为了研究致裂作用对煤岩孔隙微观结构的影响，采用低温氮吸附法与压汞法对致裂前后煤样的孔隙形貌、孔径分布等特性进行研究；基于低温氮和压汞数据并结合分形理论，计算不同范围孔隙分形维数。结果表明：经过致裂作用后，煤样孔容都有所增大，致裂煤的大孔孔容是原煤的1.4~2.2倍，微孔孔容是原煤的3.7~8.2倍；在压力小于13.8 MPa的低压区，原煤渗流孔、吸附孔分形维数均大于致裂煤，在压力大于13.8 MPa而小于137.9 MPa的高压区，原煤扩散孔分形维数均小于致裂煤。

In order to study the effect of cracking on the pore microstructure of coal rock, low-temperature nitrogen adsorption meth-od and mercury injection method were used to study the pore morphology and pore size distribution of coal samples before and after cracking, and then the fractal dimension of pores in different ranges was calculated based on the data of low-temperature nitrogen and mercury injection combined with the fractal theory. The results show that the pore volume of coal samples increases after cracking. The large pore volume of cracked coal is 1.4−2.2 times that of raw coal, and the micropore volume is 3.7−8.2 times that of raw coal. The fractal dimension of raw coal’s seepage pore and adsorption pore is greater than that of cracking coal at pressure less than 13.8 MPa and low pressure zone, and the fractal dimension of raw coal’s diffusion pore is smaller than that of cracking coal at pressure more than 13.8 MPa but less than 137.9 MPa and high pressure zone.