procedure of standarf penetration method (SPT)

Test Procedure 3.1.1. Test Hole PENETRATION TEST AND SPLIT-BARREL SAMPLING Drill the hole to the desired sampling depth and clean out all disturbed material. If a wet drill is used, flush out all cuttings. 3.1.2. Assembling Equipment Attach the split-barrel sampler to the A-rod and lower into the hole until it is sitting on the undisturbed material. Attach the drive weight assembly. Lift the 63.5 kg hammer approximately 0.76 m and allow it to fall on the anvil delivering one seating blow. Mark the drill rod in 3 successive .15 m increments to observe penetration. Mark the drive weight assembly to indicate a 0.76 m hammer lift. 3.1.3. Penetration Testing Raise and drop the hammer 0.76 m successively by means of the rope and cathead, using no more than 2 1/4 wraps around the cathead.  The hammer should be operated between 40 and 60 blows per minute and should drop freely. Continue the driving until either 0.45 m has been penetrated or 100 blows has been applied. Record the number of blows for each .15 m of the penetration.  The first 0.15 m increment is the "seating" drive.  The sum of the blows for second and third increment of 0.15 m penetration is termed "penetration resistance or "N-value". If the blow count exceeds 100 in total, terminate the test and record the number of blows for the last 0.30 m of penetration as the N- If less than 0.30 m is penetrated in 100 blows, record the depth penetrated and the blow count. If the sampler advances below the bottom of the hole under its own weight, note this condition on the log. 3.1.4. Handling Sample Bring the sampler to the surface and open it.  Remove any obvious contamination from the ends or sides and drain excess water.  Carefully scrape or slice along one side to expose fresh material and any stratification. Record the length, composition, colour, stratification and condition of sample. Remove sample and wrap it or seal in a plastic bag to retain moisture.  If the sample can be removed relatively intact, wrap it in several layers of plastic to strengthen it and seal ends with tape.  Mark the sample "top" and "bottom" if applicable and label it with an identification number