Enhanced permeability prediction in porous media using particle swarm optimization with multi-source integration

Accurately and efficiently predicting the permeability of porous media is essential for addressing a wide range of hydrogeological issues.However,the complexity of porous media often limits the effectiveness of individual prediction methods.This study introduces a novel Particle Swarm Optimization-based Permeability Integrated Prediction model(PSO-PIP),which incorporates a particle swarm optimization algorithm enhanced with dy-namic clustering and adaptive parameter tuning(KGPSO).The model integrates multi-source data from the Lattice Boltzmann Method(LBM),Pore Network Modeling(PNM),and Finite Difference Method(FDM).By assigning optimal weight coefficients to the outputs of these methods,the model minimizes deviations from actual values and enhances permeability prediction performance.Initially,the computational performances of the LBM,PNM,and FDM are comparatively analyzed on datasets consisting of sphere packings and real rock samples.It is observed that these methods exhibit computational biases in certain permeability ranges.The PSOPIP model is proposed to combine the strengths of each computational approach and mitigate their limitations.The PSO-PIP model consistently produces predictions that are highly congruent with actual permeability values across all prediction intervals,significantly enhancing prediction accuracy.The outcomes of this study provide a new tool and perspective for the comprehensive,rapid,and accurate prediction of permeability in porous media.

Discrete element method study of hysteretic behavior and deformation characteristics of rockfill material under cyclic loading

Granular geomaterials under different loading conditions manifest various behaviors,such as hysteresis.Understanding their hysteretic behavior and deformation characteristics is the basis for establishing a constitutive relation with excellent performance in deformation prediction.The deformation characteristics of crushable particle materials are analyzed through a series of cyclic loading tests conducted by numerical simulation.The hysteretic behavior is investigated from a particle scale.The increase in particles with contacts less than two may be responsible for the residual strain,and the particle breakage further promotes particle rearrangement and volume contraction.Both the accumulation of plastic strain and the resilient modulus are found to be related to confining pressures,stress levels,cyclic loading amplitudes,and the number of cycles.The plastic strain accumulation can be written as a function of the number of cycles and an evolution function of resilient modulus is proposed.