scholarly journals GPR Application for Risks Detection in Subsurface Engineering Construction Projects

2019 ◽  
Vol 21 (1) ◽  
pp. 51-58
Author(s):  
Gamil Alsharahi ◽  
Ahmed Faize ◽  
Carmen Maftei ◽  
Abdellah Driouach
Keyword(s):  
Ground Penetrating Radar ◽  
High Frequency ◽  
Construction Projects ◽  
Engineering Construction ◽  
The Road ◽  
Natural Terrain ◽  
On The Road ◽  
Subsurface Engineering ◽  
Ground Penetrating ◽  
Frequency Pulse

Abstract The aim of this work is to study and explore the causes of the landslide in different locations using Ground Penetrating Radar (GPR) technology. GPR uses the electromagnetic method related the high-frequency pulse that used widely in various field. The experimental study focused on the investigation of the landslide in the road by GPR method with antenna 200 MHz. The landslides become serious problems and required various technique and methods to investigate it in several places. GPR measurements present a useful technique for studies and investigation of the problem. The GPR can be categorized in the first place as an experimental method surveys landslide depths were recognized at 1-10 m below the natural terrain level. The results obtained revealed the causes of landslides on the road.

scholarly journals Study Effect of Objects Orientation in the Mediums On GPR Signal Reflections Using FDTD Simulation

2018 ◽  
Vol 3 (11) ◽  
pp. 73-77
Author(s):  
Aye Mint Mohamed Mostapha ◽  
Gamil Alsharahi ◽  
Abdellah Driouach
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Ground Penetrating Radar ◽  
High Frequency ◽  
Electromagnetic Waves ◽  
Ground Surface ◽  
Propagation Path ◽  
Fdtd Simulation ◽  
Ground Penetrating ◽  
Dielectric Objects

Ground penetrating radar (GPR) is a very effective tool for detecting and identifying objects below the ground surface.  based on  the propagation and reflection of high-frequency electromagnetic waves. The GPR reflection can be affected by many things like the type of objects orientation, their shapes ..ect. The purpose of this paper is to  study by simulation the effect of objects orientation in two different mediums (dry and wet sand) on the GPR signal reflection using Reflexw software which is based on a numerical method known as finite difference in time domain (FDTD).  The simulations that have been realized included a conductor  and dielectric objects. The results obtained have led us to find that the propagation path, the reflection strength and the signal form change with the change of object orientation and nature. To confirm the validity of the results, we compared them with experimental results previously published by researchers under the same conditions.

Impacts of permafrost degradation on a road embankment at Umiujaq in Nunavik (Quebec), Canada

2011 ◽  
Vol 48 (5) ◽  
pp. 720-740 ◽  
Author(s):  
Richard Fortier ◽  
Anne-Marie LeBlanc ◽  
Wenbing Yu
Keyword(s):  
Numerical Modeling ◽  
Permafrost Degradation ◽  
Sand Layer ◽  
Geophysical Investigation ◽  
The Road ◽  
Access Road ◽  
Discontinuous Permafrost ◽  
Snow Fence ◽  
On The Road ◽  
Ground Penetrating

Differential subsidence of as much as 0.85 m is affecting the access road to Umiujaq Airport in Nunavik (Quebec), Canada, located in the discontinuous permafrost zone. A geotechnical and geophysical investigation including piezocone test, ground-penetrating radar profiling, electrical resistivity tomography, and numerical modeling of the thermal regime of the road embankment and subgrade is presented to characterize the ground stratigraphy and permafrost conditions and to assess the exact causes and effects of permafrost degradation on the road embankment. The subsidence is due to thaw consolidation taking place in a layer of ice-rich silt underneath a superficial sand layer. While the seasonal freeze–thaw cycles were initially restricted to the sand layer, the thawing front has now reached the thaw-unstable ice-rich silt layer. According to our numerical modeling, the increase in air temperature recently observed in Nunavik cannot be the sole cause of the observed subsidence affecting this engineering structure. The thick embankment also acts as a snow fence favoring the accumulation of snow on the embankment shoulders. The permafrost degradation is also due to the thermal insulation of the snow cover reducing heat loss in the embankment shoulders and toes.

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