Study On Mechanics And Fatigue Properties Of Open-pit Mine Road Based On Geopolymer Modification

The roads inside the open-pit coal mine are mostly clay bound macadam pavement,and the road quality is low.The use of Geopolymer Materials to rebuild the original pavement can effectively use solid wastes such as slag and fly ash,and improve the problems of road dust pollution and driving safety hazards.Through the indoor mechanical property test,the compressive strength and shear strength of samples with different ratios are explored.On this basis,the fatigue performance is studied and the corresponding fatigue life equation is obtained.The optimal ratio is selected by analytic hierarchy process,and the on-site road construction of the mine is carried out.The main research work of this thesis is as follows:According to the initial test design,A8,A11 and A14 are selected for uniaxial compression test and variable angle shear test.The compressive strength of group A8 samples was 15.54 MPa after seven days of curing,and increased to 39.45 MPa after 28 days of curing;Compared with group A8,the strength of group A14 was increased by25% sodium hydroxide solution and 25% sodium silicate.The strength was 20.28 MPa after seven days of curing,30.5% higher than that of group A8,and 42.37 MPa after 28 days of curing,7.4% higher than that of group A8;Compared with A14 group,the proportion of fly ash in a11 group is increased.The compressive strength of A11 group is 14.9MPa after seven days of curing,which is 26.53% lower than that of A14 group.The compressive strength of A11 group is increased to 36.41 MPa after 28 days of curing,which is 14.07% lower than that of A14 group.The shear strength of samples with the same ratio shows a decreasing trend with the increase of shear angle.The shear strength of A14,A8 and A11 samples under the same shear angle gradually decreases,the cohesion gradually decreases,and the internal friction angle is approximately the same but increases.With the decrease of the maximum stress level in the fatigue test,the fatigue life of the sample shows an upward trend under the same ratio;The displacement of samples increases with the increase of fatigue cycle.The displacement change rate of stage I and stage III of samples with the same ratio is the same,and the displacement change rate of stage II increases with the increase of maximum stress level;When the specimens with different proportions are tested at the same maximum stress level,the displacement change rate of stage I and stage III changes with the change of proportion,and the displacement change rate of stage II changes with the change of maximum stress level.The fatigue equation of A11 group of samples is Smax =-0.0583 lgn +1.0035.The fatigue life data of A8 and A14 groups of samples under three different stress levels come from the same population,and the fatigue equation can be expressed as Smax =-0.0703 lgn + 1.1163.In the three groups of test proportions designed in this thesis,the content of fly ash leads to the reduction of the fatigue life of the sample,and the content of alkali activator has no effect on the fatigue life of the sample.Through the analytic hierarchy process,taking the A8,A11 and A14 ratio as the research object,analyze the final weight relative to the overall goal and sort the order.Taking the on-site road of Yimin open pit mine as the background and the A14 ratio as the basis,a geopolymer mine road construction technology based on cold regenerator is proposed.The on-site coring was carried out for the road two years after opening to traffic,and the residual compressive strength was measured to be 12.47 MPa.The thesis has 59 figures,38 tables and 67 references.