Biopolymers can effectively improve the mechanical properties of soil. In order to evaluate the application prospect of biopolymer-modified sludge in practical engineering

the effects of xanthan gum (XG)

sodium alginate (SA)

and cationic guar gum (GG) on the compressibility and permeability of high water-content sludge were studied. On the basis of one-dimensional osmotic consolidation test

the effects of different types and dosages of biopolymers on the yield stress

compression index

and coefficient of permeability of soil were investigated. Meanwhile

the microscopic mechanism of the modification of high water-content sludge by biopolymer was analyzed by scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) tests. Results show that the compressibility of modified sludge was reduced because of the formation of clay-polymer network structure. With increasing dosage

the compressibility of modified sludge decreased

while the structural yield stress increased gradually. When the vertical effective stress was greater than the structural yield stress

the Cc value of the modified sludge increased significantly

and it further increased with the increase in dosage. The permeability of the modified sludge was significantly reduced. Among the polymers used in the study

XG had the most significant effect

achieved two orders of magnitude when the dosage was 1.5%.