Integrated Geophysical Characterization of Injibara University Campus Building Site, Injibara, Amhara, Northwestern Ethiopia

Teshome AM and Wassie GM

Published on: 2022-12-30

Abstract

Integrated geophysical investigations, specifically electrical resistivity and magnetic methods were conducted for engineering characterization of the foundation conditions of the Injibara University buildings construction site located in Injibara town of Amhara Regional State, northwestern, Ethiopia. The principal objective of this research was to study the suitability of the foundation earth materials underlying the site, where Injibara University is established. The geophysical survey included 13 resistivity-sounding points and 153 magnetic data. Qualitative and quantitative interpretations have provided valuable geotechnical information using pseudo-depth and geo-electric sections, sliced-stacked maps and magnetic anomaly maps incorporated with available geologic information from the study area. Interpretation of geophysical data revealed that the subsurface geology of the area is composed of three layers. The topsoil consisted of clay, silt and sand a mixture having a 1-4 m thickness range is mapped over the whole area. The second layer low resistive layer is interpreted as highly weathered and fractured vesicular basalt. The depth extent of this layer varies from about 10m on the North West end and South East parts and to about 27m around the central part. The third layer occurred in the depth range of 10-27m is characterized by relatively high resistivity and it is due to moderately weathered and fractured basaltic bedrock, which is deeper near to the center of the profiles and gets shallower towards North West end and southeastern portions. Besides, analyses of collected data have suggested the possible locations of minor structural discontinuities (maybe local fractures).The geophysical results show that the bedrock is found at shallow depth in the northwestern end and southeastern part of the study area, whereas in the near center part of the survey area the bedrock is found relatively at high depth. Therefore, setting the building foundation is more recommended in the southeastern part of the construction site.