Atmospheric river causes emergency repairs on HWY1

In January 2023 California experienced a so-called atmospheric river causing severe rain and snow. The rainfall resulted in five slides in the Santa Cruz Mountains blocking the highway. Working for Caltrans and Granite Construction, Gregg completed (9) solid flight auger and mud rotary borings ranging from 50-63ft in depth. The solid flight auger was used to groundwater depth with casing installed and then Pitcher switched to mud rotary methods to drill to the final depth. Sampling was completed every 5ft to the rock and then HQ3 wireline rock coring was completed to the final depth.

Highlights:

• Soil sampling (SPT, Pitcher Barrel) & HQ3 wireline rock coring
• Combination of auger and rotary methods
• SPT Energy calibration & slope inclinometer installation
• Contract value $130k (Pitcher also completed two other projects for other contractors for Caltrans repairs)

Benefits/Challenges:

• Difficult and tight access locations with traffic control
• Varying site conditions including heavy rain and snow
• Drill spoils were contained and transported to staging area

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