Evaluation of Engineering Site and Subsurface Structures Using Seismic Refraction Tomography: A Case Study of Abydos Site, Sohag Governorate, Egypt

Abstract

Because of the strategic importance of the Abydos archaeological site in Egypt as a source of wealth for Egyptian tourism, this study was concerned with carrying out geophysical measurements to detect subsurface succession and measure variations in the geotechnical engineering features of the soils/rocks in order to protect this significant area. The findings will assist geologists and seismologists in collaborating with archaeologists for future site development, revitalization, and investment. The primary objectives of this work were to determine the subsurface lithology, evaluate the engineering geotechnical properties of soils/rocks, identify the layer thicknesses, and identify the site class by calculating Vs30. To achieve these goals, seventeen (17) seismic refraction tomography (SRT) P- and S-wave measurements were executed in front of the Osirion location. SeisImager Software was used for the processing and interpretation of the outcomes. The results were the travel time–distance curves, which were used for building the 2D seismic models that exhibited the velocity and the depth of the layered models. These models were validated by our previous works using electric resistivity tomography and borehole data. The results indicated that this site consisted of three geoseismic subsurface layers. The first layer was the surface that was made up of wadi deposits, which were a mixture of gravel, sand, and silt and were characterized by incompetent to slightly competent materials. The second layer corresponded to the sand and muddy sand deposits of competent rock that was of fair to moderate quality. The third layer (clay deposits) had a higher velocity and was more compact and may be employed as a bedrock layer. The elastic moduli, Vs30, petrophysical, and geotechnical properties of the three geoseismic layers were appraised as essential parameters. Integration of petrophysical and geotechnical parameters and elastic moduli revealed that the third layer was composed of competent clays, which were characterized by low values of porosity, void ratio, Poisson ratio, and stress ratio. It also had a high rigidity, Young’s and bulk moduli, concentration and material indexes, N-value, ultimate bearing capacities, and high density values, and vice versa for the first layer. The standard NEHRP site class was B (rocks). These parameters are ordinarily used as key indications and serve as significant inputs for any future work.

Effects of Water—Binder Ratio on Strength and Seismic Behavior of Stabilized Soil from Kongshavn, Port of Oslo

“…We proposed two methods for evaluating soil strength stabilized using different water/binder ratios, namely, using UCS tests implemented by the MTS 810 servohydraulic universal testing machine, and using sonic tests with evaluated velocities of pulsed Pwaves. Inspired by the existing approaches of seismic methods applied to civil engineering problems [115,116], we prove that a combination of state-of-the-art methods with nondestructive seismic tests can model the dependency of soil strength on binder proportions, w/b ratio and curing time. Specifically, the analysis of the presented data shows that the lowest P-wave seismic velocity of 1200 m/s is demonstrated by the highest strength and corresponding UCS values, which is achieved by the optimal proportion of water with the lowest content of binder, i.e., w/b = 7.99, and the lowest absolute content of binder, such as 2.022 mB/g.…”

Application of Seismic Refraction Tomography in Determining the Soil Hardness Level in IKN Nusantara Area

“…Seismic Refraction Tomography (SRT) has become a common method for exploring the geotechnical properties of soil (Asamoah et al, 2018;Whiteley et al, 2018;Oladotun et al, 2019;Adewoyin et al, 2021;Shin et al, 2022;Opemipo et al, 2022;El Hameedy et al, 2023). According to Jabrane et al (2023) and Abudeif et al (2023), this technique relies on the principle of seismic wave retardation, which is dispersed by layers of rocks beneath the surface. This dispersion produces a representation of the variation in compressional wave velocity (P-wave velocity -Vp) within the earth.…”