DEM contact model construction method capable of reflecting weakening of seepage to rock-soil mass strength

Abstract

The invention provides a DEM (Digital Elevation Model) contact model construction method for reflecting weakening of seepage to rock-soil mass strength, which comprises the following steps: selectinga filling body in a disaster-causing structure to obtain a change rule of accumulated loss amount of the filling body along with time under the action of seepage and a change rule of mechanical parameters of the filling body along with the loss amount of the filling body; carrying out test simulation, and determining a relation function of each group of corresponding mesomechanics parameters in each time period and DEM contact model mesomechanics parameters capable of representing the change rule of the macromechanics parameters of the filling body; embedding each mesoscopic parameter relationfunction into an existing particle contact model, carrying out test simulation, and updating the fracture failure criterion of the contact model according to the corresponding relation of macro-mesoscopic strength when the model is damaged, so as to realize the simulation of the continuous weakening process of the filling body strength; and based on an indoor seepage failure test, establishing aseepage failure discrete element calculation model, and simulating the seepage failure process of the rock-soil body by adopting the obtained particle contact model and the fracture criterion thereof.

Description

technical field [0001] The invention belongs to the field of underground engineering, and in particular relates to a method for constructing a discrete element particle contact model for describing the continuous weakening effect of seepage on rock and soil strength in the process of tunnel water inrush. Background technique [0002] Water inrush disasters caused by strong water abundance, strong structure, strong karst and high ground stress are one of the main threats to the construction of tunnels in the western mountainous areas of my country, where the terrain is steep, the canyons are deep, the karst is developed, and the geological structure is extremely complex. Among them, the seepage-destructive water inrush has the characteristics of large flow, strong suddenness, and strong destructiveness. Once a disaster occurs, it will cause heavy casualties, economic losses, and delays in construction schedules. Due to the extremely complex dynamic evolution process of water ...

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Problems solved by technology

[0005] However, the contact model of the discrete element method can only reflect the basic mechanical properties of rock and soil under certain conditions, but it is difficult to reflect the evolution of its mechanical properties during the disaster.

Taking the evolution process of tunnel seepage damage inrush disaster as an example, due to the erosion effect of seepage on rock and soil, its shear strength shows a nonlinear decrease trend with the loss of cohesive soil or fine particles, while the existing discrete In the meta-particle contact model, the bond strength is set to a fixed value, and the non-linear reduction process of bond strength caused by groundwater seepage is not considered

Therefore, the application of existing models cannot truly simulate the weakening of filling body strength in the process of seepage failure evolution.

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