Site Investigation Phases • Preliminary: • assess general site suitability and enable planning of subsequent investigation • Methods: geological survey, site inspection, existing logs • Generalexploration: • identify most suitable areas, general characterisation • simple exploration, sampling and testing • Detailed: • Characterise properties of specific features • carefully selected exploration techniques, sampling and testing
Depth & Number of Bored holes • Type of buildings • Type of Foundation B 1.5B See more details in class
Test Pits Boreholes Probes (In-situ Tests) Geophysical Choice of method depends on budget, sampling requirements, extent of investigation, and often site conditions Site Exploration Methods
Rock coring • General information • typically use rotary drilling • water is circulated in the drilling rod during coring • see Table 17.5 in Das for sizes, NX most common in this area photos courtesy of Mid-Atlantic Drilling (http://www.madrilling.com)
Seismic cone: measures tip and sleeve resistance, pore water pressure, and shear and compression waves photo courtesy of Fugro Geosciences, Inc. (http://www.geo.fugro.com)
ground penetrating radar: uses pulses of radar, can be used to locate buried features such as pipes, tanks, etc Bedrock Sinkhole photos courtesy of GeoModel (http://www.geomodel.com)
Borehole logs What does it contain? Factual information about the borehole Soil profile sampling done in-situ tests carried out How do we present site invetigation data?