Study On The Instability Mechanism Of Rock Mass Induced By The Micro-molecular State Change

China's coal mine's new excavation of sinking and driving engineering is about 25,000 km every year,the roadway roof long-term safety and security is particularly important,Statistics in recent years about Huainan and Huaibei coal mine more than 40 mines from the roof and about 28 accidents,mud roadway roof anchorage instability collapse rate of 46.4%,which occurred in faults,crushing zone,weak interlayer,hydrated mudstone and other special conditions.When the rock layer is absorbed by water and mud,the integrity of the rock formation is damaged,the strength of the surrounding rock is obviously attenuated with time,the difficulty of roadway maintenance is increasing,The mechanism of destabilizing disaster,the analysis of key influencing factors and the safety control become one of the difficult problems in coal mine roadway support.This paper analyzes the mechanical properties of the mudstone deformation and the constitutive equation of the Guobei coal mine.In this paper,the mechanical characteristics and the constitutive equation of the deformation of the mudstone are studied by means of theoretical analysis,numerical simulation,indoor experiment and field observation.The main clay composition type and the microstructure change characteristics of the mudstone in the 8106 roadway were studied.The molecular dynamics of the surface hydration of the kaolinite mudstone was simulated.At the same time,the surrounding rock was strengthened and the roadway was deformed Get some control.The following main conclusions are obtained:(1)The basic physical and mechanical properties of the mudstone are elucidated,and the experiment of the mudstone water content change is carried out according to the experiment and the specific situation of the 8106 machine lane.The relationship between the cohesion force C and the internal friction angle ? and the water content W Through the use of elasto-plastic theory and the elastic theory to establish a constitutive equation to reflect the essential relationship between the nonlinear volume strain of mudstone.(2)The immersion characteristics of microstructures(including cementation,granules,porosity,etc.)during the hydration process of mud-fractured rock mass were carried out respectively.The SEM observation of different rock samples under different water conditions was carried out.The microstructural characteristics of mudstone were studied.(3)The molecular dynamics simulation of the surface hydration of kaolinite particles was carried out by using Material Studios(MS)software.The kaolinite mudstone and the mudstone of typical montmorillonite were analyzed and analyzed.The mechanism of action is different,obtained kaolinite and other cosmids encountered water,although the unit cells are not allowed to enter the water molecules.But its cosmid surface has free valence atoms and ions,these atoms or ions with electrostatic attraction,in the clay surface to form electrostatic gravitational field.The water molecule is a dipole,one end is a positive charge,one end with a negative charge,can be attracted by electrostatic attraction.So close to the surface of the clay particles close to the water,neatly arranged conclusions.(4)The verification and industrial test of the seepage and cementing roadway in the 8106 machine tunnel of Guobei Coal Mine in Huaibei Mining Area were carried out,and the control effect of roadway was good,which indicated that the control technology was selected properly,which effectively guaranteed the normal use of roadway and achieved good Economic and social benefits.