Study On Curing Method And Strength Characteristics Of Copper Polluted Soil

With the rapid development of industrialization, the phenomenon of heavy metal pollution has become more and more serious. The problem of copper contamination was rather prominent, not only caused harm to human health and ecological environment, but also seriously affected the construction of the project. Therefore, it is an urgent need for the development of China’s social development and environmental geotechnical engineering to carry out the research on the basic properties of copper contaminated soil, and to combine with the engineering practice.In this paper, the strength variation of copper contaminated soil under three different curing methods was studied through experiments of cement, cement with fly ash and cement mixed with lime, then the further discussion of the various factors affecting the strength development was carried on. Moreover, the strength difference of copper contaminated soil under three different curing methods was compared and analyzed, and the effects of mixed fly ash and lime on the strength of solidified copper contaminated soil was studied. The main results are listed as follows:(1) When the copper ion content was lower than 0.3%, the unconfined compressive strength of the soil under the three curing methods increased first and then decreased with the increase of the content of the copper ion, but changed slightly; while the unconfined compressive strength of soil under the three kinds of curing methods decreased obviously when the content reaches 0.5%. In addition, the unconfined compressive strength of the soil under the three curing methods all increased with the increase of the curing agent content and the age of the curing agent.(2) When the total dosage was the same, the age was 7 or 14 days and the copper ion content was less than 0.3 percent, the performance of the treatment of copper contaminated soil by cement alone was better than that of the group; when the content of copper ion reached 0.5%, consequence was that group method became slightly better than that of the cement only. During the next 28,56 days, the effect of cement curing alone was better than the group method, this had nothing to do with the copper ion content. In addition, there was only little difference between the two age groups.(3) When the cement content was the same or similar and the age was 7 or 14 days, if the copper ion content was less than 0.3%, the incorporation of fly ash, lime was harm to the performance of cement curing; while as the copper ions content reached 0.5%, fly ash, lime would bring beneficial effects to cement curing. On the contrary, in the 28 and 56 days of age, the incorporation of fly ash and lime brought a negative effect on the curing action of cement and had no relationship to the volume of copper ion.