Open-pit mines often have slopes that slowly deform and fail over time. The sneakiest issue is βcreepβ β a gradual slide β especially when weak layers are present. Researchers examined a gentle slope in a Inner Mongolia mine, blending field surveys, lab tests, and computer simulations. They applied a Particle Swarm Optimization algorithm to fineβtune a creep model that merges Burgersβ law with the MohrβCoulomb criterion. Findings reveal that creep in the weak layer drives a continuous plastic zone along the slope front, causing large deformations and instability. To counteract this, the team tested a local reinforcement: inserting support only where the ground is most vulnerable. This reduced the plastic zone to the rear of the sliding mass. After reinforcement, the slope remained stable and safer. The method is not only effective but also costβefficient, offering a practical solution to prevent landslides on gently inclined, weakβlayered mine slopes.
The adopted creep model merges Burgers' viscoelastic response, which captures timeβdependent deformation of complex materials, with the MohrβCoulomb shear strength criterion, defining failure limits based on cohesion and internal friction. Particle Swarm Optimization (PSO) was used to invert model parameters from triaxial compression creep test data on weakβlayer samples. PSO, inspired by bird flock behavior, explores the parameter space with a population of candidate solutions, updating velocities and positions according to fitness criteria. This enables rapid identification of parameter sets that minimize error between experimental data and simulated response. Finiteβelement simulations revealed a continuous plastic zone along the weakβlayer front, marked by high cumulative deformation. The local reinforcement intervention was modeled by inserting consolidation elements (e.g., anchors or cement injections) only in critical zones. Results show a significant reduction of the plastic zone, decreased creep velocity, and increased overall slope safety factor. The methodβs effectiveness is confirmed by the strong agreement between numerical outcomes and field observations, suggesting that targeted reinforcement is an optimal strategy for managing creepβtype slopes with weak interlayers, balancing cost and performance.
