Research On Coupled Continuum-discrete Analysis Method And Damage Characteristics Of Rock Pillar In Deeply Buried Small Spacing Roadway

In our country' s traffic engineering and mining engineering,there are often small spacing tunnels arranged due to the impact of special environmental conditions.These tunnels are susceptible to large deformations,damages and even collapses on account of the impact of adjacent projects.The analysis of the stability of the small spacing tunnels and the rock pillars has important engineering significance.Based on the mudstone strata roadway engineering of a coal mine in North China,Using numerical simulation tools such as FLAC3 D,PFC3D,etc.,study the stress redistribution mechanism and spatial displacement and deformation law of adjacent roadway surrounding rock and rock pillars during the excavation of deep buried roadways with small spacing from a micro perspective.With certain results,the following conclusions are obtained:(1)Based on the theory of Proctor's pressure arch and previous research results,this paper discusses the mode of surrounding rock load of small spacing tunnel and the calculation formula under the condition of shallow and deep buried.At the same time,according to Wilson's theory,the discriminant of rock column strength failure is obtained.When the actual load on the rock column is greater than the ultimate load strength of the rock column,the rock column is likely to be damaged.(2)Macro meso parameter matching is one of the key steps in the application of continuous discrete coupled numerical simulation.In this paper,the control variable method is used to study the relationship between the macro mechanical parameters of mudstone and the micro parameters of particle flow.The sensitivity of macro parameters such as uniaxial compressive strength,elastic modulus and Poisson's ratio to the micro parameters is found out,which provides a certain reference for the calibration of micro parameters of engineering scale continuous discrete model.(3)On the basis of the above results,the meso parameters of engineering scale rock mass model are calibrated,and the continuous discrete numerical simulation method is used to analyze the influence of deep buried small spacing roadway excavation on adjacent roadway and rock pillar from the aspects of stress,displacement and damage area.The results show that when the roadway spacing is greater than or equal to 1.2B,the stress fluctuation of rock pillar is relatively slow,the displacement values of vault and floor of the two roadways are about 20?30mm,and the damage of roof and floor is small,only a small amount of tensile damage occurs on both sides of the roadway,and the simulated spacing of two roadways with small spacing should be greater than 1.6B.