Dynamic Response and Time-Frequency Characteristic of Dangerous Rocks under the Combined Action of Rock Cavity Weathering and Earthquake

Figure 15

HHT three-dimensional time-frequency diagram of each monitoring block in Model 1. (a) Block A1. (b) Block A2. (c) Block A3. (d) Block A4. (e) Block B1. (f) Block B2. (g) Block B3. (h) Block B4.

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)