Abstract: The use of hydraulically dredged mud as filling material for land reclamation can not only effectively resolve the shortage problem of ideal filling material such as sand and gravel, but also avoid the negative impact caused by the large amount of dredged mud disposal. However, the hydraulically dredged mud is usually in slurry-like state and has extremely high-water content, low strength and poor permeability. It is difficult to directly access the construction site for the personnel and equipment in subsequent ground improvement. Therefore, this paper proposes a flocculation-solidification combined method for the treatment of surface slurry-like mud to form a working platform. A large number of laboratory tests are conducted to verify the feasibility of the proposed method. First, the reasonable type and optimal dosage of flocculant (PAM) for the flocculation-solidification combined method are determined by syringe titration tests. Then, the flocculation and sedimentation process is simulated through the model tests with different mixing proportions. Vane shear tests are performed to measure the shear strength and water content of the samples at different curing times. The results show that, in comparison with the traditional pure cement solidification method, the flocculation-solidification combined method can enhance the undrained shear strength by more than five times. The results verify the feasibility of the flocculation-solidification combined method.

Key words: hydraulically dredged mud, flocculation, solidification, strength, water content