Optimizing Non-Invasive Techniques for Surface and Sub-Surface Soil Characterizations for a Slope in Lebanon

This work aims to be an initial investigation to the use of geophysical and limited geotechnical data to obtain soil and stratigraphy characterization. This approach is essential for developing countries where geotechnical data is typically scarce and expensive. This type of consolidation was used on a study area in Lebanon that consists of a failed slope. A consolidation of data from surface wave measurements, electrical resistivity, and in-situ data was carried out where each gave a part of the description of the site. The surface wave measurements revealed that the seismic bedrock depth was not reached in the range of measurements carried out for this study. Soil was revealed to be mostly clayey sand. Geostatistical analysis results showed that spatial variability of soil properties in both vertical and horizontal directions could be achieved from the electrical resistivity measurements. For this study area, it was shown that 9 m and 4 m were the sizes of the essential spatial structures in the data in the horizontal and vertical directions respectively. Another finding of interest was a second order trend in the resistivity data in both the horizontal and vertical directions that can be due to the decrease in resistivity with depth due to soil compression. All in all, the slope has been better understood with the merging of data and the aspects that require further investigation have been clearly depicted.