scholarly journals Study on Field Test and Seismic Performance of MJS Joint Microdisturbance Reinforcement on Existing Tunnel

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Zhanyou Luo ◽  
Yongheng Deng ◽  
Baoping Zou ◽  
Jianfeng Zhu ◽  
Mingyao Jiang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Field Test ◽  
Transverse Wave ◽  
Vertical Displacement ◽  
Seismic Intensity ◽  
Wave Direction ◽  
Subway Tunnel ◽  
Reinforcement System ◽  
Under Construction ◽  
Reinforcement Measures

Metro Jet System (MJS) joint microdisturbance reinforcement is often adopted to strengthen and remediate existing tunnels that are severely deformed by under-construction peripheral works, but analysis related to the reinforcement system of tunnel under consideration of seismic effects is insufficient at present. In this work, a field test of MJS joint microdisturbance reinforcement system of existing tunnels was conducted on the basis of a subway tunnel deformation reinforcement project. Then, a numerical simulation study of the seismic dynamic response of reinforcement system was performed in combination with seismic wave direction and intensity. Results show that the MJS joint microdisturbance reinforcement measures can effectively reduce the settlement and horizontal radial convergence deformation of the tunnel. The seismic longitudinal wave significantly affects the vertical displacement of the tunnel, and the seismic-induced vertical displacement of the tunnel increases with the rise in seismic intensity. The seismic transverse wave significantly affects the horizontal radial convergence deformation of the tunnel, and the seismic-induced horizontal radial convergence deformation of the tunnel increases with the rise in seismic intensity. The antiseismic property of MJS joint microdisturbance reinforcement measures on the existing tunnel is not obvious.

scholarly journals Research and Analysis on the Influence of Small Clear Distance Drilling and Blasting Method on the Existing Tunnel Structure

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Haibin Huang ◽  
Peng Li ◽  
Chuang Wang ◽  
Bingxiang Yuan ◽  
Minjie Chen ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Simulation Analysis ◽  
Peak Load ◽  
Vertical Displacement ◽  
Tunnel Construction ◽  
Finite Element Software ◽  
Resultant Velocity ◽  
Clear Distance ◽  
Under Construction ◽  
Blasting Method

In order to study the vibration influence of tunnel drilling and blasting method on the built tunnel with small clear distance, taking the intersection of Zhuhai Dahengqinshan No. 1 tunnel and Zhuji urban rail tunnel as the engineering background, we used ABAQUS finite element software to conduct numerical simulation analysis on the influence of different blasting loads on existing tunnels with small clear distance in Zhuji tunnel construction. The following conclusions were drawn: the blasting construction of the tunnel under construction had the greatest impact on the vault of the existing tunnel; when the peak load was reduced by half, the stress value, vertical displacement, and resultant velocity of Mises were also reduced by half, which indicates that reducing the peak value of blasting load appropriately can ensure the safety of tunnel construction. When the peak load is 2.7 MPa, the measured and simulated values were less than the resultant velocity limit required by the specification. In addition, the relative error between the measured value and the simulated value was less than 5%, indicating the accuracy of the numerical simulation.

scholarly journals Impact Anlysis of Bow Flap on LHA-1 Ship Airwake

2018 ◽  
Vol 179 ◽  
pp. 03007
Author(s):  
Jinling Wang ◽  
Guangwen Jiang ◽  
Jun Shen ◽  
Chujun Hu
Keyword(s):  
Numerical Simulation ◽  
Simulation Method ◽  
Equation Model ◽  
Separation Region ◽  
Operating Environment ◽  
Study Results ◽  
Helicopter Landing ◽  
Hybrid Grid ◽  
Under Construction ◽  
The Impact

The sharp 90°corner of bow found on American Tarawa class general amphibious assault ship LHA-1 will produce large separated region in the airwake over the ship, and the turbulence in the separation region seriously affects the operation safety of the helicopter. In order to reduce the separation in bow region of the LHA-1, and optimize the helicopter operating environment, the numerical simulation method is used to study the influence of the bow flap on the airwake of LHA-1. The study results show that: the ANSYS k-ε two equation model based on the hybrid grid can be used to predict the steady-state characteristics of the ship airwake; the bow flap can improve the flow field downwind of the flap installation position, and the impact range can cover two spots; in headwind, the optimal installation angle of the bow flap is 15°~25°. The research results of this paper can provide modification and improvement reference for the amphibious assault ship in-service and under construction, so as to achieve the purpose of optimizing the ship airwake, thereby improving the safety of helicopter landing process and extending the service life.

scholarly journals May a Standard VOF Numerical Simulation Adequately Complete Spillway Laboratory Measurements in an Operational Context? The Case of Sa Stria Dam

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1606
Author(s):  
Maria Grazia Badas ◽  
Riccardo Rossi ◽  
Michela Garau
Keyword(s):  
Numerical Simulation ◽  
Physical Model ◽  
Numerical Models ◽  
Relevant Information ◽  
Mitigation Measures ◽  
Laboratory Measurements ◽  
Concrete Gravity Dam ◽  
Flood Discharge ◽  
Vof Model ◽  
Under Construction

The present work aims to assess whether a standard numerical simulation (RANS-VOF model with k − ϵ closure) can adequately model experimental measurements obtained in a dam physical model. The investigation is carried out on the Sa Stria Dam, a roller compacted concrete gravity dam currently under construction in Southern Sardinia (Italy). The original project, for which a physical model was simulated, included a downstream secondary dam. However, due to both economic and technical reasons, the secondary dam may not be built. Hence, it is important to assess the flood discharge routing and energy dissipation in the modified plan. Numerical validation is performed adopting the same laboratory configuration, in presence of the downstream dam, and results show a good agreement with mean experimental variables (i.e., pressure, water level). An alternative configuration without the downstream dam is here numerically tested to understand the conditions of flood discharge and assess whether its results can give relevant information for the design of mitigation measures. The topic is of interest also from a more general perspective. Indeed, the feasibility to integrate numerical models with existing laboratory measurements can be very useful not only for new constructions but also for existing dams, which may need either maintenance or upgrading works, such as in case of flood discharge increment.

Field test and numerical simulation of the section mill in U-shaped wells of coalbed methane

2020 ◽  
Vol 84 ◽  
pp. 103681
Author(s):  
Jiaqi Che ◽  
Hanxiang Wang ◽  
Yanwen Zhang ◽  
Yuting Wang ◽  
Yanxin Liu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Field Test ◽  
Coalbed Methane ◽  
Section Mill

scholarly journals Numerical simulation of pounding damage to caisson under storm surge

2018 ◽  
Vol 38 ◽  
pp. 03046
Author(s):  
Chen Yu
Keyword(s):  
Numerical Simulation ◽  
Storm Surge ◽  
Failure Mode ◽  
Structural Model ◽  
Time History ◽  
Element Model ◽  
Wave Force ◽  
New Method ◽  
Wave Direction ◽  
Force Time

In this paper, a new method for the numerical simulation of structural model is proposed，which is employed to analyze the pounding response of caissons subjected to storm surge loads．According to the new method，the simulation process is divided into two steps. Firstly, the wave propagation caused by storm surge is simulated by the wave-generating tool of Flow-3D, and recording the wave force time history on the caisson. Secondly，a refined 3D finite element model of caisson is established，and the wave force load is applied on the caisson according to the measured data in the first step for further analysis of structural pounding response using the explicit solver of LSDYNA. The whole simulation of pounding response of a caisson caused by “Sha Lijia” typhoon is carried out. The results show that the different wave direction results in the different angle caisson collisions, which will lead to different failure mode of caisson, and when the angle of 60 between wave direction and front/back wall is simulated, the numerical pounding failure mode is consistent with the situation.

scholarly journals Study on reasonable grouting parameters based on UDEC numerical simulation

2019 ◽  
Vol 118 ◽  
pp. 02013
Author(s):  
Fengfeng Yang ◽  
Liping Bai ◽  
Ruiqing Su ◽  
Jufeng Zhang ◽  
Tai Xu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Field Test ◽  
Surrounding Rock ◽  
Frequent Occurrence ◽  
Roof Collapse ◽  
Grouting Reinforcement ◽  
Rock Roadway

In view of the frequent occurrence of roof collapse and chipping accidents in the broken surrounding rock roadway in the goaf, grouting reinforcement is applied to the surrounding rock of the ro ent ratio. The field test proves that the selected grouting parameters are reasonable and achieve the purpose of controlling the deformation of the surrounding rock of the roadway.

Three Dimensional Elastic-Plastic Numerical Simulation of Tunnel Excavation Sequence of Dalian Speed Railway

2012 ◽  
Vol 170-173 ◽  
pp. 1474-1478
Author(s):  
An Nan Jiang ◽  
Hong Wei Yang ◽  
Hong Fu Xin ◽  
Bing Bai
Keyword(s):  
Numerical Simulation ◽  
Damage Zone ◽  
Three Dimensional ◽  
Ground Surface ◽  
Soft Rock ◽  
Vertical Displacement ◽  
Stability Control ◽  
Surrounding Rock ◽  
Railway Tunnel ◽  
Elastic Plastic

Dalian speed railway tunnel is located in complex soft rock and soil, the road foundation deform and surrounding rock stability control is a concern problem. Along with the unloading process of excavation, surrounding rock moving to inner hole, while exceeding the elastic limitation, the plastic deform and the surrounding rock destroy then occurred. The paper adopted three dimensional elastic-plastic method based on Mohr-Coulomb yielding criterion and carried out numerical simulation of excavation process, in order to analyze and compare the surrounding rock vertical displacement contour, ground surface settlement and damage zone corresponding to different construction sequence. The elastic-plastic numerical method can reflect the damage and destroy character of nonlinear soil material of surrounding rock corresponding to different construction scheme, the simulation result has active guiding meaning for the Dalian speed railway tunnel construction design and dynamic analysis.

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