Macro And Micro Experiment Study On The Influence Of The Consolid System On The Engineering Properties Of Loess

Loess is widely distributed in our country,but its special engineering properties have brought great challenges to engineering construction in loess areas.Traditional lime and cement show obvious shortcomings.The Consolid System is produced in Switzerland,including powder SD and liquid C444,which can strengthen the protection of soil and are tested as environmentally friendly products.The main research results are as follows:(1)Through the unconfined compressive strength test of modified loess by the Consolid System,lime and cement,the stress and strain relationship and unconfined compressive strength under the same moisture content and dry density,different curing agent content and curing time are obtained.And based on BP neural network to establish an unconfined compressive strength prediction model of modified loess by the Consolid System.Tests show that the stress-strain curves of modified loess are all strain-softening,and the strength of modified loess by the Consolid System is positively correlated with curing time.At a higher curing time,a higher curing agent content can significantly increase the strength of the modified loess.When the curing time is short,the strength will first increase and then decrease;The strength of modified loess by the Consolid System is always less than that of cement-modified loess,and its early strength is greater than that of lime-modified loess.In the later period,the strength of modified loess by the Consolid System with high content is greater than that of lime-modified loess;The strength prediction model can better predict the strength of the modified loess.(2)Disintegration test,water stability coefficient test,water drop infiltration test and variable head infiltration test are carried out by the Consolid System,lime and cement modified loess,obtain the disintegration phenomenon,water stability coefficient,water infiltration time and permeability coefficient under the same moisture content,dry density and different curing agent content.The test shows that the Consolid System can improve the disintegration resistance,water repellency and impermeability of loess.With the increase of the curing agent content,the water stability coefficient and water infiltration time show an increasing trend,while the permeability coefficient is opposite;The disintegration resistance,water stability coefficient and impermeability of modified loess by the Consolid System are always better than lime-modified loess and worse than cement-modified loess.In terms of water repellency,modified loess by the Consolid System is much higher than cement and lime modified loess.(3)Through scanning electron microscopy test and nanoindentation test on the modified loess by the Consolid System,the changes of the microstructure and elastic modulus of the modified loess are obtained.The test shows that the Consolid System makes a certain change in the microstructure of the loess.With the increase of the curing agent content,the total area and average area of the pores have been greatly reduced,the proportion of large,medium and small pores has been continuously reduced,and the proportion of micro pores has become larger;The change of the microscopic modulus of elasticity of modified loess by the Consolid System with the content of curing agent and curing time is basically consistent with the change of unconfined compressive strength.(4)The liquid C444 can cause certain damage to the water film of the diffusion layer on the surface of the particles.The powder SD can cement the soil particles and fill the pores between the particles,and has extremely strong water repellency.Under the combined action of the two,the contact between particles is changed from point contact to surface contact,which makes the strength,disintegration resistance,water repellency,impermeability,and meso elastic modulus of the modified loess correspondingly changed.