GROUND DISPLACEMENT BEHAVIORS CONSIDERING UNSTEADY SEEPAGE FLOW AND NON-LINEAR DEFORMATION

One major concern for excavation projects is the ground displacement generated around the excavated zone. In this paper, a 2-dimensional model analysis was made on non-linear ground behavior around excavation due to unsteady seepage of groundwater, taking into account the saturated-unsaturated theory by using Toyo-ura sand. The finite-element method and finite-different method were employed to study the space problem and time dimension, respectively. The numerical simulation code implemented by FORTRAN was applied to predict the flow-velocity distribution and the results of ground displacement. To validate the programming, a simple model was tested for comparison with tri-axial test data. The samples were made of Toyo-ura sand with a relative density of 90%. The programming also calculated flow-velocity distribution and ground displacement results of dewatering in excavation work over time. Results showed that the effect of horizontal displacement caused by seepage flow plays a very important role in the displacement field. This numerical simulation method provides a more reasonable computing scheme compared to traditional methods. All have theoretical meaning and applicable value, and also present useful references for the excavation stability and disaster prediction.

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Numerical Simulation of Impacts of Different Types of Air Duct Outlets on Ventilation Efficiency

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.438-439.1098 ◽

2013 ◽

Vol 438-439 ◽

pp. 1098-1103

Author(s):

Chun Zi Nan ◽

Ji Ming Ma ◽

Luo Zhao

Keyword(s):

Numerical Simulation ◽

Flow Field ◽

Velocity Distribution ◽

Flow Velocity ◽

Numerical Method ◽

Concentration Effect ◽

Mixing Zone ◽

Mixing Effect ◽

Ventilation Efficiency ◽

Different Types

To enhance the exhaust efficiency during ventilation, three types of air duct outlets were imported. According to the characteristics of velocity distribution simulated by numerical method, the flow field is divided into the mixing zone and the exhaust zone. The gradual contracted air duct outlet can enhance the mixing effect between fresh air and smoke. In the exhaust zone, however, the flow velocity on the upper section of the tunnel is weakened, which is unfavorable for smoke exhaust. Gradual expanded air duct outlet, on the contrary, may weaken the concentration effect of the airflow. The flow velocity on the upper section of the tunnel is increased in the exhaust zone, thus the flow field is more homogenized, which is in favor of smoke exhaust.

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Nonlinear analysis of water-soil-barrage floor interaction

MATEC Web of Conferences ◽

10.1051/matecconf/201816203013 ◽

2018 ◽

Vol 162 ◽

pp. 03013

Author(s):

Abdul-Hassan Al-Shukur ◽

Atheer Zaki Al-Qaisi ◽

Ayaat Majid Al-Rammahi

Keyword(s):

Three Dimensional ◽

Seepage Flow ◽

Linear Analysis ◽

Exit Point ◽

Rock Foundation ◽

Operation Condition ◽

Linear Deformation ◽

Structure Interaction ◽

Non Linear ◽

Different Characteristics

Fluid - Structure Interaction (FSI) and Soil-Structure Interaction (SSI) are mostly considered in the non-linear analysis of water-soil-barrage floor interaction. A three dimensional (3D) - section of a barrage is selected and modelled via ANSY 15.0. The ogge barrage floor shape has been taken as a case study of analysis. The non-linear analysis of the structure model is developed through selecting suitable available elements in ANSYS which are related to the case under study and is compared with linear analysis. The results of the analysis are obtained by suggesting different characteristics of concrete, soil, and rock materials as a parametric study. Both closed barrage and in operation are the cases have been considered in analysis. It is concluded from this study that ANSYS/APDL is adequate tool to simulate and analysis the problem that need sufficient experiences to select suitable available elements to get the acceptable results. It is also concluded that the deformation in barrage floor has little difference by (6%) in linear and non-linear analysis in case of no operation. While this deformation in non-linear analysis with operation condition is less by (13%) than of no operation case. The non-linear deformation of barrage floor is more effective by change of density of barrage concrete itself, modulus of elasticity and yield stress of both soil and rock foundation materials, while no sensitive effect of change of Poisson’s ratio on the deformation. The maximum seepage flow at exit point downstream barrage floor with upstream and downstream piles is lesser by (67.40%) than without pile. In the view of stability, it is concluded that the barrage floor is already safe in exist gradient and piping problems with or without piles.

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Research on the Relationship of Flow Velocity and Particles’ Separation in Cyclone

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.479-481.2529 ◽

2012 ◽

Vol 479-481 ◽

pp. 2529-2532

Author(s):

Ying Zhang ◽

Zhen Wei Zhang

Keyword(s):

Numerical Simulation ◽

Velocity Distribution ◽

Flow Velocity ◽

Structure Design ◽

Rotating Flow ◽

Separation Performance ◽

Simulation Results ◽

Relationship Of ◽

The Relationship ◽

Distribution Of Flow

This paper mainly focuses on the numerical simulation of flow velocity aiming to obtain the velocity distribution of flow in the cyclone. The authors took advantage of RSM turbulence model of software FLUENT to calculate the velocity distribution. Relationship between particles separation and double-layer rotating flow can be obtained based on the simulation results, which can also provide basis for the improvement of structure design and separation performance.

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Ground Behaviors due to Seepage Force of Groundwater

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.594-597.516 ◽

2012 ◽

Vol 594-597 ◽

pp. 516-521

Author(s):

Ling Yu Meng ◽

Haruyuki Yamamoto

Keyword(s):

Vertical Displacement ◽

Seepage Flow ◽

Unconfined Aquifer ◽

The Finite Element Method ◽

Seepage Force ◽

Ground Displacement ◽

Simulation Code ◽

Capillary Zone ◽

Seepage Theory ◽

Unsaturated Seepage

Well pumping leads to both horizontal and vertical displacement, and fluctuation of groundwater level can cause serious damage to structures in a lagre affected area. Ground behaviors due to seepage force in traditional methods were rarely considered. This paper presents a numerical solution of ground displacement behaviors due to unsteady groundwater flow in unconfined aquifer by considering the effect of capillary zone based on the saturated-unsaturated seepage theory, and the numerical simulation code implemented by FORTRAN is applied to predict the flow velocity distribution and the results of ground displacement. The model uses the finite element method and finite difference method to study the problem. The analysis shows that the seepage force and the effect of capillary zone play a very important role in both seepage flow and displacement field.

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Parameter optimization of anti crystallization flocking drainage pipe based on flow field distribution characteristics

Thermal Science ◽

10.2298/tsci2106091l ◽

2021 ◽

Vol 25 (6 Part A) ◽

pp. 4091-4098

Author(s):

Shiyang Liu ◽

Kun Xiang ◽

Feng Gao ◽

Xuefu Zhang ◽

Yun Li ◽

...

Keyword(s):

Numerical Simulation ◽

Flow Field ◽

Velocity Distribution ◽

Flow Velocity ◽

Field Distribution ◽

Parameter Optimization ◽

Theoretical Basis ◽

Longitudinal Direction ◽

Distribution Characteristics ◽

Drainage Pipe

The crystal plugging of tunnel drainage pipe seriously affects the safe and normal use of the tunnel. In order to obtain the mechanism of flocking drainage pipe anti crystal plugging based on the characteristics of flow field distribution, numerical simulation was used to optimize the parameters of flocking drainage pipe. The results show that: with the existence of fluff, the velocity in the lower part of the drainage pipe decreases by about 50%, and the velocity in the upper part increases by about 25~50%. With the increase of the length of fluff, the velocity funnel between fluffs gradually increases, the velocity distribution at the bottom of the funnel is basically unchanged, and the velocity in the upper part gradually increases. The velocity in the upper part of the flocked drainage pipe fluctuates above the fluff to a certain extent. The flow velocity in the lower part of the drainage pipe forms a flow velocity ladder in the longitudinal direction of the villus, and the width of the ladder is about 2/3 of the longitudinal spacing of the villus. The optimized parameters of 3-D flow field of flocked drainage pipe are helpful to the further improvement of indoor test, and provide theoretical basis for the mechanism of preventing crystal blockage of flocked drainage pipe.

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