Theoretical Study On Damage Constitutive Model Of Karst Roc

Guizhou Province is a typical ’ mountain terrain + karst landform ’ area,karst landform area accounted for 60 % to 80 %.The mining and supporting schemes are affected by the rock mechanics parameters of mine strata,and the rock strength of carbonate rock in karstification area is dynamically affected by karstification.Based on the problem that the strength of carbonate rock is affected by karstification,the damage constitutive equation of karstified rock is studied.By using the research methods of physical test,numerical simulation and theoretical analysis,the uniaxial compression numerical simulation model of karst rock is established,and the damage constitutive equation of karst rock is constructed.The following conclusions are obtained:(1)Based on the actual geological situation of Yingping Mine in Wengfu,the influence of working face mining on the roof of carbonate rock under different karstification is simulated.The results show that it is not the most reasonable method to design the mining method affected by the dynamic strength of carbonate rock by the static strength of carbonate rock.(2)The exploratory experiment of dolomite karstification was carried out,and it was determined that the moisture content reached saturation after dolomite was soaked in water for two hours.The optimal concentration of acid solution in the simulated karst process was 1 %,which ensured that the experiment continued to determine that the optimal replacement time of acid solution was 2 hours.(3)Uniaxial compression tests are carried out on karstified dolomite specimens;Two different numerical simulation softwares were used to simulate the uniaxial compression of dolomite specimens under natural conditions and affected by karstification,respectively,and the physical experimental results were verified.(4)Based on damage mechanics,Lemaitre strain equivalence principle and its promotion,the damage caused by karstification is subdivided into pore structure damage and water content damage in physical parameters,and the overall damage variable of karstified dolomite is deduced,and the damage constitutive equation of karstified dolomite is established.The research results of this paper can provide theoretical reference for mining and support scheme optimization in karst mountainous areas.