PILE DRIVING PROCESS MONITORING BASED ON FIELD ENERGY MEASUREMENTS

ABSTRACT Modern hydraulic hammers are usually equipped with on-board energy measurement devices. Energy measurements in the field can therefore be taken continuously during entire pile driving processes. This paper outlines a method that directly uses energy measurements from the field for quantitative pile driving process monitoring. The kinetic energy delivered over one meter of pile penetration (KEMP) and the effective transferred energy delivered over one meter of pile penetration (EEMP) against soil resistance are calculated based on field measurements and are used as two indicators for pile driving process monitoring. The relationship between the EEMP and the pile capacity is confirmed by dynamic tests and static load tests on several well-monitored long steel H-piles. The EEMP values compare well with pile capacity predictions from a pile driving analyzer and from static analyses based on standard penetration tests, and with those measured from static load tests. The two energy indicators can also be used to effectively monitor the integrity of piles during construction. Potential pile damage caused by obstructions is illustrated by interpreting the KEMP and EEMP records of three abandoned long steel H-piles.