The geotechnical properties of the oolitic ironstone formation, Wadi Halfa, North Sudan

Abstract

Wadi Halfa Oolitic Ironstone Formation (WHOIF) covers large areas around Wadi Halfa border town in Northern Sudan. The detrital framework grains of sandstone of WHOIF are composed of sub-angular to sub-rounded quartz grains followed by feldspars, lithic fragments, micas and heavy minerals. The dominant cementing materials are iron oxides, carbonate cement, and some clay minerals. Twelve block samples were carefully selected and collected from six sites to represent different parts of vertical lithofacies sections of the studied formation. The petrographical characteristics of the specimens were first studied and the specimens were then subjected to laboratory tests to determine some of their basic physical and engineering properties. The physical tests constituted unit weight, specific gravity and water absorption. The measured engineering properties included uniaxial compressive strength (UCS) and ultra-sonic pulse velocity (UPV). The UCS and UPV were measured for specimens parallel and perpendicular to the bedding planes of the studied samples. The geotechnical study shows that the UCS values of WHOIF generally range from strong 83.7 MPa to very strong 153.7 MPa for perpendicular direction to bedding planes. Very good statistical correlation coefficient was developed between UCS and UPV. Good correlation was obtained between water absorption, porosity and UPV. These relations indicated that a decrease in void ratio and porosity resulted in an increase in UCS and UPV. An increase in water absorption of sandstone yielded a decrease in ultrasonic pulse velocity and uniaxial compressive strength.

Barite Concretions in Wadi Halfa Oolitic Ironstone Formation, North Sudan

“…The petrographic classification of sandstone samples of Wadi Halfa Oolitic Ironstone Formation according to mineral composition (quartz, lithic fragments, and feldspars) are classified as quartzarenite, sub lithic arenite and sub-arkose [21]. By using thin section polarized microscope for the discoidal shape of heavy gravity sediments we found that these sediments are composed of very angular to angular pure quartz grains include monocrystalline quartz grains ranging from 35.1 to 52.3% and polycrystalline quartz grains ranging from 2.0 to 20.9%.…”

Numerical and laboratory investigation of effect of soil reinforcement on settlement of strip foundations

“…This problem is more prevalent in urban areas situated in mountainous terrains, where there is no sufficient space to construct buildings, roads, bridges, etc. and therefore, the foundations of these structures must be inevitably placed on soil and rock slopes (Daoud et al, 2020). In such cases, poor assessment of the load-bearing capacity of the foundation and stability of the slopes can do irreparable *Corresponding author.…”