scholarly journals Study on Optimization of Delay Method of Wedge Cut Blasting in Tunnel

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Wenle Gao ◽  
Zhicheng Liu ◽  
Yanping Wang ◽  
Zhenwei Yan ◽  
Zehua Zhang
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Vibration Reduction ◽  
Rock Breaking ◽  
Vibration Velocity ◽  
Railway Tunnel ◽  
Tunnel Blasting ◽  
Breaking Mechanism ◽  
Coupling Algorithm ◽  
Surrounding Rock Stress

Relying on the entrance section of a high-speed railway tunnel blasting project, the fluid-solid coupling algorithm based on ANSYS/LS-DYNA was used to optimize the parameters of wedge cut blasting, and the vibration could be reduced on the basis of ensuring the blasting effect. Through the combination of visual numerical simulation results and rock-breaking mechanism of wedge cut blasting, the maximum vibration velocity of different monitoring points in the model under different segmented time delay was analyzed. The results show that the best method for detonation is dividing the blastholes into three segments from upper to lower and dividing the left and right symmetrical blastholes into one segment. When the delay time is 10 ms, the average vibration reduction ratio is the best, which is reduced by 18% compared with the six-hole simultaneous blasting. In addition, the actual surrounding rock stress has a clamping effect on the cut blasting area. The wedge cut blasting footage obtained by numerical simulation was basically consistent with the field results, which proved that the model is reasonable and effective. This study intuitively and accurately demonstrated the process of cut blasting, the superposition curve of vibration velocity and the vibration reduction results under different delay times, and the effect of cut blasting. The results can be directly applied to similar projects, and the optimal blasting parameters and related issues can be solved more accurately with the help of this engineering analysis method.

The Finite Element Simulation of Disc Cutter of Different Diameter Breaking Rock

2013 ◽  
Vol 791-793 ◽  
pp. 742-745 ◽  
Author(s):  
An Ning Zhang ◽  
Zhao Feng Zhu ◽  
Feng Zhu
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Element Model ◽  
Rock Breaking ◽  
Disc Cutter ◽  
Finite Element Software ◽  
Disc Cutters ◽  
Element Simulation ◽  
Breaking Mechanism ◽  
Different Depths

In this paper, finite element software ANSYS is used to simulate a process of disc cutters of different diameter breaking rock, get the curves of the load of disc cutter of different diameter breaking rock and the curves of the stress exerting on the cutters when the disc cutters cutting different depth. According to the rock breaking mechanism of disc cutter, and established five kinds of disc cutter of different diameter broken rock finite element model, and the numerical simulation was carried out. The loads of disc cutters of different diameter breaking rock and the stress exerting on the cutters are different when the disc cutters cutting different depths. According to the result of the analysis, draw the curve graph of the load of disc cutter breaking rock and the stress exerting on the cutters when the disc cutters of different diameter cutting different depth. According to the curve diagram, the load of disc cutter of different diameter cutting a certain depth and the stress of exerting on the disc cutters can be gotten. The simulative result is instructive for improving the design of disc cutter parameters and improving the development efficiency.

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.

scholarly journals Numerical simulation on downhole flow and temperature fields during drilling with nitrogen jet

2019 ◽  
Vol 23 (Suppl. 3) ◽  
pp. 711-717
Author(s):  
Chengzheng Cai ◽  
Keda Ren ◽  
Jiangfeng Liu ◽  
Shuang Liu
Keyword(s):  
Numerical Simulation ◽  
Temperature Distribution ◽  
High Speed ◽  
Rock Breaking ◽  
Petroleum Engineering ◽  
Temperature Fields ◽  
Thomson Effect ◽  
Cfd Model ◽  
Thermal Cracks ◽  
Rock Temperature

In petroleum engineering, nitrogen drilling is an important technology for building wellbores between surfaces and reservoirs. To uncover the downhole flow field and the change rules of rock temperature during drilling with nitrogen jet, we constructed a CFD model by coupling the property equations of nitrogen. The flow fields of nitrogen jet and rock temperature distribution at different times were simulated. Results showed that the high speed nitrogen jet can be efficiently generated because of the nozzle acceleration and the impingement effect can be induced during drilling. The temperature of the nitrogen jet decreased due to the Joule-Thomson effect. This phenomenon suggested that the nitrogen jet induced additional thermal cracks on the bottomhole rock, which was very beneficial for the improvement of rock-breaking efficiency.

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.

Numerical simulation of high-speed civil transport inlet operability with angle of attack

AIAA Journal ◽  
1998 ◽  
Vol 36 ◽  
pp. 1223-1229
Author(s):  
Ge-Cheng Zha ◽  
Doyle Knight ◽  
Donald Smith ◽  
Martin Haas
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Angle Of Attack

Numerical Simulation of High-Speed Crack Propagating and Branching Phenomena

2016 ◽  
Vol 37 (7) ◽  
pp. 729-739
Author(s):  
GU Xin-bao ◽  
◽  
ZHOU Xiao-ping ◽  
XU Xiao ◽  
Keyword(s):  
Numerical Simulation ◽  
High Speed
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