Improved Protodyakonov’s Method of the Tunnel Surrounding Rock Pressure under the Seepage Condition of Weak Interlayer

Table 2

Weak interlayer with different inclination angles corresponding to the surrounding rock pressure value of left hance, right hance, and the vault.

Dip angle of interlayer (°)	Left hance surrounding; rock pressure; (MPa)	Right hance surrounding; rock pressure; (MPa)	Vault surrounding; rock pressure; (MPa)
0	0.345	0.127	2.209
5	0.382	0.151	2.357
10	0.429	0.185	2.486
15	0.508	0.238	2.756
20	0.633	0.306	3.262
25	0.737	0.361	3.811
30	0.883	0.424	4.172
35	1.03	0.516	4.688
40	1.14	0.6	5.102
45	1.303	0.696	4.588
50	1.162	0.771	4.2
55	1.047	0.736	3.867
60	0.922	0.717	3.424
65	0.797	0.66	3.166
70	0.712	0.596	2.863
75	0.636	0.555	2.572
80	0.562	0.478	2.4
85	0.532	0.413	2.173
90	0.502	0.271	2.088