cmVkg 



10 15 20 



RESISTANCE TO BREAKAGE 



25 KG/CM^ 



Figure 62. Limit of plasticity during breakage of ice with different 

 air contents. 



LITERATURE: 9, 25, 62, 101, 136. 



Section 78. The Effect of Tfiickness, Temperature and Salinity 



on Flexural Strength 



We have seen that ice has an extremely small limit of elasticity and is extremely hetero- 

 geneous along its vertical plane. Because of this, formulas based on the theory of elasticity can 

 be applied to it only with considerable qualifications. Keeping these qualifications in mind, let us 

 apply the formula which arises from the theory of resistance of substances to a case of flexure, 

 namely: 2 



£1 = ^ 



P2 hi ' 



where p is the weight of the load placed on the ice, h is the thickness of the ice. 



From formula (1) it follows that an increase in ice thickness will increase the ability of the 

 ice to resist flexure, e. g. , a 2-fold increase in thickness results in a 4-fold increase in flexural 

 strength. 



If we know from experiments the load which an ice of certain properties and thickness can 

 support, we can, by using formula (1), compute the thickness of the ice of the same properties 

 which would support any other load. 



Thus from formula (1) Korunov arrives at the following formulas for fresh ice: 



A= 10 1/7, 



/22 



(1) 



P = 



100 ' 



(2) 

 (3) 



where h is the thickness of the fresh ice in centimeters, p is the weight of a concentrated load in 

 tons. 



191 



