the thermal regime. In these cases, the thawed ground becomes a morass in 

 which vehicle passage can be impossible and maintenance of structural sta- 

 bility of facilities becomes difficult. 



The current major solution for eliminating or greatly reducing perma- 

 frost thaw is to use gravel as either pads for structures or as roadways. 

 Although these demands exist elsewhere, the thickness of gravel required 

 in permafrost areas is far greater than in nonpermafrost areas. The gravel 

 pad in permafrost areas replaces the insulative function of the vegetative 

 mat that was removed or compressed by the gravel fill. Since the insulative 

 quality of the vegetative mat is greater than that of an equivalent thick- 

 ness of gravel, a gravel pad must be considerably thicker to maintain an 

 equivalent thermal regime. Under these circumstances the most important 

 considerations for determining pad or road thickness are: climatic factors, 

 soil surface temperatures, permafrost temperatures, and subgrade soil proper- 

 ties (McPhail et al. 1975). The objective is to establish the freeze front 

 in or slightly below the fill (McPhail et al. 1975). Where this is accom- 

 plished, potential thaw problems can be greatly diminished. 



Arctic and subarctic regions have been the focus of attention during 

 the past several decades because of the wealth of natural resources known 

 or thought to occur in these regions. The discovery of oil and gas on Naval 

 Petroleum Reserve No. 4 (now the National Petroleum Reserve-Alaska) in 

 the I940's, at Prudhoe Bay in 1968, and in northern Canada has stimulated 

 this interest and expanded it to include metallic minerals and coal. Expan- 

 sion of exploration activities can be expected to continue. 



As resource development in remote arctic and subarctic areas becomes 

 more economically feasible the region's resources will be utilized to meet 

 society's energy and material needs. These future projects will require 

 increased quantities of gravel to facilitate construction and to provide 

 stable substrates for various permanent and temporary facilities. For ex- 



ample, the gravel requirement for the Trans-Alaska Pipeline System was about 

 49 mill ion cubic meters (m ) (Michael Baker, Inc. 1977) . Sma I ler projects 

 requiring gravel, such as exploratory well drill pads and associated camps. 



