Research

21 pages, 2161 KiB

Open AccessArticle

Excavation and Construction Technology of Diversion Tunnel under Complex Geological Conditions

by Na He and Xianggang Zhang

Appl. Sci. 2023, 13(20), 11538; https://doi.org/10.3390/app132011538 - 21 Oct 2023

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During the construction of a diversion tunnel, geological problems often include faults, fragile strata, hard rock formations, karst landforms, etc., which may have adverse effects on the excavation and construction of the diversion tunnel. Based on the analysis of the engineering overview, this [...] Read more.

During the construction of a diversion tunnel, geological problems often include faults, fragile strata, hard rock formations, karst landforms, etc., which may have adverse effects on the excavation and construction of the diversion tunnel. Based on the analysis of the engineering overview, this study designed a new construction technology for the excavation of water diversion tunnels in hard rock layers and high-karst areas. Based on tunnel seismic prediction (TSP) technology to achieve advanced geological prediction, combined with actual geological conditions, construction difficulties are analyzed. Then, detection technology is used to collect two-way travel time, amplitude, and waveform data. By processing and analyzing the detection image, the spatial orientation and length of the main tunnel during the construction of the diversion tunnel are calculated. After completing the construction ventilation and wind, water, and electricity layout, the excavation construction procedure is designed. In the specific excavation design, the tunnel curtain excavation technology, tunnel body excavation and support technology, excavation grouting technology, important unfavorable geological tunnel section excavation technology, upper/lower flat section excavation technology, upper/lower curved section excavation technology, and vertical shaft section excavation technology were elaborated. Finally, a plan was made for the reuse process of slag material and a construction quality control system was established. During the testing process, it was found that the antidamage coefficient of the side wall was above 0.9 after using the technology described in this article. Therefore, it indicates that the excavation construction technology designed in this article can ensure the support capacity of the side wall of the diversion tunnel, which is suitable for the excavation of the main tunnel during the construction of the diversion tunnel. Full article

(This article belongs to the Special Issue Intelligence and Automation in Construction)

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16 pages, 1914 KiB

Open AccessArticle

Research on Deformation Monitoring of Invert Uplifts in Soft Rock Tunnels Based on 3D Laser Scanning

by Enchao Zhang, Pengtao Niu and Jianfei Liu

Appl. Sci. 2023, 13(17), 9492; https://doi.org/10.3390/app13179492 - 22 Aug 2023

Viewed by 766

Abstract

The soft surrounding rock in tunnels has the characteristics of low strength, easy softening after soaking, and poor self-stability, which makes the inverted arch structure in soft rock tunnels prone to uplift deformations. Therefore, a deformation monitoring method for inverted arch uplifts of [...] Read more.

The soft surrounding rock in tunnels has the characteristics of low strength, easy softening after soaking, and poor self-stability, which makes the inverted arch structure in soft rock tunnels prone to uplift deformations. Therefore, a deformation monitoring method for inverted arch uplifts of soft rock tunnels based on 3D laser scanning technology is studied to improve deformation monitoring. A Leica Scan Station2 3D laser scanner is used to collect 3D point cloud data of soft rock tunnel inverts. Using the automatic matching method of public landmarks and the improved Rodrigues parameter method, the collected 3D point cloud data are spliced and through the Mallat algorithm, the 3D point cloud data are reconstructed and processed after splicing. The whole least square method is used to fit the reconstructed 3D point cloud data. Through the principal component analysis method, the normal vector of the fitting plane is estimated and the best datum plane of the soft rock tunnel invert is found. By calculating and extracting the geometric parameters of the slice point cloud, the monitoring of inverted arch uplift deformations in soft rock tunnels is completed. The experiment shows that this method can effectively collect 3D point cloud data of soft rock tunnel inverts, and complete point cloud stitching and reconstruction. This method can effectively monitor the uplift deformation of inverted arches at different grouting depths. Full article

(This article belongs to the Special Issue Intelligence and Automation in Construction)

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13 pages, 4603 KiB

Open AccessArticle

Investigation on Hydraulic Fracturing and Flexible Anti-Hydrofracturing Solution for Xiaowan Arch Dam

by Yangfeng Wu, Jinsheng Jia, Yang Wang, Cuiying Zheng, Lei Zhao and Baozhen Jia

Appl. Sci. 2023, 13(16), 9302; https://doi.org/10.3390/app13169302 - 16 Aug 2023

Viewed by 682

Abstract

Understanding hydraulic fracturing in concrete super-high arch dams is vital for the implementation of safety measures on the bearing surface. In this study, we conducted tests on hydraulic fracturing for the Xiaowan arch dam (294.5 m) to analyze concrete behavior at cracks under [...] Read more.

Understanding hydraulic fracturing in concrete super-high arch dams is vital for the implementation of safety measures on the bearing surface. In this study, we conducted tests on hydraulic fracturing for the Xiaowan arch dam (294.5 m) to analyze concrete behavior at cracks under various stress conditions. The risk of hydraulic fracturing near the dam heel was identified without compressive stress. Addressing this, we propose a flexible anti-hydrofracturing system using GB sealing material and a spray polyurea coating. Simulation tests on three schemes: ‘3 mm GB plate + 4 mm polyurea’, ‘1 mm GB glue + 5 mm polyurea’, and ‘7 mm polyurea’ showed effective prevention of hydrofracturing at concrete crack openings of 5 mm, 8 mm, or 10 mm under 300 m water pressure. Field tests supported ‘3 mm GB plate + 4 mm polyurea’ and ‘7 mm polyurea’ as optimal solutions for dam sections. Implementation involves a protective block layout with ‘3 mm GB plate + 4 mm polyurea’ on blocks and ‘7 mm polyurea’ in interval zones and corners. Since 2008, maximum leakage, including rock foundation, has remained minimal at 2.78 L/s under regular water levels. These insights aid similar concrete dams in optimizing safety systems. Full article

(This article belongs to the Special Issue Intelligence and Automation in Construction)

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20 pages, 16122 KiB

Open AccessArticle

Time–Space Conflict Management in Construction Sites Using Discrete Event Simulation (DES) and Path Planning in Unity

by Sahand Fathi, Soheil Fathi and Vahid Balali

Appl. Sci. 2023, 13(14), 8128; https://doi.org/10.3390/app13148128 - 12 Jul 2023

Viewed by 1106

Abstract

Time–space conflicts are one of the most common issues facing construction practices, impacting safety and productivity in several negative ways at construction sites. Therefore, implementing and developing methods to reduce the frequency of such conflicts occurring in activity workspaces can effectively enhance project [...] Read more.

Time–space conflicts are one of the most common issues facing construction practices, impacting safety and productivity in several negative ways at construction sites. Therefore, implementing and developing methods to reduce the frequency of such conflicts occurring in activity workspaces can effectively enhance project performance. Space is usually a constrained resource in construction project sites; therefore, in this project, we propose an approach as a method of time–space conflict management in construction project sites. The method implements Informed Rapidly Exploring Random Tree-Star (Informed-RRT*) path planning, Discrete Event Simulation (DES), and geometry to automatically detect and resolve time–space conflicts in construction projects. To evaluate the method’s capabilities, it is tested on a case study of an earthwork operation, including the loading, hauling, dumping, and return phases. Finally, our method finds the shortest travel path and duration for each hauling truck between two given starting and end points in each phase without colliding with static obstacles (randomly placed in the site), intersection points of the trucks’ path, the start and stop time for the truck serving higher-priority construction activities, and the total duration of each truck’s earthwork operation. Full article

(This article belongs to the Special Issue Intelligence and Automation in Construction)

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12 pages, 4170 KiB

Open AccessArticle

Study on Impact–Echo Response of Concrete Column near the Edge

by Yunlin Liu, Hongbao Xu, Xinxin Ma, Donghua Wang and Xiao Huang

Appl. Sci. 2023, 13(9), 5590; https://doi.org/10.3390/app13095590 - 30 Apr 2023

Cited by 1 | Viewed by 1169

Abstract

The impact–echo method is a superior method for detecting the health of concrete structures, but it has the disadvantage of significant errors when identifying structural boundaries. In order to overcome this limitation, this paper proposes a calculation method using a cross-sectional vibration mode [...] Read more.

The impact–echo method is a superior method for detecting the health of concrete structures, but it has the disadvantage of significant errors when identifying structural boundaries. In order to overcome this limitation, this paper proposes a calculation method using a cross-sectional vibration mode in combination with the impact–echo method to detect concrete columns. The variation of the predominant frequency in the mid-column region and the critical boundary is studied. The influence of the edge on the detection results is analyzed. The differences in eigenvalues under different cross-section vibration modes are revealed. A quantitative method for evaluating concrete health using the impact–echo method is further established. Through field tests and finite element simulation calculations, it was verified that the eigenvalues in the fixed mode are very consistent with the predominant frequency measured near the edge region. This makes up for the defect of inaccurate measurements when the impact–echo method is used to detect the edge area of concrete members. The impact–echo method can be better used for the non-destructive testing of concrete members. Full article

(This article belongs to the Special Issue Intelligence and Automation in Construction)

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15 pages, 1180 KiB

Open AccessArticle

Safety Risk Assessment in Urban Public Space Using Structural Equation Modelling

by Xiaojuan Li, Chen Wang, Mukhtar A. Kassem, Zhou Zhang, Yuzhen Xiao and Mingchao Lin

Appl. Sci. 2022, 12(23), 12318; https://doi.org/10.3390/app122312318 - 01 Dec 2022

Cited by 5 | Viewed by 2252

Abstract

Urban public space is essential in improving population carrying capacity and economic efficiency. However, the characteristics of urban public space, such as complex structure, relatively close and large population mobility, make it prone to fire, stampedes and other safety accidents. This study aims [...] Read more.

Urban public space is essential in improving population carrying capacity and economic efficiency. However, the characteristics of urban public space, such as complex structure, relatively close and large population mobility, make it prone to fire, stampedes and other safety accidents. This study aims to develop a systematic approach to identify the key factors that affect the safety risk of urban public spaces and assess the risk. Based on the literature review, 250 structured questionnaires were randomly distributed. Finally, 219 available questionnaires were collected. Based on the above data, a model of urban public space is built using SEM. The results show that construction equipment, road traffic, social governance, urban environment and behaviour significantly affect public space (from high to low). Specifically, regardless of the model or actual situation, we should pay attention to fire awareness and empirical prevention awareness. Based on previous studies, this study considers the influencing factors of urban public safety risks hierarchically and more practically and makes contributions to the field of urban safety. In addition, governments and developers can conduct valuable actual scenario analysis from this study. Full article

(This article belongs to the Special Issue Intelligence and Automation in Construction)

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10 pages, 1664 KiB

Open AccessArticle

Vibration Fatigue Analysis of a Simply Supported Cracked Beam Subjected to a Typical Load

by Yijiang Ma, Guoping Chen, Jie Wu, Kangjia Ma and Le Fan

Appl. Sci. 2022, 12(15), 7398; https://doi.org/10.3390/app12157398 - 23 Jul 2022

Cited by 1 | Viewed by 1496

Abstract

In order to realize the accurate prediction of the vibration fatigue life of the beam in service, a loose coupling analysis method is proposed to carry out vibration fatigue analysis of a beam with an initial crack. In modal analysis, the initial crack [...] Read more.

In order to realize the accurate prediction of the vibration fatigue life of the beam in service, a loose coupling analysis method is proposed to carry out vibration fatigue analysis of a beam with an initial crack. In modal analysis, the initial crack segment is replaced with a torsion spring, and the damping loss factor is introduced by the complex modulus of elasticity; for the simply supported beam, the inherent vibration characteristic equation of the cracked beam is derived. In vibration fatigue analysis, the interaction between the crack’s growth and vibration analysis is considered, and a loose coupling analysis method is proposed to conduct modal dynamic response and vibration fatigue analysis simultaneously. Results indicate that the crack’s relative location and depth determine the modal of the cracked beam, and crack parameters, damping loss factor and external excitation frequency are important factors for the vibration fatigue life of the beam. Full article

(This article belongs to the Special Issue Intelligence and Automation in Construction)

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22 pages, 6600 KiB

Open AccessArticle

UAV Application for Typhoon Damage Assessment in Construction Sites

by Chen Wang, Yutong Tang, Mukhtar A. Kassem and Zhenquan Chen

Appl. Sci. 2022, 12(13), 6293; https://doi.org/10.3390/app12136293 - 21 Jun 2022

Viewed by 1881

Abstract

The safety inspection capability of construction sites before typhoons could be improved using a UAV, which has a rapid identification capability. However, the main safety inspection items need construction experience and technical safety specifications. This study aimed to obtain the influencing factors of [...] Read more.

The safety inspection capability of construction sites before typhoons could be improved using a UAV, which has a rapid identification capability. However, the main safety inspection items need construction experience and technical safety specifications. This study aimed to obtain the influencing factors of typhoon and their weight proportion through the knowledge of disaster theory and the analytic hierarchy process (AHP). The effectiveness of this method was verified by collecting and analyzing the field data at the construction site. A set of construction site early warning flows and disaster prevention and mitigation measures for typhoons are proposed. The results show that UAVs can be used as a tool in this scenario, helping to improve disaster prevention and enhancing the capability of construction site management to evaluate typhoon risk. The research provides a much-needed common ground for collecting and analyzing advances in UAVs and immersive technologies, as well as their influence on building projects. Furthermore, this article provides a new horizon for beginner researchers working on digitalized construction research. Full article

(This article belongs to the Special Issue Intelligence and Automation in Construction)

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