Analysis of External Water Pressure for a Tunnel in Fractured Rocks

Table 2

Geometrical parameters of the fractures.

Probability parameters	Geometrical parameters
	Strike angle (°)	Dip direction angle (°)	Dip angle (°)	Distance (m)	Broken zone (m)
Mean value
NE	50.4	140.4	69.6	123.9	1.03
NW	313.3	223.3	75.2	145.4	1.27
Standard deviation
NE	11.92	11.92	7.45	67.83	0.9
NW	9.76	9.76	8.63	84.12	1.07
Distribution form
NE	Normal distribution	Normal distribution	Normal distribution	Negative exponent	Negative exponent
NW	Normal distribution	Normal distribution	Normal distribution	Negative exponent	Negative exponent