Monitoring and analysis of the subway tunnel wall temperature and surrounding rock/soil heat absorption ratio

2021 ◽  
Vol 194 ◽  
pp. 107657
Author(s):  
Peng Zhao ◽  
Xiaozhao Li ◽  
Jiajun Liu ◽  
Donghai Zhang ◽  
Hengjun Qiao
Keyword(s):  
Wall Temperature ◽  
Surrounding Rock ◽  
Heat Absorption ◽  
Subway Tunnel ◽  
Tunnel Wall ◽  
Absorption Ratio

scholarly journals Evolution regularity of temperature field of active heat insulation roadway considering thermal insulation spraying and grouting: A case study of Zhujidong Coal Mine, China

2021 ◽  
Vol 40 (1) ◽  
pp. 151-170
Author(s):  
Weijing Yao ◽  
Happiness Lyimo ◽  
Jianyong Pang
Keyword(s):  
Sensitivity Analysis ◽  
Temperature Field ◽  
Thermal Insulation ◽  
Wall Temperature ◽  
Heat Insulation ◽  
Surrounding Rock ◽  
Rock Temperature ◽  
Grouting Materials ◽  
Zone Radius ◽  
Thermal Conductivities

Abstract To study the active heat insulation roadways of high-temperature mines considering thermal insulation and injection, a high-temperature −965 m return air roadway of Zhujidong Coal Mine (Anhui Province, China) is selected as a prototype. The ANSYS numerical simulation method is used for the sensitivity analysis of heat insulation grouting layers with different thermal conductivities and zone ranges and heat insulation spray layers with different thermal conductivities and thicknesses; thus, their effects on the heat-adjusting zone radius, surrounding rock temperature field, and wall temperature are studied. The results show that the tunneling head temperature of the Zhujidong Mine is >27°C all year round, consequently causing serious heat damage. The heat insulation circle formed by thermal insulation spraying and grouting can effectively alleviate the disturbance of roadway airflow to the surrounding rock temperature field, thereby significantly reducing the heat-adjusting zone radius and wall temperature. The decrease in the thermal conductivities of the grouting and spray layers, expansion of the grouting layer zone, and increase in the spray layer thickness help effectively reduce the heat-adjusting zone radius and wall temperature. This trend decreases significantly with the ventilation time. A sensitivity analysis shows that the use of spraying and grouting materials of low thermal conductivity for thermal insulation is a primary factor in determining the temperature field distribution, while the range of the grouting layer zone and the spray layer thickness are secondary factors. The influence of the increased surrounding rock radial depth and ventilation time is negligible. Thus, the application of thermal insulation spraying and grouting is essential for the thermal environment control of mine roadways. Furthermore, the research and development of new spraying and grouting materials with good thermal insulation capabilities should be considered.

Thermal Modeling of Thermo-Active Systems in Subway Tunnels: A Chilean Case Study

2017 ◽  
Vol 21 ◽  
pp. 489-496
Author(s):  
Williams Calderón ◽  
Mauricio J. Toledo ◽  
Raimundo Cirano
Keyword(s):  
Numerical Modeling ◽  
Heat Carrier ◽  
Low Cost ◽  
Subway Tunnel ◽  
Concrete Wall ◽  
Tunnel Wall ◽  
Carrier Fluid ◽  
Active Structure ◽  
Circular Pipes ◽  
Energy Options

Since the mid 80’s thermo-active structures have been used around the world to take advantage of shallow geothermal energy. However, these systems have just been considered as energy options in Chilean projects. In this article we explore the design, numerical modeling, and thermal behavior of a flat heat exchanger integrated to the concrete wall of a subway tunnel in Chile. The thermo-active structure is the concrete tunnel wall (energy tunnel) that has an arrangement of circular pipes with water as the heat carrier fluid. Such a system has a low-cost installation, because pipes are embedded in the concrete tunnel wall during construction. The numerical modeling considers actual environmental conditions in the tunnel and the surrounding ground properties. The considered operating condition is restricted to heat transfer from the air within the tunnel and from the surrounding ground to the heat carrier. We studied the dependency of heat absorption on the heat carrier flow rate, and on the spacing of pipe arrangements. Results predict that a 10-meter section of tunnel can capture up to 6.900W in winter and 10.300W in summer. Most heat (75%) is extracted from the air within the tunnel, which allows a reduction of the tunnel air temperature of 5°C during winter and of 8°C during summer. Thus, implementing such a system has a dual effect of cooling the tunnel (a desired outcome) and providing a source of cheap thermal energy.

Numerical Simulation for Destroy Pattern of Surrounding Rock of Circle Tunnel with M-H Coupling Action

2011 ◽  
Vol 71-78 ◽  
pp. 3572-3576
Author(s):  
An Nan Jiang ◽  
Peng Li
Keyword(s):  
Numerical Simulation ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Rock Fracture ◽  
High Stress ◽  
Surrounding Rock ◽  
Zonal Disintegration ◽  
Affecting Factors ◽  
Tunnel Wall ◽  
Shear Belt

The uniform zonal disintegration of surrounding rock is the peculiar phenomena of deep and high stress field, researching the inner mechanism and affecting factors has important meaning for guaranteeing the safety of deep engineering. The paper adopted strain soft Mohr-Coulomb model and carried out numerical simulation of surrounding rock fracture and excavation. The simulation states that along with the unloading time accumulation, the shear belt produced from tunnel wall and developed to inner rock. The corresponding shear stress concentration zone also spread to inner rock and destroy zone increasing. The pore water pressure increasing will accelerate the shear belt developing and increase the destroy degree.

Segmentation of Subway Tunnel Wall Surface Objects Based on Laser 3D Point Cloud

2020 ◽  
Vol 40 (21) ◽  
pp. 2110001
Author(s):  
曹桂萍 Cao Guiping ◽  
刘行思 Liu Xingsi ◽  
刘念 Liu Nian ◽  
杨克成 Yang Kecheng ◽  
夏珉 Xia Min
Keyword(s):  
Point Cloud ◽  
3D Point Cloud ◽  
Wall Surface ◽  
Subway Tunnel ◽  
Tunnel Wall

Research and Monitoring of Metro Tunnel Deformation Based on Internet of Things

2014 ◽  
Vol 484-485 ◽  
pp. 507-510
Author(s):  
Xiao Wei Du ◽  
Yong Tao Gao
Keyword(s):  
Detection System ◽  
Structural Safety ◽  
Subway Tunnel ◽  
Wireless Data ◽  
Tunnel Wall ◽  
Cross Sectional ◽  
Safety Testing ◽  
Wireless Data Transmission ◽  
Tunnel Section ◽  
Tunnel Cross Section

After a long subway tunnel operators will produce cross-sectional deformation. Articles designed vehicle laser ranging device for continuous measurement of tunnel wall to test their deformed state. The paper also describes the tunnel cross-section deformation measurement method, contour fitting principles and error analysis and networking technology for wireless data transmission methods. The detection system is designed to achieve a tunnel section of the structural safety testing and deformation that may occur timely disaster warning, the safe operation of the subway tunnel to provide effective protection.

Analysis of Mechanical Behavior of Subway Tunnel Constructed by Cover and Cut Reverse Method

2012 ◽  
Vol 446-449 ◽  
pp. 3623-3627
Author(s):  
Tie Cheng Wang ◽  
Yang Gao ◽  
Hai Long Zhao
Keyword(s):  
Bending Moment ◽  
Horizontal Displacement ◽  
Internal Force ◽  
Surrounding Rock ◽  
Diaphragm Wall ◽  
Tunnel Construction ◽  
Construction Process ◽  
Subway Tunnel ◽  
Diaphragm Walls ◽  
Reverse Method

In the paper, not only the internal force and displacement of structure during subway tunnel construction with cover and cut reverse method, but also the displacement field and stress field of surrounding rock are analysed. From the numerical calculation it is shown that the bending moment of diaphragm wall is affected seriously by the distribution and value of the stiffness of horizontal support; the excavation phase of the soil of the second floor underground is the key phase of the construction process because the internal force of structure has large increase; the value of surface settlement, horizontal displacement of diaphragm wall, differential settlement between middle pillar and diaphragm walls all meet the requirements, so the construction is safe and the surrounding buildings are affected slightly.

Ground Treatment and its Application in Shallow Subway Tunnel Crossing Urban River by Shield Tunneling Method

2014 ◽  
Vol 919-921 ◽  
pp. 853-856 ◽  
Author(s):  
Xiao Jun Zhou
Keyword(s):  
Surrounding Rock ◽  
Shield Tunnel ◽  
Great Success ◽  
Treatment Technique ◽  
Subway Tunnel ◽  
Shield Tunneling ◽  
Ground Treatment ◽  
Reinforced Concrete Slabs ◽  
Tunneling Method ◽  
Shallow Subway

On the basis of the geological and environmental conditions of surrounding rock around a shallow subway tunnel used to cross a river in Chengdu subway line one, the ground treatment technique such as uplift piles, cast-in-place reinforced concrete slabs and site grouting have been summarized in the paper. The riverbed above shallow shield tunnel is reinforced with covering slabs and uplift piles; meanwhile, the surrounding rock is reinforced with cement and sodium silicate grout by high pressure grouting method conducted inside the tunnel. The practice of the scenario presented in the paper turns out to be a great success and shows that the treatment technique can be used to guide the design and construction of ground reinforcement for shallow tunnel used to cross urban rivers in subway lines by shield tunneling method under similar conditions.

Analysis of Temperature Field of the Tunnel Surrounding Rock in Cold Regions

2013 ◽  
Vol 753-755 ◽  
pp. 745-749 ◽  
Author(s):  
Hui Mei Zhang ◽  
Hai Bo Cao ◽  
Meng Jun Zhang
Keyword(s):  
Temperature Field ◽  
Temperature Distribution ◽  
Great Influence ◽  
Transient Heat Conduction ◽  
Surrounding Rock ◽  
Tunnel Wall ◽  
Cold Regions ◽  
Freeze Thaw ◽  
Tunnel Design ◽  
Heat Conduction Differential Equation

Freeze-thaw disaster is an outstanding problem of geotechnical engineering in cold regions. The temperature field of tunnel surrounding rock in Qilian mountain Osaka hill was calculated according to the transient heat conduction differential equation, meanwhile the freezing conditions of tunnel surrounding rock was forecasted and analyzed after its opening. The study shows that the freeze-thaw environment has a great influence on the temperature distribution of surrounding rock. The tunnel wall and near the mouth of the cave area are more susceptible to the influence of the open ground temperature and air convection, thus the temperature changes violently , but the temperature distribution in surrounding rock tends to be dynamic stable equilibrium as time goes on. The research results can provide a reference for tunnel design and construction in cold regions.

Unsteady Heat Transfer Between Gas and Tube in a Wave Rotor Refrigerator

2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Dapeng Hu ◽  
Jingxian Wang ◽  
Mei Wu ◽  
Tingjiang Liu ◽  
Yiming Zhao ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Shock Wave ◽  
High Pressure ◽  
Wave Propagation ◽  
Wall Temperature ◽  
Great Influence ◽  
Longitudinal Direction ◽  
Heat Absorption ◽  
Wave Rotor ◽  
Unsteady Heat Transfer

Abstract The performance of a wave rotor refrigerator (WRR) is strongly affected by unsteady heat transfer between gas and tubes. In this work, the mechanism of the heat transfer and its effects on WRR were investigated numerically and experimentally. Results show that the heat absorption of wave rotor occurs in the process of shock wave propagation, and heat release happens in other processes. The unsteady heat transfer causes an uneven wall temperature. The temperature varies along the longitudinal direction, while the time variation can be neglected. Furthermore, the position of the bolts, which link the wave rotor and the shaft, has a great influence on WRR gaps. The closer the position of bolts to the high-pressure (HP) nozzle is, the less effect of gaps would be. The research is an important guiding significance to the improvement of WRR refrigeration performance and WRR design.

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