PERMAFROST — BLACK 283 



and thickness of permafrost (Eiienstein, 1947; Swartz and Shepard, 

 1946; Muller, 1945; and Joestings, 1941). Generall}^ resistivities of 

 frozen silt and gravel are several thousand ohms higher than com- 

 parable unfrozen materials and may be 20 to 120 times as high (Swartz 

 and Shepard, 1946; Joestings, 1941). However, it is well known that 

 the type of material is less important than the amount of unfrozen 

 ground water and dissolved salts within the material. Even in frozen 

 ground these factors are so variable that resistivity data can be in- 

 terpreted with reliability only by experienced men and generally only 

 in areas where some positive checks can be made through drilling. 

 Sumgin and Petrovsky (1947) discuss a new radio-wave technique 

 used where permafrost is below — 5° C. 



ENGINEERING SIGNIFICANCES 



In Alaska during World War II the difficulties encountered by our 

 armed forces in obtaining permanent water supplies and in construct- 

 ing runways, roads, and buildings in permafrost areas focused atten- 

 tion on pennaf rost as nothing else could (Wilson, 1948 ; Jaillite, 1947 ; 

 Barnes, 1946 ; Taber, 1943b) . Only then did most people realize that 

 in Russia similar difficulties with railroads, roads, bridges, houses, and 

 factories had impeded colonization and development of the north for 

 decades. Now with the recent progress in aviation, and because of 

 the strategic importance of the noith, active construction and settle- 

 ment for military and civilian personnel must increase, and the prob- 

 lems of permafrost must be solved. 



Fortunately we can draw on the vast experience of the Soviet 

 Union. Their engineers have shown that it is — 



... a losing battle to fight the forces of frozen ground simply by using 

 stronger materials or by resorting to more rigid designs. On the other hand, 

 the same experience has demonstrated that satisfactory results can be achieved 

 and are allowed for in the design in such a manner that they appreciably mini- 

 mize or completely neutralize and eliminate the destructive effect of frost 

 action . . . Once the frozen ground problems are understood and correctly 

 evaluated, their successful solution is for the most part a matter of common 

 sense whereby the frost forces are utilized to play the hand of the engineer 

 and not against it. ... it is worth noting that in Soviet Russia since about 

 1938 all governmental organizations, municipalities, and cooperative societies 

 are required to make a thorough survey of the permafrost conditions accord- 

 ing to a prescribed plan before any structure may be erected in the permafrost 

 region. [Muller, 1945, pp. 1-2, 85-86.] 



Specifically we must think of permafrost in construction of build- 

 ings, roads, bridges, rmiways, railroads, dams, and reservoirs, in prob- 

 lems of water supply, sewage disposal, telephone lines, drainage, exca- 

 vation, gromid storage, and in many other ways. Permafrost can be 

 used as a construction material or as a base for construction, but steps 



