E – 1406 Soil Sampling in Frozen Ground

Description

This course covers the processes equipment special conditions and issues encountered in the drilling and sampling of frozen soils. Drilling and sampling in frozen ground is somewhat similar to performing the same operations in rock.

Based on documented observations experiences of drilling in a range of geotechnical materials are covered.

For finer grained materials such as silt clay organic material and ice at a few degrees below freezing

For coarser-grained frozen soils such as coarse sands and gravels drilling was reported to be similar to drilling in concrete. Likewise reports from drillers describe drilling in frozen sand as “much like drilling sandstone.”

The principal decisions for drilling and sampling in frozen soils include the selection of suitable drilling equipment a method of advancing and stabilizing the borehole drilling fluid and a refrigeration unit to cool the drilling fluid and drill string to a temperature equivalent to or slightly less than the temperature of the in situ formation.

This course is based on the US Corps of Engineers’ Manual: Geotechnical Investigations Chapter F-9 Pub. # EM 1110-1-1804

• Introduction to sampling soil in frozen ground
• Drilling equipment
• Drill bits
• Drill bit stability factors
• Advantages and Disadvantages of utilizing augers
• Use of drilling fluids and compressed air in the drilling process
• Minimizing the thermal disturbance of the borehole wall and core
• Specialty equipment: core lifters
• Procedures used in advancing the borehole
• Special considerations