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Northwest A&F University (2019)

Experimental Investigation of Microbial Solidification of Aeolian Sand

张世参

Titre : Experimental Investigation of Microbial Solidification of Aeolian Sand

Auteur : 张世参;

Grade : Master’s Theses 2019

Université : Northwest A&F University

Résumé partiel
Aeolian sand is mainly distributed in arid and rainless desert areas.It is a kind of special soil with loose structure,fine and uniform particles,poor self-stabilization ability and not easy to compact.It should be reinforced when it is used as building foundation.Therefore,the reinforcement technology of aeolian sand is an important research topic.Microbial induced calcite precipitation(MICP)is a novel microbial soil-strengthening technique.In this paper,microbial-induced calcium carbonate precipitation technology and Bacillus pasteurium are used to reinforce aeolian sand,which can provide technical support for the engineering application of aeolian sand.(1)Using Sporosarcina pasteurii and cementing solution(mixed solution of urea and calcium chloride)by microbial induced calcium carbonate deposition(MICP)technology,calcium carbonate crystals with cementation effect can be formed between aeolian sand particles,effectively solidifying aeolian sand,improving the strength of aeolian sand,and improving the engineering performance of aeolian sand.(2)The injection rate of the cementing solution had a significant effect on the uniformity of the solidified aeolian sand.When the injection rate of the cementing solution was 0.278mol·L-1·h-1,the solidified aeolian sand sample was relatively uniform,and the calcium carbonate generated in the sample was evenly distributed,and the solidified aeolian sands have moderate unconfined compressive strength between 4.585.03MPa.The texture of solidified aeolian sand samples is relatively uniform.(3)The more calcium carbonate crystals are formed on the surface and pore of aeolian sand particles by MICP technology,the greater the density of solidified aeolian sand,the smaller the permeability coefficient and the greater the unconfined compressive strength.The permeability coefficient of the solidified aeolian sand gradually decreased from1.08×10-3cm/s of the original sand to 1.67×10-5 cm/s.The maximum unconfined compressive strength reached 14.01MPa.Unconfined compressive strength increases with the increase of calcium carbonate content,and the two are positively correlated.(4)Layered consolidation can effectively increase the volume of cemented aeolian sand.T

Mots clés : aeolian sand; microbially induced calcium precipitation; solidification; sporosarcina pasteurii; engineering mechanical properties;

Présentation (CNKI)

Page publiée le 18 mai 2020