US Patent 7234362 Subsurface material property measurement

Subsurface material property measurements, such as soil or chemical properties, are obtained in situ by a direct push method that includes rotating a ring bit at the end of a casing to drill through subsurface materials, lowering a measurement probe through the advanced casing, extending the lowered measurement probe through the ring bit, and advancing the extended probe through the soil at a controlled rate while gathering material property data from sensors attached to the probe. The probe may be withdrawn for drilling, and then replaced for further data gathering.