Study on the Fracture Behavior of Cracks Emanating from Tunnel Spandrel under Blasting Loads by Using TMCSC Specimens

Table 2

Stress wave propagation time and crack propagation time.

Crack angle (°)	TCDA (μs)	TA (μs)	TCEB (μs)	TB (μs)
−75	321.81	64.6	326.75	168.2
−60	323.87	68.2	329.22	169.6
−45	327.57	71.8	332.92	188.6
−30	331.69	74.6	337.04	177.4
−15	335.39	75.8	341.15	181.4
0	331.69	77.4	337.45	187.0
15	327.57	76.2	333.33	181.0
30	323.05	75.6	328.81	175.4
45	319.75	72.4	325.05	164.6
60	316.05	70.6	321.40	168.8
75	313.58	67.4	318.93	166.8

T_CDA and T_CEB were obtained from geometric calculation, and T_A and T_B were derived from monitoring data of CPG in subsequent blasting tests.