Numerical Simulation of the Tunnel Blasting Process in Weak Intercalated Layer

2011 ◽  
Vol 314-316 ◽  
pp. 452-456
Author(s):  
Chun Mei Mu ◽  
Qing Zhang ◽  
Zhi Kui Liu ◽  
Wang Xing Li
Keyword(s):  
Numerical Simulation ◽  
Stress Wave ◽  
Theoretical Basis ◽  
Blast Hole ◽  
Tunnel Blasting ◽  
Weak Intercalated Layer ◽  
The Law ◽  
Different Thickness

In order to study the effect which weak intercalated layer produces in the rock during the process when explosives transferring the energy, this research uses ANSYS/LS-DYNA toexplore the numerical simulation of the law which the stress wave of weak intercalated layer rock with different thickness propagates and decays. It also compares the effect to stress wave in certain position when the thickness of the intercalated layer is different or inexistent. The outbreak pheno-menon of the rock with weak intercalated layer occurs in the blasting process is analyzed as well, so the effect of weak intercalated layer should be fully considered when arranging blast hole around the tunnel. Then the research provides the theoretical basis for selecting blasting parameters.

The Numerical Simulation and Quantitative Study of Testing the Segregation Pile with the Low Strain Method

2012 ◽  
Vol 170-173 ◽  
pp. 863-867
Author(s):  
Zhi Qiang Zhang ◽  
Xue Qian Gu ◽  
Nan Gai Yi
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Finite Element Model ◽  
Stress Wave ◽  
Quantitative Study ◽  
Element Model ◽  
Error Range ◽  
Different Thickness ◽  
Strain Method

With ANSYS/LS-DYNA dynamic analyzing method, the 3-D finite element model of testing segregation piles with low strain method is got. By analyzing reflective oscillogram of the segregation layer with the same thickness but different strength, the method to analyze the strength of the segregation layer is got. By comparing the reflective oscillogram of the concrete with the same strength but different thickness of the segregation layer, the method to test segregation thickness is formed. The experiment states that when the pile defect is qualitatively validated as segregation by accurately analyzing the amplitude of the stress wave of the segregation part and the amplitude of the reflective wave of the bottom pile, including the time corresponding to the amplitude. The level of the defect of the segregation layer can be judged quantitatively in a much smaller error range.

Numerical Simulation Research on Single Hole_unilateral Protecting Borehole Wall Blasting

2011 ◽  
Vol 368-373 ◽  
pp. 395-398
Author(s):  
Liang Niu ◽  
Zhi Cheng Zhang ◽  
Xiao Ling Liu ◽  
Jun Lin Tao ◽  
Yong Gang Lu
Keyword(s):  
Numerical Simulation ◽  
Stress Wave ◽  
Blast Hole ◽  
Borehole Wall ◽  
Rock Blasting ◽  
Pressure Relief ◽  
Simulation Research ◽  
Hole Wall ◽  
Material Substance

3-D Numerical simulation on the directional pressure relief partition side of blast hole isolation material though LS-DYNA software. The result shows: the semicircle isolation material can put off the time that the explosion stress wave arrived at the hole-wall and reduce the peak of stress wave. Meanwhile, it proves that the explosion in the material substance is more powerful than that in the air. So it has certain directive significance on rock blasting on the slope.

scholarly journals Penetration Form of Inter-Hole Cracks under Double-Hole Blasting Conditions with Inclined Fissures

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Shiwei Shen ◽  
Yue Zhao ◽  
Chang Liu ◽  
Shulin Dai ◽  
Fei Wu ◽  
...  
Keyword(s):  
Stress Wave ◽  
Blast Hole ◽  
Vertical Direction ◽  
Propagation Mode ◽  
Expansion Velocity ◽  
Propagation Law ◽  
Tunnel Blasting ◽  
Dynamic Caustics ◽  
Inclined Cracks ◽  
Peak Value

During blasting construction in tunnel engineering, an inclined fissure near the blast hole produces the “Z” type of over-excavation and subsequently affects the overall blasting effect and stability of the tunnel. In this work, dynamic caustics testing was used to study the burst propagation mode and penetration form of explosive cracks at different positions between holes under double-hole blasting conditions. Results showed that the existence of gently inclined cracks changed the propagation law of explosive stress wave. The dominant fracture surface was formed in the vertical direction between the borehole and the fracture. Finally, the crack penetrates to form “Z”-type over-excavation, which was analyzed by the dynamic caustics test. The expansion velocity of the burst crack reached the maximum under the reflection of the explosion stress wave and then decreased with the attenuation of the stress wave intensity. The peak propagation velocity decreased with the increasing vertical distance between the prefabricated fracture and the borehole, and the stress intensity factor at the crack tip immediately reached its peak value after detonation, and the oscillation then decreased. These research results can serve a basis for reducing tunnel blasting over-excavation under this condition and optimizing blasting parameters.

Research on Propagation Numerical Simulation of Blast Shock Waves in Subway Station

2013 ◽  
Vol 380-384 ◽  
pp. 1725-1728
Author(s):  
Yang Hu ◽  
Huai Yu Kang
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Experimental Study ◽  
Shock Waves ◽  
Theoretical Basis ◽  
Damage Effect ◽  
Subway Station ◽  
Element Calculation ◽  
Dynamic Finite Element ◽  
Walking Pattern

In this paper, we Research on Propagation Numerical Simulation and damage effect of Blast Shock Waves in Subway Station by using LS-DYNA dynamic finite element calculation program , the results reproduce the formation process of the explosive flow field, and analysis the shock wave waveform, attenuation and walking pattern, provides the theoretical basis for further experimental study.

Simulation and Analysis of Swing Motion of Lifting Load System on Rescue Vehicle

2012 ◽  
Vol 538-541 ◽  
pp. 725-729
Author(s):  
Han Ming Liu ◽  
Heng Zhao ◽  
Ning Li
Keyword(s):  
Numerical Simulation ◽  
Theoretical Basis ◽  
Safety Assessment ◽  
Kinematic Model ◽  
Excitation Frequency ◽  
Lagrange’S Equation ◽  
Set Up

In lifting, remoted operated dive vehicle（ROV） may swing with the effect of wave. Based on the general form of Lagrange’s equation, a 3-DOF nonlinear swing motion kinematic model was set up. The kinematic response was studied using methods of numerical simulation. The results demonstrated that the kinematic response depends on the length of cable, lifting speed and excitation frequency. Conclusions drawn from this work can be used for safety assessment and theoretical basis for lifting ROV.

scholarly journals Complex Dynamical Behavior of a Predator-Prey System with Group Defense

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Jianglin Zhao ◽  
Min Zhao ◽  
Hengguo Yu
Keyword(s):  
Numerical Simulation ◽  
Theoretical Basis ◽  
Dynamical Behavior ◽  
Turing Instability ◽  
Equilibrium Density ◽  
Prey Refuge ◽  
Predator Prey ◽  
Prey System ◽  
Group Defense ◽  
Complex Dynamical Behavior

A diffusive predator-prey system with prey refuge is studied analytically and numerically. The Turing bifurcation is analyzed in detail, which in turn provides a theoretical basis for the numerical simulation. The influence of prey refuge and group defense on the equilibrium density and patterns of species under the condition of Turing instability is explored by numerical simulations, and this shows that the prey refuge and group defense have an important effect on the equilibrium density and patterns of species. Moreover, it can be obtained that the distributions of species are more sensitive to group defense than prey refuge. These results are expected to be of significance in exploration for the spatiotemporal dynamics of ecosystems.

FEM Analysis of Contact for Converter Spherical Hinge

2013 ◽  
Vol 365-366 ◽  
pp. 331-334
Author(s):  
Xue Ping Ren ◽  
Jian Da Gao
Keyword(s):  
Numerical Simulation ◽  
Thermal Stress ◽  
Optimum Design ◽  
Theoretical Basis ◽  
Fem Analysis ◽  
Structure Design ◽  
Coupling Field ◽  
Main Components ◽  
Spherical Hinge

The role of converter spherical hinge is one of the main components, combined with practical work and With help of FEM, Thermal Stress coupling field of spherical washer can been obtained through numerical simulation. The result supplies substantial theoretical basis for further structure design and optimum design of mechanism.

Excusable consent in duress

Legal Studies ◽  
2017 ◽  
Vol 37 (3) ◽  
pp. 418-436
Author(s):  
Alexander F H Loke
Keyword(s):  
Theoretical Basis ◽  
Analytical Framework ◽  
Contract Law ◽  
Value Judgments ◽  
Additional Element ◽  
The Law ◽  
Will Theory

While the illegitimate pressure theory provides a more satisfactory theoretical basis for duress in contract law than the overborne will theory, it insufficiently addresses why a victim who has given deliberated consent should be excused from contractual responsibility. The paper proposes that the additional element of ‘excusable consent’ enhances the current analytical framework: first, by recognising that the law makes value judgments of both the threatening party's actions and the victim's response; secondly, by lightening the burden of the illegitimate pressure element and providing it greater focus; and, thirdly, by providing a better fit for considerations such as ‘no practical alternatives’ that strain the existing framework.

scholarly journals Discussion on the Theoretical Basis for Cross-Over Method Applied to Downhole Wave Velocity Test

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Qing Dong ◽  
Zheng-hua Zhou ◽  
Su Jie ◽  
Bing Hao ◽  
Yuan-dong Li
Keyword(s):  
Numerical Simulation ◽  
Numerical Simulations ◽  
Wave Velocity ◽  
Theoretical Basis ◽  
Influence Factors ◽  
P Wave ◽  
Engineering Practice ◽  
S Wave ◽  
Simulation Results ◽  
The Cross

At engineering practice, the theoretical basis for the cross-over method, used to obtain shear wave arrival time in the downhole method of the wave velocity test by surface forward and backward strike, is that the polarity of P-wave keeps the same, while the polarity of S-wave transforms when the direction of strike inverted. However, the characteristics of signals recorded in tests are often found to conflict with this theoretical basis for the cross-over method, namely, the polarity of the P-wave also transforms under the action of surface forward and backward strike. Therefore, 3D finite element numerical simulations were conducted to study the validity of the theoretical basis for the cross-over method. The results show that both shear and compression waves are observed to be in 180° phase difference between horizontal signal traces, consistent with the direction of excitation generated by reversed impulse. Furthermore, numerical simulation results prove to be reliable by the analytic solution; it shows that the theoretical basis for the cross-over method applied to the downhole wave velocity test is improper. In meanwhile, numerical simulations reveal the factors (inclining excitation, geophone deflection, inclination, and background noise) that may cause the polarity of the P-wave not to reverse under surface forward and backward strike. Then, as to reduce the influence factors, we propose a method for the downhole wave velocity test under surface strike, the time difference of arrival is based between source peak and response peak, and numerical simulation results show that the S-wave velocity by this method is close to the theoretical S-wave velocity of soil.

scholarly journals Analysis of Mathematics and Sustainability in an Impulsive Eutrophication Controlling System

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Hengguo Yu ◽  
Min Zhao ◽  
Qi Wang
Keyword(s):  
Numerical Simulation ◽  
Theoretical Basis ◽  
Algal Bloom ◽  
Critical Parameters ◽  
Critical Factors ◽  
Experiment Data ◽  
Threshold Functions ◽  
Controlling System ◽  
Best Value ◽  
Mathematical System

Eutrophication removal problems have captured the attention of biologists, mathematicians, and environmental scientists. Within this framework, an impulsive eutrophication controlling system is studied analytically and numerically. A key advantage of the eutrophication system is that it can be quite accurate to describe the interaction effect of some critical factors (fishermen catch and releasing small fry, etc.), which enables a systematic and logical procedure for fitting eutrophication mathematical system to real monitoring data and experiment data. Mathematical theoretical works have been pursuing the investigation of two threshold functions of some critical parameters under the condition of all species persistence, which can in turn provide a theoretical basis for the numerical simulation. Using numerical simulation works, we mainly focus on how to choose the best value of some critical parameters to ensure the sustainability of the eutrophication system so that the eutrophication removal process can be well developed with maximizing economic benefit. These results may be further extended to provide a basis for simulating the algal bloom in the laboratory and understanding the application of some impulsive controlling models about eutrophication removal problems.

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