Experimental Study On Durability Of SH And Lime Reinforced Loess

Chinese loess distribution is of width and thick,and the stratum of loess is relatively complete.Applied to a large number of loess works,such as roadbed engineering,slope engineering,channel engineering and so on,the loess needs to be studied further and improved,so as to achieve the ideal engineering properties.Due to the special geographical and climatic conditions in the northwest region,many loess structures have been subjected to freezing,thawing and wetting,the damage caused by these natural environmental factors need to be improved.At present,loess improver has inorganic,organic,ionic and biological enzymes four kinds,the reinforcement effect of each has their own strength.Before reinforcement,it must be clear the purpose,and it is necessary to have a correct understanding of the reinforcement effects.When a single curing agent itself is deficient,it is possible to select two kinds of complementary modifiers to improve the loess.In this paper,a new type of organic curing agent SH combined with hydrated lime was used to improve loess,and the basic strength characteristics,quality,volume,unconfined compressive strength and microstructure changes of the improved soil were studied after freeze-thaw and dry-wet cycles,the results show that:1.the curing agent SH and the lime can increase the unconfined compressive strength of the loess respectively.Lime has a significant effect on strength enhancement.When the SH and lime strengthen loess at the same time,with the increase of the SH concentration,the strength of the soil which enhanced by different amount of lime begin to decrease,and the growth slows down when the SH concentration is 1.5%.2.repeated freeze-thaw cycle test makes the quality of soil sample block gradually reduced,unconfined compressive strength decreased.Compared with SH,lime has better effect to keep the integrity of particle skeleton and to reduce the loss of unconfined compressive strength.When the samples were mixed with SH,the strength reduction rate decreased gradually after 5 times of freeze-thaw cycle.3.repeated wet and dry cycle test makes the mass of soil sample block gradually reduced and unconfined compressive strength decreased.Compared with lime,SH has better effect to keep the integrity of soil pore structure.On the contract,lime has better effect on the maintaining of soil strength.And the higher the dosage,the greater the strength.4.Based on the comprehensive evaluation index,the experimental results show that the compressive strength and durability of the samples show great popularization prospect in practical engineering application.when the concentration of curing agent SH is 1.5% and the lime content is 6%.