The reconstruction of rock mass fracture is crucial for accurately constructing fracture rock mass model and obtaining its mechanical properties. To ensure the reconstructed fractures fit the natural state

this paper first proposed the D-n threshold formula and modified the Weierstrass-Mandelbrot (W-M) function used in rock mass fracture simulation. Barton’s 10 profile lines were digitized using binarized gray images

and Hurst values for 10 roughness levels were determined using the equi-difference method

trial and error method and comprehensive analysis method. The new parameter Spp

representing the magnitude feature

is obtained by Fourier transforming the 10 profile lines. The parameter Spp is then combined linearly with the standard deviation of the angle  to construct a new joint roughness coefficient (JRC) calculation formula. The optimal scaling constant G value corresponding to the target JRC value is obtained using the dichotomy method

establishing the mapping relationship between JRC and the W-M function. The W-M function considers random terms and realizes the differentiation of reconstructed fractures. The roughness quantification research and laboratory tests are conducted to verify the validity of the new parameter Spp

the new JRC formula

and the mapping relationship. This study provides a new approach for expanding the method of obtaining fracture in rock mass

and lays the foundation for studying the mechanical properties of fractured rock mass.