It becomes apparent in figure 61 that the resistance of ice to penetration increases very 

 rapidly with a decrease in temperature to -9° C, and hardly changes with a further decrease in 

 temperature. 



As a result of investigation into the effect of continuous pressure on the deformation of ice, 

 Royer presented the formula 



3 _ 



^2 = hVT, (2) 



where T is the duration of pressure in hours, 



k is the constant for a given sample of ice, 

 e is the relative deformation of the ice. 



The deformation of ice also changes in connection with a change in load. In determining this 

 dependence, Royen conducted a series of experiments with paraffin, and considering it possible to 

 extend the obtained results to ice, offered the formula 



e __M_ (3) 



where k is the constant for a given sample of ice, 

 a is the compressive stress, 

 c, is the breaking compressive stress (plastic limit). 



If the compressive stress is considerably less than the plastic limit, inasmuch as the limit of 

 plasticity is constant for a given sample, this formula can be simplified and appears as 



£4= k^o 



(4) 



Incorporating the effective temperature, duration, and the amount of load, Royen suggested the 



following general formula: 



3 _ 



e = ^''^^^^ (5) 



1—/ ' 



where e is the relative plastic deformation during compression, 



k is the constant for a given sample, fluctuating during experiments within the 

 limits of 60 x 10-5 to 90 x 10"^, 



cr is the compressive stress in kg/cm^, 



T is the loading time in hours, 



t is the average temperature of the ice. 



LITERATURE: 25, 62, 89, 169. 



187 



