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Dynamic probe test is done to determine the penetration resistance of soil. Apparatus required for dynamic probe test of soil are:
(a) Dynamic Probe: The anvils shall be rigidly fixed to the guide rod; the lower anvil shall also be rigidly fixed to the extension rods. The mass of the lower anvil shall be 1.5 kg to 1.8 kg. The combined mass of the anvils and guide rod shall not exceed 5.0 kg.
(b) Extension rods with a length of 1000 mm ±10 mm. The rods shall be attached to bear against each other by means of external couplers.
Procedure for dynamic probe test:
(a) The lower end of the probe shall be rested against the ground at the test location, with the first extension rod and guide rod in a vertical position.
(b) The hammer shall be raised to bear against the upper anvil, and shall be allowed to fall freely. It shall not be connected to objects which may influence its acceleration and deceleration, and shall be stationary when released in the upper position. The fall shall be 300 mm ± 5 mm.
(c) The hammer shall be used to drive the probe into the ground, with a rate of driving between 20 and 60 blows per minute.
(d) Additional extension rods shall be added as necessary. The rods shall be rotated clockwise one full turn each time a rod is added to ensure that screw joints are tight.
(e) The blow count for every 100 mm of penetration shall be recorded, or at refusal the penetration distance for 50 blows of the hammer. Interruptions exceeding 5 minutes shall be recorded.
(f) If any obstruction to the probe is encountered which cannot be penetrated over 100 mm by 100 blows of the driving hammer, then that probe shall be considered to have reached refusal and the test shall be terminated.
The following is reported after the test:
(a) Blow count for every 100 mm penetration or at refusal the penetration distance for 50 blows of the hammer.
(b) Interruptions exceeding 5 minutes.
(c) Dynamic probe record that the test was carried out in accordance with the code.
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