Mechanical Response And Damage Of Roadway Composite Surrounding Rock And Structure Under Coupling Of High Prestress And Dynamic Impact

With the continuous enrichment of shallow roadway research,the superposition stress of high ground stress and dynamic impact and the transient unloading of ground stress gradually come.Structural changes and stress evolution of roadway caused by high prestress and dynamic impact are very complex,showing nonlinearity,variability and uncertainty.Therefore,the study of stress distribution and damage of deep composite structure roadway under dynamic impact has important engineering significance to guide deep roadway mining and explosion-proof design.This thesis mainly studied the mechanical response and damage of composite structure roadway surrounding rock under coupling of prestress and explosion loading:fine modeling of the deep composite structure roadway was built,mechanical response of roadway surrounding rock was studied under explosion loading,and damage of roadway surrounding rock was characterized according to mechanical response and evolution.According to mechanical response and damage,supporting of roadway surrounding rock was targeted.Based on finite element numerical simulation software ANSYS LS-DYNA and SHPB(Split Hopkinson Pressure Bar),mechanical response and damage of composite structure roadway surrounding rock under prestress and explosion loading were studied.Secondary stress is formed by prestress redistribution after roadway excavation.Partial stress relaxation zone appears in the process of stress redistribution on both sides of roadway,and stripe cracks appear due to uneven stress distribution.With the increase of prestress,prestress damage and displacement of roadway surrounding rock increase.Under coupling of explosion loading and in-situ stress,stress evolution of roadway surrounding rock can be divided into three stages: initial stress concentration,stress concentration expansion and local stress unloading.As a whole,explosion loading and prestress of roadway surrounding rock show positive correlation in space,while as for roadway surrounding rock unit,prestress shows numerical negative correlation and inhibition.These results show that displacement of roadway surrounding rock increases with increase of stress,prestress of roadway surrounding rock and displacement show positive correlation and consistency in space and unit particle;stress curves of roadway surrounding rock and composite coal-rock appear bimodal under prestress.Damage of composite structure roadway surrounding rock under the action of prestress and explosion impact can be divided into four stages: prestress damage,instantaneous damage expansion,surrounding rock fracture damage and post-peak unloading dilatancy damage.Damage of roadways urrounding rock is consistent in space and element,and element damage promotes space damage(post-peak unloading dilatancy damage).Damage of roadway surrounding rock is intensified under prestress and explosion loading.Coupling damage is found and tested by SHPB test.Damage of roadway surrounding rock under coupling of explosion loading and in-situ stress can be divided into prestress damage,blasting damage and unloading damage according to causes,showing a domino type damage chain and great harm.According to causes of damage,a variety of support methods are selected for comprehensive support so that roadway stability can be maintained.These results have a certain scientific value to enrich and improve rock damage theory,and have important engineering significance to guide design of roadway explosion-proof and disaster resistance.In addition,during the degree period,two related academic papers were published,including one EI and one SCI.There are 54 figures,7 tables and 94 references in this thesis.