System of Theories and Methods Monitoring Metro Tunnel Structure Safety during Operation Period

2009 ◽  
Author(s):  
Guihua Li ◽  
Teng Huang ◽  
Hongyu Chen ◽  
Pi Cheng
Keyword(s):  
Tunnel Structure ◽  
Operation Period ◽  
Metro Tunnel

Evaluation of Effects of Static Pile Driving on Existing Metro Tunnel Structure

2019 ◽  
Vol 33 (4) ◽  
pp. 04019045
Author(s):  
Xuezeng Liu ◽  
Yunlong Sang ◽  
Fang Zhao ◽  
Gang Shi ◽  
Yu Heng
Keyword(s):  
Pile Driving ◽  
Tunnel Structure ◽  
Metro Tunnel

scholarly journals Vibration Response Characteristics of the Cross Tunnel Structure

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Jinxing Lai ◽  
Kaiyun Wang ◽  
Junling Qiu ◽  
Fangyuan Niu ◽  
Junbao Wang ◽  
...  
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Time History ◽  
Element Model ◽  
Vibration Response ◽  
Shield Tunnel ◽  
Tunnel Structure ◽  
Response Characteristics ◽  
Vehicle Load ◽  
Metro Tunnel

It is well known that the tunnel structure will lose its function under the long-term repeated function of the vibration effect. A prime example is the Xi’an cross tunnel structure (CTS) of Metro Line 2 and the Yongningmen tunnel, where the vibration response of the tunnel vehicle load and metro train load to the structure of shield tunnel was analyzed by applying the three-dimensional (3D) dynamic finite element model. The effect of the train running was simulated by applying the time-history curves of vibration force of the track induced by wheel axles, using the fitted formulas for vehicle and train vibration load. The characteristics and the spreading rules of vibration response of metro tunnel structure were researched from the perspectives of acceleration, velocity, displacement, and stress. It was found that vehicle load only affects the metro tunnel within 14 m from the centre, and the influence decreases gradually from vault to spandrel, haunch, and springing. The high-speed driving effect of the train can be divided into the close period, the rising period, the stable period, the declining period, and the leaving period. The stress at haunch should be carefully considered. The research results presented for this case study provide theoretical support for the safety of vibration response of Metro Line 2 structure.

Deformation Analysis of Adjacent Metro during Deep Pit Excavation

2011 ◽  
Vol 90-93 ◽  
pp. 651-655
Author(s):  
Yue Ying Liang ◽  
Guo Nan Liu ◽  
Rong Hua Hu ◽  
Ming Zhang
Keyword(s):  
Slope Stability ◽  
Remote Monitoring ◽  
Deformation Analysis ◽  
Tunnel Structure ◽  
Underground Structures ◽  
Control Factors ◽  
Deep Pit ◽  
Metro Tunnel

At space compacted, pipeline-intensive, buildings and underground structures adjacent places, environmental deformation is sensitive to deep pit excavation, so deformation as well as slope stability is the control factors for safety. With FEM and automatic remote monitoring, the deformation of adjacent metro in operation was analyzed during the deep pit excavation; acquired results showed deformation caused by pit construction met the requirements of metro tunnel structure less than 4mm.

A Method of Metro Tunnel Deformation Measurement Based on the Theory of Close Range Photogrammetry

2014 ◽  
Vol 488-489 ◽  
pp. 755-758
Author(s):  
Zhen Hua Chen ◽  
Ming Zhao
Keyword(s):  
Measurement Method ◽  
Light Metal ◽  
Deformation Measurement ◽  
Shield Tunnel ◽  
Tunnel Structure ◽  
Close Range Photogrammetry ◽  
Close Range ◽  
Metal Frame ◽  
Metro Tunnel

In order to solve the difficulties in the deformation measurement of subway shield tunnel structure, a non-contact measurement method of close range photogrammetry technology based on movable base is put forward. A light metal frame is designed as the movable base, which is calibrated by the electronic total station. And the case study verified the feasibility of the measurement.

scholarly journals Response Mechanism of Metro Tunnel Structure under Local Collapse in Loess Stratum

2021 ◽  
Author(s):  
Junling Qiu ◽  
Feifei Fan ◽  
Chengping Zhang ◽  
Jinxing Lai ◽  
Ke Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Large Scale ◽  
Linear Trend ◽  
Water Inrush ◽  
Internal Force ◽  
Beam Model ◽  
Tunnel Structure ◽  
Response Mechanism ◽  
Metro Tunnel ◽  
Theoretical Results

Abstract Due to the frequent occurrence of large-scale water inrush accidents in metro tunnels under the condition of local collapse of loess stratum, there are few reports on the response mechanism of loess metro tunnel under the condition of local collapse. Based on the actual project of tunnel water gushing in a certain section of Xi'an Metro Line 4, the research method of combining theoretical derivation with numerical simulation is adopted, the expressions of internal force and deformation of loess metro tunnel structure under different collapsibility conditions are derived and verified by finite difference method . The results show that the development of water transport channels and the law of collapsibility morphology of loess under local collapsibility are analyzed. Based on the elastic foundation beam model, the structural response model and analytical solutions of internal force and deformation of metro tunnel under different collapsibility conditions (upper collapsibility, side collapsibility and bottom collapsibility) are derived. Combined with the actual data of water inrush accident, the calculation case of the supporting project under the upper collapsible condition is analyzed. When the water head height is 7.5 m, the internal force and deformation of the tunnel structure only occur at about 20 m of the collapsible center. The internal force and deformation of the segment in the main influence range show an obvious non-linear trend, and the strong, weak and no influence zones are defined. Moreover, the numerical simulation results are consistent with the theoretical results under the supporting conditions, which verifies that the theoretical results can effectively predict the influence range of metro tunnel structure under local collapsibility of loess stratum. This research can provide new ideas for the construction, operation and disaster prevention of metro tunnels under the condition of local collapsibility in loess stratum.

scholarly journals Research on the Evaluation of Service Status of Tunnel Structure Near the Station

2021 ◽  
Author(s):  
Z J Lin ◽  
S Gao ◽  
J Li ◽  
J C Wang
Keyword(s):  
Disease Detection ◽  
Tunnel Structure ◽  
Distribution Law ◽  
Water Leakage ◽  
Operation Period ◽  
Status Level

To study the service status of the tunnel structure near the station, a disease detection of Metro Line 1 near the station during the operation period was carried out. The four major tunnel structural diseases including water leakage, segment stagger, open joints, and lining cracks were counted. The distribution law of the structural diseases along the longitudinal and circumferential directions of the interval tunnel was analyzed. The service status of segment components and connecting bolts were evaluated based on existing specification. The overall service status of the tunnel was determined. The service status level of the upstream line was determined as “iii”, and the service status was “degradation”, the service status level of the downstream line was determined as “iv” and the service status was “deteriorated”.

Potassium Pre-Inserted K1.04Mn8O16 Cathode Materials for Aqueous Li-Ion and Na-Ion Hybrid Capacitors

2019 ◽  
Author(s):  
Yamin Zhang ◽  
Lina Chen ◽  
Chongyang Hao ◽  
Xiaowen Zheng ◽  
Yixuan Guo ◽  
...  
Keyword(s):  
Cycling Performance ◽  
High Energy ◽  
High Energy Density ◽  
Potassium Ions ◽  
Tunnel Structure ◽  
Hybrid Supercapacitor ◽  
Hybrid Supercapacitors ◽  
Li Ion ◽  
Power Densities ◽  
Hybrid Capacitors

For the applications of aqueous Li-ion hybrid capacitors and Na-ion hybrid capacitors, potassium ions are pre-inserted into MnO<sub>2</sub> tunnel structure, the as-prepared K<sub>1.04</sub>Mn<sub>8</sub>O<sub>16</sub> materials consist of <a>nanoparticles</a> and nanorods were prepared by facile high-temperature solid-state reaction. <a></a>The as-prepared materials were well studied andthey show outstanding electrochemical behavior. We assembled hybrid supercapacitors with commercial activated carbon (YEC-8A) as anode and K<sub>1.04</sub>Mn<sub>8</sub>O<sub>16 </sub>as cathode. It has high energy densities and power densities. Li-ion capacitors reach a high energy density of 127.61 Wh kg<sup>-1 </sup>at the power density of 99.86 W kg<sup>-1</sup> and Na-ion capacitor obtains 170.96 Wh kg<sup>-1 </sup>at 133.79 W kg<sup>-1</sup>. In addition, the <a>hybrid supercapacitor</a>s demonstrate excellent cycling performance which maintain 97 % capacitance retention for Li-ion capacitor and 85 % for Na-ion capacitor after 10,000 cycles.

Bituminous Insulations Durability of Underground Metallic Pipelines I Field investigations

2017 ◽  
Vol 68 (3) ◽  
pp. 581-585 ◽  
Author(s):  
Gabriela Oprina ◽  
Ladislau Radermacher ◽  
Daniel Lingvay ◽  
Dorian Marin ◽  
Andreea Voina ◽  
...  
Keyword(s):  
Cathode Current Density ◽  
Induced Voltage ◽  
Cathodic Current ◽  
Field Investigations ◽  
Operation Period ◽  
Cathode Current ◽  
Protection Potential ◽  
Cathodic Protection System ◽  
Corrosion State ◽  
Good Agreement

The corrosion state of an underground metallic pipeline of �161 mm and 565 m length was assessed by specific electrical and electrochemical measurements. The investigated pipe, buried in 1997, was protected against corrosion by successive layers of bituminous material with a total thickness of 1 to 1.2 mm. The pipeline crosses three electrified railway lines (50 Hz - 28 kV), and then its route is approximately parallel to these lines; thus, the induced AC voltages between line and ground were calculated obtaining values between 4.05 and 7.1 Vrms, in good agreement with the values measured in the accessible points. The measurements regarding the insulation capacity against corrosion of the bituminous insulation, performed at one month and after 19 years of burial, showed an increase of the average cathode current density needed for obtaining the protection potential in the range �1.00 � �1.28 VCu/CuSO4 of approx. three times (from 6.65 up to 19.96 mA/m2), in good agreement with the evolution of the insulation resistance measured between the steel pipe (having a contact area with the ground of 270.5 m2) and a ground socket of 4 W, which decreased from 995 to 315 kW. Following the analysis and processing of the field collected data, it is considered that, by implementing a cheap cathodic protection system (without cathodic current power supply), based on the rectification of the AC induced voltage, the safe operation period of the investigated pipeline may be extended by at least 50 years.

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