DOI: 10.3724/SP.J.1249.2017.02147

Journal of Shenzhen University Science and Engineering (深圳大学学报理工版) 2017/34:2 PP.147-156

Compression process of the landfilled solidified sludge soil and its microstructure change

In order to explore the compression deformation characteristics of the landfilled solidified sludge soil as foundation soil, confined compression test by separate loading method and scanning electron microscope observation is carried to study the deformation rule and microstructure changes of the soil under different stresses. Compression tests show that, the remold solidified sludge soil has the characteristics of high porosity and compressibility. It has a metastable stage between 100 to 200 kPa, and the compression amount is small. The water content decreases exponentially during compression. Component analysis shows that, the composition of the solidified sludge soil is quite complex, including sheet aggregated clay domain, mineral fragment, hydrated calcium silicate, single sulfur type calcium aluminate, insect eggs, bio detritus, and other organic matters. Microstructure observation shows that, in the low level stress stage, there are a lot of large overhead voids between elements, which is the reason for the high compressibility of the soil. Due to the effect by the cement solidification, the soil has some large voids with highly strength which leads to the metastable stage. When the compress stress comes to 400 kPa, the metastable stage is broken and the particles are damaged and deformed seriously with the contact becoming mosaic. Further increasing the stress to 800 kPa, the micro voids inside the particles are also compressed, and the density of the soil increases, the void reaches 1.445.

Key words:geotechnical engineering,landfilled solidified sludge soil,compression test,separate loading,microstructure observation,metastable stage

ReleaseDate:2017-04-10 18:10:19

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