Structures and Settlement Control of Yujingshan High-Speed Railway Tunnel Crossing Massive Rockfill in a Giant Karst Cave

2021 ◽  
pp. 036119812110624
Author(s):  
Yipeng Xie ◽  
Junsheng Yang ◽  
Cong Zhang ◽  
Jinyang Fu
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Three Dimensional ◽  
Railway Tunnel ◽  
High Speed Railway ◽  
Settlement Behavior ◽  
Underground River ◽  
Convergence Trend ◽  
Dimensional Coupling

The Yujingshan high-speed railway tunnel crosses a giant cavern system with a 108 × 104 m3 volume chamber and an 18 km long underground river. The massive project, which lasted three years, was eventually awarded the “Overcoming the Challenges” award by the International Tunneling and Underground Space Association (ITA) in 2020. However, since the cave chamber was filled with large-scale rockfill, structural settlement is a non-negligible problem. This paper presents the unique structures of a bridge supporting railway tracks wrapped by tunnel lining and the settlement control of the Yujingshan tunnel crossing massive rockfill in the giant cave. The geological characteristics and design considerations are systematically introduced. A three-dimensional coupling discrete element method (DEM) and finite difference method (FDM) numerical model and 13 months of long-term settlement monitoring were conducted to evaluate the settlement behavior. The results indicate that the morphology of cavern and internal deposits caused the whole rockfill to migrate to the lower left. The tunnel structure consequently developed a significant inclined settlement. The continuous construction load would increase the settlement value by 31.4%. The bottom reinforcement of steel-pipe pile with grouting could effectively inhibit settlement and differential settlement. Considering the simulation results, the tunnel bottom had greater settlement than the limit standard for high-speed railway embankment, which means this special structure form is reasonable for operation. Meanwhile, the monitoring results show that the tunnel bottom settlement in D3K279+891~D3K279+947 had not performed an apparent convergence trend after 13 months. Further structural monitoring and compensation grouting should be actively considered for operation maintenance.

Research of Train Wind Characteristics in High-Speed Railway Tunnel

2014 ◽  
Vol 919-921 ◽  
pp. 865-868 ◽  
Author(s):  
Rui Zhen Fei ◽  
Li Min Peng ◽  
Wei Chao Yang ◽  
Wei Guang Yan
Keyword(s):  
High Speed ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Time History ◽  
Space Distribution ◽  
Navier Stokes ◽  
Railway Tunnel ◽  
High Speed Railway ◽  
Navier Stokes Equations ◽  
Tunnel Cross Section

According to the 100㎡ high-speed tunnel cross-section which is generally used in high-speed railway of China, this paper develops a tunnel-air-train simulation model, based on the three-dimensional incompressible Navier-Stokes equations and the standard k-e turbulence model. Time-history variation rules and space distribution characteristics of train wind are studied respectively. The results show that: train wind is complex three-dimensional flow changing with time and space, air at the front of train flows away from the train head, while air at the rear of train flows to the train tail.

scholarly journals Vibration reduction performance of rubber concrete backfill layer in high-speed railway tunnel

2018 ◽  
Vol 50 (1) ◽  
pp. 22-32
Author(s):  
Yanke Liang ◽  
Xiaopei Cai ◽  
Yanrong Zhang ◽  
Yanglong Zhong
Keyword(s):  
Elastic Modulus ◽  
High Speed ◽  
Vibration Isolation ◽  
Damping Ratio ◽  
Vibration Reduction ◽  
Three Dimensional ◽  
Railway Tunnel ◽  
High Speed Railway ◽  
Spatial Coupling ◽  
Rubber Concrete

A novel approach to reduce vibration was put forward by applying rubber concrete as backfill layer of the high-speed railway tunnel, and its feasibility was analyzed based on the vibration isolation theory. A three-dimensional spatial coupling model of vehicle-track-tunnel-rock mass was established by means of vehicle-track coupling dynamics theory. The dynamic response of the vehicle, track, and tunnel structure under common and rubber concrete backfill layer was compared. The vibration reduction performance and the characteristics of rubber concrete were discussed. The change in tunnel vibration under different elastic modulus and damping ratios of backfill layer was analyzed, and the vibration reduction effect of rubber concrete combined with damping cushion was studied. Results show that the influence of the rubber concrete backfill layer on the dynamic indices of vehicle and track structure can be neglected. Because of the application of rubber concrete, the vibration acceleration of tunnel decreases by about 40%, and 4–8 dB can be reduced in the corresponding frequency of 100–200 Hz. With decrease in the elastic modulus and increase in the damping ratio, the vibration of the tunnel decreases gradually. Moreover, the influence of damping ratio is more significant than that of elastic modulus. The combination of rubber concrete backfill layer and damping cushion demonstrates a superior effect in reducing vibration, which decreases the vibration level by 3–5 dB compared with setting the damping cushion only. The article is expected to provide theoretical guidance for the application of rubber concrete in the high-speed railway.

Three Dimensional Numerical Simulation Study on Lining Pressure of High-Speed Railway Tunnel

2011 ◽  
Vol 243-249 ◽  
pp. 3670-3675
Author(s):  
Yun Dong Ma ◽  
Bo Li ◽  
Bin Fan
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Compressible Flows ◽  
Three Dimensional ◽  
Simple Algorithm ◽  
High Speed Train ◽  
Railway Tunnel ◽  
Time Curve ◽  
High Speed Railway ◽  
Aerodynamic Effect

The aerodynamic numerical simulation model of high-speed railway tunnel was established based on the analyzing of the aerodynamic effect characteristics of high-speed railway tunnel. FLUENT three dimensional compressible flows SIMPLE algorithm was adopted, the three dimensional aerodynamic effect of high-speed railway tunnel was simulated on the condition that the high-speed train was in motion. The pressure changes law in the tunnel was obtained during the whole process when high-speed train traveling, and the pressure-time curve in the tunnel middle cross-section was plotted. It laid a foundation for the further development of tunnel lining dynamics analysis.

Risk Assessment of High-Speed Railway Tunnel Construction Based on Fuzzy Synthetic Evaluation

2012 ◽  
Vol 594-597 ◽  
pp. 1251-1256
Author(s):  
Li Wu ◽  
Liang Gang Zhang ◽  
Yun Lai ◽  
Jian Chen
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Evaluation Index System ◽  
Tunnel Construction ◽  
Fuzzy Synthetic Evaluation ◽  
Railway Tunnel ◽  
Analytic Hierarchy ◽  
High Speed Railway ◽  
Construction Risk ◽  
Synthetic Evaluation

Because of its large scale, long cycle and complex construction, the high speed railway tunnel construction exists many uncertain risk factors which are random and fuzzy, that makes it difficult to do quantitative analysis by general research methods. A synthetic evaluation index system for tunnel construction risk of high-speed railway is established by analyzing the factors that influence high-speed railway construction, and the analytic hierarchy process is used to determine the weight of each stage factor. Based on the hierarchy of each factor, a model of three-stage fuzzy synthetic evaluation is proposed, the fuzzy sets method is used to determine membership function, and risk ranking is also classified. The proposed method is applied to a Tian jiashan Tunnel construction of Shanghai-Kunming (Hu-Kun) high-speed railway. The analysis results show that the method is reasonable and practical, and it will be taken as an example by other similar projects.

scholarly journals Prevention of Mountain Disasters and Maintenance of Residential Area through Real-Time Terrain Rendering

2021 ◽  
Vol 13 (5) ◽  
pp. 2950
Author(s):  
Su-Kyung Sung ◽  
Eun-Seok Lee ◽  
Byeong-Seok Shin
Keyword(s):  
Real Time ◽  
Graphics Processing Units ◽  
High Speed ◽  
Large Scale ◽  
Civil Engineering ◽  
Three Dimensional ◽  
Sampled Data ◽  
Residential Areas ◽  
Terrain Rendering ◽  
Mountain Disasters

Climate change increases the frequency of localized heavy rains and typhoons. As a result, mountain disasters, such as landslides and earthworks, continue to occur, causing damage to roads and residential areas downstream. Moreover, large-scale civil engineering works, including dam construction, cause rapid changes in the terrain, which harm the stability of residential areas. Disasters, such as landslides and earthenware, occur extensively, and there are limitations in the field of investigation; thus, there are many studies being conducted to model terrain geometrically and to observe changes in terrain according to external factors. However, conventional topography methods are expressed in a way that can only be interpreted by people with specialized knowledge. Therefore, there is a lack of consideration for three-dimensional visualization that helps non-experts understand. We need a way to express changes in terrain in real time and to make it intuitive for non-experts to understand. In conventional height-based terrain modeling and simulation, there is a problem in which some of the sampled data are irregularly distorted and do not show the exact terrain shape. The proposed method utilizes a hierarchical vertex cohesion map to correct inaccurately modeled terrain caused by uniform height sampling, and to compensate for geometric errors using Hausdorff distances, while not considering only the elevation difference of the terrain. The mesh reconstruction, which triangulates the three-vertex placed at each location and makes it the smallest unit of 3D model data, can be done at high speed on graphics processing units (GPUs). Our experiments confirm that it is possible to express changes in terrain accurately and quickly compared with existing methods. These functions can improve the sustainability of residential spaces by predicting the damage caused by mountainous disasters or civil engineering works around the city and make it easy for non-experts to understand.

Investigation of a loess-mudstone landslide and the induced structural damage in a high-speed railway tunnel

2020 ◽  
Vol 79 (5) ◽  
pp. 2201-2212
Author(s):  
Shunhua Zhou ◽  
Zhiyao Tian ◽  
Honggui Di ◽  
Peijun Guo ◽  
Longlong Fu
Keyword(s):  
Structural Damage ◽  
High Speed ◽  
Railway Tunnel ◽  
High Speed Railway

scholarly journals Event-Driven Simulation Scheme for Spiking Neural Networks Using Lookup Tables to Characterize Neuronal Dynamics

2006 ◽  
Vol 18 (12) ◽  
pp. 2959-2993 ◽  
Author(s):  
Eduardo Ros ◽  
Richard Carrillo ◽  
Eva M. Ortigosa ◽  
Boris Barbour ◽  
Rodrigo Agís
Keyword(s):  
Synaptic Plasticity ◽  
High Speed ◽  
Large Scale ◽  
Computational Cost ◽  
Brain Structures ◽  
Spike Timing ◽  
Neuronal Dynamics ◽  
Event Driven ◽  
Synaptic Dynamics

Nearly all neuronal information processing and interneuronal communication in the brain involves action potentials, or spikes, which drive the short-term synaptic dynamics of neurons, but also their long-term dynamics, via synaptic plasticity. In many brain structures, action potential activity is considered to be sparse. This sparseness of activity has been exploited to reduce the computational cost of large-scale network simulations, through the development of event-driven simulation schemes. However, existing event-driven simulations schemes use extremely simplified neuronal models. Here, we implement and evaluate critically an event-driven algorithm (ED-LUT) that uses precalculated look-up tables to characterize synaptic and neuronal dynamics. This approach enables the use of more complex (and realistic) neuronal models or data in representing the neurons, while retaining the advantage of high-speed simulation. We demonstrate the method's application for neurons containing exponential synaptic conductances, thereby implementing shunting inhibition, a phenomenon that is critical to cellular computation. We also introduce an improved two-stage event-queue algorithm, which allows the simulations to scale efficiently to highly connected networks with arbitrary propagation delays. Finally, the scheme readily accommodates implementation of synaptic plasticity mechanisms that depend on spike timing, enabling future simulations to explore issues of long-term learning and adaptation in large-scale networks.

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