Physical simulation and impact analysis of large-scale tailings dam reach based on multi-dource densing monitoring

Liu Yongfeng; Zhang Chao

doi:10.16186/j.cnki.1673-9787.2025030071

Abstract：Objectives An investigation is conducted into the dynamic evolution of pore water pressure and earth pressure during dam breaching in large tailings reservoirs under extreme conditions,as well as the im-pact characteristics and kinematics of released tailings flow,to establish a scientific basis for risk assess-ment and safety control of high-potential-energy tailings reservoirs.Methods Using a large valley-type tail-ings reservoir in Guangdong as the prototype,a high-precision indoor physical model with a geometric simi-larity ratio of 1∶100 was constructed,and a multi-source sensing and monitoring system was innovatively in-tegrated.The experiment simulated a dam-breach scenario induced by extreme rainfall with a 500-year re-turn period leading to overtopping,and systematically recorded the entire process from impoundment and overtopping through breach initiation and enlargement to eventual failure.Results The results indicate that:(1)Pore water pressure exhibits a three-phase evolution pattern:stepwise increase during impoundment,abrupt drop during breaching,and gradual decrease during the dissipation-with the dissipation rate near the dam being 40%faster than at the the reservoir tail.(2)Earth pressure responds most strongly in the fore-dam region,reaching a peak of 13.6 kPa before decaying linearly,while remaining stable in the middle and rear sections,indicating spatial non-uniformity in the breach influence zone.(3)Breach dis-charge is nonlinearly and positively correlated with the instantaneous sediment detachment.The maximum breach volume reached 2.4 million m³,equivalent to 48.7%of the prototype's total storage,with a peak breach velocity of 2.6 m/s.(4)The velocity distribution of the released tailings flow is controlled by terrain roughness:mid-channel velocity shows a"hump-shaped"profile,which evolves into a"double-hump"pat-tern with increasing discharge;transverse to the channel,the velocity is"fast in the center,slow on the sides"and peak vorticity is positively correlated with terrain roughness.Conclusions The proposed"double-hump velocity model"reveals the flow regime and vorticity evolution of tailings slurry release under com-plex topography,offering a new theoretical tool and technical support for predicting downstream hazard ex-tent,assessing impact forces,and designing protective works for tailings reservoirs.