Uniaxial compression experiments were carried out on prefabricated borehole samples. Acoustic emission (AE) and digital image correlation (DIC) monitoring technology were applied to explore the mechanical response characteristics of samples arranged in multiple rows and lines

and analyze the influence of the drillhole on the bursting liability

deformation and failure

accumulation and release of energy of coal samples. The results show that

destressing drillhole in coal seam could reduce the bursting liability

control the deformation and increase the deformation energy dissipation of samples. Compared with an intact sample

the strength of the samples with drillhole was significantly attenuated

and as the number of drilling rows increased

the pre-peak elastic modulus

peak stress

and the bursting energy index KE gradually decreased

and the bursting liability was reduced. Destressing drillhole could increase the activity intensity of AE events and reduce the proportion of high-energy events. The layout of the destressing drillhole caused change of the fracture mode of the samples. A strain localization area generates from the middle on the sample surface of the intact samples

and the final fracture occurs in this area as the weak surface. For the samples with single row and multiple lines of drillhole arrangement

cracks occur on the upper and lower sides of drillholes

forming a localization zone

which extend up and down to form macroscopic cracks. For the samples with double rows and multiple lines drillhole arrangement

cracks easily occur in the rock bridge between the same row of drillholes

and then the cracks in the rock bridge between the vertical drillholes further develope

and finally form the vertical and horizontal and oblique macroscopic cracks. Morevoer

the drillhole in sample could increase the vertical drilling direction (x-direction) deformation

reduce the parallel drilling direction (y-direction) deformation

enlarge the vertical direction (z-direction) deformation

and reduce the volume deformation. The drillholes could reduce the growth UV and peak value Umax of deformation energy density

and delayed the release rate URV of deformation energy at the moment of failure. When drillhole number is greater

the reduction amplitude of the peak deformation energy density Umax and the release rate URV are greater.