Engineering Classification of Jointed Rock Mass Based on Connectional Expectation: A Case Study for Songta Dam Site, China

Table 3

Evaluation indexes of rock mass in each adit are expressed by the interval number.

Evaluating index	Interval number	PDS1			PD222			PD224			PD226
		Section 1	Section 2	Section 3	Section 1	Section 2	Section 3	Section 1	Section 2	Section 3	Section 1	Section 2	Section 3
Rock strength (MPa)	Minimum	47.4	25.7	73.9	34.8	67.3	51.3	62.6	60.2	87.8	49.3	129.9	117.0
	Maximum	163.6	241.5	138.9	83.0	131.6	99.4	145.3	189.1	192.0	130.1	234.1	239.7
	Expectation	102.2	96.8	106.0	56.9	116.1	94.0	114.4	111.9	148.1	85.0	171.0	195.7
Joint spacing (m)	Minimum	0.007	0.006	1.311	0.003	0.003	0.112	0.020	0.033	0.277	0.044	0.032	4.153
	Maximum	4.573	7.349	7.311	8.016	5.233	18.781	11.155	7.524	33.844	4.699	8.838	8.333
	Expectation	0.802	1.164	4.046	0.791	0.999	4.294	0.981	0.875	7.097	0.846	2.006	6.481
RQD (%)	Minimum	54	35	94	14	78	72	54	45	92	34.3	86.8	81.8
	Maximum	85	100	100	98	98	100	98	100	100	97.0	100.0	100.0
	Expectation	74	84	98	68	91	96	74	92	98	66	96	98
Roughness	Minimum	1	1	4	4	4	4	4	4	4	4	4	4
	Maximum	9	7	7	8	8	9	8	9	9	7	8	5
	Expectation	5.70	4.89	4.67	5.49	5.18	5.25	6.32	6.78	4.54	4.57	4.79	4.06
Aperture	Minimum	1	1	1	1	1	1	1	1	1	1	1	1
	Maximum	6	6	3	6	4	3	6	5	5	6	4	5
	Expectation	2.43	1.79	1.33	1.83	1.42	1.15	2.00	2.01	1.73	2.07	1.14	1.63
Weathering	Minimum	2	2	1	2	2	1	1	1	1	2	1	1
	Maximum	4	4	4	4	3	2	4	4	3	4	2	2
	Expectation	2.46	2.67	1.94	2.51	2.18	1.97	2.96	1.72	1.77	2.85	1.92	1.94
Groundwater	Minimum	1	1	1	1	1	1	1	1	1	1	1	1
	Maximum	4	4	4	3	2	4	5	5	2	4	4	4
	Expectation	1.58	1.92	1.72	1.49	1.25	1.13	1.92	2.07	1.50	1.28	1.71	2.13
Dip difference (°)	Minimum	−44	−45	−23	−44	−27	−39	−32	−42	−34	−36	−30	−12
	Maximum	6	17	10	19	15	6	11	33	−5	14	16	25
	Expectation	−33.31	−19.94	−2.50	−11.70	−6.90	−12.47	−16.16	−9.36	−24.62	−16.10	−5.88	8.20