Abstract:

The pore characteristics and the change rule of soft soils have significant influence on their compressibility and permeability. The study can reveal the drainage consolidation process of soft soil and its deformation law so as to provide a strong basis for establishing draining water solidifying model based on the pore compression mechanism of drainage patterns and flow model. AutoPore machine made in United States was used to test pore diameter and pore-scale distribution of Guangzhou Panyu silt soil under different load levels, then gave the quantitative analysis of pore criterion distribution characteristics according to the test results. The studied results have shown that: small pores within particles and aggregates intermediated in the range of 0.4-2.5 μm is the largest proportion in the sludge soil; the number of large pores larger than 10 μm and micro pores less than 30 nm is very small; more large pore more easily be compressed and annihilated or splited into tiny pores; consolidation pressure will significantly change pore scale and pore distribution characteristics of the silt soil which results in the changes of its compressibility and permeability. Pore-scale is greater in the early stage of consolidation( 200 kPa); compression coefficient and permeability coefficient are large and rapid decrease with the increasing consolidation pressure; and pore scale is small in the late consolidation( 200 kPa); compression coefficient and permeability coefficient are small, and with the consolidation pressure change flatten out.

Key words: saturated soft soil, micropore, pore scale, pore distribution characteristics, compressibity, permeability