Extension and application of Discontinuous Deformation Analysis with a damped contact spring model

Abstract

Discontinuous Deformation Analysis (DDA) is widely used in geological and geotechnical engineering. To provide an alternative approach to considering damping effect in dynamic analysis, a damped contact spring model is implemented. The model assumes that the damping component – linear dashpot - takes place in joints of DDA models. The normal and shear damping forces are determined according to the relative velocities of the two contacted points. A semi-analytical solution is also proposed to calculate damping coefficient from a given damping ratio. The viscous damping effect produced by the damped contact spring model is independent to step size. The proposed model is incorporated into DDA program, and then several classic damping dynamic examples are constructed to validate the contact model, showing good agreement with analytical solutions. After that, a seismic spectrum of a recorded ground motion is analyzed to show the contact model is suitable for response spectrum generation. Finally, the Donghekou landslide case is studied under different parameters, suggesting that the proper consideration of damping is essential to natural hazard analysis.