Stress-dependent method for calculating the modulus improvement factor in geocell-reinforced soil layers

2021 ◽  
Vol 49 (1) ◽  
pp. 146-158
Author(s):  
R.S. Garcia ◽  
J.O. Avesani Neto
Keyword(s):  
Reinforced Soil ◽  
Soil Layers ◽  
Improvement Factor ◽  
Stress Dependent

scholarly journals Subsidence prediction of reinforced soil layer by geosynthetic using large-scale 1g physical model

2020 ◽  
Vol 382 ◽  
pp. 721-726
Author(s):  
Marwan Al Heib ◽  
Mouhamad Hassoun ◽  
Pascal Villard ◽  
Fabrice Emeriault ◽  
Abbas Farhat
Keyword(s):  
Large Scale ◽  
Soil Layer ◽  
Physical Modelling ◽  
Reinforced Soil ◽  
Experimental Results ◽  
Ground Movement ◽  
Analytical Models ◽  
Soil Layers ◽  
Existing Structures ◽  
The Impact

Abstract. Subsidence can result from the collapse of underground cavities. The impact of the movements on existing structures and infrastructures is generally dramatic. Geosynthetic sheets (RG) can be used to reduce their impact. This paper focuses on the use of large-scale physical modelling to study the subsidence mechanisms and to estimate the RG efficiency for cohesive or granular soil layers. The results have shown that the RG reduced the ground movement even under important overload. The deformation of the RG and the surface settlement depend both on the soil type and overload intensity. The experimental results are compared to analytical solutions proposed to design the RG for cohesive and granular soils. Stress distribution on the RG was investigated. The analytical and experimental results are rather similar, that shows the relevance of the analytical models to predict the behaviour of reinforced soil layers.

On the pullout resistance of geosynthetics

1993 ◽  
Vol 30 (3) ◽  
pp. 409-417 ◽  
Author(s):  
R.J. Fannin ◽  
D.M. Raju
Keyword(s):  
Relative Displacement ◽  
Coarse Sand ◽  
Reinforced Soil ◽  
Small Displacement ◽  
Sand Sample ◽  
Similar Response ◽  
Pullout Resistance ◽  
Interaction Factor ◽  
Values In Design ◽  
Stress Dependent

Pullout tests are reported on geosynthetic test specimens embedded in a relatively dense, coarse sand sample. The tests are displacement controlled and are performed at different vertical effective stresses. Tests are reported for a smooth and textured geomembrane and for geogrids of a high and low junction strength. Behaviour is compared with an inextensible, rough sheet. Pullout resistance is governed by progressive tensile strain in the geosynthetic which is a result of relative displacement between it and the soil. Values of interface bond that are described by an interaction factor vary significantly and are stress dependent. Both types of geogrid and the textured geomembrane exhibit a similar response to loading at small displacement, and mobilize a much larger interaction factor than the smooth geomembrane. A rationale is suggested for selection of appropriate values in design. Key words : pullout testing, geogrid, geomembrane, interface friction, reinforced soil.

scholarly journals Water Table Effects on the Behaviors of the Reinforced Marine Soil-footing System

2021 ◽  
Vol 2 (3) ◽  
pp. 296-305
Author(s):  
Ramin Vali
Keyword(s):  
Finite Element Analysis ◽  
Water Table ◽  
Soft Soil ◽  
Reinforced Soil ◽  
Qeshm Island ◽  
Element Analysis ◽  
Soil Layers ◽  
System A ◽  
The Finite Element Analysis ◽  
Geotechnical Tests

This study evaluates the effects of a water table on the behaviors of a geogrid reinforced soil-footing system on marine soft soil layers in Qeshm Island, Iran. The main aim of this research is to recommend the optimum specification of the reinforced soil-footing system. A series of geotechnical tests were adopted to measure the properties of the soil profile. The impacts of the water table and the geogrid layer specifications were evaluated by the finite element analysis to investigate the system’s behaviors. Finally, the optimal reinforced soil-footing is suggested. Doi: 10.28991/HEF-2021-02-03-09 Full Text: PDF

Microspectroscopy Using a Solid Immersion Lens

2001 ◽  
Vol 7 (S2) ◽  
pp. 148-149
Author(s):  
C.D. Poweleit ◽  
J Menéndez
Keyword(s):  
Spatial Resolution ◽  
Focal Plane ◽  
Numerical Aperture ◽  
Normal Incidence ◽  
Spot Size ◽  
Index Of Refraction ◽  
Objective Lens ◽  
Improvement Factor ◽  
Oil Immersion ◽  
Long Time

Oil immersion lenses have been used in optical microscopy for a long time. The light’s wavelength is decreased by the oil’s index of refraction n and this reduces the minimum spot size. Additionally, the oil medium allows a larger collection angle, thereby increasing the numerical aperture. The SIL is based on the same principle, but offers more flexibility because the higher index material is solid. in particular, SILs can be deployed in cryogenic environments. Using a hemispherical glass the spatial resolution is improved by a factor n with respect to the resolution obtained with the microscope’s objective lens alone. The improvement factor is equal to n2 for truncated spheres.As shown in Fig. 1, the hemisphere SIL is in contact with the sample and does not affect the position of the focal plane. The focused rays from the objective strike the lens at normal incidence, so that no refraction takes place.

Pre-Processing of Hyperspectral Images Using Nonlinear Filters

2013 ◽  
Vol 11 (1) ◽  
pp. 8-13
Author(s):  
V. Behar ◽  
V. Bogdanova
Keyword(s):  
Signal To Noise Ratio ◽  
Correlation Coefficients ◽  
Hyperspectral Images ◽  
Spectral Correlation ◽  
Edge Preserving ◽  
Improvement Factor ◽  
Filter Output ◽  
Average Improvement ◽  
Processing Procedure

Abstract In this paper the use of a set of nonlinear edge-preserving filters is proposed as a pre-processing stage with the purpose to improve the quality of hyperspectral images before object detection. The capability of each nonlinear filter to improve images, corrupted by spatially and spectrally correlated Gaussian noise, is evaluated in terms of the average Improvement factor in the Peak Signal to Noise Ratio (IPSNR), estimated at the filter output. The simulation results demonstrate that this pre-processing procedure is efficient only in case the spatial and spectral correlation coefficients of noise do not exceed the value of 0.6

FEATURES OF SALTS MIGRATION IN DELTAIC ECOSYSTEMS

1970 ◽  
pp. 28-29
Author(s):  
М. I. Dzhalalova ◽  
P. А. Abdurashidova ◽  
R. М. Zagidova
Keyword(s):  
Cover Crop ◽  
Groundwater Salinity ◽  
Salt Composition ◽  
Material Resource ◽  
Aboveground Phytomass ◽  
Soil Layers ◽  
Material Energy ◽  
Theoretical Foundations ◽  
Pasture Plants ◽  
Salinity Seawater

The coastal strip of the northwestern Caspian is characterized by hydromorphism and salinization processes which depending on the Caspian piled-up water, groundwater salinity, seawater, and salt composition of the underlying rocks. The migrational salts capability in deltoic ecosystem components in dynamic over the main representatives of pasture plants occurring in the Western Caspian and playing an important role in developing the theoretical foundations of a system of measures to increase the productivity of cover crop have studied. Salts migration from soil layers into plants which taking place in synthesis of material-energy and material resource of environment is one of the chains of bio-substrat links. The research results confirm the data that the ash elements stock in the ephemeral-absinthial group varies from 21.5 to 64.5 kg per 1 ha. The organogens prevail in them – 944 kg / ha, K is dominant, then Ca and Mg. The amount of halogens is 7.05 kg / ha, of which Cl portion includes 3.31 and Na – 2.80 kg / ha. In the ephemeral-absinthial group cenoses rather high values of aboveground phytomass are up to 50 centners / ha and the supply of ash elements (halogens 32.14 and organogens 36.18 mg-eq) is much higher compared to their content in soil (7.05 and 6, 31 mg-eq). In roots difference in quantity of organogens and halogens is insignificant – 2.03 and 2.04 mg-eq. We associate such differences with a greater proportion of absinthial in the aboveground phytomass composition

POTENTIALLY TOXIC CHEMICAL ELEMENTS OF SHALE PLAYS – ECOLOGICAL THREAT TO THE ENVIRONMENT

2020 ◽  
Author(s):  
Svetlana Punanova
Keyword(s):  
Chemical Elements ◽  
Organometallic Compounds ◽  
Cost Effective ◽  
Potentially Toxic Elements ◽  
Shale Oil ◽  
Toxic Chemical ◽  
Horizontal Drilling ◽  
Soil Layers ◽  
Valuable Metals ◽  
Economic Use

This research considered the content of trace elements (TE), including potentially toxic elements (PTE) in shale plays and deposits in various regions of the world. Their comparative analysis was carried out and the highest concentrations of PTE in the shales of some regions were revealed. The author notes that the destruction of organometallic compounds occurs during the development of shale hydrocarbon (HC) using horizontal drilling with hydraulic fracturing – injecting large volumes of chemicals while increasing the temperature. During such destruction processes, PTE can escape into the environment: into groundwater, soil layers, and other objects of economic use, and also deteriorate well equipment. In connection with the noted environmental hazards present during the development of shale HC, this paper proposes to monitor the content of TE in both shale rocks as well as in extracted shale oil in order to mitigate the risks of their release into the environment. In addition, developers and scientists should consider the losses of industrially significant volumes of valuable metals that occur due to the lack of cost-effective technologies for their capture and extraction from naphthides.

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