This soil investigation was carried out for the completion of Farin Ruwa multipurpose Dam to ascertain the engineering properties of the soil on which the Dam and the spillway were to be built and recommendation of the foundation type. The sub-surface investigation was carried using standard penetration test (SPT), a total of Sixteen boreholes were bored to refusal at between 1.5m to 10.5m with 7Nos from spillway, and 9Nos from dam axis, Deep coring was done on the main dam embankment. Water levels were recorded and samples recovered were carefully identified and taken to laboratory for tests and analysis, test result on soil samples showed permeability ranging from. 0.0490m/s to 0.0630/s (spill way zone) and 0.0430m/s to 0.0630m/s (also from dam axis ) with an average of 0.0540m/s at depth 3.0-3.6m describing the drainage condition as poorly drainage situation, earth bearing pressure ranged from 166.27kn/m2 to 340.06kn/m2 at depth 3.0 – 3.6m (spill way zone) and 156.99kn/m2 to 363.06kn/m2 at depth 3.0m – 3.6m (Dam axis), percentage of fine (75km) ranged from 1.30% to 54.50% at depth < 4.6 – 5. 1m (Spill way zone) and generally low percentage of fines were encountered within the dam axis. The result of the soil investigation showed that sub-surface soil conditions are of generally fairly poor drainage condition (low seepage) an added advantage to earth dam. Allowable bearing pressure lies between 85.60kN/m2 at depth 1.5-2.1m and 191.17kN/m2 at depth 4.6-50m and recommended use of compacted clay material to be used as core material which should be embedded with embankment fill material, lateritic soil of enhanced property at depth not loss than 5.1m on the dam axis and coring to ascertain the presence of fractures, rock type and other strength properties.
IRE Journals:
Nsikak Andrew , Pam Gyang , Appolos Bokos
"Geo-technical and Geophysical investigation for the completion of Farin Ruwa multi-purpose Dam, Nasarawa state, Nigeria." Iconic Research And Engineering Journals Volume 6 Issue 12 2023 Page 371-381
IEEE:
Nsikak Andrew , Pam Gyang , Appolos Bokos
"Geo-technical and Geophysical investigation for the completion of Farin Ruwa multi-purpose Dam, Nasarawa state, Nigeria." Iconic Research And Engineering Journals, 6(12)