scholarly journals Field Tests on the Attenuation Characteristics of the Blast Air Waves in a Long Road Tunnel: A Case Study

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Yong Fang ◽  
Yi-Lun Zou ◽  
Jian Zhou ◽  
Zhi-gang Yao ◽  
Shuai Lei ◽  
...  
Keyword(s):  
Field Tests ◽  
Blast Waves ◽  
Original Equation ◽  
Road Tunnel ◽  
Highway Tunnel ◽  
Attenuation Characteristics ◽  
Modified Equation

After an explosion occurs in a tunnel, the blast waves take on diverse forms of attenuation in different regions when it propagates along the tunnel. However, the prediction of the overpressure decay laws proposed in previous studies has not taken into account the influence of the different regions in the tunnel. The present paper uses the example of the Micangshan highway tunnel in China and considers many factors that influence the propagation of the blast waves by dividing the tunnel into four zones. The paper modifies the decay equation proposed by Smith and applies it to the Micangshan highway tunnel in China. The decay equations are different in different zones. Field tests in this tunnel show that the modified equation is more suitable to describe the attenuation of the blast waves in the tunnel than the original equation.

scholarly journals Cooperative Control Mechanism of Long Flexible Bolts and Blasting Pressure Relief in Hard Roof Roadways of Extra-Thick Coal Seams: A Case Study

2021 ◽  
Vol 11 (9) ◽  
pp. 4125
Author(s):  
Zhe Xiang ◽  
Nong Zhang ◽  
Zhengzheng Xie ◽  
Feng Guo ◽  
Chenghao Zhang
Keyword(s):  
Coal Seam ◽  
Cooperative Control ◽  
Field Tests ◽  
Surrounding Rock ◽  
Deep Hole ◽  
Coal Seams ◽  
Thick Coal Seam ◽  
Structure Damage ◽  
Hard Roof

The higher strength of a hard roof leads to higher coal pressure during coal mining, especially under extra-thick coal seam conditions. This study addresses the hard roof control problem for extra-thick coal seams using the air return roadway 4106 (AR 4106) of the Wenjiapo Coal Mine as a case study. A new surrounding rock control strategy is proposed, which mainly includes 44 m deep-hole pre-splitting blasting for stress releasing and flexible 4-m-long bolt for roof supporting. Based on the new support scheme, field tests were performed. The results show that roadway support failure in traditional scenarios is caused by insufficient bolt length and extensive rotary subsidence of the long cantilever beam of the hard roof. In the new proposed scheme, flexible 4-m-long bolts are shown to effectively restrain the initial expansion deformation of the top coal. The deflection of the rock beam anchored by the roof foundation are improved. Deep-hole pre-splitting blasting effectively reduces the cantilever distance of the “block B” of the voussoir beam structure. The stress environment of the roadway surrounding rock is optimized and anchorage structure damage is inhibited. The results provide insights regarding the safe control of roadway roofs under extra-thick coal seam conditions.

scholarly journals Should We Expect a Disastrous Fire Accident in an Urban Road Tunnel? Literature Data Review and a Case Study for Selected Tunnels in Poland

2021 ◽  
Vol 13 (11) ◽  
pp. 6172
Author(s):  
Krystian Szewczyński ◽  
Aleksander Król ◽  
Małgorzata Król
Keyword(s):  
Time Horizon ◽  
Road Traffic ◽  
Traffic Intensity ◽  
Road Tunnel ◽  
Urban Road ◽  
Road Tunnels ◽  
High Uncertainty ◽  
Fire Outbreak ◽  
Fire Accident

Urban road tunnels are a reasonable remedy for inconvenience due to congested road traffic. However, they bring specific threats, especially those related to the possibility of fire outbreak. This work is a case study for selected urban road tunnels. Considering tunnel specificity, road traffic intensity, and structure and based on the literature data for vehicle fire probability, the chances of a fire accident were estimated for selected tunnels in Poland. It was shown that low power tunnel fires could be expected in the 10–20-year time horizon. Although such threats cannot be disregarded, tunnel systems are designed to cope with them. The chances of a disastrous fire accident were estimated as well. Such events can occur when an HGV with flammable goods or a tanker are involved. Such accidents are fortunately very rare, but, on the other hand, that is the reason why the available data are scanty and burdened with high uncertainty. Therefore, a discussion on the reliability of the obtained results is also provided.

Simulation, controller design and field tests for a hydropower plant—A case study

Automatica ◽  
1990 ◽  
Vol 26 (3) ◽  
pp. 475-485 ◽  
Author(s):  
Karl Heinz Fasol ◽  
Georg Michael Pohl
Keyword(s):  
Controller Design ◽  
Field Tests ◽  
Hydropower Plant

Numerical simulation of fire in road tunnel. Selection of calculation grid

2021 ◽  
pp. 47-54
Author(s):  
И.А. Болодьян ◽  
С.В. Пузач ◽  
А.С. Барановский
Keyword(s):  
Field Tests ◽  
Field Method ◽  
Research Field ◽  
Computational Grids ◽  
Maximum Temperature ◽  
Road Tunnel ◽  
Road Tunnels ◽  
The Masses ◽  
Control Volumes ◽  
Calculation Grid

Рассматривается вопрос выбора расчетной сетки при моделировании пожара в тоннеле с помощью полевого метода и проводится оценка возможного влияния размеров ячеек сетки, а также граничного условия постоянства давления на результаты расчета. Выполнено моделирование пожара для четырех размеров расчетной сетки. Обоснована возможность применения наиболее грубой из используемых сеток с точки зрения инженерных расчетов, в том числе с оговоркой относительно постановки граничного условия. The issue of fire safety of road tunnels is currently an urgent task. Road tunnels are usually not standard typical facilities, but the unique structures. Therefore, it is necessary to study the influence of various parameters on the development of fire in order to take into account the characteristics of a particular object and make decisions on its effective fire protection. Implementation of field tests in this case is expensive and time-consuming. In this regard, numerical modeling is one of the most effective methods of such research. Field models are the most common and currently used for numerical calculations. These models are based on the numerical solution of the system of conservation equations for small control volumes of the calculation grid. This paper examines the issues of selection the calculation grid when modeling a fire in tunnels using the field method is considered and the possible influence of the size of the grid cells is estimated. The mathematical model used in this work is based on a set of differential equations of hydrodynamics, heat transfer, as well as the equation of conservation of the masses of components. Four computational grids were selected for a horizontal (without slope) model tunnel to determine the optimal cell size. As a result of conducted calculations it was established the following: the size of calculated grid is not fundamental for the initial stage of the fire; the use of smaller grid may be preferable at further development of fire, accompanied by increase of combustion capacity to the maximum; the maximum temperature values, especially in the far sections, are obtained on the coarsest grid. The use of such a grid for estimated engineering calculations can be allowed.

scholarly journals Preliminary Field Tests and Long-Term Monitoring as a Method of Design Risk Mitigation: A Case Study of Gdańsk Deepwater Container Terminal

2017 ◽  
Vol 24 (3) ◽  
pp. 106-114 ◽  
Author(s):  
Mikołaj Miśkiewicz ◽  
Oskar Mitrosz ◽  
Tadeusz Brzozowski
Keyword(s):  
Risk Mitigation ◽  
Container Terminal ◽  
Field Tests ◽  
Long Term Results ◽  
Design Solution ◽  
Gantry Crane ◽  
Real Performance ◽  
Method Of Design

Abstract Appropriate risk assessment plays a fundamental role in the design. . The authors propose a possible method of design risk mitigation, which follows recommendations included in Eurocode 7. The so-called “Observational Method” (OM) can produce savings in costs and programmes on engineering projects without compromising safety. The case study presented is a complex design solution that deals with the heavy foundations of a gantry crane beam as one of the elements of a Deepwater Container Terminal extension. The paper presents a detailed process of the design of the rear crane beam being a part of the brand new berth, together with its static analysis, as well as the long-term results of observations, which have revealed the real performance of the marine structure. The case presented is based on excessive preliminary field tests and technical monitoring of the structure, and is an example of a successful OM implementation and design risk mitigation.

Recent Advances in Intelligent Tutoring Systems

2013 ◽  
pp. 631-647
Author(s):  
Joel J. P. C. Rodrigues ◽  
Pedro F. N. João ◽  
Isabel de la Torre Díez
Keyword(s):  
Learning Process ◽  
Intelligent Tutoring Systems ◽  
Intelligent Tutoring ◽  
Field Tests ◽  
Study Guide ◽  
Web Based ◽  
Tutoring Systems ◽  
Recent Advances ◽  
The Web

Intelligent Tutoring Systems (ITS) include interactive applications with some intelligence that supports the learning process. Some of ITS have had a very large impact on educational outcomes in field tests, and they have provided an important ground for artificial intelligence research. This chapter elaborates on recent advances in ITS and includes a case study presenting an ITS called EduTutor. This system was created for the Web-Based Aulanet Learning Management System (LMS). It focuses on subjects for the first cycle of studies of the Portuguese primary education system, between the first and the fourth year. It facilitates the perception of the learning process of each student, individually, in a virtual environment, as a study guide. Moreover, EduTutor has been designed and its architecture prepared for being easily integrated into higher levels of studies, different subjects, and several languages. Currently, it is used in the Aulanet LMS platform.

scholarly journals Road Tunnel Axial Fan Performance In Situ Test: Taking Qinling Zhongnan Mountain Highway Tunnel as an Example

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Yongdong Wang ◽  
Xingbo Han ◽  
Tianyue Zhou ◽  
Zhiwei He ◽  
Feilong Tian ◽  
...  
Keyword(s):  
Spline Interpolation ◽  
Road Tunnel ◽  
Axial Fan ◽  
In Situ Test ◽  
The Road ◽  
Highway Tunnel ◽  
Fitting Method ◽  
Axial Fans ◽  
Biharmonic Spline Interpolation

Axial fans play a pivotal role in the road tunnel ventilation system. Qualified performance of the axial fan is important for both safety and air quality maintenance reasons. Axial fans performance in situ test of Qinling Zhongnan Mountain highway tunnel, the second longest road tunnel in the world, is presented in this research. Performance test items and the qualification criterion, as well as a general framework for the road tunnel axial fan assessment, are recommended. Log-Tchebycheff method is suggested to confirm the location for the measuring lines and points. The precision of the log-Tchebycheff method in air flow rate measuring is verified by comparing with the biharmonic spline interpolation fitting result. The research shows that the log-Tchebycheff method has high precision and good efficiency in the air flow rate measurement of the road tunnel air duct. What is more, the biharmonic spline interpolation fitting method can be applied to obtain a more accurate result. The number of interpolation points of the biharmonic spline interpolation fitting method should be bigger than 2000 to provide quality results.

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