Study on micro-scale mechanical properties of coal rock basedon atomic force microscopy

In order to study the mechanical properties and influencing factors of coal rock at the microscopic scale, this paper takes the bituminous coal sample (Ro=0.80%) in Baode area as the research object. The mechanical performance quantification module in atomic force microscopy is used to measure Young′s modulus and adhesion at different locations on coal rock surface and the data obtained were processed and analyzed by NanoScope Analysis software to obtain coal surface topography, Young′s modulus, adhesion force image and deformationimage.And the influencing factors of surface mechanical properties were analyzed.The results show that the average Young′s modulus of the whole scanning area is 7.62 GPa, which is larger than the traditional rock mechanics test method. The Young′s modulus of organic matter is about 2 GPa, and the average Young′s modulus of clay minerals is about 15 GPa.The adhesion force ranges from 10 nN to 40 nN. The main factor affecting Young′s modulus and adhesion force is roughness.The distribution of pores also affects the adhesion force, and the location of the pore often has a larger value of the adhesion force.