Empirical relationship between electrical resistivity and geotechnical parameters: A case study of Federal University of Technology campus, Akure SW, Nigeria

Peer review under responsibility of National Research Institute of Astronomy and Geophysics.

Figures & data

Fig. 6 Percentage passing 0.075 mm sieve (PCS) versus apparent resistivity (ρ_a).

Fig. 7 Specific gravity (SG) versus apparent resistivity (ρ_a).

Fig. 8 Liquid limit (LL) versus apparent resistivity (ρ_a).

Fig. 9 Plastic limit (PL) versus apparent resistivity (ρ_a).

Fig. 10 Plasticity index (PI) versus apparent resistivity (ρ_a).

Fig. 11 Linear shrinkage (LS) versus apparent resistivity (ρ_a).

Fig. 12 Optimum moisture content (OMC) versus apparent resistivity (ρ_a).

Fig. 13 Maximum dry density (MDD) versus apparent resistivity (ρ_a).

Fig. 14 California bearing ratio (CBR) versus apparent resistivity (ρ_a).

Fig. 1 Map of the Federal University of Technology, Akure (FUTA) showing the study area.

Fig. 2 Topographic map of the study area.

Fig. 3 Geological map of the study area showing the sample locations (modified after Kareem, 1997).

Fig. 4 Schlumberger configuration flow pattern used for the electrical resistivity measurement.

Fig. 5 Natural moisture content (NMC) versus apparent resistivity (ρ_a).

Fig. 15 Unconfined compression shear strength (UCSS) versus apparent resistivity.

Table 1 Summary of the results of the apparent resistivity and geotechnical parameters at the depth of 1 and 2 m.

Sample Location	ApparentRes. (ρa)	Moisture Content (%)	Clay & Silt Content (%)	Specific Gravity	Liquid Limit (%)	Plastic Limit (%)	Plastic Index (%)	Linear Shrinkage (%)	OMC (%)	MDD (kg/m^3)	CBR (%)	UCSS (kPa)
	Depth of 1 m
10	45	21.1	41.28	2.687	42.7	28.8	13.9	9.3	13.2	1878	15	145.7
9	61	29.2	45.8	2.578	51	31.2	19.8	9.3	20.04	1578	10	112.1
2	112	21.1	35.3	2.694	50	42.9	7.1	9.3	11.86	1788	20	164.9
3	148	24.2	55.6	2.6	54	43.7	10.4	11.4	19.6	1625	12	69.3
7	164	17.7	37.8	2.55	24.4	16.2	8.2	5	8.4	2055	41	49.5
8	227	19.2	38.4	2.613	42.4	29.9	12.5	7.1	13.6	1978	28	63.1
1	259	14.8	34.8	2.639	46.2	36.7	9.5	6.4	13.2	1850	27	78.9
6	370	10.1	27.6	2.761	30.6	20.5	10.1	5	11	1978	33	46.5
4	373	15.7	29.2	2.601	36.5	22.5	14	7.1	10.6	1887	45	40.4
5	487	9.2	24.1	2.802	35	29.2	5.8	4.3	8.3	2142	48	40.6
	Depth of 2 m
10	8	20.3	40.88	2.619	45.3	31.7	13.6	7.9	16.4	1804	11	102.7
9	97	28.2	47.5	2.604	56	34.5	21.5	8.6	22.08	1608	9	106.8
3	101	27.3	58.36	2.614	55.5	46.7	8.8	10.7	22.4	1600	13	80.3
2	173	24.2	48.5	2.676	52	31	21.1	5.7	19.6	1700	15	51.8
1	249	16.7	41.4	2.622	45	34.9	10.2	6.4	13.6	1880	24	73.7
7	251	18.2	29.8	2.631	32	18.7	13.3	7.1	8.6	2070	27	34.6
4	337	22.4	34.2	2.498	44.8	36.7	8.1	5.7	22.02	1639	39	57.1
6	396	13.5	38.4	2.601	35.5	23.2	12.3	6.4	14.5	1820	23	46.2
8	405	17.2	26	2.719	38.6	30.3	8.3	5.7	11.4	2052	32	68.5
5	701	8.3	21.2	2.83	33.1	28.2	4.9	3.6	8.2	2255	54	46.2

Direct Relationship.

Inverse Relationship.

Table 2 Empirical equations relating the geotechnical parameters and apparent resistivity.

Geotechnical parameter (GP)	General empirical equation	Coefficient of correlation (R)
		1 m depth	2 m depth
Natural moisture content	NMC = −0.031ρa + 26.5	0.82	0.87
Percentage of clay and silt	PCS = −0.046ρa + 49.2	0.78	0.78
Specific gravity	SG = 0.0003ρa + 2.579	0.54	0.58
Liquid limit	LL = −0.0325ρa + 50.57	0.52	0.71
Plastic limit	PL = −0.018ρa + 35.21	0.34	0.38
Plasticity index	PI = −0.015ρa + 15.38	0.44	0.63
Linear shrinkage	LS = −0.01ρa + 9.46	0.73	0.80
Optimum moisture content	OMC = −0.017ρa + 18.57	0.59	0.62
Maximum dry density	MDD = 0.79ρa + 1662.5	0.65	0.72
California bearing ratio	CBR = 0.0714ρa + 8.74	0.83	0.93
Unconfined compression shear strength	UCSS = −0.156ρa + 110.7	0.76	0.65