scholarly journals Research on the Fracture Grouting Mechanism and PFC Numerical Simulation in Loess

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Zhenlong Zhang ◽  
Zhushan Shao ◽  
Xiaobo Fang ◽  
Xijun Liang
Keyword(s):  
Numerical Simulation ◽  
Diffusion Process ◽  
Model Test ◽  
Reference Value ◽  
Pressure Variation ◽  
Particle Flow ◽  
Fracture Grouting ◽  
Three Stages ◽  
And Diffusion

According to the model test of fracture grouting in loess, the grout changes with the pressure variation, which can be divided into three stages, foundation, expansion and fracturing, and diffusion, and ultimately splits into “Y” shaped grout fractures. Using PFC2D particle flow software simulates the slurry diffusion process on loess, and the results of the simulation display the same “Y” shaped slurry vein with the experiment, which has a certain reference value for fracture grouting in loess.

The Application of Numerical Simulation to Liquid Pipeline Leakage at LNG Terminal in China

2020 ◽  
Author(s):  
Zhichao Guo ◽  
Zhaoci Li
Keyword(s):  
Numerical Simulation ◽  
Liquid Phase ◽  
Natural Gas ◽  
Diffusion Process ◽  
Gas Phase ◽  
Stokes Equations ◽  
Response Strategy ◽  
Movement Trajectory ◽  
Two Phase ◽  
And Diffusion

Abstract In 2018, China’s natural gas import reached 90.39 million tons, and the liquefied natural gas (LNG) import was 53.78 million tons, accounting for 59.5% of total natural gas imports. With the construction of LNG terminals, more studies on the leakage of LNG storage and transportation facilities have emerged to prevent catastrophic consequences such as explosions and frostbite. However, most of previous researches focused on gas pipeline leakage after LNG gasification, and few of those have been done on LNG liquid pipeline leakage. In this paper, Fluent software is used to numerically simulate the process of LNG liquid pipeline leakage. After the occurrence of LNG leakage, it will suffer the process of endothermic, evaporation, and diffusion, which is considered as a two-phase diffusion process. The Euler-Lagrangian method is introduced to simulate the diffusion process of gas phase and liquid phase separately. In the simulation, the liquid phase is regarded as discrete droplets for discrete processing. The movement trajectory, heat transfer process and evaporation process of each droplet are tracked respectively. Different from the liquid phase, the gas phase is regarded as a continuous phase and the Navier-Stokes equations are adopted for calculation. Thereafter, coupling calculations of two phase are performed to determine the concentration field and temperature field of the LNG liquid pipeline leakage. As a supplement to this research, the influence of wind speed on LNG leakage and diffusion process is analysed in detail. Finally, the numerical simulation method is applied to a coastal LNG terminal in northern China to determine the distribution of natural gas concentration and temperature, as well as delimit the combustion range. The results can provide scientific reference for the delimitation of risky zones and the formulation of emergency response strategy.

Meso-Mechanical Simulation of Fracture Grouting under Fluid-Solid Coupling Environment and Engineering Applications

2013 ◽  
Vol 477-478 ◽  
pp. 485-491 ◽  
Author(s):  
Feng Sun ◽  
Rong Pan ◽  
Xiu Yun Zhu ◽  
Tie Lin Chen
Keyword(s):  
Numerical Simulation ◽  
Soil Properties ◽  
Bearing Capacity ◽  
Field Test ◽  
Particle Flow ◽  
Particle Flow Code ◽  
Engineering Applications ◽  
Weathered Rock ◽  
Grouting Pressure ◽  
Fracture Grouting

Due to the complication of grouting process in soil, design of fracture grouting works is still mainly based on empirical considerations and experiences from past projects. Based on the theory of particle flow, the domain of flow is defined by using Fish language implemented in PFC and the formulas for flow and pressure are put forward respectively. Combined with above study, the process of fracture grouting in soil is simulated with particle flow code (PFC2D) from micro-viewpoint under coupling environment. In addition, the emergence and development of crack and grouting pressure in soil is analyzed under different grouting pressure and soil properties. The research results show that pressure plays a key role in consolidating the soil by fracture grouting, but in fact it should be kept in a reasonable value in order to forming grouting slurry net entirely. Filed test indicates that fracture grouting greatly increases the bearing capacity of weathered rock in Xiamen Xiangan subsea tunneling and the conclusions of numerical simulation agrees well with the field test and grouting theory.

scholarly journals POLLUTANT ADVECTION AND DIFFUSION PROCESSES IN THE LAGOON OF FUNAFUTI ATOLL, TUVALU

2018 ◽  
pp. 60
Author(s):  
Daisaku Soto ◽  
Hiromune Yokoki
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Diffusion Process ◽  
Diffusion Processes ◽  
Domestic Wastewater ◽  
South Pacific ◽  
The South ◽  
Eastern Side ◽  
Advection Diffusion ◽  
And Diffusion

Funafuti Atoll, where is located on the South Pacific (179° 11’ 50”E, 8° 31’ 16”S) is the capital atoll of Tuvalu. Most of residents live in Fongafale Island which is located in the eastern-side of the atoll. Lagoonal nearshore of Fongafale Island has a problem of nearshore pollutant caused by outflowing of untreated domestic wastewater. Sato et al.(2015) conducted the numerical simulation of the lagoonal flow field, and the particle advection simulation for estimating the pollutant transportation in the lagoon. However, the simulation was not included the diffusion process of pollutant. In this study, numerical simulation including advection-diffusion processes was conducted to understand the characteristics of the pollutant behavior in the lagoon of Funafuti Atoll.

Numerical Simulation of Rolling Compaction Process for Rockfill Dam by Particle Flow Code

2012 ◽  
Vol 170-173 ◽  
pp. 2000-2003 ◽  
Author(s):  
Yang Liu ◽  
Xiao Zhu Li
Keyword(s):  
Numerical Simulation ◽  
Particle Flow ◽  
Particle Flow Code ◽  
Test Results ◽  
Compaction Process ◽  
Rockfill Dam ◽  
Field Compaction ◽  
Vibration Compaction ◽  
Three Stages

Based on field compaction test of Nuozhadu I district rockfill engineering, numerical simulation was conducted to study the rolling compaction (RC) process using Particle Flow Code (PFC). Effects of different particle content to the quality of dam filling were discussed based on both numerical and filed test results. Numerical results also revealed the particle movement of the rockfill, the density of the formation mechanism and compaction characteristics during the RC process. Field test and simulated results both indicated that the RC process can be divided into three stages of vibration compaction, void filling and the unloading rebound phase

Collaborative Filtering Model Fusing Singularity and Diffusion Process

2014 ◽  
Vol 24 (8) ◽  
pp. 1868-1884 ◽  
Author(s):  
Xing-Yao YANG ◽  
Jiong YU ◽  
IBRAHIM Turgun ◽  
Bin LIAO ◽  
Yu-Rong QIAN
Keyword(s):  
Diffusion Process ◽  
Collaborative Filtering ◽  
And Diffusion

Numerical Simulation of Ship Collision and Validations With Experimental Results

2021 ◽  
Author(s):  
Xiangbiao Wang ◽  
Chun Bao Li ◽  
Ling Zhu
Keyword(s):  
Numerical Simulation ◽  
Model Test ◽  
Structural Damage ◽  
Added Mass ◽  
Ship Motion ◽  
Time Dependent ◽  
Structural Deformation ◽  
Structure Interaction ◽  
Ship Collision ◽  
Good Agreement

Abstract Ship collision accidents occur from time to time in recent years, and this would cause serious consequences such as casualties, environmental pollution, loss of cargo on board, damage to the ship and its equipment, etc. Therefore, it is of great significance to study the response of ship motion and the mechanism of structural damage during the collision. In this paper, model experiments and numerical simulation are used to study the ship-ship collision. Firstly, the Coupled Eulerian-Lagrangian (CEL) was used to simulate the fluid-structure interaction for predicting structural deformation and ship motion during the normal ship-ship collision. Meanwhile, a series of model tests were carried out to validate the numerical results. The validation presented that the CEL simulation was in good agreement with the model test. However, the CEL simulation could not present the characteristics the time-dependent added mass.

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