Influence of Duration of Stress Wave on the Spallation Process in Inhomogeneous Material

Based on mesoscopic damage mechanics, a numerical code RFPA2D (dynamic version) is developed to simulate the spallation process of inhomogeneous medium induced by reflection of stress wave, and the influence of duration of stress wave on spallation is discussed. For convenience of description and discussion, the failure area in the immediate vicinity of loading position of model is divided into two zones, i.e. comminution zone and fracture zone; and the failure area caused by spalling in model is defined as spalling zone. The comminution zone is affected little by the duration of stress wave, but the fracture zone and the spalling zone are affected to a greater extent by duration, also, the stability of specimen is affected by the duration of stress wave. Furthermore, if the duration becomes significantly long, the fracture zone corresponding to the maximum extension of the radial tensile cracks will be dominant in specimen. If the duration of stress wave becomes short to some extent, the spalling zone corresponding to the maximum extension of the tangential tensile cracks will be dominant in specimen. In addition, if the duration of stress wave is long enough, the specimen may lose stability.

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Influence of the Rise Time and Decay Time of Stress Wave on Spalling Process of Rock-Like Material

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.462-463.587 ◽

2011 ◽

Vol 462-463 ◽

pp. 587-592

Author(s):

Qing Yun Chen ◽

Yu Jun Zuo ◽

Chun An Tang ◽

Shu Cai Li

Keyword(s):

Stress Wave ◽

Decay Time ◽

Fracture Zone ◽

Rise Time ◽

Numerical Code ◽

Time Increase ◽

Dynamic Version ◽

The Stability ◽

Radial Cracks

Using numerical code RFPA2D (dynamic version), spallation processes of rock-like medium induced by reflection of stress wave with different rise time and decay time are simulated, and based on description and discussion on the failure area in the document [1], the influence of the rise time and decay time of stress wave on spalling process of rock-like material are numerically analyzed and discussed. Results indicate that the comminution zone is affected little by the duration of stress wave regardless of the rise time or decay time, and the fracture zone is affected to a greater extent by the rise time than the decay time, and the spalling zone is affected to some extent by the duration of stress wave regardless of the rise time or decay time, also, the stability of specimen is affected by the duration of stress wave regardless of the rise time or decay time, and the specimen loses stability at a certain decay time earlier than that at the same rise time. Furthermore, the effects of rise time and decay time on the number of failure elements are also investigated. Results show that a shorter rise and decay time increase the number of radial cracks. At longer rise time and decay time, the number of cracks is reduced and the cracks extend longer. In addition, the spalling increases to some extent as the rise time or decay time decreases.

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Numerical Tests on Failure Process of Rock Particle under Impact Loading

Shock and Vibration ◽

10.1155/2015/678573 ◽

2015 ◽

Vol 2015 ◽

pp. 1-12 ◽

Cited By ~ 5

Author(s):

Yu-Jun Zuo ◽

Qin Zhang ◽

Tao Xu ◽

Zhi-Hong Liu ◽

Yue-Qin Qiu ◽

...

Keyword(s):

Stress Wave ◽

Impact Loading ◽

Wave Amplitude ◽

Impact Load ◽

Failure Process ◽

Dynamic Strength ◽

Numerical Code ◽

Rock Particle ◽

Dynamic Version ◽

Particle Sample

By using numerical code RFPA2D(dynamic version), numerical model is built to investigate the failure process of rock particle under impact loading, and the influence of different impact loading on crushing effect and consumed energy of rock particle sample is analyzed. Numerical results indicate that crushing effect is good when the stress wave amplitude is close to the dynamic strength of rock; it is difficult for rock particle to be broken under too low stress wave amplitude; on the other hand, when stress wave amplitude is too high, excessive fine particle is produced, and crushing effect is not very good on the whole, and more crushing energy is consumed. Secondly, in order to obtain good crushing effect, it should be avoided that wavelength of impact load be too short. Therefore, it is inappropriate to choose impact rusher with too high power and too fast impact frequency for ore particle.

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Study on the Geological Forecast and Treatment for Water-Bearing Fault of the Qingdao Kiaochow Bay Subsea Tunnel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.671-674.1114 ◽

2013 ◽

Vol 671-674 ◽

pp. 1114-1121

Author(s):

Zhi Peng Li ◽

Shu Cai Li ◽

Qing Song Zhang ◽

De Ming Wang ◽

Bing Hui ◽

...

Keyword(s):

Fracture Zone ◽

Surrounding Rock ◽

Tunnel Excavation ◽

Bearing Fault ◽

Grouting Material ◽

Fault Fracture Zone ◽

Analysis Of Results ◽

Subsea Tunnel ◽

The Stability ◽

Fissure Water

Water-bearing fault of subsea tunnel has fissure water developed, fractured surrounding rock with low strength, which gets a risk of sudden water inflow and affects the tunnel security. This paper takes the geological forecast and treatment for water-bearing fault of the Qingdao kiaochow bay subsea tunnel for example, according to the water assignment characteristics, using the detect method of TEM and advance borehole to make accurate decision for the position of water-bearing body、the scale of fracture zone and the inflow of water. Through the analysis of results, the grouting form, materials and parameters are chosen and adjusted. The grouting material seals the water flowing fracture, forming water-stopping curtain outside tunnel excavation contour line and strengthening the fault fracture zone to improve the stability of rock.

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Effect of Slip Surface’s Continuity on Slope Dynamic Stability Based on Infinite Slope Model

Mathematics ◽

10.3390/math7010058 ◽

2019 ◽

Vol 7 (1) ◽

pp. 58

Author(s):

Chuanzheng Liu ◽

Gang Wang ◽

Wei Han

Keyword(s):

Dynamic Stability ◽

Stress Wave ◽

Safety Factor ◽

Slip Surface ◽

Great Influence ◽

Stress Wave Propagation ◽

Surface Model ◽

Infinite Slope ◽

Research Results ◽

The Stability

The slip surface is an important control structure surface existing in the landslide. It not only directly affects the stability of the slope through the strength, but also affects the stress field by affecting the propagation of the stress wave. Many research results have been made on the influence of non-continuous stress wave propagation in rock and soil mass and the dynamic response to seismic slopes. However, the effect of the continuity of the slip surface on the slope dynamic stability needs further researches. Therefore, in this paper, the effect of slip surface on the slope’s instantaneous safety factor is analyzed by the theoretical method with the infinite slope model. Firstly, three types of slip surface model were established, to realize the change of sliding surface continuity in the infinite slope. Then, based on wave field analysis, the instantaneous safety factor was used to analyze the effect of continuity of slip surface. The results show that with the decreasing of slip surface continuity, the safety factor does not simply increase or decrease, and is related to slope features, incident wave and continuity of slip surface. The safety factor does not decrease monotonically with the increasing of slope angle and thickness of slope body. Moreover, the reflection of slope surface has a great influence on the instantaneous safety factor of the slope. Research results in this paper can provide some references to evaluate the stability of seismic slope, and have an initial understanding of the influence of structural surface continuity on seismic slope engineering.

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An Iterative Algorithm to Determine the Dynamic User Equilibrium in a Traffic Simulation Model

International Journal of Modern Physics C ◽

10.1142/s0129183198000303 ◽

1998 ◽

Vol 09 (03) ◽

pp. 393-407 ◽

Cited By ~ 104

Author(s):

C. Gawron

Keyword(s):

Probability Distribution ◽

Simulation Model ◽

Iterative Algorithm ◽

Traffic Simulation ◽

User Equilibrium ◽

Dynamic User Equilibrium ◽

Queuing Model ◽

Travel Costs ◽

Dynamic Version ◽

The Stability

An iterative algorithm to determine the dynamic user equilibrium with respect to link costs defined by a traffic simulation model is presented. Each driver's route choice is modeled by a discrete probability distribution which is used to select a route in the simulation. After each simulation run, the probability distribution is adapted to minimize the travel costs. Although the algorithm does not depend on the simulation model, a queuing model is used for performance reasons. The stability of the algorithm is analyzed for a simple example network. As an application example, a dynamic version of Braess's paradox is studied.

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Numerical Simulation on Failure Mechanism of Rock Slope Using RFPA

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.50-51.568 ◽

2011 ◽

Vol 50-51 ◽

pp. 568-572 ◽

Cited By ~ 2

Author(s):

Nu Wen Xu ◽

Chu Nan Tang ◽

Chun Sha ◽

Ru Lin Zhang

Keyword(s):

Rock Slope ◽

Slip Surface ◽

Process Analysis ◽

Failure Process ◽

Numerical Code ◽

Natural State ◽

Left Bank ◽

Good Tool ◽

Deep Rock ◽

The Stability

This research applied a numerical code, RFPA2D (Realistic Failure Process Analysis) to evaluate the stability and investigate the failure mode of the high rock slope during excavations based on Strength Reduction Method (SRM). The corresponding shapes and positions of the potential slip surfaces are rationally simulated in different stages, and the related safety coefficients are obtained, which agrees well with the allowable minimum safety factors of the slope. The numerical results show that the safety coefficient drops from 1.25 at the natural state to 1.09 after excavation, and then increases to 1.35 after slope reinforcement. Moreover, the potential slip surface of the left bank moves into deep rock mass after taking support measures, which demonstrates the reinforcement is reasonable and efficient. The study shows that cracks and faults will cause crucial influences on the slope stability, and RFPA2D is a good tool to directly display the potential slip surface of the slope, which will offer valuable guidance for bolt support.

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Failure behavior of the surrounding rock of jointed rock masses in a gold mine under impact disturbance

10.21203/rs.3.rs-236125/v1 ◽

2021 ◽

Author(s):

Peng Li ◽

Yunquan Wu ◽

Meifeng Cai

Keyword(s):

Stress Wave ◽

Shear Failure ◽

Jointed Rock ◽

Surrounding Rock ◽

Tensile Failure ◽

Tensile Shear ◽

Underground Engineering ◽

Impact Stress ◽

The Stability ◽

The Impact

Abstract The impact disturbance has an important influence on the safety of underground engineering openings. In this paper, based on the in-situ stress measurement and structural plane investigation, the model of jointed rock roadway was established using the discrete element method (3DEC) to study the instability and failure characteristic of roadway surrounding rock with dominant joint planes under impact disturbance and to further analyze the influence of different buried depths, impact stress wave peaks, and stress wave delays on the stability of the surrounding rock. The results show that the stability of the surrounding rock is poor, and the whole convergence deformation of the surrounding rock occurs under the impact stress wave. There are three failure modes in the surrounding rock: tensile-shear failure, tensile failure, and shear failure. Tensile-shear failure mainly occurs in a small range close to the roof and floor of the roadway and the free surfaces of the two sides, and tensile failure occurs locally, while shear failure mainly occurs along the joint plane outside this range. Moreover, the greater the buried depth and stress wave peak value, the more serious the deformation of the surrounding rock. With the increase of stress wave delay, the deformation of the surrounding rock shows complex characteristics. In addition, the impact failure mechanism of the surrounding rock in jointed rock masses was discussed. The research results have important guiding significance for the prevention and control of underground engineering cavern disasters.

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Mass of dusty clumps with temperature and density structure

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936334 ◽

2019 ◽

Vol 631 ◽

pp. A65 ◽

Cited By ~ 1

Author(s):

R. Cesaroni

Keyword(s):

Flux Density ◽

Cylindrical Symmetry ◽

Numerical Code ◽

Effect Of Temperature ◽

Density Gradients ◽

Density Structure ◽

The Stability ◽

Spherical And Cylindrical Symmetry ◽

Account Temperature ◽

Approximate Expressions

We consider a dusty clump in two cases of spherical and cylindrical symmetry to investigate the effect of temperature and density gradients on the observed flux density. Conversely, we evaluate how the presence of these gradients affects the calculation of the clump mass from the observed flux. We provide approximate expressions relating flux density and mass in the optically thick and thin limits and in the Rayleigh-Jeans regime, and we discuss the reliability of these expressions by comparing them to the outcome of a numerical code. Finally, we present the application of our calculations to three examples taken from the literature, which shows how the correction introduced after taking into account temperature and density gradients may affect our conclusions on the stability of the clumps.

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