On The Preparation Of Bionic Erosive Media And Tribochemical Wear Behavior Of Marble

Insufficient tunneling efficiency and excessive energy consumption caused by the difficulty of hard rock crushing are bottlenecks that hinder the development of TBM and other tunneling equipment.With the initiation of the Sichuan-Tibet railway project as well as the implementation of state strategy “Going deep into the earth”,a further requirement on the tunnelling efficiency has been put forward on tunnelling equipment.Thus,it is essential to study the high-efficiency removal of rock materials.In fact,there are many rock-eroding organisms in nature,and most of them break rocks through the coupling of mechanical and chemical effects.Therefore,it is necessary to design and prepare bionic erosive media based on the chemical erosion mechanism of the organisms,and improve the mechanical rock breaking efficiency of TBM cutters through the chemical weakening of rock mechanical properties.The results can not only enrich the basic theory of bionic-tribology but also provide certain theoretical support for the research and development of efficient tunneling technology.In this paper,marble was used as the rock sample,surface morphology observation,hardness measurement and reciprocating tribological tests were performed to investigate the effects of two typical biological erosive media including chondroitin sulfate(CS)and carbonic anhydrase(CA)on the surface properties of marble.The ideas of design and preparation of bionic erosive medium were established.On this basis,a bionic erosive media(EP)was designed and prepared,and the influence of EP on the tribo-removal behavior of the marble was studied.The main results and conclusions are as follows:(1)Both of the two bio-erosion media,CS and CA,had the potential to weaken the surface properties of the marble and then make the marble more prone to damage under the action of external loading.However,the destruction efficiency of biological erosive media on marble was low and could not be directly applied to projects such as TBM rock breaking.(2)Based on the rock-eroding mechanism of natural organisms through complexing chemical media,a neutral chemical erosive medium EP for marble was designed and prepared through compound optimization.EP could effectively dissolve the mineral particles in the marble,and a large number of secondary cracks and pits were generated on the rock surface in a short time,leading to a significant decrease in hardness.(3)Under the given reciprocating ball-on-flat sliding wear condition,the tribo-removal efficiency on the marble surface treated by EP for 10 s at 25 °C was three times that on the original surface.The mechanical weakening effect of EP on marble was positively correlated with the corrosion temperature.The hardness of marble decreased by 11.7% after treated by EP for 30 s at 25 °C and by 25.7% after treated by EP for 30 s at 80 °C.The steady-state wear rate of the latter increased by 23% as compared with the former.