Xu Liang, Jian Xu, Yapeng Zhang, Xinquan Gao, Xuetao Zhou, Zonghao Yuan, Min Zhang, Jian Wu, Long Liu
In recent years, to effectively mitigate the issue of urban traffic congestion, tunnels have become widely used new type of road. However, when the soil layer is excavated and disturbed, the resulting vibration affects the safety of the buildings above it, especially for ancient buildings that are very sensitive to vibrations. Taking the White Tower in Hangzhou as an example, in this paper, the vibration response propagation of large-diameter shield tunnel excavation to adjacent ancient towers is studied through field measurements. The vibration response of the unexcavated south line tunnel is predicted by using 3D numerical analysis software, and the optimal construction parameters are obtained. The study found that the frequency domain component of the White Tower bedrock vibration caused by shield tunneling is mainly 5–20 Hz, and the vibration response attenuates significantly beyond 40 m. Further, reducing the propulsive force can reduce the vibration response of the White Tower; therefore, controlling the propulsion and reducing the tunneling velocity can reduce the vibration response.
{"title":"Influence and the Control of Shield Tunneling on Ancient Tower Vibration","authors":"Xu Liang, Jian Xu, Yapeng Zhang, Xinquan Gao, Xuetao Zhou, Zonghao Yuan, Min Zhang, Jian Wu, Long Liu","doi":"10.1155/2024/9922218","DOIUrl":"https://doi.org/10.1155/2024/9922218","url":null,"abstract":"In recent years, to effectively mitigate the issue of urban traffic congestion, tunnels have become widely used new type of road. However, when the soil layer is excavated and disturbed, the resulting vibration affects the safety of the buildings above it, especially for ancient buildings that are very sensitive to vibrations. Taking the White Tower in Hangzhou as an example, in this paper, the vibration response propagation of large-diameter shield tunnel excavation to adjacent ancient towers is studied through field measurements. The vibration response of the unexcavated south line tunnel is predicted by using 3D numerical analysis software, and the optimal construction parameters are obtained. The study found that the frequency domain component of the White Tower bedrock vibration caused by shield tunneling is mainly 5–20 Hz, and the vibration response attenuates significantly beyond 40 m. Further, reducing the propulsive force can reduce the vibration response of the White Tower; therefore, controlling the propulsion and reducing the tunneling velocity can reduce the vibration response.","PeriodicalId":7242,"journal":{"name":"Advances in Civil Engineering","volume":"18 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139688958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Faisal I. Shalabi, Javed Mazher, Kaffayatullah Khan, Muhammad Nasir Amin, Mesfer Alqahtani, Hosam Awad, Ali Alghannam, Hussain Albaqshi
Despite its collapsible nature and weakness, desert sand can be used for construction purposes all over the world if properly stabilized. Therefore, the aim of this study is to evaluate the effectiveness of cement and fiber in stabilizing locally available dune sand. A test plan was used to investigate the effects of varying quantities of alkali resistance glass (ARG) fiber (F: 0%, 0.2%, 0.4%, and 0.6%) and portland cement (C: 0.0%, 1.0%, 3.0%, and 5.0%) on the mechanical and microstructural properties of dune sand. Mechanical properties such as unconfined strength (UCS), strain at failure (εf), California bearing ratio (CBR), and modulus of elasticity (Es) were evaluated, and microstructure properties were investigated using Raman spectrum and laser-scanning microscopy (LSM) tests on stabilized sand samples. The results of the experimental study showed that the percentage of cement in the treated sand has a more significant impact on the investigated properties of the treated sand than the percentage of fibers. In addition, increasing fiber content results in an increase in the ductility of the sand mix. Raman analysis revealed significant interactions between sand mix components. Moreover, LSM results showed that fiber–cement interaction increased with increasing cement percentage, as calcium silicate hydrates (CSH) formed in the mix and filamentous and intrastrand binding occurred. The findings of this study indicate that ARG fiber and cement can be effective in the stabilization of dune sand for construction purposes even with the use of low percentages of ARG fiber (0.2%–0.4%) and cement (3%).
{"title":"Evaluating the Effect of Cement and ARG Fiber on the Mechanical and Microstructural Properties of Dune Sand","authors":"Faisal I. Shalabi, Javed Mazher, Kaffayatullah Khan, Muhammad Nasir Amin, Mesfer Alqahtani, Hosam Awad, Ali Alghannam, Hussain Albaqshi","doi":"10.1155/2024/5538831","DOIUrl":"https://doi.org/10.1155/2024/5538831","url":null,"abstract":"Despite its collapsible nature and weakness, desert sand can be used for construction purposes all over the world if properly stabilized. Therefore, the aim of this study is to evaluate the effectiveness of cement and fiber in stabilizing locally available dune sand. A test plan was used to investigate the effects of varying quantities of alkali resistance glass (ARG) fiber (F: 0%, 0.2%, 0.4%, and 0.6%) and portland cement (C: 0.0%, 1.0%, 3.0%, and 5.0%) on the mechanical and microstructural properties of dune sand. Mechanical properties such as unconfined strength (UCS), strain at failure (<i>ε<sub>f</sub></i>), California bearing ratio (CBR), and modulus of elasticity (<i>E</i><sub><i>s</i></sub>) were evaluated, and microstructure properties were investigated using Raman spectrum and laser-scanning microscopy (LSM) tests on stabilized sand samples. The results of the experimental study showed that the percentage of cement in the treated sand has a more significant impact on the investigated properties of the treated sand than the percentage of fibers. In addition, increasing fiber content results in an increase in the ductility of the sand mix. Raman analysis revealed significant interactions between sand mix components. Moreover, LSM results showed that fiber–cement interaction increased with increasing cement percentage, as calcium silicate hydrates (CSH) formed in the mix and filamentous and intrastrand binding occurred. The findings of this study indicate that ARG fiber and cement can be effective in the stabilization of dune sand for construction purposes even with the use of low percentages of ARG fiber (0.2%–0.4%) and cement (3%).","PeriodicalId":7242,"journal":{"name":"Advances in Civil Engineering","volume":"295 1 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139662212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
With the large-scale maintenance and renovation of asphalt pavement, a considerable amount of reclaimed asphalt pavement (RAP) will be generated. Stacking these wastes occupies a large amount of land and seriously damages the ecological environment. Hence, efficient regeneration of RAP through recycling technology has gained more and more attention. In this paper, some topics were reviewed to further promote the cold recycling (CR) technology and better follow-up the research progress. First, it discussed the raw materials and the differences and similarities between cement-emulsified asphalt mortar (CEAM) and cold-recycled mixtures with emulsified asphalt (CRME). Second, it reviewed the adhesion development of emulsified asphalt mastic, the application of X-ray technology in microscopic study of CRME and the characteristic of strength development of CRME. The adhesion development of CRME begins with the process of demulsification and hydration caused by the migration and dissipation of water inside the emulsified asphalt mastic. In addition, many factors would influence this process simultaneously. However, the microbehavior mechanism of internal water transport in emulsified asphalt mortar has not yet been thoroughly revealed, and it lacked scientific measurement research on the promoting effect of complex conditions on the development of adhesive properties of mixtures. Therefore, in this paper, they were suggested for future research.
{"title":"Microstructure in Adhesion Development Process and Strength Formation Mechanism in Early Stage of Cold Recycled Mixture with Emulsified Asphalt","authors":"Xueying Zhao, Baofu Ma","doi":"10.1155/2024/7940655","DOIUrl":"https://doi.org/10.1155/2024/7940655","url":null,"abstract":"With the large-scale maintenance and renovation of asphalt pavement, a considerable amount of reclaimed asphalt pavement (RAP) will be generated. Stacking these wastes occupies a large amount of land and seriously damages the ecological environment. Hence, efficient regeneration of RAP through recycling technology has gained more and more attention. In this paper, some topics were reviewed to further promote the cold recycling (CR) technology and better follow-up the research progress. First, it discussed the raw materials and the differences and similarities between cement-emulsified asphalt mortar (CEAM) and cold-recycled mixtures with emulsified asphalt (CRME). Second, it reviewed the adhesion development of emulsified asphalt mastic, the application of X-ray technology in microscopic study of CRME and the characteristic of strength development of CRME. The adhesion development of CRME begins with the process of demulsification and hydration caused by the migration and dissipation of water inside the emulsified asphalt mastic. In addition, many factors would influence this process simultaneously. However, the microbehavior mechanism of internal water transport in emulsified asphalt mortar has not yet been thoroughly revealed, and it lacked scientific measurement research on the promoting effect of complex conditions on the development of adhesive properties of mixtures. Therefore, in this paper, they were suggested for future research.","PeriodicalId":7242,"journal":{"name":"Advances in Civil Engineering","volume":"73 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139659475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cement concrete, as an extensively used engineering material, is omnipresent in various infrastructure projects such as bridges and roads. However, these structures often need to operate for extended periods under varying and harsh environmental conditions, facing not only complex vehicular loads but also the effects of temperature differential cycling. Consequently, understanding how temperature differential cycling impacts the compressive fatigue life of cement concrete has become a pivotal research topic. In this study, through a comprehensive experimental design, the fatigue life of cement concrete under typical temperature difference conditions (20–60°C) and different number of temperature differential cycling (60, 120, 180, 240, 300) was tested at three stress levels (0.70, 0.75, 0.85). Statistical analysis was conducted to obtain the Weibull distribution parameters of the compressive fatigue life of cement concrete. The Pf–S–N relationship of concrete considering reliability was analyzed, and a fatigue life prediction model under different reliability probabilities was established. The results show that the fatigue life of concrete subjected to temperature differential cycling follows a two-parameter Weibull distribution well. From the Pf–N curve, it can be seen that, regardless of the stress level, the calculated fatigue life under the same reliability probability decreases with the increase of temperature differential cycling times. At a 95% reliability probability, the decrease can reach 77.5%–87.5%. Based on the exponential function, a concrete fatigue life prediction model based on different reliability levels was established. Using this model, the S–lgN curve was plotted, and it was found that, regardless of the temperature differential cycling, an increase in reliability probability could lead to a 7.3%–14.4% reduction in logarithmic fatigue life (lgN). Additionally, this study also defined a fatigue life safety factor related to the number of temperature differential cycling and reliability probability, aiming to provide a theoretical basis for the design of cement concrete materials under the coupled environment of temperature differential cycling and fatigue loading.
{"title":"Reliability Analysis of Compressive Fatigue Life of Cement Concrete under Temperature Differential Cycling","authors":"Chengyun Tao, Lin Dong, Tianlai Yu, Qian Chen","doi":"10.1155/2024/8852631","DOIUrl":"https://doi.org/10.1155/2024/8852631","url":null,"abstract":"Cement concrete, as an extensively used engineering material, is omnipresent in various infrastructure projects such as bridges and roads. However, these structures often need to operate for extended periods under varying and harsh environmental conditions, facing not only complex vehicular loads but also the effects of temperature differential cycling. Consequently, understanding how temperature differential cycling impacts the compressive fatigue life of cement concrete has become a pivotal research topic. In this study, through a comprehensive experimental design, the fatigue life of cement concrete under typical temperature difference conditions (20–60°C) and different number of temperature differential cycling (60, 120, 180, 240, 300) was tested at three stress levels (0.70, 0.75, 0.85). Statistical analysis was conducted to obtain the Weibull distribution parameters of the compressive fatigue life of cement concrete. The <i>P</i><sub><i>f</i></sub>–<i>S–N</i> relationship of concrete considering reliability was analyzed, and a fatigue life prediction model under different reliability probabilities was established. The results show that the fatigue life of concrete subjected to temperature differential cycling follows a two-parameter Weibull distribution well. From the <i>P</i><sub><i>f</i></sub>–<i>N</i> curve, it can be seen that, regardless of the stress level, the calculated fatigue life under the same reliability probability decreases with the increase of temperature differential cycling times. At a 95% reliability probability, the decrease can reach 77.5%–87.5%. Based on the exponential function, a concrete fatigue life prediction model based on different reliability levels was established. Using this model, the S–lgN curve was plotted, and it was found that, regardless of the temperature differential cycling, an increase in reliability probability could lead to a 7.3%–14.4% reduction in logarithmic fatigue life (lgN). Additionally, this study also defined a fatigue life safety factor related to the number of temperature differential cycling and reliability probability, aiming to provide a theoretical basis for the design of cement concrete materials under the coupled environment of temperature differential cycling and fatigue loading.","PeriodicalId":7242,"journal":{"name":"Advances in Civil Engineering","volume":"11 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139647385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Premalatha Krishnamurthy, Priyadharshini Maniam Rajan
The working mechanism of a geotechnical structure can be understood from the deformations and the vertical stresses in the soil media. This article attempts to study the deformation, vertical stress development, and distribution of improved clay deposits carrying a single isolated footing. Through PLAXIS 3D software, numerical analyses were conducted for the ground improvement methods, such as the geogrid reinforced sand-bed (GRSB) and ordinary and geogrid encased stone column installation (OSC and GESC). In GRSB, the results show that the stresses were maximum at the sand–clay interface at a depth of 0.67 B (B—footing width). It is proposed to place an additional layer of geogrid at the interface, and it must be within the critical depth, i.e., the width of the footing. Furthermore, for the current study, the stiffness of the geogrid in the sand layer greater than 500 kN/m was insignificant in soil improvement, whereas the optimum axial stiffness of the stone column encasement was 1,000 kN/m based on the stress concentration factor. The stone column installation improved the clay layer even below the depth of 0.67 B, improving the capacity of clay to carry higher vertical stresses on par with the stone columns. The GRSB carried higher vertical stresses than the unimproved ground. However, the OSC and GESC could carry vertical stresses higher than the GRSB. This knowledge can allow the practitioners to decide the depth of placement of the reinforcement and also to choose an alternate if one method is not feasible for the site.
岩土结构的工作机制可以从土壤介质的变形和垂直应力中了解。本文试图研究承载单个孤立基脚的改良粘土沉积的变形、垂直应力发展和分布。通过 PLAXIS 3D 软件，对土工格栅加固砂床（GRSB）和普通及土工格栅包裹石柱安装（OSC 和 GESC）等地基改良方法进行了数值分析。结果表明，在土工格栅加固砂床中，砂粘土界面处的应力最大，深度为 0.67 B（B 基底宽度）。建议在界面处多铺一层土工格栅，且必须在临界深度（即基脚宽度）范围内。此外，在本次研究中，砂层中土工格栅的刚度大于 500 kN/m 对土壤改良作用不大，而根据应力集中系数，石柱围护结构的最佳轴向刚度为 1 000 kN/m。石柱的安装甚至改善了 0.67 B 深度以下的粘土层，提高了粘土承受更大垂直应力的能力，与石柱相当。与未经改良的地层相比，地下连续墙承受了更高的垂直应力。然而，奥氏体层和普通砂浆沉积层承受的垂直应力高于普通砂浆砌块。这些知识可以帮助施工人员决定加固的深度，如果一种方法在施工现场不可行，还可以选择另一种方法。
{"title":"Comparative Study on the Reinforced Sand-Bed and the Stone Column in Improving the Clay Deposit Supporting Isolated Footing","authors":"Premalatha Krishnamurthy, Priyadharshini Maniam Rajan","doi":"10.1155/2024/8836116","DOIUrl":"https://doi.org/10.1155/2024/8836116","url":null,"abstract":"The working mechanism of a geotechnical structure can be understood from the deformations and the vertical stresses in the soil media. This article attempts to study the deformation, vertical stress development, and distribution of improved clay deposits carrying a single isolated footing. Through PLAXIS 3D software, numerical analyses were conducted for the ground improvement methods, such as the geogrid reinforced sand-bed (GRSB) and ordinary and geogrid encased stone column installation (OSC and GESC). In GRSB, the results show that the stresses were maximum at the sand–clay interface at a depth of 0.67 B (B—footing width). It is proposed to place an additional layer of geogrid at the interface, and it must be within the critical depth, i.e., the width of the footing. Furthermore, for the current study, the stiffness of the geogrid in the sand layer greater than 500 kN/m was insignificant in soil improvement, whereas the optimum axial stiffness of the stone column encasement was 1,000 kN/m based on the stress concentration factor. The stone column installation improved the clay layer even below the depth of 0.67 B, improving the capacity of clay to carry higher vertical stresses on par with the stone columns. The GRSB carried higher vertical stresses than the unimproved ground. However, the OSC and GESC could carry vertical stresses higher than the GRSB. This knowledge can allow the practitioners to decide the depth of placement of the reinforcement and also to choose an alternate if one method is not feasible for the site.","PeriodicalId":7242,"journal":{"name":"Advances in Civil Engineering","volume":"50 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139647378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rencong Dai, Wei Gong, Xiao Wang, Xiaoyan Wang, Decheng Cui
The seismic performance analysis of research reactor plants is crucial for ensuring the safety of the entire reactor system. This paper analyzes the plant structure seismic performance of the 2WMt Thorium Molten Salt Reactor-Liquid Fuel 1 (TMSR-LF1) at the Shanghai Institute of Applied Physics, Chinese Academy of Sciences under the action of frequent earthquakes, fortification earthquakes, and rare earthquakes was analyzed by finite element software PKPM based on the seismic design method of civil code +1°. On this basis, a comparison was made between the seismic responses of structural pushover analysis and elastoplastic time history analysis under the action of rare earthquakes, and the conservatism of these two commonly used methods for elastoplastic analysis was systematically analyzed. The results indicate that the TMSR-LF1 plant structure exhibits well bearing and deformation capacity. It meets the seismic design goal of “no damage under small earthquakes,” “no unrepairable damage under medium earthquakes,” and “no collapse under large earthquakes (using static pushover analysis),” and the critical regions are entirely within the elastic range. Furthermore, the analysis reveals that the elastoplastic time history analysis method produced a significantly higher seismic response than the pushover analysis method, which indicates the conservativeness of the time history method. Therefore, it is recommended to use the elastoplastic time history analysis method to evaluate the seismic performance of research reactor plants under rare earthquake actions. The research in this paper provides important references for the seismic performance analysis of other Class II research reactor plants.
{"title":"Conservativeness Study on the Seismic Analysis Method for Research Reactor Plant Structure Based on TMSR-LF1","authors":"Rencong Dai, Wei Gong, Xiao Wang, Xiaoyan Wang, Decheng Cui","doi":"10.1155/2024/1672269","DOIUrl":"https://doi.org/10.1155/2024/1672269","url":null,"abstract":"The seismic performance analysis of research reactor plants is crucial for ensuring the safety of the entire reactor system. This paper analyzes the plant structure seismic performance of the 2WMt Thorium Molten Salt Reactor-Liquid Fuel 1 (TMSR-LF1) at the Shanghai Institute of Applied Physics, Chinese Academy of Sciences under the action of frequent earthquakes, fortification earthquakes, and rare earthquakes was analyzed by finite element software PKPM based on the seismic design method of civil code +1°. On this basis, a comparison was made between the seismic responses of structural pushover analysis and elastoplastic time history analysis under the action of rare earthquakes, and the conservatism of these two commonly used methods for elastoplastic analysis was systematically analyzed. The results indicate that the TMSR-LF1 plant structure exhibits well bearing and deformation capacity. It meets the seismic design goal of “no damage under small earthquakes,” “no unrepairable damage under medium earthquakes,” and “no collapse under large earthquakes (using static pushover analysis),” and the critical regions are entirely within the elastic range. Furthermore, the analysis reveals that the elastoplastic time history analysis method produced a significantly higher seismic response than the pushover analysis method, which indicates the conservativeness of the time history method. Therefore, it is recommended to use the elastoplastic time history analysis method to evaluate the seismic performance of research reactor plants under rare earthquake actions. The research in this paper provides important references for the seismic performance analysis of other Class II research reactor plants.","PeriodicalId":7242,"journal":{"name":"Advances in Civil Engineering","volume":"146 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139649525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To fully control the roof and surface and reduce the ecological damage caused by mining, it is necessary to understand the deformation response law of the surrounding rock in solid backfill mining. The similarities and differences of overburden movement characteristics between natural caving method and solid backfill method are analyzed and compared by means of on-site investigation and monitoring, theoretical derivation and analysis, numerical simulation and effect verification. The control mechanism of backfill mining on the roof is clarified, and the relationship between stope roof displacement and support pressure of backfill body is established. Furthermore, the mechanical conditions of immediate roof in equilibrium state during backfill mining are established. The FLAC3D simulation indicates that the solid backfill mining face has a concentrated stress peak located 15 m ahead of the coal wall. Within the range from 0 to 5 m, the abutment pressure is reduced gradually. However, within the range from 5 to 15 m, the abutment pressure is increased evidently. The stress concentration is located 35 m behind the working face. With continuous backfilling of the goaf, the maximum displacement occurs in the backfill body near the working face. The total deformation of the surrounding rock in the goaf is reduced by 58%. The total deformation of coal wall is reduced by ∼37.5%. The subsidence coefficient is reduced from 0.59 to 0.013 by using the backfill mining technology. The research results provide theoretical guidance and reference for roof control and ecological protection of backfill mining.
{"title":"Study on Deformation Response Law of Surrounding Rock in Solid Backfill Mining Stope","authors":"Xingping Lai, Longquan Wu, Jiantao Cao, Yuhang Tu","doi":"10.1155/2024/8880234","DOIUrl":"https://doi.org/10.1155/2024/8880234","url":null,"abstract":"To fully control the roof and surface and reduce the ecological damage caused by mining, it is necessary to understand the deformation response law of the surrounding rock in solid backfill mining. The similarities and differences of overburden movement characteristics between natural caving method and solid backfill method are analyzed and compared by means of on-site investigation and monitoring, theoretical derivation and analysis, numerical simulation and effect verification. The control mechanism of backfill mining on the roof is clarified, and the relationship between stope roof displacement and support pressure of backfill body is established. Furthermore, the mechanical conditions of immediate roof in equilibrium state during backfill mining are established. The FLAC<sup>3D</sup> simulation indicates that the solid backfill mining face has a concentrated stress peak located 15 m ahead of the coal wall. Within the range from 0 to 5 m, the abutment pressure is reduced gradually. However, within the range from 5 to 15 m, the abutment pressure is increased evidently. The stress concentration is located 35 m behind the working face. With continuous backfilling of the goaf, the maximum displacement occurs in the backfill body near the working face. The total deformation of the surrounding rock in the goaf is reduced by 58%. The total deformation of coal wall is reduced by ∼37.5%. The subsidence coefficient is reduced from 0.59 to 0.013 by using the backfill mining technology. The research results provide theoretical guidance and reference for roof control and ecological protection of backfill mining.","PeriodicalId":7242,"journal":{"name":"Advances in Civil Engineering","volume":"22 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139647544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The main objective of this study was to evaluate the potential use of reclaimed asphalt pavement aggregate (RAPA) and waste plastic bottles (WPBs) for sustainable asphalt pavements production in hot weather conditions. To enhance the adhesion between neat bitumen, RAPA, and WPBs-coated aggregates, a rougher surface texture is created for aggregate particles in the modified asphalt mix. This improvement enhances asphalt mix engineering properties, rutting resistance, and stability. However, bituminous mixtures containing 20% RAPA exhibit tendencies toward strip resistance, this mixture is weak in terms of strength and incapable of supporting loads when utilizing the RAPA. Therefore, due to the moisture susceptibility of the RAPA, it is advised to employ several types of aggregates in future studies to determine the optimal aggregate that can resist stripping and, at the same time, handle heavy loads. Finally, for better asphalt mix performance, it is recommended to use a combination of 70% crushed stone aggregate, 20% RAPA, and 10% WPBs in asphalt mix with a 5.0% optimum modifier content. The experimental results for tensile strength ratio, proportional rut depth, and mean rut depth meet the required specifications of the Ethiopian Road Authority for all properties tested. Therefore, this combination is strongly advised for use in hot mix asphalt production.
{"title":"Potential Use of Reclaimed Asphalt Pavement Aggregate and Waste Plastic Bottles for Sustainable Asphalt Pavement Production","authors":"Tibebu Birega, Anteneh Geremew, Mekonnen Nigatu","doi":"10.1155/2024/8292632","DOIUrl":"https://doi.org/10.1155/2024/8292632","url":null,"abstract":"The main objective of this study was to evaluate the potential use of reclaimed asphalt pavement aggregate (RAPA) and waste plastic bottles (WPBs) for sustainable asphalt pavements production in hot weather conditions. To enhance the adhesion between neat bitumen, RAPA, and WPBs-coated aggregates, a rougher surface texture is created for aggregate particles in the modified asphalt mix. This improvement enhances asphalt mix engineering properties, rutting resistance, and stability. However, bituminous mixtures containing 20% RAPA exhibit tendencies toward strip resistance, this mixture is weak in terms of strength and incapable of supporting loads when utilizing the RAPA. Therefore, due to the moisture susceptibility of the RAPA, it is advised to employ several types of aggregates in future studies to determine the optimal aggregate that can resist stripping and, at the same time, handle heavy loads. Finally, for better asphalt mix performance, it is recommended to use a combination of 70% crushed stone aggregate, 20% RAPA, and 10% WPBs in asphalt mix with a 5.0% optimum modifier content. The experimental results for tensile strength ratio, proportional rut depth, and mean rut depth meet the required specifications of the Ethiopian Road Authority for all properties tested. Therefore, this combination is strongly advised for use in hot mix asphalt production.","PeriodicalId":7242,"journal":{"name":"Advances in Civil Engineering","volume":"8 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139584424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kadhim Z. Naser, Yousif J. Lafta, Thamer H. Alhussein
Reactive powder concrete (RPC) can provide enhanced mechanical properties and durability compared to conventional concrete. RPC has been developed in this study using locally available materials. Six types of steel fibers and three curing regimens were considered to examine their effect on the mechanical properties of RPC. Steel fibers were incorporated by 1% and 2% of the total volume of mixtures. Generally, the experimental results showed that 1% steel fibers enhanced the compressive, flexural, and splitting tensile strengths by 23.6%, 65.1%, and 72.7%, respectively, compared to control mixtures (no fibers). On the other hand, the 2% of fibers improved the compressive, flexural, and tensile strengths by 39.2 %, 155.0%, and 191.7%, respectively. The curing regimen, which consisted of 2 days at 60°C and 3 days at 90°C, followed by 21 days of moist curing at 21°C, indicated the ultimate enhancement of the mechanical properties of RPC. Also, hooked fibers appeared to enhance flexural strength and tensile strength compared to other types of fibers.
{"title":"Effect of Steel Fiber Type and Curing Regimen on the Mechanical Properties of Reactive Powder Concrete","authors":"Kadhim Z. Naser, Yousif J. Lafta, Thamer H. Alhussein","doi":"10.1155/2024/6616375","DOIUrl":"https://doi.org/10.1155/2024/6616375","url":null,"abstract":"Reactive powder concrete (RPC) can provide enhanced mechanical properties and durability compared to conventional concrete. RPC has been developed in this study using locally available materials. Six types of steel fibers and three curing regimens were considered to examine their effect on the mechanical properties of RPC. Steel fibers were incorporated by 1% and 2% of the total volume of mixtures. Generally, the experimental results showed that 1% steel fibers enhanced the compressive, flexural, and splitting tensile strengths by 23.6%, 65.1%, and 72.7%, respectively, compared to control mixtures (no fibers). On the other hand, the 2% of fibers improved the compressive, flexural, and tensile strengths by 39.2 %, 155.0%, and 191.7%, respectively. The curing regimen, which consisted of 2 days at 60°C and 3 days at 90°C, followed by 21 days of moist curing at 21°C, indicated the ultimate enhancement of the mechanical properties of RPC. Also, hooked fibers appeared to enhance flexural strength and tensile strength compared to other types of fibers.","PeriodicalId":7242,"journal":{"name":"Advances in Civil Engineering","volume":"85 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139584396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The steel plate shear wall (SPSW) coupled with steel side columns (SSCs) through steel coupling beams, or the SPSW–SSC coupled structural system, is a novel lateral force resisting system that introduces coupling mechanism to the isolated SPSW pier. To simplify the complex iteration of the conventional seismic design procedure and obtain the favorable plasticity development and distribution pattern determined by the coupling mechanism, the energy-balance concept and the plastic design method are combined to develop the energy-balance-based plastic design (EBPD) method for the SPSW–SSC coupled system with the consideration of the degradation of hysteretic behavior. Twelve SPSW–SSC coupled system prototype cases with different story numbers and coupling ratios (CRs) were designed and numerically modeled to simulate the main seismic behavior. The pushover analyses and the incremental dynamic analyses were further carried out to examine the lateral load capacity and deformation relationships and the seismic fragility curves with respect to the performance levels quantified by the maximum interstory drift ratios. The analysis results prove that the coupling mechanism can be realized in the SPSW–SSC coupled system with preferred yielding sequence and plasticity distribution mode. The influences of story number and CR on the lateral load capacity curves are revealed. The seismic fragility analysis results indicate the exceeding probability of the limit states corresponding to different performance levels with the consideration of the influences of story number and CR, which further proves the effectiveness of the proposed EBPD methods in terms of the realization of the coupling mechanism and the earthquake collapse safety of the SPSW–SSC coupled structural system.
{"title":"Energy-Balance-Based Plastic Design and Seismic Fragility Analysis of Steel Plate Shear Wall Coupled with Steel Side Columns","authors":"Y. T. Wu, Aozhou Liu, Jiazheng Zhao, Bo Zhang","doi":"10.1155/2024/2316053","DOIUrl":"https://doi.org/10.1155/2024/2316053","url":null,"abstract":"The steel plate shear wall (SPSW) coupled with steel side columns (SSCs) through steel coupling beams, or the SPSW–SSC coupled structural system, is a novel lateral force resisting system that introduces coupling mechanism to the isolated SPSW pier. To simplify the complex iteration of the conventional seismic design procedure and obtain the favorable plasticity development and distribution pattern determined by the coupling mechanism, the energy-balance concept and the plastic design method are combined to develop the energy-balance-based plastic design (EBPD) method for the SPSW–SSC coupled system with the consideration of the degradation of hysteretic behavior. Twelve SPSW–SSC coupled system prototype cases with different story numbers and coupling ratios (CRs) were designed and numerically modeled to simulate the main seismic behavior. The pushover analyses and the incremental dynamic analyses were further carried out to examine the lateral load capacity and deformation relationships and the seismic fragility curves with respect to the performance levels quantified by the maximum interstory drift ratios. The analysis results prove that the coupling mechanism can be realized in the SPSW–SSC coupled system with preferred yielding sequence and plasticity distribution mode. The influences of story number and CR on the lateral load capacity curves are revealed. The seismic fragility analysis results indicate the exceeding probability of the limit states corresponding to different performance levels with the consideration of the influences of story number and CR, which further proves the effectiveness of the proposed EBPD methods in terms of the realization of the coupling mechanism and the earthquake collapse safety of the SPSW–SSC coupled structural system.","PeriodicalId":7242,"journal":{"name":"Advances in Civil Engineering","volume":"54 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139584420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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