📄 METHODOLOGY FOR PILE BORING
(For Bored Cast-in-Situ RCC Piles – Using Rotary Hydraulic Rig)
1. Scope of Work
This methodology covers the procedure for execution of pile boring work for cast-in-situ
reinforced concrete piles of diameter ___ mm and depth up to ___ meters for foundation
works.
2. Reference Codes & Standards
IS 2911 (Part 1/Sec 2): 2010 – Bored Cast-in-Situ Piles
IS 456: 2000 – Code of Practice for Plain and Reinforced Concrete
MoRTH Specification Section 1000 and 1600
Project Drawings and Specifications
3. Equipment & Tools
Hydraulic rotary piling rig with Kelly bar
Temporary casing (if required)
Chisels (for hard strata)
Tremie pipe with funnel
Slurry pump and bentonite tank (if bentonite used)
Reinforcement cage lifting crane
Concrete transit mixers and pump
Water tanker (for cleaning and slurry preparation)
4. Sequence of Activities
4.1. Setting Out
Surveyor will mark pile locations as per approved layout.
Ensure clear working space and accessibility to the pile point.
Drive reference pegs for pile center.
4.2. Installation of Temporary Casing
(if required)
Drive temporary casing using rotary rig to prevent bore collapse in loose strata.
Casing diameter slightly more than pile diameter (e.g., 600 mm casing for 500 mm
pile).
4.3. Boring Operation
Start boring using rotary hydraulic rig.
Bore vertically to the required depth or till hard stratum is reached as per soil report.
Use bentonite slurry to stabilize the bore if soil is collapsible.
Ensure verticality of bore within 1 in 200 tolerance.
Maintain bore depth as per approved drawings and founding level.
4.4. Cleaning the Borehole
Use bailers or airlift to remove loose soil, slurry or debris from bore bottom.
Clean borehole till sound founding strata is exposed and bottom is free from muck.
4.5. Reinforcement Cage Placement
Prepare reinforcement cage as per approved bar bending schedule (BBS).
Lower the cage carefully using crane ensuring minimum cover (typically 50 mm).
Provide necessary spacers and centralizers.
4.6. Concreting through Tremie Method
Use tremie pipe (min 150 mm dia) inserted till the bottom of bore.
Concrete to be poured continuously without interruption.
Maintain sufficient head of concrete inside tremie to avoid segregation.
Ensure no contamination of concrete with slurry.
Monitor concrete level and overflow from top.
4.7. Casing Withdrawal
Withdraw casing gradually after concreting ensuring concrete does not uplift.
Vibrator may be used to avoid concrete bridging or segregation.
4.8. Curing
Top of pile shall be cured and protected from drying for minimum 7 days.
Cut-off level to be trimmed after concrete gains required strength.
5. Quality Control & Records
Check verticality and depth of boring with bore log.
Slump of concrete: 150–180 mm (for tremie)
Cube testing for concrete (1 set per 50 m³ or as per specs)
Maintain pile boring log and concrete pour card for each pile.
Ensure reinforcement length and cage alignment as per design.
6. Safety Measures
Barricade working area.
PPE for all personnel.
Rig to be operated by licensed and trained operator.
Emergency rescue and fire extinguishers at site.
