Study On Stability Control Of Surrounding Rock In Deep Large Section Chamber Under Dynamic Load Disturbance

At present,the mining of metal mineral resources is gradually extending to the deep,and at the same time,the underground application of large-scale equipment has led to the emergence of more and more large-section chambers under complex geological conditions;under the complex stress environment formed by the superposition of mining dynamic load disturbance and deep high stress,the stability control of surrounding rocks in deep large-section chambers has become one of the key issues in the mining of deep mineral resources.In this thesis,the No.2 crushing chamber of Baowu Luohe Iron Mine is taken as the engineering background,and the response law of surrounding rock under dynamic load disturbance is studied according to the field vibration monitoring;the dynamic mechanical characteristics of the surrounding rock of the chamber under the dynamic load disturbance are analyzed through the laboratory mechanical test.Numerical simulation was used to reveal the mechanical response and deformation evolution of the surrounding rock of the deep large-section chamber under the dynamic load disturbance;based on the comprehensive research results,a technical scheme for the stability control and support of the surrounding rock of the deep large-section chamber under the dynamic load disturbance was proposed,and carried out engineering tests.The research content is mainly as follows:(1)Under the action of dynamic load disturbance,the failure of the surrounding rock of the deep large-section chamber is essentially: the evolution process of stress superposition mechanics driven by the deep high stress and the dynamic load disturbance.The results of onsite vibration monitoring show that the peak value of the vibration velocity in the Y direction on the surrounding rock of the chamber is the largest under the dynamic load disturbance,and the surrounding rock is prone to tensile failure.Combined with the Sadovsky formula to fit the data,the attenuation law of the peak vibration velocity of the surrounding rock particles of the chamber is obtained,and based on this,the stability and safety criterion of the chamber is established.(2)Under different dynamic load disturbance conditions,the deformation and failure characteristics of the surrounding rock of the chamber are different: the results of the high-stress graded cyclic loading test show that the failure of the rock sample under low-amplitude dynamic load disturbance is mainly tensile fatigue failure;the axial strain of the rock sample increases with the increase of the number of cycles;the elastic modulus increases with the increase of the upper limit stress of the loading,and the change of the dissipated energy per unit volume of the rock sample during cyclic loading generally presents a "decline-stabilization-rise" pattern.Under the action of high-stress cyclic impact,the failure of rock samples under high-amplitude dynamic load disturbance mainly presents the failure form of tensile splitting;with the increase of the number of cyclic impact loads,the overall trend of elastic modulus decreases,the peak stress also showed a decreasing trend,and the maximum strain showed a trend of first decreasing and then increasing.The research results show that the rock sample presents a deformation and failure mechanism of "compaction first and then damage" under the action of cyclic impact.(3)Under the relative static load,the deformation and crack development range of the surrounding rock in the deep large-section chamber is more serious under the dynamic load disturbance,the deformation and stress distribution of the surrounding rock in the large-section chamber are significantly increased,The positions on both sides of the maximum vertical stress on the surrounding rock are further shifted to the deep and cause stress concentration,and the damage depth and influence range of the plastic zone of the surrounding rock on the roof of the chamber suddenly increase.At the same time,according to the influence of different initial static load strength,dynamic load peak strength and dynamic load source distance under the action of dynamic load disturbance,the mechanism of deformation,failure and instability of surrounding rock in deep large-section chambers is obtained.(4)Aiming at the problem of stability control of surrounding rocks in deep large-section chambers under dynamic load disturbance,an optimization technical scheme for the joint support of the roof and floor of the chamber is proposed;Numerical simulation and engineering application verification show that the support optimization technical scheme has a good effect on the stability control of the surrounding rock of the deep large-section chamber under dynamic load disturbance,and effectively ensures the safe and stable production of the No.2crushing chamber.This thesis has 76 figures,18 tables and 95 references.