The Stability Of Magnesium Phosphate Cement Solidified/Stabilized Cu-contaminated Soils Under Freezing And Thawing Cycles

With the rapid advancement of urbanization and industrialization in China,problems such as environmental pollution,resource scarcity and ecological destruction are imminent.Among them,the problem of heavy metal contaminated soil has become a topic of great concern to experts and scholars in the field of environmental geotechnical and engineering fields.The method of repair and processing.At the same time,in the northern part of China,there is often a problem of frozen soil.The change of freeze-thaw cycle may change the strength of solidified soil and the long-term chemical stability of heavy metal ions.The authors solidified copper contaminated soil by artificially prepared magnesium phosphate cement,and under the action of freezing and thawing cycles,the freeze-thaw cycle test was carried out by changing the number of freeze-thaw cycles,the amount of magnesium phosphate cement and the initial copper ion concentration in contaminated soil.Unconfined compressive strength test,toxic leaching(TCLP)test and scanning electron microscopy(SEM)test,explored the strength,leaching and microstructure of copper phosphate cement cured copper contaminated soil under freeze-thaw cycles.Stability.The specific research contents are as follows:(1)Analysis of the unconfined compressive strength values of copper-contaminated soil solidified by magnesium phosphate cement under the action of freezing and thawing cycles,and analyzing the number of different freeze-thaw cycles(3,6,9,12 times)and different magnesium phosphate cements(S5,S10,S15,S20)and the influence of initial copper ion concentration(Cu0,Cu0.1,Cu0.5,Cu1.0,Cu2.0)on the non-lateral line compressive strength and the variation mechanism.(2)Study on the effect of freezing and thawing cycles,the amount of magnesium phosphate cement and the initial copper ion concentration of contaminated soil on the concentration of Cu2+in the leachate under the action of freeze-thaw cycle by the leaching test of magnesium phosphate cement.China's toxicity identification standard GB5085.3-2007,to explore the curing effect of solidified soil under the action of freezing and thawing cycles.(3)The effects of freezing and thawing cycles,the amount of magnesium phosphate cement and the initial copper ion concentration of contaminated soil on the microstructure of solidified contaminated soil of magnesium phosphate cement were analyzed by scanning electron microscopy.The mechanism of the properties of solidified contaminated soil was analyzed qualitatively.