Study On Mechanical Properties And Rock Brust Mechanism Of Acid Rock Under Combined Static And Dynamic Action

The problem of deep rock mechanics is the focus in the field of rock mechanics and underground engineering.In the exploitation process of deep underground engineering.Redistribution of rock mass stress due to excavation unloading in deep rock.The energy stored in the rock is suddenly released.Resulting in the production of rock burst disaster.Rock burst mechanism is extremely complex.Closely related to the surrounding environment of deep rock mass.In deep underground environment.The deep rock is subjected to the static load produced by high ground stress and the dynamic interaction of engineering disturbance or earthquake.In addition,acidic aqueous solution exists widely in deep underground engineering.Deep rock is immersed in acidic solution immersion corrosion for a long time.Its mechanical properties are completely different from that of shallow rocks.Based on the actual situation of deep underground engineering.In this paper,the mechanical properties and rock burst mechanism of rock under dynamic and static action are studied.Provide reference for rock burst mechanism research and rock burst prediction of deep underground engineering.Firstly.Coring and polish rock by core machine and millstone.Preparation for marble and red sandstone rock specimen.Make 50×25mm and 50×100mm cylinder specimen by cutting machine.Secondly.Dilute the concentrated hydrochloric acid to PH=4 by water.And use PH test pen to test solution PH value.Placed above samples in the acid solution and maintain 30 days.Keeping solution PH value at PH=4 by drop hydrochloric acid after testing PH value every 12 hour.Using universal pressure testing machine to measure uniaxial compressive strength and uniaxial compressive strength of rock.Then carried out the dynamic mechanical test of rock under dynamic and static combination on Hopkinson pressure bar.Use two wave method to process the test data and get the rock dynamic failure stress-strain curve.According to the energy theory,the dynamic mechanism of rock burst is studied.This study draws the following conclusions:1?The uniaxial compressive strength and tensile strength of rock decreased significantly under chemical corrosion.The uniaxial compressive strength decreased more obviously than the tensile strength.The quality of damage of red sandstone is greater than marble.The mechanical properties of marble and red sandstone ratio change is more obvious.2?Under the impact of dynamic load.The dynamic compressive strength of acid red sandstone is far greater than the acidification of marble.And the dynamic compressive strength of red sandstone and marble were increased with the increase of the impact pressure increases.Axial static load and confining pressure can significantly improve the dynamic compressive strength of rock.3 ? Under the action of one-dimensional and three-dimensional static and dynamic combination.With the increase of shock pressure or average strain rate.The broken rock fragments of particle diameter decreased significantly.Showed significant strain rate dependence.4 ? The dynamic compressive strength of acidified red sandstone increases with the absorption energy of red sandstone under the action of static and dynamic combination.And the results show that the rock has no rock burst tendency in this experiment.