Effect of Pipeline Construction on Soil Compaction in Alberta

A study was initiated in 1988 to evaluate the effects of pipeline construction on soil compaction in the province of Alberta. The pipelines were located throughout Alberta on a number of different soils and were constructed using various techniques. Cone penetration resistance of soils (soil strength) was monitored to a depth of 31.5 cm at 14 study areas. Soil strength measurements were taken from right-of-way locations as well as from an adjacent undisturbed control. Soils were also analyzed to determine percent organic matter, moisture and clay. Soil strength information from the 14 study areas suggests that pipeline construction procedures can cause changes in soil strength on pipeline rights-of-way in Alberta. However, decreases in soil strength on the RoW compared to adjacent controls are more common than increases. These differences in soil strength appear to be short lived in the majority of cases; most differences, both increases and decreases, had disappeared one year after construction or were less than 2 bars. Although pipelines constructed through a number of different soils types were monitored, no clear relationships emerged between soil Orders, zones, or soil parent materials and the effect of pipeline construction on soil compaction. Soil moisture conditions appear to be more important. Pipelines constructed under moist to wet soil conditions were more likely to be compacted than if construction took place under dry soil conditions. Gleysolic soils for example were no more likely to be compacted during construction than soils of any other Order, provided construction took place under dry soil conditions.