Pub Date : 2023-07-31DOI: 10.14311/cej.2023.02.0020
Jingyang Liu, Hexiang Wu, Quansheng Sun
To solve the problem of excessive deflection in the post-operation process of a rigid frame-continuous girder bridge and provide a basis for the setting of its initial camber, this paper, based on the results of finite element analysis, uses three methods to predict and verify the deflection of a rigid frame-continuous girder bridge. The results show that the average deflection method can be used to fit the average deflection value for a relatively long period of time and predict the average deflection value for the next longer period of time. Both the back-propagation (BP) neural network model and the radial basis function (RBF) neural network model can predict deflection well, but the RBF neural network model has higher prediction accuracy, with a mean absolute error (MAE) of 2.55 cmm and a relative error not exceeding 1%. The prediction model established by the RBF neural network has higher stability, better generalization ability, and better overall prediction performance. The established model has some reference significance for similar engineering projects and can achieve the optimization of structural parameters.
{"title":"Research on the Prediction of Rigid Frame-Continuous Girder Bridge Deflection Using BP and RBF Neural Networks","authors":"Jingyang Liu, Hexiang Wu, Quansheng Sun","doi":"10.14311/cej.2023.02.0020","DOIUrl":"https://doi.org/10.14311/cej.2023.02.0020","url":null,"abstract":"To solve the problem of excessive deflection in the post-operation process of a rigid frame-continuous girder bridge and provide a basis for the setting of its initial camber, this paper, based on the results of finite element analysis, uses three methods to predict and verify the deflection of a rigid frame-continuous girder bridge. The results show that the average deflection method can be used to fit the average deflection value for a relatively long period of time and predict the average deflection value for the next longer period of time. Both the back-propagation (BP) neural network model and the radial basis function (RBF) neural network model can predict deflection well, but the RBF neural network model has higher prediction accuracy, with a mean absolute error (MAE) of 2.55 cmm and a relative error not exceeding 1%. The prediction model established by the RBF neural network has higher stability, better generalization ability, and better overall prediction performance. The established model has some reference significance for similar engineering projects and can achieve the optimization of structural parameters.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86701173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-31DOI: 10.14311/cej.2023.02.0016
Mohamed Zohair Kaab, H. Khelaifa, B. Athamnia, Tarek Djedid, A. Hima
This study optimizes the effect of recycled rubber aggregates and dune sand of El-Oued's region by maximizing the compressive strength of cementitious mortar using Taguchi's design experiments. The experiments were designed using an L9 orthogonal array to see the different relationships between the factors targeted in our research, namely: water/cement (W/C) ratio, rubber aggregates (RA) content, and dune sand (SD) content, with the levels of each factor in the mortar mixture. The samples were tested at 28 days in each of the nine trial conditions for two responses: compressive strength and ultrasonic pulse velocity. The results of the analysis of variation (ANOVA) show that RA content is the factor that has the largest effect on the two tests, and the second factor affecting the two tests is the W/C ratio. Then, the analysis shows that the SD content has no significant effect on the mechanical resistance of the mortar for the two tests. And from the mathematical models investigated in this study, we conclude that the factors RA content and W/C ratio have a negative influence on the responses of the compression test and the ultrasonic test together
{"title":"THE EFFECT OF RECYCLED RUBBER AGGREGATES AND DUNE SAND OF EL-OUED REGION ON THE COMPRESSIVE STRENGTH OF CEMENTITIOUS MORTAR: OPTIMIZATION USING TAGUCHI METHOD","authors":"Mohamed Zohair Kaab, H. Khelaifa, B. Athamnia, Tarek Djedid, A. Hima","doi":"10.14311/cej.2023.02.0016","DOIUrl":"https://doi.org/10.14311/cej.2023.02.0016","url":null,"abstract":"This study optimizes the effect of recycled rubber aggregates and dune sand of El-Oued's region by maximizing the compressive strength of cementitious mortar using Taguchi's design experiments. The experiments were designed using an L9 orthogonal array to see the different relationships between the factors targeted in our research, namely: water/cement (W/C) ratio, rubber aggregates (RA) content, and dune sand (SD) content, with the levels of each factor in the mortar mixture. The samples were tested at 28 days in each of the nine trial conditions for two responses: compressive strength and ultrasonic pulse velocity. The results of the analysis of variation (ANOVA) show that RA content is the factor that has the largest effect on the two tests, and the second factor affecting the two tests is the W/C ratio. Then, the analysis shows that the SD content has no significant effect on the mechanical resistance of the mortar for the two tests. And from the mathematical models investigated in this study, we conclude that the factors RA content and W/C ratio have a negative influence on the responses of the compression test and the ultrasonic test together","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89415332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-31DOI: 10.14311/cej.2023.02.0013
L. Běloch
The article focuses on the design and implementation of a Low-cost GNSS device for autonomous position monitoring and for determining parameters of the atmosphere. The first part is dedicated to the specification of individual components and their combination into several devices. The primary part includes a test of these GNSS devices and the parameters of data collection. This is followed by a quality test of these collected datasets, in several graphs is shown device capabilities. Also, we can see some problems with components, but we were able to specify what causes them. The final part deals with positioning and determining atmospheric parameters by G-Nut software with the selected GNSS sensor.
{"title":"Design of Autonomous Position and Secondary Estimation of Atmospheric Parameters Sensor Using Low-cost GNSS","authors":"L. Běloch","doi":"10.14311/cej.2023.02.0013","DOIUrl":"https://doi.org/10.14311/cej.2023.02.0013","url":null,"abstract":"The article focuses on the design and implementation of a Low-cost GNSS device for autonomous position monitoring and for determining parameters of the atmosphere. The first part is dedicated to the specification of individual components and their combination into several devices. The primary part includes a test of these GNSS devices and the parameters of data collection. This is followed by a quality test of these collected datasets, in several graphs is shown device capabilities. Also, we can see some problems with components, but we were able to specify what causes them. The final part deals with positioning and determining atmospheric parameters by G-Nut software with the selected GNSS sensor.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83154840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To study the dynamic failure mechanism and damage development law of highway bridge structure under the boundary effect in the process of seismic dynamic duration, the Wenchang Highway Bridge with the largest canal crossing in the South-to-North Water Diversion is taken as an example for seismic design analysis. Based on the finite element and infinite element coupling theory, the infinite element method boundary is introduced, the concrete damage plasticity is introduced, and the half-space free field model is established to study the energy dispersion phenomenon of waves in the boundary and the absorption effect of the infinite element method boundary on wave energy is verified. Under different peak acceleration intensities, the seismic response analysis of the bridge structure was carried out. The results show that: Under the action of selected artificial waves, the damage location of the bridge mainly concentrated in the junction of the box girder supported by the pier, the bottom of the pier and the junction of the pier and beam. The damage tends to develop downward near the bottom of the box girder. The damage at both ends of the beam extends from both ends to the middle. And the bottom and top of the pier have penetrating damage. These are weak points in seismic design. At a horizontal peak acceleration of 0.6g, in addition to damage to the pier column, damage also occurred to the bottom of the box girder. Therefore, when the horizontal peak acceleration of the seismic wave is greater than 0.6g, the failure of the bottom of the box girder is paid attention to. Moreover, the IEM boundary has a good control effect on the far-field energy dissipation of the wave, which is simpler and more efficient than the viscous–spring boundary.
{"title":"STUDY ON EARTHQUAKE DESTRUCTION MODE OF THE LARGEST CANAL CROSSING HIGHWAY BRIDGE BASED ON IEM BOUNDARY IN SOUTH-TO-NORTH WATER DIVERSION","authors":"X. Xu, Honghao Zhang, Jinchang Liang, Xuhui Liu, Chen Xie, Jianwei Zhang","doi":"10.14311/cej.2023.02.0012","DOIUrl":"https://doi.org/10.14311/cej.2023.02.0012","url":null,"abstract":" To study the dynamic failure mechanism and damage development law of highway bridge structure under the boundary effect in the process of seismic dynamic duration, the Wenchang Highway Bridge with the largest canal crossing in the South-to-North Water Diversion is taken as an example for seismic design analysis. Based on the finite element and infinite element coupling theory, the infinite element method boundary is introduced, the concrete damage plasticity is introduced, and the half-space free field model is established to study the energy dispersion phenomenon of waves in the boundary and the absorption effect of the infinite element method boundary on wave energy is verified. Under different peak acceleration intensities, the seismic response analysis of the bridge structure was carried out. The results show that: Under the action of selected artificial waves, the damage location of the bridge mainly concentrated in the junction of the box girder supported by the pier, the bottom of the pier and the junction of the pier and beam. The damage tends to develop downward near the bottom of the box girder. The damage at both ends of the beam extends from both ends to the middle. And the bottom and top of the pier have penetrating damage. These are weak points in seismic design. At a horizontal peak acceleration of 0.6g, in addition to damage to the pier column, damage also occurred to the bottom of the box girder. Therefore, when the horizontal peak acceleration of the seismic wave is greater than 0.6g, the failure of the bottom of the box girder is paid attention to. Moreover, the IEM boundary has a good control effect on the far-field energy dissipation of the wave, which is simpler and more efficient than the viscous–spring boundary.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"118 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83959830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-31DOI: 10.14311/cej.2023.02.0018
Jing Sun
In this paper, based on the numerical calculation, the reasonable rise-span ratio (RSR) and its influencing factors of the arch in the PBA method are compared and analyzed, and the mechanical properties of the arch under different influencing factors (RSR, lateral pressure coefficient (LPC), and structure thickness) is further obtained. The results show that the deformation and bending moment of the arch structure decreases first and then increases with the increase of the RSR, that is, optimal RSR exists. Different LPCs have a great influence on the stress of arch structure, and the deformation and bending moment of arch structure decrease with the increase of LPC. The increase in arch structure thickness can effectively reduce structural deformation, but may also lead to an increase in structural stress due to the increase in self-weight. At the same time, the comprehensive factors show that the optimal RSR increases with the increase of LPC and structure thickness, and it is suggested that the reasonable RSR should be 0.2-0.3. The rationality of the calculation is also verified by the application status of the station RSR with the PBA method in China.
{"title":"Study on the reasonable RSR of arch and its influencing factors in PBA method","authors":"Jing Sun","doi":"10.14311/cej.2023.02.0018","DOIUrl":"https://doi.org/10.14311/cej.2023.02.0018","url":null,"abstract":"In this paper, based on the numerical calculation, the reasonable rise-span ratio (RSR) and its influencing factors of the arch in the PBA method are compared and analyzed, and the mechanical properties of the arch under different influencing factors (RSR, lateral pressure coefficient (LPC), and structure thickness) is further obtained. The results show that the deformation and bending moment of the arch structure decreases first and then increases with the increase of the RSR, that is, optimal RSR exists. Different LPCs have a great influence on the stress of arch structure, and the deformation and bending moment of arch structure decrease with the increase of LPC. The increase in arch structure thickness can effectively reduce structural deformation, but may also lead to an increase in structural stress due to the increase in self-weight. At the same time, the comprehensive factors show that the optimal RSR increases with the increase of LPC and structure thickness, and it is suggested that the reasonable RSR should be 0.2-0.3. The rationality of the calculation is also verified by the application status of the station RSR with the PBA method in China.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79205889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-31DOI: 10.14311/cej.2023.02.0015
B. Hu, Jianxi Yang, Quansheng Sun, Chao Zhang
This article studies a concrete hollow slab simply supported-continuous actual engineering project in a certain city. Before the reinforcement of the bridge, there were cracks and exposed rebars, etc. In order to ensure the safe operation of the bridge, a reinforcement method of simply supported-continuous was adopted, prestressed steel strands are used to convert the simple-supported structure into a continuous structure, thereby improving the structural load-bearing capacity and overall integrity. Through conducting comparative analysis of load tests on a bridge before and after reinforcement, this article studies the improvement effect of the simply-supported-to-continuous reinforcement method on the bearing capacity of the bridge. A finite element model of the bridge was established, and comparative analysis was carried out before and after the reinforcement of the bridge. The bearing capacity and work performance of the bridge structure were evaluated. The research shows that the simply supported-continuous reinforcement method has a good improvement effect on the load-bearing capacity of the concrete hollow slab and can be used to improve the insufficient load-bearing capacity of the concrete hollow slab bridge in the city.
{"title":"Experimental study on real bridge before and after simple-supporting to continuous reinforced concrete hollow slab","authors":"B. Hu, Jianxi Yang, Quansheng Sun, Chao Zhang","doi":"10.14311/cej.2023.02.0015","DOIUrl":"https://doi.org/10.14311/cej.2023.02.0015","url":null,"abstract":"This article studies a concrete hollow slab simply supported-continuous actual engineering project in a certain city. Before the reinforcement of the bridge, there were cracks and exposed rebars, etc. In order to ensure the safe operation of the bridge, a reinforcement method of simply supported-continuous was adopted, prestressed steel strands are used to convert the simple-supported structure into a continuous structure, thereby improving the structural load-bearing capacity and overall integrity. Through conducting comparative analysis of load tests on a bridge before and after reinforcement, this article studies the improvement effect of the simply-supported-to-continuous reinforcement method on the bearing capacity of the bridge. A finite element model of the bridge was established, and comparative analysis was carried out before and after the reinforcement of the bridge. The bearing capacity and work performance of the bridge structure were evaluated. The research shows that the simply supported-continuous reinforcement method has a good improvement effect on the load-bearing capacity of the concrete hollow slab and can be used to improve the insufficient load-bearing capacity of the concrete hollow slab bridge in the city.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72665740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-31DOI: 10.14311/cej.2023.02.0021
Tiezeng Zhu, Xudan Li
Asphalt materials have a very wide range of applications in roads, but with the increase of traffic pressure and the intensification of cracking and rutting in traditional asphalt pavements, there is an urgent need to further improve the performance of asphalt materials. In this paper, composite asphalt materials containing 10%, 20%, and 30% trinidad lake asphalt (TLA) and 0%, 2%, 3%, and 4% styrene-butadiene rubber (SBR) were prepared. Their basic properties and the properties of the mixes used for road rehabilitation were analyzed. It was found that the addition of TLA and SBR caused a decrease in the penetration degree of the material, but significantly increased the softening point of the material, TLA was detrimental to the ductility of the material, and SBR could improve the ductility. From the analysis of the performance of road rehabilitation mixes, the comprehensive performance of 20% TLA+3% SBR was good, its dynamic stability reached 3,712.66 times/mm, its water stability was also good, and its stiffness modulus was 3,332.64 MPa. The results prove the improvement of TLA and SBR for asphalt performance, and this method can be applied in practical projects.
{"title":"Preparation of the composite asphalt material and its performance in road rehabilitation","authors":"Tiezeng Zhu, Xudan Li","doi":"10.14311/cej.2023.02.0021","DOIUrl":"https://doi.org/10.14311/cej.2023.02.0021","url":null,"abstract":"Asphalt materials have a very wide range of applications in roads, but with the increase of traffic pressure and the intensification of cracking and rutting in traditional asphalt pavements, there is an urgent need to further improve the performance of asphalt materials. In this paper, composite asphalt materials containing 10%, 20%, and 30% trinidad lake asphalt (TLA) and 0%, 2%, 3%, and 4% styrene-butadiene rubber (SBR) were prepared. Their basic properties and the properties of the mixes used for road rehabilitation were analyzed. It was found that the addition of TLA and SBR caused a decrease in the penetration degree of the material, but significantly increased the softening point of the material, TLA was detrimental to the ductility of the material, and SBR could improve the ductility. From the analysis of the performance of road rehabilitation mixes, the comprehensive performance of 20% TLA+3% SBR was good, its dynamic stability reached 3,712.66 times/mm, its water stability was also good, and its stiffness modulus was 3,332.64 MPa. The results prove the improvement of TLA and SBR for asphalt performance, and this method can be applied in practical projects.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"69 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89833933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-31DOI: 10.14311/cej.2023.02.0014
Yunwei Meng, Shibao Li, Kang Chen, Binbin Li, G. Qing
Mountainous road landscape is the main source of driving information. The characteristics of two-lane mountainous road result in real-time dynamic changes in the driver's vision interesting areas. In order to explore the dynamic gaze characteristics, a driving experiment is conducted, and the gaze data of 10 drivers are collected. Markov chain is used to analyze the change process of gaze. The results show that: (1) when the current gaze point is in the straight front area, different road landscape has no significant impact on the gaze shift probability; (2) when the current gaze point is in the near left area, next gaze will expand the search scope to obtain much more driving information; (3) when the current gaze point is in the near right area, there is a high probability that the driver's next gaze will return to the front area; (4) when the current gaze point is in the far right area, the gaze will move back and forth between the near right and the far right areas; (5) when the current gaze point is in the far left area, there is a high probability that the gaze will remain in current area; (6) the main source of traffic information obtained by the driver in mountainous road landscape is the straight front area in the vision field, and the gaze point constantly shifts between the far ahead and the near ahead. The research results can provide technical reference for the construction of landscape in mountainous two-lane road.
{"title":"STUDY ON THE DRIVING GAZE SHIFT CHARACTERISTICS OF VISION INTERESTING AREA ON MOUNTAINOUS ROAD","authors":"Yunwei Meng, Shibao Li, Kang Chen, Binbin Li, G. Qing","doi":"10.14311/cej.2023.02.0014","DOIUrl":"https://doi.org/10.14311/cej.2023.02.0014","url":null,"abstract":"Mountainous road landscape is the main source of driving information. The characteristics of two-lane mountainous road result in real-time dynamic changes in the driver's vision interesting areas. In order to explore the dynamic gaze characteristics, a driving experiment is conducted, and the gaze data of 10 drivers are collected. Markov chain is used to analyze the change process of gaze. The results show that: (1) when the current gaze point is in the straight front area, different road landscape has no significant impact on the gaze shift probability; (2) when the current gaze point is in the near left area, next gaze will expand the search scope to obtain much more driving information; (3) when the current gaze point is in the near right area, there is a high probability that the driver's next gaze will return to the front area; (4) when the current gaze point is in the far right area, the gaze will move back and forth between the near right and the far right areas; (5) when the current gaze point is in the far left area, there is a high probability that the gaze will remain in current area; (6) the main source of traffic information obtained by the driver in mountainous road landscape is the straight front area in the vision field, and the gaze point constantly shifts between the far ahead and the near ahead. The research results can provide technical reference for the construction of landscape in mountainous two-lane road.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87629113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-31DOI: 10.14311/cej.2023.02.0017
Y. Li, Huijian Zhang, Gongning Liu, Yuchao Zheng, Wei Fang, Lichuan Wang
Nowadays, there is no precedent for building a high-speed railway in diatomite area. Due to the complex structure and poor mechanical properties of diatomite as well as the lack of relevant engineering experience, more attention has been paid to the proper constitutive model of the tunnel in diatomite layer using the numerical calculation method, while the traditional Elastoplastic calculation model is the most used yet. Therefore, relying on the Feifengshan tunnel, through FLAC3D software as well as the on-site monitoring, the analysis of the settlement law about tunnelling in diatomite stratum is carried out based on different constitutive models. The research results show that diatomite has obvious strain-softening characteristics. The calculated surface settlement and vault settlement based on the Strain Softening model was greater than that based on the Mohr Coulomb model. When compared with the on-site monitoring data, it was found that the Strain Softening model would more accurately show the settlement law of the tunnel in diatomite and has better applicability in the diatomite area. The above-mentioned research results may provide some references for the construction and design of tunnels in similar strata in the future.
{"title":"Study on the settlement law of tunnel in diatomite stratum based on Strain Softening model","authors":"Y. Li, Huijian Zhang, Gongning Liu, Yuchao Zheng, Wei Fang, Lichuan Wang","doi":"10.14311/cej.2023.02.0017","DOIUrl":"https://doi.org/10.14311/cej.2023.02.0017","url":null,"abstract":"Nowadays, there is no precedent for building a high-speed railway in diatomite area. Due to the complex structure and poor mechanical properties of diatomite as well as the lack of relevant engineering experience, more attention has been paid to the proper constitutive model of the tunnel in diatomite layer using the numerical calculation method, while the traditional Elastoplastic calculation model is the most used yet. Therefore, relying on the Feifengshan tunnel, through FLAC3D software as well as the on-site monitoring, the analysis of the settlement law about tunnelling in diatomite stratum is carried out based on different constitutive models. The research results show that diatomite has obvious strain-softening characteristics. The calculated surface settlement and vault settlement based on the Strain Softening model was greater than that based on the Mohr Coulomb model. When compared with the on-site monitoring data, it was found that the Strain Softening model would more accurately show the settlement law of the tunnel in diatomite and has better applicability in the diatomite area. The above-mentioned research results may provide some references for the construction and design of tunnels in similar strata in the future.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88317251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to study the stress and deformation characteristics of Jigongzui U-shaped thin shell aqueduct structure, shell element in ANSYS is proposed to establish the three-dimensional finite element model of the aqueduct for numerical calculation, and the relevant mechanical parameters are obtained by detecting the depth of concrete carbonization. The simulated results show that: (1) The concrete carbonization depth of Jigongzui aqueduct reached 20mm, accounting for about 20% of the total thickness of the channel wall; (2) With the increase of aqueduct water level, the deformation and stress of the aqueduct body gradually increase. The maximum deflection in the middle of the span is 6.98mm, which is less than the limit value of the specification, but the tension in some areas at the bottom of the middle of the span is obvious, exceeding the allowable tensile strength. It is suggested to strengthen the aqueduct body by pasting high-performance fiber materials to improve the stress distribution of the aqueduct body; (3) Shell element has fast calculation speed and high efficiency when simulating similar U-shaped thin shell aqueduct, which can be popularized in simulating similar thin shell structures.
{"title":"STRESS AND DEFORMATION ANALYSIS OF A U-SHAPED THIN AQUEDUCT BASED ON SHELL ELEMENT","authors":"Chuan Zhao, L. Zhang, Sanming Feng, Peng Zeng, Qiang Zhou, Rui Yu","doi":"10.14311/cej.2023.02.0011","DOIUrl":"https://doi.org/10.14311/cej.2023.02.0011","url":null,"abstract":"In order to study the stress and deformation characteristics of Jigongzui U-shaped thin shell aqueduct structure, shell element in ANSYS is proposed to establish the three-dimensional finite element model of the aqueduct for numerical calculation, and the relevant mechanical parameters are obtained by detecting the depth of concrete carbonization. The simulated results show that: (1) The concrete carbonization depth of Jigongzui aqueduct reached 20mm, accounting for about 20% of the total thickness of the channel wall; (2) With the increase of aqueduct water level, the deformation and stress of the aqueduct body gradually increase. The maximum deflection in the middle of the span is 6.98mm, which is less than the limit value of the specification, but the tension in some areas at the bottom of the middle of the span is obvious, exceeding the allowable tensile strength. It is suggested to strengthen the aqueduct body by pasting high-performance fiber materials to improve the stress distribution of the aqueduct body; (3) Shell element has fast calculation speed and high efficiency when simulating similar U-shaped thin shell aqueduct, which can be popularized in simulating similar thin shell structures.","PeriodicalId":21974,"journal":{"name":"Stavební obzor - Civil Engineering Journal","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73949036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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