Experimental Study On Improvement Of Dredged Sludge With Lime And Red Brick Powder

On the one hand,a great deal of dredged sludge was produced every year in China,encroaching on a large number of land;on the other hand,a large number of construction waste needs to be dealt with urgently during the rapid process of urbanization in China.With the national attention to environmental protection,it is the development trend that dredged sludge and construction waste resources are further utilized to attend the reduction and resources in the future.Dredged sludge has been widely used in engineering,but it still faces the problem of excessive settlement of foundation after treatment.Large amounts of construction waste are also used in gravel pile and other foundation treatment,but the finer particles in construction waste have not been fully used.In order to solve the above problems,the strength,compression and permeability of dredged sludge treated with different amounts of lime and red brick powder were comprehensively studied in this paper.The main tasks are as follows:(1)The effects of lime content and red brick powder content on the stress-strain curve and unconfined compressive strength of dredged sludge after treatment are analyzed by unconfined compression test.In addition,the effects of lime content and red brick powder content on cohesion c and internal friction angle ? were analyzed by direct shear test.It provides a reference for cyclic consolidation test.(2)The static consolidation tests of natural and treated dredged sludge were carried out by using the modified consolidation instrument.The effects of lime and red brick powder content on compression curve,compression index and consolidation yield stress were analyzed.The relationship between consolidation yield stress and red brick powder content,void index and effective vertical stress was discussed.(3)The consolidation permeability tests of natural and treated dredged sludge were carried out.The influence of lime and red brick powder content on e-logk curve was analyzed,and the relationship between permeability index and initial void ratio,lime content and slope and intercept of logf-logk curve was discussed.(4)According to the results of unconfined compressive strength test,direct shear test and consolidation permeability test,the cyclic consolidation test of dredged sludge with lime content of 4% and 5% was carried out.The strain variation of lime-treated soil sample and the effect of red brick powder content on springback deformation,springback modulus,total deformation and pore pressure of treated dredged sludge were analyzed.