Application of MEMS sensors in abnormal deformation monitoring of metro tunnel structure

2021 ◽  
Author(s):  
K. T. Sun ◽  
Y. Gao ◽  
X. D. Wu
2012 ◽  
Vol 8 (10) ◽  
pp. 972893 ◽  
Author(s):  
L. Ran ◽  
T. H. Yi ◽  
X. W. Ye ◽  
X. B. Dong

The project of Hangzhou Metro Line 1 is the first metro line of the urban rapid rail transit system in Hangzhou, China, which is one of the largest municipal projects of Hangzhou and is being constructed commencing from March 28, 2007 and expected to be completed by October 1, 2012. This metro line has a total length of 48 km and 34 stations, connecting Hangzhou downtown with the suburban area of the city. Owing to the complex geological condition, harsh construction situation, and immature computational methodology, construction of metro systems is often subjected to considerable sources of uncertainties. To ensure the safety of the adjacent building structures, it is a vital necessity to monitor deep excavations of metro tunnels at their in-construction stage. This paper introduces the instrumentation system for settlement monitoring of a metro-tunnel airshaft of the project of Hangzhou Metro Line 1 during the construction of deep excavation. The long-term settlement data monitored by the measurement markers installed at the surface ground and in the depth direction of the airshaft excavation construction site are analyzed and presented in detail. The obtained results indicate that the settlements at the instrumented locations of the construction site during different construction steps vary steadily in an allowable variation range.


2013 ◽  
Vol 405-408 ◽  
pp. 1810-1814
Author(s):  
Liang Hong Shi ◽  
Chuan Bao Feng ◽  
Tong Gang Zhang ◽  
Shang Dian Sha ◽  
You Wei Su ◽  
...  

With the development of the high-speed railway (HSR) and metro, the metro crossing the HSR in operation usually happened in metropolis. Considering the stability of railway bridge foundation is very critical to the safety of HSR in operation, it is very important to monitor the influence of the construction of metro tunnel. The no.6 metro line of Nanjing city is crossing the railway bridge group, including three HSR lines, Beijing-Shanghai HSR, Nanjing-Anqing intercity railway, and Shanghai-Wuhan-Chengdu railway. A real-time deformation system using sensors with high accuracy and wireless network is designed to monitor the bridge piers, which are adjacent to the metro tunnel and may be affected in the bridge group. The tilt and settlement of bridge piers and horizontal displacement of pier head are considered in this system. The monitoring results show the feasibility of the system and grantee the operation and bridge engineerings safety.


2019 ◽  
Vol 33 (4) ◽  
pp. 04019045
Author(s):  
Xuezeng Liu ◽  
Yunlong Sang ◽  
Fang Zhao ◽  
Gang Shi ◽  
Yu Heng

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Jinxing Lai ◽  
Kaiyun Wang ◽  
Junling Qiu ◽  
Fangyuan Niu ◽  
Junbao Wang ◽  
...  

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.


2011 ◽  
Vol 90-93 ◽  
pp. 651-655
Author(s):  
Yue Ying Liang ◽  
Guo Nan Liu ◽  
Rong Hua Hu ◽  
Ming Zhang

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.


2014 ◽  
Vol 488-489 ◽  
pp. 755-758
Author(s):  
Zhen Hua Chen ◽  
Ming Zhao

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.


2021 ◽  
Vol 2 (3) ◽  
Author(s):  
Jianbing Qian

In the process of tunnel construction, data on deformation monitoring magnifies the direct reflection of the stability of tunnel structure, and the setting of early warning value is more related to the safety of project construction. In this paper, a tunnel project is taken as an example, and based on a large number of previous engineering practices and the statistical characteristics of monitoring data, the probability statistics method is used to obtain the warning threshold, which is used to give suggestions for the construction of the tunnel project and provide technical reference for the monitoring and warning management of similar tunnel construction.


2021 ◽  
Author(s):  
Junling Qiu ◽  
Feifei Fan ◽  
Chengping Zhang ◽  
Jinxing Lai ◽  
Ke Wang ◽  
...  

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.


Author(s):  
M. Omidalizarandi ◽  
I. Neumann ◽  
E. Kemkes ◽  
B. Kargoll ◽  
D. Diener ◽  
...  

Abstract. In this study, the feasibility of Micro-Electro-Mechanical System (MEMS) accelerometers and an image-assisted total station (IATS) for short- and long-term deformation monitoring of bridge structures is investigated. The MEMS sensors of type BNO055 from Bosch as part of a geo-sensor network are mounted at different positions of the bridge structure. In order to degrade the impact of systematic errors on the acceleration measurements, the deterministic calibration parameters are determined for fixed positions using a KUKA youBot in a climate chamber over certain temperature ranges. The measured acceleration data, with a sampling frequency of 100 Hz, yields accurate estimates of the modal parameters over short time intervals but suffer from accuracy degradation for absolute position estimates with time. To overcome this problem, video frames of a passive target, attached in the vicinity of one of the MEMS sensors, are captured from an embedded on-axis telescope camera of the IATS of type Leica Nova MS50 MultiStation with a practical sampling frequency of 10 Hz. To identify the modal parameters such as eigenfrequencies and modal damping for both acceleration and displacement time series, a damped harmonic oscillation model is employed together with an autoregressive (AR) model of coloured measurement noise. The AR model is solved by means of a generalized expectation maximization (GEM) algorithm. Subsequently, the estimated model parameters from the IATS are used for coordinate updates of the MEMS sensor within a Kalman filter approach. The experiment was performed for a synthetic bridge and the analysis shows an accuracy level of sub-millimetre for amplitudes and much better than 0.1 Hz for the frequencies.


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