A Systematic Approach to Foundation Selection for Remote Transmission Line Projects: The Investigative Drilling Method-Paper

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The paper proposes a systematic method for selecting foundations for transmission-line towers in remote, geologically variable areas. Its central tool is Investigative Drilling (ID), which uses Measurement While Drilling (MWD) to record drilling parameters continuously and recover disturbed samples. Combined with field observations and selected conventional tests, these data help characterize ground conditions at tower locations more quickly and extensively than conventional drilling alone.<br /><br />The investigation proceeds in four stages: a desktop review of geological and remote-sensing information; field reconnaissance to assess terrain, environmental constraints, and access; ID drilling at each structure, supplemented by targeted conventional tests for calibration; and integrated analysis to develop site-specific ground models and foundation recommendations.<br /><br />Foundation alternatives are compared using a weighted decision matrix. Criteria include geotechnical performance, constructability and access, environmental disturbance, cost and logistics, construction schedule, and long-term maintenance. Options may include pads, rock-socketed foundations, piles, micropiles, anchors, and precast systems.<br /><br />The authors argue that matching foundations to local conditions can reduce conservative designs, material use, construction delays, and environmental impacts. Project experience cited in the paper suggests potential cost savings of 10% or more compared with projects supported by less thorough investigation. However, ID data correlations remain dependent on geological context and require validation with conventional testing. The authors identify further needs for stronger parameter correlations, improved environmental-impact measurement, and long-term foundation monitoring.

Keywords

Investigative Drilling

Measurement While Drilling

transmission-line towers

foundation selection

geotechnical investigation

ground conditions

foundation alternatives

weighted decision matrix

remote geological areas

site-specific foundation design