## 1 Introduction  
With the rapid development of underground resource extraction and subsurface energy storage infrastructure, studies on the mechanical properties of rocks have become an important foundation for engineering safety assessment [1, 2]. As a geological material widely present in oil and gas reservoirs and geotechnical engineering, moderately consolidated sandstone requires in-depth research on its mechanical behavior to ensure engineering safety and resource development [3,4]. Traditional rock mechanics research primarily relies on physical experiments to characterize the macroscopic mechanical properties and failure behavior of rocks. However, this approach encounters several limitations, including the intrinsic heterogeneity of rock specimens, high operational costs, and invisibility of the failure process. The advent and application of numerical simulation techniques have introduced novel approaches for simulating rock failure processes under a wide range of loading and boundary conditions. Although conventional finite element methods can effectively simulate the deformation characteristics of continuous media, they are limited by the discontinuous structure of rocks (composed of particles and cementitious materials), making it difficult to accurately characterize the progressive failure process caused by cementation failure. The discrete element method (DEM), which explicitly simulates particle interactions and discontinuity behavior in rocks, has garnered considerable scholarly attention as a promising tool for investigating rock failure mechanisms. [PERSON] employed the two-dimensional Particle Flow Code (PFC) to investigate the biaxial failure mechanisms of transversely bedded concrete layers under varying bedding angles and thicknesses [5]. [PERSON] utilized DEM simulations to examine borehole stability under in situ stress conditions, exploring the effects of particle bonding variations and confined aquifers on instability within poorly cemented formations [6]. They employed PFC to develop new three-dimensional rock mass strength criteria through polyaxial, triaxial, and biaxial tests on jointed rock blocks containing single or double joint sets, supported by an analysis of 284 numerical simulations [7]. [PERSON] integrated laboratory experiments and PFC simulations to evaluate both direct and indirect approaches for determining the mode-I fracture toughness of concrete, including compaction tensile tests, notched Brazilian discs, semi-circular bending specimens, and hollow-centered cracked discs [8]. Among these, the discrete element method has emerged as an effective tool for studying the micromechanical response of sandstone due to its ability to simulate particle bond fracture and energy dissipation mechanisms. The accurate input of modeling parameters is a fundamental prerequisite for precisely simulating the mechanical behavior of rocks under various working conditions. The micromechanical parameters in discrete element models do not directly correspond to the macroscopic mechanical parameters of rocks. Consequently, the problem of how to quickly and accurately acquire the micromechanical parameters for discrete element models of rocks has attracted extensive attention from researchers. [PERSON] employed PFC software to investigate the effects of friction angle, accumulation factor, expansion coefficient, and disc distance on the failure patterns, compressive strength, and tensile strength observed in unconfined compression tests and Brazilian tests [9]. [PERSON] utilized a trial-and-error approach to inversely calibrate the micromechanical parameters of Hawkesbury sandstone, sequentially adjusting those influencing the elastic modulus (_E_), Poisson's ratio (\(\mu\)), and uniaxial compressive strength (_UCS_). Due to the combined effects of multiple micromechanical parameters on macroscopic mechanical properties, a single set of micromechanical rock parameters required the completion of ten uniaxial compression tests [10].