Research On The Curing Effect Of Coal-gas Wastewater Contaminated Aeolian Sand

The coal gasification industry in Inner Mongolia desert region discharged a large amount of waste water in the production process,which made the soil be polluted.In order to treat the sandy soil polluted by coal gas wastewater in this area,the solidification method was adopted to treat the polluted sand soil.Based on the study of the unconfined compressive strength and resistivity characteristics of solidified compounds with the change of pollutant content and age,combined with the physical changes of solidified compounds,the influence of pollutant content and age on curing effect and its mechanism are analyzed.Mathematical model of unconfined compressive strength and resistivity of sand contaminated with coal gas wastewater.Considering the influence factors of temperature in North China,polypropylene fiber was introduced as admixture to investigate its effect on freeze-thaw resistance of cured compounds.The research results provide a certain basic data for the solidified soil as the building material of the shallow foundation,so as to achieve the purpose of the two use of the contaminated soil.The main research results of this topic are as follows:1.The unconfined compressive strength and resistivity of solidified compounds decrease with the increase of pollutant content and increase with the increase of age.The pollutant content of 20000mg·kg^-1is a threshold of unconfined compressive strength and resistivity of solidified compounds.The content of humic acid below the threshold value will not affect the unconfined compressive strength and resistivity in the early stage of solidified contaminated soil.With the increase of age,the influence of humic acid content on the unconfined compressive strength and resistivity of solidified contaminated soil is more obvious.The humic acid content above the threshold value will seriously hinder the hydration reaction of cement,the strength will decrease,the resistivity will decrease,and with the increase of age,the strength will increase very slowly,and the resistivity will increase slowly.2.The change trend of the resistivity of the solidified compounds with the influencing factors is similar to that of the unconfined compressive strength.Based on the fitting results of unconfined compressive strength and resistivity with influencing factors.It is proved that the resistivity method is also applicable to the contaminated soil of coal gas wastewater3.Establish a mathematical model of unconfined compressive strength-resistance to provide a non-destructive testing method for cement-soil mixing piles,and infer the strength of the pile material.4.Pollution has a bad effect on the freeze-thaw resistance of polypropylene fiber solidified compounds.With the increase of the content of pollutants,the effect of degradation is greater.When the content of pollutants exceeds the content of20000mg·kg^-1,The freezing and thawing resistance of solidified contaminated soil will not deteriorate with the increase of humic acid content.The effect of pollution on the freezing and thawing resistance of cured compounds was effectively inhibited by adding polypropylene fiber,and the optimum content of polypropylene fiber was 0.4;5.Study on the influence of various factors on moisture content,Volume change rate and density of cured compounds.The water content and volume change of solidified compounds were positively correlated with the pollutant content,and the density was negatively correlated with the pollutant content.The volume change rate and density of the cured compounds were positively correlated with the age,and the moisture content was negatively correlated with the age.