Stability of a Rock Tunnel Passing through Talus-Like Formations: A Case Study in Southwestern China

Table 1

Detailed information of boreholes.

Borehole no.	Chainage (left line)	Chainage (right line)	Depth of borehole (m)	Range of tunnel section (m)	[BQ]	Grade
BH-01	—	K62 + 875	80.69	72.34∼80.69	265	IV ∼ V
BH-02	Z5K63 + 396.4	K63 + 375.64	145.01	126.13∼145.01	215	V
BH-03	Z5K63 + 620.67	K63 + 597	141.7	128.8∼141.7	92.5	V
BH-04	—	K63 + 643	153.5	140∼153.5	105	V
BH-05	Z5K63 + 769.3	K63 + 753	200.6	185.2∼200.6	272	IV
BH-06	Z5K63 + 842.65	K63 + 817.7	209.5	195∼209.5	255	IV ∼ V
BH-07	Z5K63 + 954.91	K63 + 930	255.2	233.5∼255.2	312	IV
BH-08	Z5K64 + 180.23	K64 + 156.45	305	278.7∼300.1	275	IV
BH-09	Z5K64 + 310.46	K64 + 286	305.3	283∼305.3	267	IV ∼ V
BH-10	—	K64 + 700	213.67	193.08∼213.67	265	IV ∼ V

Note: [BQ] is the estimated BQ value according to the geological conditions of boreholes.