Civil Engineering Journal-Stavebni Obzor最新文献

Investigation on the Rock-Fragmentation Process of Conical-Shaped TBM Cutterhead in Extremely Hard Rock Ground 锥形TBM刀盘在极硬岩石地层中的破岩过程研究

Civil Engineering Journal-Stavebni Obzor Pub Date : 2023-10-30 DOI: 10.14311/cej.2023.03.0031

Shijun Chen, Xinyu Jin, Rucheng Hu, Fei Liu, Zhongsheng Hu

{"title":"Investigation on the Rock-Fragmentation Process of Conical-Shaped TBM Cutterhead in Extremely Hard Rock Ground","authors":"Shijun Chen, Xinyu Jin, Rucheng Hu, Fei Liu, Zhongsheng Hu","doi":"10.14311/cej.2023.03.0031","DOIUrl":"https://doi.org/10.14311/cej.2023.03.0031","url":null,"abstract":"Conical-shaped cutterhead is one type of tunnel boring machine (TBM) cutterhead which may have advantage of high rock-breaking efficiency in extremely hard rock ground. This study investigated the rock-fragmentation process of disc cutters on the conical-shaped cutterhead via a series of numerical simulations that had been verified by laboratory rock-fragmentation tests. Firstly, the rock-fragmentation numerical model of the six cutters in the 'flat-cone' contiguous part was built based on cutting mode analysis of the conical-shape cutterhead. The rock sample in the numerical model was synthesized using a grain-based discrete element method (GB-DEM) and the reliability of this approach was verified via scaled rock-fragmentation tests conducted on a self-developed linear cutting machine (LCM). Then, a series of numerical simulations were conducted to study the influence of cutterhead cone angle, cutter spacing, and cutter installation angle on the rock-fragmentation performance. The results were as follows: 1) the nature of rock fragmentation in the cone area is the rock fragmentation under side free-face condition; 2) the penetration specific energy can be reduced and thus the rock-fragmentation efficiency can be improved by appropriately increasing the conical angle, reducing the cutter spacing, and increasing the cutter installation angle; 3) for the studied granite, the optimal conical angle is 25°, the cutter spacing is suggested to be no more than 70 mm, and the cutter tilt angle is suggested to be no more than 3°. The results obtained in this paper can be used as guidance for the design of the conical-shaped cutterhead.","PeriodicalId":42993,"journal":{"name":"Civil Engineering Journal-Stavebni Obzor","volume":"66 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136132634","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}

引用次数: 0

HISTORICAL RETAINING WALLS MONITORING: A CASE STUDY OF DEBOSQUETTE WALL OF KYIV-PECHERSK LAVRA 历史挡土墙监测:以基辅-佩切尔斯克拉拉的墙为例

Civil Engineering Journal-Stavebni Obzor Pub Date : 2023-10-30 DOI: 10.14311/cej.2023.03.0024

Roman Shults, Mykola Bilous, Andrii Khailak

{"title":"HISTORICAL RETAINING WALLS MONITORING: A CASE STUDY OF DEBOSQUETTE WALL OF KYIV-PECHERSK LAVRA","authors":"Roman Shults, Mykola Bilous, Andrii Khailak","doi":"10.14311/cej.2023.03.0024","DOIUrl":"https://doi.org/10.14311/cej.2023.03.0024","url":null,"abstract":"Geospatial monitoring of historic buildings has a valuable meaning for their restoration and preservation measures. The preparation and accomplishment of such monitoring have their features and cannot be standardized. Therefore, in each particular case, monitoring is carried out for specific requirements and conditions. The paper presents the results of geospatial monitoring for a part of the UNESCO object Kyiv-Pechersk Lavra. The primary subject of geospatial monitoring is a retaining wall known as the Debosquette Wall. The wall was built in the XVIII century and underwent restoration in 2014. A geospatial monitoring system has been established to prevent undesirable damage and displacements. Assigning the necessary observation accuracy for such a complex object is difficult. In the paper, the modern approach to observation accuracy calculation has been suggested and studied. The approach is based on the application of structural mechanics principles. The structural analysis of the Debosquette Wall has been accomplished. The output of the analysis was applied to calculate the required observation accuracy. The geospatial network and monitoring scheme were developed based on the calculated accuracy. The monitoring proceeded for half a year in 2012-2013, was interrupted for one year, and kept on in 2015. The primary stress was made on the horizontal displacements in that these displacements are the primary threats to the wall stability. The in-depth analysis of the monitoring results has been accomplished. It was found that the displacements have stayed within the allowable values. The developed monitoring approach is recommended for similar projects.","PeriodicalId":42993,"journal":{"name":"Civil Engineering Journal-Stavebni Obzor","volume":"40 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136132635","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}

引用次数: 0

PM2.5 Estimation in the Czech Republic using Extremely Randomized Trees: A Comprehensive Data Analysis 捷克共和国使用极度随机树估算PM2.5:一项综合数据分析

Civil Engineering Journal-Stavebni Obzor Pub Date : 2023-10-30 DOI: 10.14311/cej.2023.03.0027

Saleem Ibrahim, Martin Landa, Eva Matoušková, Lukáš Brodský, Lena Halounová

{"title":"PM2.5 Estimation in the Czech Republic using Extremely Randomized Trees: A Comprehensive Data Analysis","authors":"Saleem Ibrahim, Martin Landa, Eva Matoušková, Lukáš Brodský, Lena Halounová","doi":"10.14311/cej.2023.03.0027","DOIUrl":"https://doi.org/10.14311/cej.2023.03.0027","url":null,"abstract":"The accuracy of artificial intelligence techniques in estimating air quality is contingent upon a multitude of influencing factors. Unlike our previous study that examined PM2.5 over whole Europe using unbalanced spatial-temporal data, the focus of this study was on estimating PM2.5 specifically over the Czech Republic using more balanced dataset to train and evaluate the model. Moreover, the spatial autocorrelation between the ground-based station was taken into consideration while building the model. The feature importance while developing the Extra Trees model revealed that spatial autocorrelation had greater significance in comparison to commonly used inputs such as elevation and NDVI. We found that R2 of the 10-CV for the new model was 16% higher than the previous one. R2 reached 0.85 when predicting unseen data in new locations. The developed spatiotemporal model was employed to generate comprehensive daily maps covering the entire study area throughout the 2018–2020 years. The temporal analysis showed that the levels of PM2.5 exceeded recommended limits of 20 µg/m3 during the year 2018 in many regions. The eastern part of the country suffered from the highest concentrations especially over Zlín and Moravian-Silesian Regions where in the 2018 winter, the values reached risky average concentrations of 30 µg/m3 and 35 µg/m3 respectively. Air quality improved during the next two years in all regions reaching promising levels in 2020 where almost all regions had average concentrations less than 20 µg/m3. The generated dataset will be available for other future air quality studies.","PeriodicalId":42993,"journal":{"name":"Civil Engineering Journal-Stavebni Obzor","volume":"131 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136132628","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}

引用次数: 0

MODELING THE COMPRESSIVE STRENGTH OF ULTRA-HIGH PERFORMANCE CONCRETE (UHPC) BY A MACHINE LEARNING TECHNIQUE OPTIMIZED BY NOVEL ALGORITHM 采用新算法优化的机器学习技术对超高性能混凝土(uhpc)抗压强度进行建模

Civil Engineering Journal-Stavebni Obzor Pub Date : 2023-10-30 DOI: 10.14311/cej.2023.03.0025

Xin Zuo, Die Liu, Yunrui Gao, FengJing Yang, Guohui Wong

{"title":"MODELING THE COMPRESSIVE STRENGTH OF ULTRA-HIGH PERFORMANCE CONCRETE (UHPC) BY A MACHINE LEARNING TECHNIQUE OPTIMIZED BY NOVEL ALGORITHM","authors":"Xin Zuo, Die Liu, Yunrui Gao, FengJing Yang, Guohui Wong","doi":"10.14311/cej.2023.03.0025","DOIUrl":"https://doi.org/10.14311/cej.2023.03.0025","url":null,"abstract":"The Ultra-High Performance Concrete (UHPC) as an efficient material in constructional projects needs to be investigated in terms of ingredients and their magnitudes to compute the compressive strength of concrete. Empirical determination of relationships between constituents can demand more energy and cost. At the same time, the intelligent systems have enabled us to appraise the compressive strength based on ingredients' composition. Also, choosing eco-friendly materials in concrete as one of the widely-used items worldwide should be encouraged. This study has attempted to model the compressive strength of UHPC. Support Vector Regression (SVR), as a machine learning technique aligned with the Particle Swarm Optimization (PSO) and Henry's Gas Solubility Optimization (HGSO), have been used to simulate the compressive strength of concrete calculated based on different materials used in the present article. Eight constituents were tested to generate the compressive strength values. Various metrics were used to evaluate the modeling process. In this regard, the R2 of test phase modeling for SVR-HGSO was obtained 0.960 while for SVR-PSO, 0.925. In the training stage, the correlation rate was computed 0.902 for SVR-HGSO, which is 1.7 percent higher than SVR-PSO with R2 0.887.","PeriodicalId":42993,"journal":{"name":"Civil Engineering Journal-Stavebni Obzor","volume":"66 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136132633","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}

引用次数: 0

EMPIRICAL VULNERABILITY ANALYSIS OF RAILWAY BRIDGE SEISMIC DAMAGE BASED ON 2022 MENYUAN EARTHQUAKE 基于2022年门源地震的铁路桥梁震害易损性实证分析

Civil Engineering Journal-Stavebni Obzor Pub Date : 2023-10-30 DOI: 10.14311/cej.2023.03.0028

Jing He, Yong Huang

{"title":"EMPIRICAL VULNERABILITY ANALYSIS OF RAILWAY BRIDGE SEISMIC DAMAGE BASED ON 2022 MENYUAN EARTHQUAKE","authors":"Jing He, Yong Huang","doi":"10.14311/cej.2023.03.0028","DOIUrl":"https://doi.org/10.14311/cej.2023.03.0028","url":null,"abstract":"A 6.9 magnitude earthquake at a depth of 10 km struck Menyuan County, Haibei Prefecture, Qinghai Province, China, on January 8, 2022. This earthquake damaged some railway bridges on the Lanzhou-Xinjiang Passenger Dedicated Line. This study combines relevant historical earthquake damage experience, considers the effects of earthquake intensity, site soil classification, superstructure type, foundation failure factor, number of spans, and total bridge length, and develops empirical formulas for seismic damage prediction of railway bridges using ordinal logistic regression model in SPSS software. The seismic damage matrix, as were the anticipated multi-intensity mean damage index and the empirical vulnerability curve based on the two-parameter lognormal distribution function, were generated on this basis. According to the conclusions, although the suggested particular equations and vulnerability curves do not apply to the remainder of the region owing to geographical uniqueness, the technical approach is valid. It may be used as a reference for seismic damage prediction and vulnerability evaluation in other regions. The empirical vulnerability analysis based on the earthquake damage prediction matrix derived from the regression analysis can provide reasonable and fast forecasts before the next earthquake.","PeriodicalId":42993,"journal":{"name":"Civil Engineering Journal-Stavebni Obzor","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136132629","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}

引用次数: 0

RESEARCH ON UNBALANCED WEIGHING EXPERIMENT OF MULTI-POINT BRACED SWIVEL CABLE-STAYED BRIDGE 多点支撑旋转斜拉桥不平衡称重试验研究

Civil Engineering Journal-Stavebni Obzor Pub Date : 2023-10-30 DOI: 10.14311/cej.2023.03.0029

Zhipeng Tang, Quansheng Sun, Zifeng Gu, Yafeng Zhao, Haoyang Zhang

{"title":"RESEARCH ON UNBALANCED WEIGHING EXPERIMENT OF MULTI-POINT BRACED SWIVEL CABLE-STAYED BRIDGE","authors":"Zhipeng Tang, Quansheng Sun, Zifeng Gu, Yafeng Zhao, Haoyang Zhang","doi":"10.14311/cej.2023.03.0029","DOIUrl":"https://doi.org/10.14311/cej.2023.03.0029","url":null,"abstract":"To guarantee the safety of the swivel process, the weighing experiment before the swivel is especially important. Based on this, this paper takes a twin-tower, double-cable prestressed concrete swivel cable-stayed bridge as the background and suggests a multi-point braced swivel weighing experiment involving the joint force of the arm-brace and the spherical hinge to solve problems such as a particular obstacle in the relying project's swivelling process. Firstly, the relevant weighing experiment formulas for various circumstances were theoretically derived. The field test results were then used to calculate the jacking force at the limit state during the jacking process, which was then substituted into the relevant formulae, and the relevant parameters of the weighing experiment were calculated. Finally, the counterweight is adjusted based on the weighing results to carry out the structural rotation. The angular velocity was stable during the swivelling process, and the structure was successfully swivelled. The successful practice of a multi-point braced swivel weighing experiment involving the joint force of the arm-brace, and the spherical hinge can provide a reference for the design and construction of similar bridges.","PeriodicalId":42993,"journal":{"name":"Civil Engineering Journal-Stavebni Obzor","volume":"67 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136132630","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}

引用次数: 0

Analysis of the influence of side wall opening on the arch structure of metro station using the PBA method 用PBA法分析地铁车站侧墙开口对拱结构的影响

Civil Engineering Journal-Stavebni Obzor Pub Date : 2023-10-30 DOI: 10.14311/cej.2023.03.0030

Yongxing Dai, Xingkai Pei, Zekun Chen, Bolun Shi, Huijian Zhang, Yujie Yang, Wei Chen

{"title":"Analysis of the influence of side wall opening on the arch structure of metro station using the PBA method","authors":"Yongxing Dai, Xingkai Pei, Zekun Chen, Bolun Shi, Huijian Zhang, Yujie Yang, Wei Chen","doi":"10.14311/cej.2023.03.0030","DOIUrl":"https://doi.org/10.14311/cej.2023.03.0030","url":null,"abstract":"In order to meet the traffic and commercial needs, it is sometimes necessary to open the side wall of the metro station, while the current research on the mechanical properties and safety of the arch caused by the opening of the side wall of the station by pile-beam-arch (PBA) method is rarely involved. In this paper, based on the Tianhe East Station project of Guangzhou Metro Line 11 located in soft-hard uneven stratum using PBA method, the settlement law and mechanical characteristics of the arch under different side wall opening conditions is analyzed, and the influence of opening construction and opening span on the safety of arch is also further studied. The results show that the settlement caused by the opening of the side wall is mainly concentrated in the upper part of the opening area, and gradually expands around the opening area with the increase of opening span, and the maximum settlement occurs in the middle part of the arch. Opening leads to the differential settlement at both ends of the arch. With the increase in opening span, the settlement growth trend of the right side of the arch is greater than that of the left side. The opening of the side wall leads to the increase of the safety factor of the arch body and the decrease of the safety factor of the right arch foot, while the change of the safety factor of the left arch foot is not obvious, and the safety factor meets the specification requirements.","PeriodicalId":42993,"journal":{"name":"Civil Engineering Journal-Stavebni Obzor","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136132631","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}

引用次数: 0

Deformation rule of bored pile & steel support for deep foundation pit in sandy pebble geology 钻孔灌注桩的变形规律砂卵石地质中深基坑钢支护

Civil Engineering Journal-Stavebni Obzor Pub Date : 2023-10-30 DOI: 10.14311/cej.2023.03.0022

Xuansheng Cheng, Jiuru He, Xinlei Li, Qingchun Xia, Hongling Su, Chaobo Chen

引用次数: 0

CONSTRUCTION VERIFICATION OF UNDER-BEARING ARCH BRIDGE BASED ON CONSTRUCTION MONITORING AND TEST 基于施工监测与试验的下承力拱桥施工验证

Civil Engineering Journal-Stavebni Obzor Pub Date : 2023-10-30 DOI: 10.14311/cej.2023.03.0023

Xilong Zheng, Dachao Li, Kexin Zhang, Xiaojie Xue, Fanhua Min

{"title":"CONSTRUCTION VERIFICATION OF UNDER-BEARING ARCH BRIDGE BASED ON CONSTRUCTION MONITORING AND TEST","authors":"Xilong Zheng, Dachao Li, Kexin Zhang, Xiaojie Xue, Fanhua Min","doi":"10.14311/cej.2023.03.0023","DOIUrl":"https://doi.org/10.14311/cej.2023.03.0023","url":null,"abstract":"In this paper, a bottom-bearing arch bridge is taken as an example to carry out the bridge construction monitoring and load tests. In order to ensure the safety of the arch bridge structure in construction and reach the internal force state of the bridge, in the construction monitoring, the construction process of the main girder type and stress, construction error and safety state is monitored. At the same time, in order to verify whether the bridge can meet the design requirements, static and dynamic load tests are carried out after the bridge is completed. The results of construction monitoring show that the stress state of the structure during the construction process is basically consistent with the theoretical calculation and design requirements, and both meet the design and code requirements. The final measured stress state of the structure is within the allowable range of the beam and arch composite bridge, and the stress state of the structure is normal and meets the code requirements. The results of load test show that the measured deflection values of the middle section of the main girder of the test hole are all less than the theoretical calculation values, and the deflection is between 1.54~3.40 mm, indicating that the bearing capacity of the structure meets the design requirements. In addition, under the four working conditions, the measured values of the transverse strain of the main girder are all less than the theoretical values, and the values are all positive. The stress at the measured points is in the tensile state, which meets the design requirements, indicating that the structure has a good elastic recovery ability after unloading. This study can provide important reference value for the construction and design of the same kind of under-bearing arch bridge.","PeriodicalId":42993,"journal":{"name":"Civil Engineering Journal-Stavebni Obzor","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136132632","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}

引用次数: 0

MONITORING AND ANALYSIS OF CANTILEVER JACKING OF HIGH SLOPE PRESTRESSED CONCRETE CONTINUOUS BOX GIRDER 高边坡预应力混凝土连续箱梁悬臂顶进监测与分析

Civil Engineering Journal-Stavebni Obzor Pub Date : 2023-10-30 DOI: 10.14311/cej.2023.03.0032

Zhe Zhang, Quansheng Sun, Chao Zhang, Xiaoqian Li

引用次数: 0