Experimental Study on Influence of Borehole Arrangement on Energy Conversion and Acoustic Characteristics of Coal-Like Material Sample

Figure 5

Typical curve of internal energy conversion and elastic energy growth rate of coal-like material sample under different borehole arrangements. (a) Scheme I 01: complete samples. (b) Scheme II 03: samples with boreholes. (c) Scheme III 02: samples with borehole with stepwise increased borehole depth. (d) Scheme IV 03: samples with borehole with stepwise increased borehole diameter. (e) Scheme V 01: samples with borehole with stepwise increased borehole depth and borehole diameter.

(a)

(b)

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(d)

(e)