analysis,it was found that hardness has a significant impact on the maximum dry density of gravelly soil,followed by gravel content,and lastly,moisture *** gravel compositions with an average saturated uniaxial compressive strength less than 60 MPa,the order of compacted maximum dry density is soft gravels>hard gravels>extremely soft *** type of gravelly soil has a threshold for gravel content,with 60%for hard and soft gravels and 50%for extremely soft *** these thresholds,the compacted dry density decreases *** is a certain interaction between hardness,gravel content,and moisture *** hardness increases the influence of gravel content,whereas lower hardness increases the influence of moisture *** soils with the coarse aggregate(CA)between 0.7 and 0.8 typically achieve higher dry densities after *** addition,the prediction equations for the particle breakage rate and CA ratio in the Bailey method were proposed to estimate the compaction performance of gravelly soil *** results further revealed the compaction mechanism of different gravelly soils and can provide reference for subgrade filling construction.

关键词： Gravelly soil Hardness Compaction characteristics Crushing characteristics Particle breakage rate Bailey method

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Graph Convolutional Networks Embedding Textual Structure Information for Relation Extraction

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Computers, Materials & Continua 2024年第5期79卷 3299-3314页

作者： Chuyuan Wei Jinzhe Li Zhiyuan Wang Shanshan Wan Maozu Guo school of Electrical and Information engineering Beijing University of Civil Engineering and ArchitectureBeijing102616China

Deep neural network-based relational extraction research has made significant progress in recent years,andit provides data support for many natural language processing downstream tasks such as building knowledgegraph,sentiment analysis and question-answering ***,previous studies ignored much unusedstructural information in sentences that could enhance the performance of the relation extraction ***,most existing dependency-based models utilize self-attention to distinguish the importance of context,whichhardly deals withmultiple-structure *** efficiently leverage multiple structure information,this paperproposes a dynamic structure attention mechanism model based on textual structure information,which deeplyintegrates word embedding,named entity recognition labels,part of speech,dependency tree and dependency typeinto a graph convolutional ***,our model extracts text features of different structures from theinput *** Structure information Graph Convolutional Networks employs the dynamic structureattention mechanism to learn multi-structure attention,effectively distinguishing important contextual features invarious structural *** addition,multi-structure weights are carefully designed as amergingmechanismin the different structure attention to dynamically adjust the final *** paper combines these featuresand trains a graph convolutional network for relation *** experiment on supervised relation extractiondatasets including SemEval 2010 Task 8,TACRED,TACREV,and Re-TACED,the result significantly outperformsthe previous.

关键词： Relation extraction graph convolutional neural networks dependency tree dynamic structure attention

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Production of the C/TiO_(2)composite with a high-performance electrochemical property from titanium-rich sludge via in-situ C coating

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Journal of Environmental Sciences 2024年第3期137卷 131-143页

作者： Hualong Wu Yanxia Zhao Jiexi Wang Xiaoyan Li Kaimin Shih Xuguang Li Wei Liu school of water conservancy and Environment University of JinanJinan 250022China State Key Lab of Physical Chemistry of Solid Surface Collaborative Innovation Center of Chemistry for Energy MaterialsCollege of MaterialsXiamen UniversityXiamen 361005China school of Metallurgy and Environment Central South UniversityChangsha 410083China Department of civil engineering The University of Hong KongPokfulamHong KongChina Institute of Environment and Ecology Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China

Resource recycling from waste-water and sludge is an important part of the 14th Five-Year Plan in *** emerging titanium-based coagulants have drawn growing attentions due to their strong coagulation capability in water purification and value-added Ti-loaded sludge *** and recovery of the high value-added sludge into functional nanomaterials is highly significant for both sludge reduction and environmental *** present study was carried out to investigate the recycle of the coagulated Ti-loaded sludge to produce functional C/TiO_(2)composites as the anode materials for lithium-ion batteries(LIBs).It is the first time that the application of the Ti-loaded wastewater sludge derived C/TiO_(2)was evaluated for *** experimental results showed that the carbon coating through in-situ carbonization of the sludge produced the C/TiO_(2)composites with a high specific surface area,stable structural integrity,and excellent electrochemical properties that would facilitate Li+diffusion in long-term LIBs *** C/TiO_(2)composites calcinated from the polytitanium sulfate-coagulated sludge at 800℃(N_(2))exhibited the best electrochemical performance during the cycling tests(601 m Ah/g at 100 m A/g after 200 cycles).The research work demonstrates the promising prospect of the recycle and value-added utilization of the Ti-loaded sludge in the production of high-performance C/TiO_(2)composites for energy storage *** study provides a new way for the management and reuse of Ti-loaded waste-sludge.

关键词： Sludge recovery Ti-loaded sludge In-situ coating Lithium-ion battery

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Ballistic performances of the hourglass lattice sandwich structures under high-velocity fragments

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Defence Technology（防务技术） 2024年第1期31卷 312-325页

作者： He-xiang Wu Jia Qu Lin-zhi Wu Key Laboratory of Advanced Ship Materials and Mechanics College of Aerospace and Civil EngineeringHarbin Engineering UniversityHarbin150001China school of civil engineering Northeast Forestry UniversityHarbin150040China

In this paper,the numerical simulation method is used to study the ballistic performances of hourglass lattice sandwich structures with the same mass under the vertical incidence of *** is paid to elucidating the influences of rod cross-section dimensions,structure height,structure layer,and rod inclination angle on the deformation mode,ballistic performances,and ability to change the ballistic direction of *** results show that the ballistic performances of hourglass lattice sandwich structures are mainly affected by their structural *** this respect,structural parameters optimization of the hourglass lattice sandwich structures enable one to effectively improve their ballistic limit velocity and,consequently,ballistic performances.

关键词： Hourglass lattice sandwich structures Ballistic performances high-velocity Finite element analysis

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Extending the decision-making process during yellow phase from human drivers to autonomous vehicles:A microsimulation study with safety considerations

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Journal of Traffic and Transportation engineering(English Edition) 2024年第2期11卷 362-379页

作者： Efthymis Papadopoulos Anastasia Nikolaidou Emmanouil Lilis Ioannis Politis Panagiotis Papaioannou Transport engineering Laboratory School of Civil EngineeringFaculty of EngineeringAristotle University of ThessalonikiThessaloniki 54124Greece

One of the main factors affecting the safety of signalised intersections is the stop/go behaviour during the yellow *** previous research has exhaustively examined drivers’stop/go decision-making,the expected autonomous vehicles’(AVs’)stop/go behaviour has not yet been thoroughly *** a series of simulation experiments developed for conventional and autonomous vehicles using different carfollowing,lane-changing,lateral placement and stop/go model parameter values,we examine here whether the default VISSIM stop/go parameter values can adequately replicate the observed drivers’behaviour at the considered intersection and assess the suitability of using the currently available options,albeit referring to human drivers,to simulate the expected stop/go behaviour of *** also propose a policy framework for determining the desired behaviour of AVs in yellow interval,which is integrated into an AVs logic and achieved in the last simulation to explore the effect of automation on the stop/go outcome and,hence,on the safety level of signalised *** data analysis and modeling techniques were used for the formulation of certain scenarios,including binary choice *** default stop/go parameter values were found unfit to replicate the observed stop/go behaviour and subjected to *** to the currently available options,the proposed AVs logic proved to produce the most accurate results,in terms of the stop/go simulation *** the impact of automation on the stop/go outcome,the simulation experiments showed that AVs preferred a more conservative behaviour in favor of road safety,as indicated by the significant reduction(≈15%)in the number of vehicles crossing the stop line during the yellow light and zero instances of red light ***,compared to the conservative drivers represented by the default stop/go parameter values,AVs preferred a more rational behaviour in favor of intersection capacit

关键词： Driver behaviour AVs behaviour Signalised intersection Choice model Micro-simulation Policy framework

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Influence of water coupling coefficient on the blasting effect of red sandstone specimens

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International Journal of Coal Science & Technology 2024年第1期11卷 148-166页

作者： Yang Li Renshu Yang Yanbing Wang Dairui Fu school of Mechanics and civil engineering China University of Mining and Technology(Beijing)Beijing100083China school of civil and Resource engineering University of Science and Technology BeijingBeijing100083China

This study investigates the impact of different water coupling coefficients on the blasting effect of red *** analysis is based on the theories of detonation wave and elastic wave,focusing on the variation in wall pressure of the blasting *** DDNP explosive as the explosive load,blasting tests were conducted on red sandstone specimens with four different water coupling coefficients:1.20,1.33,1.50,and *** study examines the morphologies of the rock specimens after blasting under these different water coupling ***,the fractal dimensions of the surface cracks resulting from the blasting were calculated to provide a quantitative evaluation of the extent of rock *** scanning and 3D reconstruction were performed on the post-blasting specimens to visually depict the extent of damage and fractures within the ***,the volume fractal dimension and damage degree of the post-blasting specimens are *** findings are then combined with numerical simulation to facilitate auxiliary *** results demonstrate that an increase in the water coupling coefficient leads to a reduction in the peak pressure on the hole wall and the crushing zone,enabling more of the explosion energy to be utilized for crack propagation following the *** specimens exhibited distinct failure patterns,resulting in corresponding changes in fractal *** simulated pore wall pressure–time curve validated the derived theoretical results,whereas the stress cloud map and explosion energy-time curve demonstrated the buffering effect of the water *** the water coupling coefficient increases,the buffering effect of the water medium becomes increasingly prominent.

关键词： water coupling coefficient Radial uncoupled charge Numerical simulation Fractal dimension

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