Study on the Deformation Mechanism of Soft Rock Roadway under Blasting Disturbance in Baoguo Iron Mine

Table 2

Classification criterion of swelling soft rock by He Manchao.

Classification	Montmorillonite content (%)	Dry saturated water absorption ratio (%)	Free expansion deformation ratio (%)
Poor expansibility	<10	<20	<10
Medium expansibility	10∼30	20∼50	10∼15
Strong expansibility	>30	>50	>15