scholarly journals Comparative Analysis of Support Stiffness Based on On-Site Laying of Rectangular Parallelepiped Fiber Reinforcement Sack

2020 ◽  
Vol 20 (6) ◽  
pp. 47-53
Author(s):  
Yoon-Sik Park ◽  
Ja-Yeon Kim ◽  
Ki-Young Eum ◽  
KookHwan Cho
Keyword(s):  
Bearing Capacity ◽  
Large Scale ◽  
Field Tests ◽  
Fiber Reinforcement ◽  
Physical Property ◽  
Vertical Displacement ◽  
Rectangular Parallelepiped ◽  
Train Speed ◽  
Comparison And Analysis ◽  
Large Scale Tests

The roadbed reinforcement method, in which a rectangular parallelepiped fiber reinforcement sack is used, is ecofriendly and overcomes the disadvantages of the conventional roadbed reinforcement method. Through large-scale tests, the effects of improving the bearing capacity, stability, and constructability according to the train speed were confirmed. Physical property investigations of the field test were conducted to analyze the conditions of the roadbed. The settlement degree of the site, where the reinforced section and unreinforced section were placed, was measured and analyzed. A rectangular parallelepiped fiber reinforcement sack was laid. Based on the physical properties determined during the field tests, this section was found to be soft ground composed of silt sand with a low bearing capacity. In addition, through comparison and analysis of the degree of settlement caused by the laying of rectangular parallelepiped fiber reinforcement sack, the dynamic vertical displacement of rails and sleepers decreased by at least 84%. It was shown that the track stability improved when the rectangular-parallelepiped fiber reinforcement sack was laid, which reduced the dynamic behavior along and improved the track support.

scholarly journals Study of Ballast Track Dynamic Behavior Evaluation Comparative Analysis According to the On-Site Laying of Rectangular-Parallelepiped Fiber Reinforcement Sack

2021 ◽  
Vol 21 (6) ◽  
pp. 239-245
Author(s):  
Young-Man Cha ◽  
Ki-Young Eum ◽  
Ja-Yeon Kim ◽  
KookHwan Cho
Keyword(s):  
Comparative Analysis ◽  
Fiber Reinforcement ◽  
Physical Property ◽  
Vertical Displacement ◽  
Rectangular Parallelepiped ◽  
Reinforcing Effect ◽  
Fine Grained ◽  
Dynamic Movement ◽  
Train Operation ◽  
Ballast Track

The roadbed reinforcement method using cuboidal fiber reinforcement is an eco-friendly method that compensates for the shortcomings of various existing roadbed reinforcement technologies. A rectangular parallelepiped fiber reinforcement was installed in section oo of the existing line where fine-grained gravel, floating sleepers, and sleeper cracks occurred. The basic physical property test of the upper subgrade was conducted, and the vertical displacement and acceleration of rails and sleepers were compared and analyzed according to the train operation of the reinforced and non-reinforced sections. A comparative analysis of the vertical displacement and acceleration according to train operation after laying the rectangular parallelepiped fiber reinforcement demonstrated that the vertical displacement and acceleration were reduced by up to 84% and 80%, respectively. The dynamic movement of the rail was reduced owing to the reinforcing effect of the rectangular parallelepiped reinforcement, thereby improving the roadbed bearing capacity and stability.

Experimental and large-scale field tests of grid-anchor system performance in increasing the ultimate bearing capacity of granular soils

2016 ◽  
Vol 53 (7) ◽  
pp. 1047-1058 ◽  
Author(s):  
M. Mosallanezhad ◽  
N. Hataf ◽  
S.H. Sadat Taghavi
Keyword(s):  
Bearing Capacity ◽  
Large Scale ◽  
Field Tests ◽  
Experimental Tests ◽  
Ultimate Bearing Capacity ◽  
Soil Reinforcement ◽  
Granular Soils ◽  
Anchor System ◽  
Scale Field ◽  
Large Scale Field

Soil reinforcement by means of geogrid is an effective method of increasing the ultimate bearing capacity (UBC) of granular soils. In this study a new system, created by adding cubic anchors to ordinary geogrids, is introduced to increase the UBC of granular soils. This system is called “grid-anchor” (G-A). To analyse the performance of the G-A system in increasing the UBC of granular soils, 45 experimental tests and 9 field tests were performed, the results of which show that the G-A system is 1.8 times more capable than ordinary geogrids in increasing the UBC in square foundations. Furthermore, the failure of soil reinforced by the ordinary geogrid takes place at a settlement of 9% of the foundation width, while the same value for the G-A system is almost 13%.

scholarly journals On mechanical behaviour of clastic soils: numerical simulations and constitutive modelling

2021 ◽  
Author(s):  
shun wang ◽  
Wei Wu ◽  
Deshan Cui
Keyword(s):  
Numerical Simulations ◽  
Mechanical Behaviour ◽  
Large Scale ◽  
Field Tests ◽  
Stress Path ◽  
Constitutive Modelling ◽  
Failure Pattern ◽  
Soil Matrix ◽  
Deformation And Failure ◽  
Large Scale Tests

Clastic soil is ubiquitous in practice but still poses challenges for testing and modelling. Conventional laboratory tests with small sizes are not suitable for the large grain size, while large-scale tests and field tests are often too costly and time-consuming. In this paper, the mechanical behaviour of clastic soil is described by a hypoplastic constitutive model based on numerical simulations considering both the soil matrix and breccia. The numerical simulations indicate that the breccia content, gradation, and overconsolidation ratio have a significant influence on the strength, deformation, and failure pattern of the clastic soil. The coarse particles are found to change the stress path developed in the soil matrix and consequently influence the critical state of the soil matrix. Moreover, the coarse particle distribution based on computed tomography scan seems to have a larger impact than the breccia content for the failure pattern of the clastic soils.

scholarly journals Wireless Sensor Networks for Smart Cities: Network Design, Implementation and Performance Evaluation

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 218
Author(s):  
Ala’ Khalifeh ◽  
Khalid A. Darabkh ◽  
Ahmad M. Khasawneh ◽  
Issa Alqaisieh ◽  
Mohammad Salameh ◽  
...  
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Experimental Evaluation ◽  
Large Scale ◽  
Performance Metrics ◽  
Smart Cities ◽  
Field Tests ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Real Field

The advent of various wireless technologies has paved the way for the realization of new infrastructures and applications for smart cities. Wireless Sensor Networks (WSNs) are one of the most important among these technologies. WSNs are widely used in various applications in our daily lives. Due to their cost effectiveness and rapid deployment, WSNs can be used for securing smart cities by providing remote monitoring and sensing for many critical scenarios including hostile environments, battlefields, or areas subject to natural disasters such as earthquakes, volcano eruptions, and floods or to large-scale accidents such as nuclear plants explosions or chemical plumes. The purpose of this paper is to propose a new framework where WSNs are adopted for remote sensing and monitoring in smart city applications. We propose using Unmanned Aerial Vehicles to act as a data mule to offload the sensor nodes and transfer the monitoring data securely to the remote control center for further analysis and decision making. Furthermore, the paper provides insight about implementation challenges in the realization of the proposed framework. In addition, the paper provides an experimental evaluation of the proposed design in outdoor environments, in the presence of different types of obstacles, common to typical outdoor fields. The experimental evaluation revealed several inconsistencies between the performance metrics advertised in the hardware-specific data-sheets. In particular, we found mismatches between the advertised coverage distance and signal strength with our experimental measurements. Therefore, it is crucial that network designers and developers conduct field tests and device performance assessment before designing and implementing the WSN for application in a real field setting.

scholarly journals Spatiotemporal behavior of a large-scale landslide at Mt. Onnebetsu-dake, Japan, detected by three L-band SAR satellites

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Youichiro Takada ◽  
George Motono
Keyword(s):  
Large Scale ◽  
Fluid Pressure ◽  
Surface Displacement ◽  
Length Change ◽  
Vertical Displacement ◽  
Phase Changes ◽  
Annual Rainfall ◽  
Spatiotemporal Behavior ◽  
Spatially Periodic ◽  
L Band

Abstract We applied differential InSAR analysis to the Shiretoko Peninsula, northeastern Hokkaido, Japan. All the interferograms of long temporal baseline (~ 3 years) processed from SAR data of three L-band satellites (JERS-1, ALOS, ALOS-2) commonly indicate remarkable phase changes due to the landslide movement at the southeastern flank of Mt. Onnebetsu-dake, a Quaternary stratovolcano. The area of interferometric phase change matches to known landslide morphologies. Judging from the timing of the SAR image acquisitions, this landslide has been moving at least from 1993 to the present. Successive interferograms of 1-year temporal baseline indicate the temporal fluctuation of the landslide velocity. Especially for the descending interferograms, the positive line-of-sight (LOS) length change, which indicates large subsidence relative to the horizontal movement, is observed in the upslope section of the landslide during 1993–1998, while the negative LOS change is observed in the middle and the downslope section after 2007 indicating less subsidence. The landslide activity culminates from 2014 to 2017: the eastward and the vertical displacement rates reach ~ 6 and ~ 2 cm/yr, respectively. Utilizing high spatial resolution of ALOS and ALOS-2 data, we investigated velocity distribution inside the landslide. During 2007–2010, the eastward component of surface displacement increases toward the east, implying that the landslide extends toward the east. During 2014–2017, the vertical displacement profile exhibits spatially periodic uplift and subsidence consistent with surface gradient, which indicates the ongoing deformation driven by gravitational force. Heavy rainfall associated with three typhoons in August 2016 might have brought about an increase in the landslide velocity, possibly due to elevated pore-fluid pressure within and/or at the base of the landslide material. Also, annual rainfall would be an important factor that prescribes the landslide velocity averaged over 3 years.

scholarly journals Reservoir-Induced Land Deformation: Case Study from the Grand Ethiopian Renaissance Dam

2021 ◽  
Vol 13 (5) ◽  
pp. 874
Author(s):  
Yu Chen ◽  
Mohamed Ahmed ◽  
Natthachet Tangdamrongsub ◽  
Dorina Murgulet
Keyword(s):  
Land Surface ◽  
Large Scale ◽  
Surface Deformation ◽  
Vertical Displacement ◽  
Nile River ◽  
Reservoir Volume ◽  
Novel Approach ◽  
Land Deformation ◽  
Large Scale Land ◽  
The Impact

The Nile River stretches from south to north throughout the Nile River Basin (NRB) in Northeast Africa. Ethiopia, where the Blue Nile originates, has begun the construction of the Grand Ethiopian Renaissance Dam (GERD), which will be used to generate electricity. However, the impact of the GERD on land deformation caused by significant water relocation has not been rigorously considered in the scientific research. In this study, we develop a novel approach for predicting large-scale land deformation induced by the construction of the GERD reservoir. We also investigate the limitations of using the Gravity Recovery and Climate Experiment Follow On (GRACE-FO) mission to detect GERD-induced land deformation. We simulated three land deformation scenarios related to filling the expected reservoir volume, 70 km3, using 5-, 10-, and 15-year filling scenarios. The results indicated: (i) trends in downward vertical displacement estimated at −17.79 ± 0.02, −8.90 ± 0.09, and −5.94 ± 0.05 mm/year, for the 5-, 10-, and 15-year filling scenarios, respectively; (ii) the western (eastern) parts of the GERD reservoir are estimated to move toward the reservoir’s center by +0.98 ± 0.01 (−0.98 ± 0.01), +0.48 ± 0.00 (−0.48 ± 0.00), and +0.33 ± 0.00 (−0.33 ± 0.00) mm/year, under the 5-, 10- and 15-year filling strategies, respectively; (iii) the northern part of the GERD reservoir is moving southward by +1.28 ± 0.02, +0.64 ± 0.01, and +0.43 ± 0.00 mm/year, while the southern part is moving northward by −3.75 ± 0.04, −1.87 ± 0.02, and −1.25 ± 0.01 mm/year, during the three examined scenarios, respectively; and (iv) the GRACE-FO mission can only detect 15% of the large-scale land deformation produced by the GERD reservoir. Methods and results demonstrated in this study provide insights into possible impacts of reservoir impoundment on land surface deformation, which can be adopted into the GERD project or similar future dam construction plans.

scholarly journals Application of paleoseismological techniques to the study of Late Pleistocene-Holocene deep-seated gravitational movements at the Mortirolo Pass (central Alps, Italy)

2001 ◽  
Vol 80 (3-4) ◽  
pp. 209-227 ◽  
Author(s):  
M. Onida ◽  
F. Galadini ◽  
F. Forcella
Keyword(s):  
Late Pleistocene ◽  
Large Scale ◽  
Vertical Displacement ◽  
Central Alps ◽  
Glacial Retreat ◽  
Activation Mechanisms ◽  
Loading And Unloading ◽  
Shear Planes ◽  
Geometry And Kinematics

AbstractPaleoseismological techniques have been used to investigate gravitational deformations at the Mortirolo Pass (Valtellina region, central Alps), in order to improve the knowledge on the activation mechanisms and the evolution of deep-seated gravitational slope movements. The deformation has been responsible for mass sliding towards the Valtellina depression through the activation of several-hundred-metre-long shear planes. Minor shear planes dipping towards the mountain played the role of antithetic structures. Four trenches were excavated across scarps representing the surficial expression of shear planes affecting the bedrock and Late Pleistocene-Holocene deposits. The excavations enabled to investigate the stratigraphy of Quaternary deposits and the geometry and kinematics of the shear planes affecting them. Radiocarbon analyses on organic material contained in sediments and paleosols enabled to define a succession of displacement events which occurred during the Late Pleistocene-Holocene. Collected data indicate the persistence of the activity until recent times (last movement related to 1810-1540 cal. BP). A sudden movement has been detected along one of the main shear surfaces (dipping towards the valley) with a vertical displacement of several metres. In contrast, numerous displacements (with lower vertical offset) have been detected along the antithetic shear planes. Different hypotheses have been proposed in the past to define the origin of huge gravitational movements (glacial retreat, uplift of the Alpine chain, fault activity). However, the Late Pleistocene cycles of glacial loading and unloading on the mountain slopes seem to be the most probable factors causing deep-seated gravitational movements in the investigated region. A recent dramatic landslide in an area adjacent to the investigated one (Mt. Zandila-Valpola) testifies to the paroxistic evolution of the large scale gravitational deformations. The densely inhabited Valtellina region is affected by a large number of gravitational structures similar to those of the Mortirolo area. In consideration of the possible effects of the paroxistic activation of these structures, detailed studies on the chronology and kinematics of the deformations through the application of paleoseismological techniques should therefore be encouraged.

Large scale field tests on geogrid-reinforced granular fill underlain by clay soil

2013 ◽  
Vol 38 ◽  
pp. 1-15 ◽  
Author(s):  
Ahmet Demir ◽  
Mustafa Laman ◽  
Abdulazim Yildiz ◽  
Murat Ornek
Keyword(s):  
Large Scale ◽  
Clay Soil ◽  
Field Tests ◽  
Scale Field ◽  
Granular Fill ◽  
Large Scale Field

The Influence of Stochastic Imperfection Field on the Bearing Capacity of Hyperbolic Cooling Towers

2011 ◽  
Vol 374-377 ◽  
pp. 2297-2300
Author(s):  
Hai Zhao ◽  
Ya Zhou Xu ◽  
Guo Liang Bai
Keyword(s):  
Bearing Capacity ◽  
Large Scale ◽  
Initial Imperfection ◽  
Orthogonal Basis ◽  
Imperfection Sensitivity ◽  
Stochastic Field ◽  
Buckling Mode ◽  
Material Inhomogeneity ◽  
Initial Imperfections ◽  
Distribution Form

The uncontrollable factors such as construction errors, material inhomogeneity, etc. will inevitably lead to a certain initial imperfections. It is generally known that the stochastic initial imperfection of the structure is an important factor for affecting structural stability and bearing capacity. Since these imperfections are random in nature, this paper proposes the method mainly based on the standard orthogonal basis to expand the stochastic field, taking into account the decomposition of the stochastic initial imperfections related to structures, which is projected in the buckling mode orthogonal basis. In the end, the article by the stability analysis example shows that this method can use less random variables effectively describing the original stochastic imperfection field, and efficiently search for the most unfavorable initial imperfection distribution form in order to ensure the imperfection sensitivity structures have a higher reliability, so it can be applied to large-scale engineering structure stochastic imperfection analysis.

Sign in / Sign up

Export Citation Format

Share Document