In order to examine the effect of soybean urease without CaCl₂ curing treatment on the long-term stability of lead-zinc contaminated soil after restoration without greatly improving the strength of cultivated soil, the long-term stability of contaminated soil after restoration under the complex environment of dry-wet cycles, freeze-thaw cycles and acid rain leaching was discussed by using pH value, heavy metal ion leaching rate and soil heavy metal occurrence form, respectively. The results show that the surface strength of the soil cured by soybean urease without CaCl₂ is significantly reduced and the permeability is improved compared with that cured by EICP. With the increase of dry-wet cycles and freeze-thaw cycles, soil pH value decreases slowly but remains weakly alkaline, and the increasing trend of heavy metal leaching rate slows down. Under the action of acid rain, with the increase of pH value of acid rain solution, the contents of Pb²⁺ and Zn²⁺ in leached solution gradually decrease, and both meet the requirements of hazardous waste disposal regulations. In addition, different types of acid rain have different effects on repaired soil, and its stability under sulfuric acid rain is better than that under nitric acid rain.

To explore the environmental durability of heavy metal contaminated soil remediated by enzyme induced carbonate precipitation (EICP) technology, acid soaking, freeze-thaw tests, and rainfall tests were carried out on the zinc and lead contaminated soil after EICP remediation, respectively. The durability and influence of the zinc and lead contaminated soil remediated by EICP technique under different environmental conditions and the corresponding influence regularity were discussed in this paper. The results showed that under different concentrations and types of acid solutions, the leaching amount of heavy metal ions in exchangeable and carbonate bound forms in the zinc and lead contaminated soil after EICP remediation decreased with pH value, with the content of ions in carbonate bound forms decreasing and the content of ions in exchangeable forms gradually increasing. It was also found that the stability in sulfuric acid solution was greater than that in nitric acid solution. As the number of freeze-thaw cycles increased, the leaching amount of exchangeable ions in the zinc and lead contaminated soil remediated by EICP technique increased, while the content of ions in the carbonate bound form reduced. Under the condition of heavy rain, Zn²⁺ and Pb²⁺ were mainly released within the first 20 minutes and migrated from top to bottom. All the results demonstrate that the heavy metal contaminated soil remediated by EICP technology has a good durability under acid soaking, freeze-thaw cycles, and heavy rain.