Simulation of the fragmentation and propagation of jointed rock masses in rockslides: DEM modeling and physical experime
- PDF / 7,158,053 Bytes
- 17 Pages / 595.276 x 790.866 pts Page_size
- 19 Downloads / 174 Views
Qi-wen Lin I Qian-Gong Cheng I Yu Xie I Feng-shou Zhang I Kun Li I Yu-feng Wang I Yuan-yuan Zhou
Simulation of the fragmentation and propagation of jointed rock masses in rockslides: DEM modeling and physical experimental verification
Abstract Rockslides are among the most dangerous geohazards. The discrete element method (DEM) has been increasingly used to simulate the emplacement process of rockslides. However, few studies have modeled the fragmentation of jointed rock masses during movement via DEM simulations and verified the reliability of the results through comparison with the results of laboratory experiments and field events. In this paper, a series of DEM simulations based on PFC3D5.0 was conducted to replicate laboratory experiments in which breakable blocks with different structural forms impact and slide on a horizontal plane and experience fragmentation. The results show that the DEM model provides first-order estimates that are comparable with the results of experiments in terms of the kinetic features and depositional characteristics of rockslides, including crack propagation, velocity distribution, preservation of source stratigraphy, progressive fragmentation, and spreading of fragments. Conversely, the normalized horizontal runout and degree of fragmentation are poorly represented in the DEM model. A theoretical analysis is further conducted to discuss the causes of travel distance discrepancy between the DEM model and experiments. It is found that the inconsistency of fragment interactions caused by the defect of the fragmentation process in DEM simulation may take primary responsibility. An alterable restitution coefficient method based on the rock mass fragmentation process is proposed for application to the fragmenting rock mass movement in DEM simulation, with the utilization of additional laboratory experimentation as the calibration benchmark. Further verification of our method needs to be performed in the future. Keywords Rockslides . Discrete element method . Fragmentation process . Laboratory experiments . Deposit characteristics Introduction Rockslides are among the most dangerous geohazards (Kelfoun and Druitt 2005); they usually have a volume larger than 106 m3 and a velocity of > 20 m/s, which is far beyond the speed of human escape (Hungr et al. 2014). These hazards often occur in large mountain belts, threatening lives and infrastructure in local communities. Many efforts have been made to investigate the causes, triggers, movements, and consequences of rockslides over the past several decades (Korup et al. 2010; Weidinger and Korup 2014). However, the dynamic mechanisms of rockslides are still largely unknown (Legros 2002), which greatly hinders disaster risk assessment. With the development of computer technology and improvements in computing ability, numerical simulation has become an important method to study the propagation of rockslides (hereafter, propagation simply represents the entire movement process of
a rockslide from rock mass failure to its emplacement). The discr
Data Loading...
