Unconfined compressive strength of phosphogypsum/lignin solidified lead contaminated soil
Industrial solid waste phosphogypsum and lignin were used to solidify the artificially formulated lead contaminated soil.Through the unconfined compressive strength(UCS)test,the effect of curing agent dosage and curing age on the stress-strain curve,failure pattern and UCS of the soil with different levels of lead contamination after solidification were investigated,and the curing effects of the two curing agents were compared and analyzed.The microscopic characteristics of soil samples before and after curing were analyzed by scanning electron microscopy(SEM)test.The results show that both phosphogypsum and lignin can increase the UCS of stabilized soil and reduce the failure strain.UCS of solidified soil increases continuously with the increase of phosphogypsum content,and increases first and then decreases with the increase of lignin content.Extended curing time can effectively improve the UCS of stabilized soil.With the increase of dosage and curing age,the internal cementation level of soil increases,and the failure pattern of soil sample gradually changes from local tension cracking to shear failure,showing brittle failure characteristics.The two curing agents have their own advantages and disadvantages in curing soil.Lignin is more effective than phosphogypsum in curing high concentration lead contaminated soil and has better resistance to deformation,while phosphogypsum has better ability to improve strength and fix lead in a short time.SEM tests show that the curing agent can fill the pores and cement soil particles,and the hydration products form a dense structure in the soil,which is macroscopically expressed as strength enhancement.
万方数据
维普
