摘要
以铜矿采空区大型冒落体冲击隐患为研究背景,基于Hertz接触力学理论,建立了考虑垫层弹塑性效应、垫层厚度、垫层孔隙率的冲击力理论修正计算模型。依据该理论公式,分析了各影响因素的敏感性,进一步以案例形式分析了采空区大型冒落体冲击载荷下有效合理的垫层厚度。结果表明:(1)垫层厚度缓冲效应较弱,垫层孔隙率缓冲效应、垫层强度缓冲效应较强,即增大垫层厚度,冲击力降幅较低,而增大垫层孔隙率和减小垫层弹性模量可有效降低冲击载荷;(2)垫层厚度缓冲效应在较小冒落体质量、较低垫层材料强度、较大落体冲击速度、较大垫层孔隙率情况下表现较强,反之,则较弱;(3)冲击力随冒落体冲击质量、冲击速度增大增幅显著,冲击速度对冲击力大小的影响有一定限值,一旦超过该极限,冲击力不再增大;(4)考虑矿柱简化为固支梁和简支梁两种情形,得出垫层有效厚度分别为8.5 m和17.5 m,综合考虑两种简化模式,确定碎石垫层厚度不应小于17.5 m。研究成果可以为大型采空区设置合理结构垫层防治动力冲击灾害提供理论依据。
A one-dimensional geometric model is developed for the impact of falling rock mass on a substructure along an inclined orebody.This model simplifies the caving rock mass as a longitudinal cylinder of infinite length along the orebody and considers the rock cushion as an infinitely ideal elastic-plastic body.Drawing on Hertz elastic contact mechanics theory,a modified theoretical calculation model for impact force is established.This model integrates factors such as elastic-plastic effects,cushion thickness,and porosity.The influences of cushion thickness,elastic modulus,porosity,falling rock mass,and impacting velocity on dynamic loading are analyzed using the sensitivity of each factor relative to the others through the new theoretical model.Additionally,by simplifying the pillar under the cushion as a deep beam and integrating bulk stress diffusion theory with classical tensile fracture strength theory from material mechanics,the effective and reasonable cushion thickness protecting goaf pillars from damage under the impact of large falling bodies,using metal mines as a case study,is examined.The results indicate that the cushion thickness has a weak buffering effect,while the porosity and strength of the cushion exhibit strong buffering effects.Specifically,an increase in cushion thickness leads to only a slight reduction in impacting force,whereas higher porosity and lower cushion elastic modulus effectively reduce impacting loading.The buffering effect of cushion thickness is stronger for smaller caving masses,weaker cushion materials,higher impacting velocities,and greater porosity;otherwise,it diminishes gradually.Impacting force increases notably with greater mass and velocity of falling bodies,yet impacting speed imposes a limit on force increase—once exceeded,impacting force stabilizes.Based on simplified pillar models of fixed and simply supported beams,the deduced effective cushion thicknesses are 8.5 m and 17.5 m respectively.Comprehensive analysis suggests that the gravel cushion thickness should not be less than 17.5 m.
作者
董川龙
祝洪刚
张飞
宁掌玄
杨东辉
雷利兴
DONG Chuanlong;ZHU Honggang;ZHANG Fei;NING Zhangxuan;YANG Donghui;LEI Lixing(School of Coal Engineering,Shanxi Datong University,Datong 037003,Shanxi,China;Inner Mongolia Mining Development Limited Company,Hohhot 010020,China;Institute of Mining Research,Inner Mongolia University of Science and Technology,Baotou 014010,Inner Mongolia,China)
出处
《安全与环境学报》
CAS
CSCD
北大核心
2024年第9期3439-3448,共10页
Journal of Safety and Environment
基金
山西省基础研究计划项目(202203021212489)
山西大同大学基础科研基金项目(2022K26)。
关键词
安全工程
Hertz理论
缓冲垫层
冲击载荷
修正算法
safety engineering
Hertz theory
buffer cushion
impacting loading
modified algorithm
