The effective early warning of surrounding rock mass deformation is crucial in geotechnical engineering for ensuring the safety and stability of underground constructions.This study introduces a novel risk early warni...The effective early warning of surrounding rock mass deformation is crucial in geotechnical engineering for ensuring the safety and stability of underground constructions.This study introduces a novel risk early warning model based on multi-parameter fuzzy comprehensive evaluation,which quantitatively assesses the risk state of the surrounding rock mass.The microseismic(MS)monitoring system is set up for the underground powerhouse.The spatial and temporal distribution of MS events and the frequency characteristics of MS signals are analyzed during the top arch excavation.The early warning indices for characterizing MS spatial aggregation and frequency-energy dispersion are proposed based on the octree theory to assess the deformation of the surrounding rock mass.The risk warning model for the surrounding rock mass in underground engineering is developed through the integration of the formulated index and the frequency characteristics of MS signals.The results indicate that the multiparameter fuzzy comprehensive assessment model can achieve three-dimensional visualization of risk warnings for the surrounding rock mass.The quantitative results regarding warning time and potential deformation areas are highly consistent with the characteristics of MS precursors.These research results can provide an important reference for early warning of surrounding rock mass risk in similar underground projects.展开更多
The Three Gorges Reservoir area hosts numerous high-risk columnar rock masses,but predicting their full-process of collapse dynamics in narrow-deep terrains remains challenging.This study investigated the Changdongzi ...The Three Gorges Reservoir area hosts numerous high-risk columnar rock masses,but predicting their full-process of collapse dynamics in narrow-deep terrains remains challenging.This study investigated the Changdongzi columnar dangerous rock mass(CCDRM)through field surveys and simulated its collapse dynamics with Material Point Method(MPM),and analyzed the collapse-diffusionsurge generation mechanisms.Field investigations revealed a 0.8 m-thick lotus-like extrusion structure at the base,severely degraded by cyclic water fluctuations,predisposing the rock mass to base-crushing failure.Numerical simulations indicate collapse velocities up to 42 m/s,amplified spreading with a 318 m deposition range and 11 m maximum thickness,and two major collisions causing 50%-60%velocity reduction.Gully topography buffers kinetic energy,retaining 5%debris on slopes and channeling 7%into the river.High-speed river impact generates a 20 m-diameter cavity,producing an 11 m surge,identifying the Guandukou Town waterfront 1.2 km downstream as a high-risk zone.These results clarify the collapse mechanisms of columnar dangerous rock mass and inform its hazard mitigation strategies.展开更多
基金support from the Sichuan Science and Technology Program(Grant No.2023NSFSC0812).
文摘The effective early warning of surrounding rock mass deformation is crucial in geotechnical engineering for ensuring the safety and stability of underground constructions.This study introduces a novel risk early warning model based on multi-parameter fuzzy comprehensive evaluation,which quantitatively assesses the risk state of the surrounding rock mass.The microseismic(MS)monitoring system is set up for the underground powerhouse.The spatial and temporal distribution of MS events and the frequency characteristics of MS signals are analyzed during the top arch excavation.The early warning indices for characterizing MS spatial aggregation and frequency-energy dispersion are proposed based on the octree theory to assess the deformation of the surrounding rock mass.The risk warning model for the surrounding rock mass in underground engineering is developed through the integration of the formulated index and the frequency characteristics of MS signals.The results indicate that the multiparameter fuzzy comprehensive assessment model can achieve three-dimensional visualization of risk warnings for the surrounding rock mass.The quantitative results regarding warning time and potential deformation areas are highly consistent with the characteristics of MS precursors.These research results can provide an important reference for early warning of surrounding rock mass risk in similar underground projects.
基金supported by the Regional Innovation Development Joint Fund of the National Natural Science Foundation of China(U23A2045)the scientific research project of the Chongqing Municipal Bureau of Planning and Natural Resources(KJ-2023046)the scientific and technological project of the Hubei Provincial Bureau of Geological Survey(KJ2024-34)。
文摘The Three Gorges Reservoir area hosts numerous high-risk columnar rock masses,but predicting their full-process of collapse dynamics in narrow-deep terrains remains challenging.This study investigated the Changdongzi columnar dangerous rock mass(CCDRM)through field surveys and simulated its collapse dynamics with Material Point Method(MPM),and analyzed the collapse-diffusionsurge generation mechanisms.Field investigations revealed a 0.8 m-thick lotus-like extrusion structure at the base,severely degraded by cyclic water fluctuations,predisposing the rock mass to base-crushing failure.Numerical simulations indicate collapse velocities up to 42 m/s,amplified spreading with a 318 m deposition range and 11 m maximum thickness,and two major collisions causing 50%-60%velocity reduction.Gully topography buffers kinetic energy,retaining 5%debris on slopes and channeling 7%into the river.High-speed river impact generates a 20 m-diameter cavity,producing an 11 m surge,identifying the Guandukou Town waterfront 1.2 km downstream as a high-risk zone.These results clarify the collapse mechanisms of columnar dangerous rock mass and inform its hazard mitigation strategies.
