Gregg Drilling recently completed a project requiring a CPT and drilling investigation for railroad bridge replacements.
The project presented unique
access challenges, but Gregg was able to maneuver the equipment into place on
the railroad using self-propelled low-railers. This allowed a 25-ton cone
truck, a limited-access hollow-stem auger rig, and a mud-rotary drill rig to
move easily on the railroad lines to the exact locations for drilling and
Holes were cut through the low-railers to allow
for the cone and drilling equipment to pass directly through. Initially, the
drill rigs were used to set casing through the gravels of the rail line so that
the cone could be pushed to characterize the soil. In total, 25 CPT locations
were tested to a maximum depth of 120 feet. A few borings also were conducted
with the mud rotary drill rig to collect samples and verify the soil
conditions. The main concern was discovering the depth of bedrock so that bridge
piles could be designed to the correct length.
Gravels were encountered while drilling, causing a loss of drilling-fluid
circulation. Gregg’s knowledgeable operators quickly installed casing, and were
able to complete the sampling to bedrock.