Piezocone Penetration Testing Device

The piezocone penetration testing device is known as one of the two more reliable geotechnical testing devices (Lunne et al. 1997), and Nebraska Department of Roads (NDOR) has one portable unit which is actively deployed on their existing drill rigs. The built-in piezometer in the piezocone measures the pore pressure response during penetration and used to profile soil layering systems. For saturated soils, this piezometer is also used to conduct dissipation tests in order to obtain hydraulic conductivity or coefficient of consolidation of soils. This dissipation test usually takes four to eight hours, which considerably lowers the testing efficiency (speed) of this device. (Usually it takes one to two hours for one Piezocone test without the dissipation test while it takes one whole day with the dissipation test.) Recently a technique was developed by Song and Pulijala (2010) to estimate the hydraulic conductivity or coefficient of consolidation without resorting to the dissipation tests. Song and Pulijala’s (2010) method is essentially an advanced analytical technique that does not need any mechanical modification of the existing piezocone system. Infusing Song and Pulijala (2008) to the current piezocone system of NDOR will provide real-time estimation of hydraulic conductivity information. Once this technique is infused into the current NDOR’s piezocone system, the efficiency of the piezocone penetration testing device will be significantly improved with no or very little additional cost.