Laserfiche WebLink
2 <br />Request for Technical Revision — US 287 Geotechnical Investigation <br />Figure 2. CME 55OX off-road buggy rig (credit: Central Mine Equipment Company) <br />Subsurface Boring Plan <br />The current preliminary geotechnical investigation consists of 28 borings to be advanced within the <br />disturbed limits of the Quant'. Planned boring depths are dependent on the structure (e.g., pavement, <br />embankment foundation, bridge foundation, etc.), and follow the minimum boring depth guidelines outlined <br />in the CDOT Geotechnical Design Manual (revised in April 2017). In general, pavement borings extend <br />approximately 10 -ft below planned subgrade elevation, and shallow foundation and embankment borings <br />extend 2-3 times the bearing width or height of the embankment (or to bedrock, whichever comes first), and <br />deep foundations for bridges extend to bedrock. Drilling methods are outlined in the table below, but in <br />general all borings will utilize hollow -stem auger (HSA) down to competent bedrock. Advancing into <br />competent bedrock requires a wireline rock core recovery drilling system, advanced with a diamond core bit <br />(1-103 size). Table 1 lists the boring number, location within the quarry property, maximum planned drilling <br />depths and method of drilling. <br />Table 1. Current Planned Subsurface Investigation within Quarry Limits <br />(progressing from South to North along proposed alignment) <br />Hole Na? <br />Location (WGS 84) <br />Maximum <br />Depth? (ft) <br />Ddllin Method3 <br />g <br />P-1 <br />40.6522,-105.1416 <br />10 <br />MSA <br />P-2 <br />40.6549,-105.1419 <br />10 <br />HSA <br />B-224 <br />40.6548.-105.1409 <br />120 <br />HSA/Coring <br />B-234 <br />40.6553.-105.1407 <br />80 <br />HSA/Coring <br />B-24 <br />40.6569.-105.1406 <br />40 <br />HSA/Coring <br />B-5 <br />40.6603,-105.1417 <br />40 <br />HSA/Coring <br />P-3 <br />40.6658,-105.1457 <br />10 <br />HSA <br />P4 <br />40.6687,-105.1460 <br />10 <br />HSA <br />