Evaluation of structural fatigue properties of metro tunnel by model test under dynamic load of high-speed railway

Qian, Wangping; Qi, Taiyue; Yi, Haiyang; Liang, Xiao; Jin, Zhiyi; Lei, Bo; Li, Yan; Li, Zongyang

doi:10.1016/j.tust.2019.103099

Cited by 22 publications

(12 citation statements)

References 22 publications

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“…e test model is composed by the tunnel segment and soil. e tunnel segment with the strength grade C50 in the real project, segments in the model were fabricated by mixing water, and plaster and kieselguhr are at a ratio of 1 :1.2 : 0.1 (by mass) materials according to the simulation rules in Table 3 by our previous study [34]. e mechanical parameters of the protype and model of the segment were shown in Table 1.…”

Section: Materials and Ratio Of The Modelmentioning

confidence: 99%

Radial Joints Behavior of a Precast Asymmetric Underpass Induced by Long-Term Loads of Ground Vehicles

Jin

Liang

et al. 2020

Shock and Vibration

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With the rapid development of the urbanization, many underpasses are designed and constructed in big cities to alleviate the huge traffic pressure. The construction method has been changed from traditional on-site concrete pouring technology to prefabricated assembly technology. However, this change will inevitably bring out some new problems to be studied such as the behaviour of the radial joints. In this study, the numerical simulation model of Moziqiao precast and assemble underpass with large asymmetric cross section was constructed by using the ABAQUS software to study the transient response of the underpass induced by ground surface dynamic load. Based on the similarity theory a 1/10 scaled model test was carried out to study the long-term radial joint behaviour of the underpass considering the prestress loss during the 2000 000 loading cycles. The results transient dynamic response from computed and tested was compared in terms of acceleration. The comparison showed that the transient response accelerations have good consistency. The results of the physical model test were analysed in terms of joint opening, closure, and slipping. The accumulative joint opening was closely correlated to the prestress level, and the joint opening at different prestress levels increased with the loss of the prestress. The joints closure decreased with the increase of the previous accumulative color value. The joint slipping mainly attributed to the slipping of the top segment. Both the opening and slipping of the joints at RJ 1 were larger than that of RJ3 due to the wider span of RJ1, which reflected an asymmetric effect. This study revealed the long-term accumulative behaviour of the radial joints, which convinced us that the long-term accumulative deformation of the joints should be taken into consideration during the design stage for similar projects.

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Section: Materials and Ratio Of The Modelmentioning

confidence: 99%

Radial Joints Behavior of a Precast Asymmetric Underpass Induced by Long-Term Loads of Ground Vehicles

Jin

Liang

et al. 2020

Shock and Vibration

Self Cite

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“…With the increase in urbanization and population influx around the world, urban problems such as insufficient urban space capacity and frequent traffic jams are constantly emerging (Zho et al, 2019;He et al, 2019;Zhang et al, 2020aZhang et al, , 2020b. Urban metro systems are popular due to their energy savings, high passenger flow, safety, green transportation characteristics, and so on (Rahim et al, 2015;Qian et al, 2019;Pan et al, 2019c). By the end of 2019, metros had been built and had begun operating in 40 areas in mainland China, with a total length of approximately 6700 km.…”

Section: Introductionmentioning

confidence: 99%

Risk Prediction and Diagnosis of Water Seepage in Operational Shield Tunnels Based on Random Forest

Liu

Chen

Zhang

et al. 2021

Journal of Civil Engineering and Management

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Water seepage (WS) is a paramount defect during tunnel operation and directly affects the operational safety of tunnels. Effectively predicting and diagnosing WS are problems that urgently need to be solved. This paper presents a standard and an evaluation index system for WS grades and constructs a sample dataset from monitoring recoreds for demonstration purposes. First, we use bootstrap resampling to build a random forest (RF) seepage risk prediction model. Second, the optimal branch and parameters are selected by the 5-fold cross-validation method to establish the RF prediction training model. Additionally, to illustrate the effectiveness of the method, the operational stage of Wuhan Metro Line 3 in China is taken as a case study. The results conclude that the segment spalling area, crack width, and loss rate of the rebar cross-section have a strong influence on WS. Finally, the test data are predicted, and the prediction result error index is calculated. Compared with the predictions of some traditional machine learning methods, such as support vector machines and artificial neural networks, RF prediction has the highest accuracy and is the closest to the true value, which demonstrates the accuracy of the model and its application potential.

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“…At the same time, the previous researches mainly focus on the comparative analysis and applicability analysis between different construction methods [27][28][29], and seldom collaboratively consider the mechanical characteristics and deformation laws of the supporting structure, which is very important for the safety and stability and dynamic control of the tunnel construction. In the past, numerical simulation is often used in the complicated excavation process [30][31][32][33][34]. However, the difficulty of obtaining the simulation parameters accurately and the large difference between the model and the engineering practice made the simulation results often differ from the actual situation.…”

Section: Introductionmentioning

confidence: 99%

Analysis for bearing performance and construction mechanical behavior of supporting structure for the large cross-section tunnel by half bench CD method

Zhao

2021

PLoS ONE

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Based on the engineering practice of large cross-section highway tunnel, this paper reveals the space-time coordinated evolution law of the construction mechanical characteristics and deformation distribution of the support structure in the construction by half bench CD method through field test. At the same time, the mechanical response calculation model of the supporting structure in the partial excavation is constructed, and the mechanical characteristics of the support structure in the partial excavation process are analyzed by above mechanical calculation model. Then, the mechanical and deformation distribution of the feet-reinforcement bolt in the steel frame—foot-reinforcement bolt combined support system is analyzed under different levels of surrounding rock load and different structural parameters of the feet-reinforcement bolt. The research results show that: (1) The internal force of the supporting structure changes most obviously during the excavation of Part Ⅰ, Part Ⅱ and Part Ⅲ, and the internal force of the support structure gradually tends to be stable after a slight increase in the excavation of Part Ⅳ and Part Ⅴ; (2) The horizontal deformation and vertical deformation of the support structure mainly occur in the excavation process of Part Ⅰ, Part Ⅱ and Part Ⅲ, and the excavation of Part Ⅳ and Ⅴ has little effect on the deformation response of the structure. The vertical displacement of the supporting structure is larger than the horizontal displacement, and the dynamic response of the temporary diaphragm structure during tunnel excavation is shrinkage-expansion-shrinkage-expansion; (3) The bending strain of each measuring point decreases with the increase of the distance from the loading point, and the bending strain of section 1 and section 2 is much larger than that of the other three sections; (4) With the increase of the angle, the section position with strain close to 0 gradually moves to the deeper position of the bolt, and the axial strain of each section on the bolt gradually changes from positive strain to negative strain.

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Evaluation of structural fatigue properties of metro tunnel by model test under dynamic load of high-speed railway

Cited by 22 publications

References 22 publications

Radial Joints Behavior of a Precast Asymmetric Underpass Induced by Long-Term Loads of Ground Vehicles

Radial Joints Behavior of a Precast Asymmetric Underpass Induced by Long-Term Loads of Ground Vehicles

Risk Prediction and Diagnosis of Water Seepage in Operational Shield Tunnels Based on Random Forest

Analysis for bearing performance and construction mechanical behavior of supporting structure for the large cross-section tunnel by half bench CD method

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