Experimental And Numerical Simulation Study On Mechanical Properties Of Lime/Fly Ash Mixed Soil

With the continuous development of engineering technology and applications,more and more materials are used to stabilize soil,and mixed soil is increasingly used in engineering practice.Although many foreign and domestic scholars have also carried out corresponding mechanical properties research on lime fly ash stabilized materials,the current research rarely involves artificial slopes filled with mixed materials such as high fill subgrade slopes stability issue.In view of the huge prospects of the use of lime fly ash in China,the stability study of the subgrade slopes is carried out,and it is expected to bring certain application value to the promotion and use of the later lime fly ash stabilized soil,and improve the slope stability.In this paper,the mixed soil samples with different mixing ratios were produced,and the direct shear and unconfined compressive strength tests were carried out to study the effects of different mixing ratios on the strength of the mixed soil.It can be concluded from the test results that as the content of lime and fly ash increases,the physical and mechanical parameters c and ? of the mixed soil also increase.The compressive strength of the lime-soil test piece with a mix ratio of 10:20:70 is the largest,and the greater the two-ash ratio,the greater the strength of the two-ash soil.As the content of lime and fly ash increases,the compressive strength also increases.The same dose of lime and fly ash,lime has a greater impact on the strength of the mixed soil,while fly ash has no significant effect on the strength of the mixed soil compared to lime.The same test piece model was established and the uniaxial compression numerical simulation of the mixed soil test piece was carried out by FLAC3 D software.It was found that the weighted average method obtained for this type of mixed soil was closer to reality.Comparing the results of the numerical simulation with the experimental results,it is found that the stress-strain curve reached by the numerical simulation is close to the test results,and the variation law is also consistent.However,since the numerical simulation does not consider the influence of water,the simulated value is greater than the experimental value.A roadbed slope model is established,and the numerical simulation of different mixed soil slopes is carried out based on the strength reduction method.The following conclusions can be drawn.The stability coefficient of the limestone slope with the ratio of 10:20:70 is the largest,and the displacement of the lime-soil slope with a mix ratio of 10:30:60 is the smallest.The safety factor of the slope increases with the increase of the lime/fly ash content,and the sliding tendency of the slope gradually decreases.The vertical and horizontal displacement of monitoring point A decreases as the lime/fly ash content increases,and the magnitude of the decrease decreases as the lime/fly ash content increases.Compared with lime,the effect of fly ash is poor.Under the same content,lime has a significant effect on the improvement of slope stability coefficient.