Experimental inference on dual-porosity aggravation of soft clay after freeze-thaw by fractal and probability analysis

Variation of micro-structure is very important and virtually the internal nature of macro-behaviours, especially when the macro phenomenon is complex and the mechanism is obscure. The dual-pore structure can be regarded as a special pore structure in clay with a primary network of large inter-aggregate pores overlapped by a secondary network of small intra-aggregate pores. The main hydrodynamic and mechanical properties of soils appear to be largely controlled by this hierarchical partitioning of porosity. Aiming to more specific mechanical properties control during artificial ground freezing from microstructure aspect, this paper focuses on the pore-structure characteristics and computational inference of soft clay after the action of artificial ground freezing. Mercury Intrusion Porosimetry (MIP), as a direct quantization method, was employed to obtain the soil pore-size distribution. And scanning electron microscopy (SEM) was conducted as well, as visible supplementary to describe and qualitatively characterize the microporosity structure. Based on these two aspects, experimental results show a dual-porosity characteristic aggravated after artificial freeze-thaw. Then the influence factor analysis of freeze-thaw effects including different freezing temperature and freezing time, was discussed under uniform design methodology. The influence of each parameter respectively on the variation of dual-pore structure has been discussed to provide valuable reference for AGF practice. Finally, a new comprehensive dual-porosity computational model of soft clay on freeze-thaw effects is developed based on fractal and probability analysis. The application of this model is discussed for the further study.