Table 1.

Details of AI models available in the literature review.

References	AI technique	Number of datapoints	Details of input variables		R2 Test
			Variables used	Nos
Nguyen et al.25	SSO-ELM	216	B/S, DI, ST, MC, PF, HD, RQD, N, SD	9	0.91
Ragam et al.26	XGBoost-RF	121	DI, ST, MC, PF, HD	5	0.95
Zhang et al.27	RF, CART, CHAID	102	DI, MC	2	0.94
Zhou et al.28	RF	102	DI, MC, PF, B, S, HD	6	0.93
Huang et al.29	FA-ANN	88	DI, MC, B, S, N	5	0.91
Zhou et al.30	GEP-MC	102	B/S, DI, ST, MC, PF, HD	6	0.91
Nguyen et al.11	SVR-GA	125	DI, MC	2	0.99
Nguyen et al.12	HKM-CA	136	DI, MC	2	0.99
Armaghani et al.31	ICA	73	B, S, ST, D, HD, PF, MC, DI	8	0.95
Hasanipanah et al.32	CART	86	DI, MC	2	0.95
Shahnazar et al.33	PSO-ANFIS	81	–	–	0.98
Ghoraba et al.34	ANN, ANFIS	115	DI, MC	2	0.95
Shirani Faradonbeh et al.35	GEP	102	DI, MC	2	0.88
Hajihassani et al.36	ICA-ANN	95	MC, DI, TC	3	0.98
Dindarloo37	SVM	100	S, B, ST, PF, MC, D, N, RD, SD	9	0.99
Hajihassani et al.38	PSO-ANN	88	BS, ST, PF, MC, DI, Vp, E	7	0.89
Hasanipanah et al.39	SVM	80	RD, E, UCS, TS, Js, B, S, HD/B, SC, ST, DPR, DI	12	0.96
Armaghani et al.6	ANFIS	109	BS, MC, HD, ST, SD, DI, PF, RQD	8	0.97
Armaghani et al.40	PSO-ANN	44	B, S, ST, N, MC, DI	6	0.94
Ghasemi et al.41	FIS	120	DI, MC	2	0.95
Monjezi et al.42	ANN	20	–	–	0.93
Mohamadnejad et al.43	SVM, ANN	37	DI, MC	2	0.89
Monjezi et al.44	ANN	182	CD, DI, ST, HD	4	0.95
Mohamed45	ANN, FIS	162	DI, MC	2	0.94
Khandelwal et al.1	ANN	130	–	–	0.92
Fişne et al.46	FIS	33	DI, MC	2	0.92
Iphar et al.47	ANFIS	42	DI, CD	2	0.99
Singh and Singh48	ANN	–	D, N, HD, B, S, ST, MC, HDI, RDI	9	0.82

*Bold values represent the best soft computing model in the reported study.