Experimental study on the strength and deformation characteristics of sludge solidified soil after crushing and remodeling

In order to investigate the strength loss and strength recovery characteristics of the sludge solidified soil after crushing and remodeling, a series of unconfined compressive strength(<italic>UCS</italic>) tests were conducted. The effects of curing agent content, initial water content of sludge, pre-curing age, two-stage solidification method, crushing degree and post-curing age on the strength and deformation characteristics of the remodeled solidified soil(<italic>RSS</italic>) were studied. In addition, the comparative analysis was carried out with that of solidified soil. The results show that the strength of the initial <italic>RSS</italic> tends to be stable as the strength of the solidified soil is greater than 600 kPa. Shortening the pre-curing age and increasing the amount of curing agent are conducive to the recovery of the strength of the <italic>RSS</italic> in the later stage, and the final strength of the <italic>RSS</italic> can be restored to 40%–70% of the strength of the solidified soil. For the two-stage solidified <italic>RSS</italic>, the strength is generally smaller than that of one-stage solidified <italic>RSS</italic> when the total amount of curing agent kept the same, and the higher the agent content used in the first stage solidification, the more obvious the strength decrease. For the influence of crushing degree, the initial strength of the two-stage solidified <italic>RSS</italic> after strong crushing is less than that of the normal crushing, but the later strength increases with the increase of the agent content used in the second stage solidification, and even be greater than that of the later strength after normal crushing. For the relationship between <italic>UCS</italic> and failure strain of the <italic>RSS</italic>, the failure strain decreases with the increase of strength as the <italic>UCS</italic> of the <italic>RSS</italic> is less than 200 kPa. As the <italic>UCS</italic> of the <italic>RSS</italic> is greater than 200 kPa, the failure strain is close to that of the solidified soil between 1%–2%. Finally, the relationship between the deformation modulus and the compressive strength of <italic>RSS</italic> and solidified soil is basically the same, which agrees linear relationship of <italic>E</italic>₅₀ = 73.8<italic>q</italic>_u.