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| Experimental study on fracture toughness and its correlation with strength characteristic of sandstone under freeze-thaw cycles and dry-wet cycles |
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Abstract According to the actual occurrence environment of the hydro-fluctuation belt of a typical bank slope, two test schemes of dry-wet cycles and freeze-thaw cycles are adopted to explore the mechanical properties of the sandstone specimens sampled from the hydro-fluctuation belt of a typical bank slope in the Three Gorges Reservoir Region. And the variation regularities of several mechanical parameters of the sandstone specimens immersed in different chemical solutions after they undergo different cycle times are analyzed. Experimental results show that the sandstone specimens have a significant weakening tendency under the dry-wet cycles and freeze-thaw cycles. The degradation trends of its fracture toughness, uniaxial compressive strength, splitting tensile strength are consistent basically. However, a difference exists in the deterioration degree of the mechanical parameters, i.e., the deterioration degree of the fracture toughness KIC is the greatest followed by that of the splitting tensile strength and that of the compressive strength is relatively small. The degradation degree of the mechanical parameters of the sandstone specimens during the process of the dry-wet cycles and the freeze-thaw cycles is very significant, which shows that the action of the dry-wet cycles and freeze-thaw cycles can not be ignored in the simulation of the rock mass of the hydro-fluctuation belt of a typical bank slope subjected to chemical solution. Comparing to the two test schemes，the degradation degree of the mechanical parameters of the sandstone specimens is more apparent under freeze-thaw cycles. The different chemical solutions may have a different effect on the mechanical properties of the sandstone specimens, i.e., strong acid solutions may aggravate the damage deterioration in sandstones, SO42-ions have a greater effect on deterioration in sandstones than HCO3-ions.
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Received: 01 December 2015
Published: 28 August 2016
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2016, Vol. 37 
