Numerical Study of Stone Column Reinforced Composite Foundation of Highway under Static and Seismic Load

2012 ◽  
Vol 602-604 ◽  
pp. 1526-1531
Author(s):  
Min Min Jiang ◽  
Shang Yu Han ◽  
Hong Li
Keyword(s):  
Numerical Study ◽  
Horizontal Displacement ◽  
Calculation Model ◽  
Composite Foundation ◽  
Traffic Load ◽  
Stone Column ◽  
Seismic Load ◽  
Reinforced Composite ◽  
Drainage Effect ◽  
Pile Length

Stone column reinforced composite foundation of highway under static and seismic load is simulated by numerical method. Fist, calculation model was built up, and verified by in situ test. Then the whole construction process of highway stone column reinforced composite foundation is simulated, after 3 years of traffic load, a seismic load was imposed on bottom of the model. Calculation result show that: in construction and run time period, drainage effect of stone column is significant, when pile length reached to 12m, maximum pore pressure in middle of stone column reduced to about 4 kPa, when pile length reached to 10m, effect of pile length on settlement is small; composite foundation has smaller maximum horizontal displacement in stone column; surface and toe of embankment slope is apt to liquefy under seismic load, stone column can eliminate liquefaction potential to a certain extent, especially in composite foundation range.

Character Analysis of Balance and Imbalance of Varying Rigidity of Rigid Pile Composite Foundation under Seismic Load

2014 ◽  
Vol 1065-1069 ◽  
pp. 19-22
Author(s):  
Zhen Feng Wang ◽  
Ke Sheng Ma
Keyword(s):  
Finite Element ◽  
Bending Moment ◽  
Horizontal Displacement ◽  
Element Model ◽  
Composite Foundation ◽  
Seismic Load ◽  
Seismic Loads ◽  
Element Analysis ◽  
Rigid Pile ◽  
Rigid Pile Composite Foundation

Based on ABAQUS finite element analysis software simulation, the finite element model for dynamic analysis of rigid pile composite foundation and superstructure interaction system is established, which selects the two kinds of models, by simulating the soil dynamic constitutive model, selecting appropriate artificial boundary.The influence of rigid pile composite foundation on balance and imbalance of varying rigidity is analyzed under seismic loads. The result shows that the maximum bending moment and the horizontal displacement of the long pile is much greater than that of the short pile under seismic loads, the long pile of bending moment is larger in the position of stiffness change. By constrast, under the same economic condition, the aseismic performance of of rigid pile composite foundation on balance of varying rigidity is better than that of rigid pile composite foundation on imbalance of varying rigidity.

scholarly journals Comparative Study of Existing Cement Fly Ash Gravel pile and Encased Stone Column Composite Foundation

2021 ◽  
Vol 1197 (1) ◽  
pp. 012002
Author(s):  
N. B. Umravia ◽  
C.H. Solanki
Keyword(s):  
Fly Ash ◽  
Lateral Displacement ◽  
Ground Improvement ◽  
Pile Group ◽  
Composite Foundation ◽  
Excess Pore Pressure ◽  
Stone Column ◽  
Seismic Load ◽  
Total Settlement ◽  
Lateral Behavior

Abstract The Cement Fly Ash and Gravel (CFG) Pile and Encased Stone Column (ESC) are the ground improvement techniques. The main object of the study is to the numerical analysis of the Both techniques pile group were used to support the Embankment with and without the geotextile both techniques composite foundation by the Finite Element method under static and dynamic load analysis. Numerical simulation has been carried out in Plaxis 3D. A case study from china’s highspeed embankment supported by CFG and ESC have investigated the load caring capacity by soil and pile. While the failure behaviors, settlement, excess pore pressure, and lateral behavior with variable embankment loading and number of geosynthetic effect moreover, the diameter of CFG piles and ESC at various locations in an embankment has been varied to study its influence on the load distribution among the CFG piles/ESC and lateral load displacement of the pile group. The results show that increasing the diameter of both techniques reduced the total settlement and differential settlement of embankment. It observed that the seismic load has a significant effect on the vertical and lateral displacement.

The Numerical Analysis of Gravel Pile Reinforcing Liquefiable Silt

2013 ◽  
Vol 353-356 ◽  
pp. 265-269
Author(s):  
Dong Hua Ruan ◽  
Yan Mei Zhang ◽  
Zhen Wang ◽  
Chun Xia Huang
Keyword(s):  
Permeability Coefficient ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Composite Foundation ◽  
Seismic Load ◽  
Vibration Acceleration ◽  
Earthquake Intensity ◽  
Natural Foundation ◽  
Drainage Effect ◽  
Gravel Pile

A three-dimensional numerical simulation about gravel pile reinforcing liquefiable silt foundation was built, and the influence of gravel pile on the liquefiable silt anti-liquefaction was discussed. Results show that under seismic load, gravel pile has obvious cushioning effect, and compared with natural foundation, the maximum horizontal vibration acceleration of the gravel pile composite foundation surface layer is obviously decreased; drainage effect of gravel pile is very significant and the larger is the gravel pile permeability coefficient, the better is the drainage effect; as earthquake intensity largens, silt liquefaction scope increases; of both natural foundation and composite foundation, the pore pressure ratio variation with depth is that the middle is bigger than the top and bottom, and middle layers are more likely to be liquefied; the greater is the seismic acceleration, the larger is the shear stress.

scholarly journals Method of Calculating the Compensation for Rectifying the Horizontal Displacement of Existing Tunnels by Grouting

2020 ◽  
Vol 11 (1) ◽  
pp. 40
Author(s):  
Yongjie Qi ◽  
Gang Wei ◽  
Feifan Feng ◽  
Jiaxuan Zhu
Keyword(s):  
Volume Expansion ◽  
Soil Layer ◽  
Horizontal Displacement ◽  
Soil Mass ◽  
Calculation Model ◽  
Additional Stress ◽  
Corrective Effect ◽  
Engineering Data ◽  
Subway Tunnels ◽  
Good Agreement

Sleeve valve pipe grouting, an effective method for reinforcing soil layers, is often employed to correct the deformation of subway tunnels. In order to study the effect of grouting on rectifying the displacement of existing tunnels, this paper proposes a mechanical model of the volume expansion of sleeve valve pipe grouting taking into consideration the volume expansion of the grouted soil mass. A formula for the additional stress on the soil layer caused by grouting was derived based on the principle of the mirror method. In addition, a formula for the horizontal displacement of a tunnel caused by grouting was developed through a calculation model of shearing dislocation and rigid body rotation. The results of the calculation method proposed herein were in good agreement with actual engineering data. In summary, enlarging the grouting volume within a reasonable range can effectively enhance the grouting corrective effect. Further, with an increase in the grouting distance, the influence of grouting gradually lessens. At a constant grouting length, setting the bottom of the grouting section at the same depth as the lower end of the tunnel can maximize the grouting corrective effect.

Manufacturing a carbon/epoxy NACA 23018 airfoil skin using a circular braiding machine: experimental and numerical study

2021 ◽  
pp. 152808372199377
Author(s):  
Jalil Hajrasouliha ◽  
Mohammad Sheikhzadeh
Keyword(s):  
Numerical Study ◽  
Filament Winding ◽  
Bending Test ◽  
Elastic Response ◽  
Manufacturing Processes ◽  
Fiber Reinforced Composite ◽  
Four Point Bending ◽  
Reinforced Composite ◽  
Four Point Bending Test ◽  
Meso Scale

In the interest of reducing the weight and also cost of blade skins, various automatic preform manufacturing processes were developed including tape laying, filament winding and braiding. Among them, the circular braiding process was found to be an efficient method in producing seamless preforms on mandrels with various geometries. In this regard, an attempt was made to produce a carbon fiber reinforced composite with the shape of NACA 23018 airfoil using a circular braiding machine. Thus, suitable wooden mandrels were manufactured using NACA 23018 airfoil coordinates, which were obtained by assuming the perimeter of 20 cm. Furthermore, both biaxially and triaxially braided preforms were produced and subsequently impregnated with epoxy resin through an appropriate fabrication method. To assess their performance, four-point bending test was carried out on samples. Ultimately, the elastic response of braided composite airfoils was predicted using a meso-scale finite element modeling and was validated with experimental results.

Nonlinear dynamic behaviour of guy cables in turbulent winds

2001 ◽  
Vol 28 (1) ◽  
pp. 98-110 ◽  
Author(s):  
Bruce F Sparling ◽  
Alan G Davenport
Keyword(s):  
Finite Element ◽  
Dynamic Behaviour ◽  
Aerodynamic Drag ◽  
Numerical Study ◽  
Horizontal Displacement ◽  
Wind Loading ◽  
Second Phase ◽  
Nonlinear Coupling ◽  
Wide Range ◽  
Cable Vibrations

Large amplitude cable vibrations are difficult to predict using linear theory due to the presence of sag in the suspended profile. A numerical study was therefore undertaken to investigate the dynamic behaviour of inclined cables excited by imposed displacements. To model the nonlinear nature of cable response, a time domain finite element approach was adopted using nonlinear catenary cable elements. Two types of horizontal displacement patterns were enforced at the upper end of the guy. In the first phase of the study, harmonic displacement histories with a wide range of forcing frequencies were considered. In the second phase, random enforced displacements were used to simulate the motion of a guyed mast in gusty winds. The influence of aerodynamic drag and damping forces was investigated by performing analyses under still air, steady wind, and turbulent wind conditions. It was found that nonlinear coupling of related harmonic response components was significant at certain critical frequencies, particular when the excitation was harmonic and acted in the plane of the guy. Positive aerodynamic damping was shown to effectively suppress resonant and nonlinear coupling response.Key words: cables, structural dynamics, wind loading, finite element method, nonlinear analysis, guyed towers.

scholarly journals Numerical Study of a Multi-Layered Strain Sensor for Structural Health Monitoring of Asphalt Pavement

Proceedings ◽  
2019 ◽  
Vol 42 (1) ◽  
pp. 41
Author(s):  
Jiayue Shen ◽  
Minghao Geng ◽  
Abby Schultz ◽  
Weiru Chen ◽  
Hao Qiu ◽  
...  
Keyword(s):  
Structural Health Monitoring ◽  
Polyurethane Foam ◽  
Health Monitoring ◽  
Numerical Study ◽  
Asphalt Pavement ◽  
Strain Sensor ◽  
Traffic Load ◽  
Structural Health ◽  
Initiation And Propagation ◽  
Load Monitoring

Crack initiation and propagation vary the mechanical properties of the asphalt pavement and further alter its designate function. As such, this paper describes a numerical study of a multi-layered strain sensor for the structural health monitoring (SHM) of asphalt pavement. The core of the sensor is an H-shaped Araldite GY-6010 epoxy-based structure with a set of polyvinylidene difluoride (PVDF) piezoelectric transducers in its center beam, which serve as a sensing unit, and a polyurethane foam layer at its external surface which serves as a thermal insulation layer. Sensors are coated with a thin layer of urethane casting resin to prevent the sensor from being corroded by moisture. As a proof-of-concept study, a numerical model is created in COMSOL Multiphysics to simulate the sensor-pavement interaction, in order to design the strain sensor for SHM of asphalt pavement. The results reveal that the optimum thickness of the middle polyurethane foam is 11 mm, with a ratio of the center beam/wing length of 3.2. The simulated results not only validate the feasibility of using the strain sensor for SHM (traffic load monitoring and damage detection), but also to optimize design geometry to increase the sensor sensitivity.

Piled Raft Structure Finite Element Analysis of Composite Foundation Settlement in Da XI Passenger Dedicated Line

2014 ◽  
Vol 937 ◽  
pp. 438-443
Author(s):  
Xiao Tong Ma ◽  
Guang Long Liu
Keyword(s):  
Finite Element ◽  
Composite Foundation ◽  
Foundation Settlement ◽  
Pile Spacing ◽  
Finite Element Software ◽  
Piled Raft ◽  
Pile Diameter ◽  
Foundation Treatment ◽  
Pile Length ◽  
Passenger Dedicated Line

Composite foundation settlement of piled raft structure in Da Xi passenger dedicated line is analyzed by the large finite element software MIDAS/GTS and established calculation model of foundation treatment. The problem of pile-soil contact is highlighted in the trail and analyzes the settlement nephogram and pile-soil stress nephogram. On this basis the foundation settlement factors was analyzed systematically that focus on the elastic modulus of pile, pile spacing, pile diameter and pile length in foundation treatment, especially for the characteristics parameters of contact element. Result shows that increasing the pile modulus, pile diameter, pile length and decreasing the pile spacing is all conducive to reducing settlement. The best advice is got that the pile diameter should be not more than 0.5m, pile length not more than 27m and the pile spacing be around 2m.

Numerical Study on Flow Field in a Peripheral Ported Rotary Engine Under the Action of Apex Seal Leakage

2020 ◽  
Author(s):  
Baowei Fan ◽  
Yuanguang Wang ◽  
Jianfeng Pan ◽  
Yaoyuan Zhang ◽  
Yonghao Zeng
Keyword(s):  
Velocity Field ◽  
Flow Field ◽  
Combustion Chamber ◽  
Numerical Study ◽  
Particle Image Velocimetry Data ◽  
Calculation Model ◽  
Flow Area ◽  
Rotary Engine ◽  
Unidirectional Flow ◽  
Rotary Engines

Abstract Apex seal leakage is one of the main defects restricting the performance improvement of rotary engines. The aim of this study is to study the airflow movement in a peripheral ported rotary engine under the action of apex seal leakage. For this purpose, a 3D dynamic calculation model considering apex seal leakage was firstly established and verified by particle image velocimetry data. Furthermore, based on the established 3D model, the flow field in the combustion chamber under the four apex seal leakage gaps (0.02, 0.04, 0.06 and 0.08 mms) and the three engine revolution speeds (2000, 3500, and 5000 RPMs) was calculated. By comparing with the flow field under the condition without leakage, the influences of the existence of apex seal leakage on the velocity field, the turbulent kinetic energy and the volumetric efficiency in the combustion chamber were investigated. Thereinto, the influences of the existence of apex seal leakage on the velocity field is that at the intake stroke, a vortex formed in the middle of the combustion chamber under the condition without apex seal leakage, was intensified by the apex seal leakage action. At the compression stroke, irrespective of the condition with or without apex seal leakage, all vortexes in the combustion chamber are gradually broken into a unidirectional flow. However, there is an obvious "leakage flow area" at the end of combustion chamber due to the existence of apex seal leakage.

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