The peculiarities of the dynamic behaviour of silty soils in laboratory experiments that simulate their interaction with gas mining equipment are analyzed. These seasonally thawing soils appear to be very sensitive to dynamic loading and sometimes even liquefaction. Several peculiarities of their dynamic behaviour include: (i) their special sensitivity to very definite and narrow vibration frequency ranges, which vary with grain size and moisture content, and result from the resonant effects in the soil; (ii) the redistribution of pore water during the vibration and subsequent regain; (iii) the thixotropic recovery of the soil after vibration, resulting in the regain of its strength over initial levels, water content and density being constant. Both dilatant and thixotropic effects take place in such soils during dynamic loading, distinguishing them from both clean sands and clayey soils. On the basis of the peculiarities of dynamic behaviour discussed, the authors consider such soils as dilatantly thixotropic dispersed systems. Key words : dynamic properties, soils, thixotropy, liquefaction, resonance, silts.
Ricochets on Asteroids II: Sensitivity of laboratory experiments of low velocity grazing impacts on substrate grain size
