This document discusses problems that can occur during bored pile construction. It covers issues with excavating the pile borehole such as overbreak and water ingress. Problems with designing and lowering the pile reinforcement cage are described. Placement of concrete is discussed, including using a tremie pipe and delays between batches. Extracting temporary casing and pile construction in soft soil is also covered.

2. SCOPE 1. EXCAVATION OF PILE BORE 2. DESIGN AND LOWERING OF PILE REINFORCEMENT 3. CONCRETING THE PILE

4. 2.DESIGN AND LOWERING OF PILE REINFORCEMENT 2.1 DESIGN OF PILE REINFORCEMENT 2.2 LOWERING OF PILE REINFORCEMENT

5. 3. CONCRETING THE PILE BORE 3.1 QUALITY OF CONCRETE 3.2 PLACING OF CONCRETE 3.3 EXTRACTING TEMPORAEY CASING 3.4 PROBLEMS IN SOFT GROUND

7. WET DRILLING BY REVERSE ROTARY

9. OVER BREAK

11. 1.5 EFFECT OF W/T In dry drilling of borehole ingress of small quantity of water from sides of the borehole reduces the Skin Friction and from the bottom of borehole reduces the End Bearing. In this condition concreting should be carried out with Tremmie Pipe otherwise segregation of concrete may occur as shown in Fig. SEGREGATION OF CONCRETE

13. SPACING DRAGS DOWNWARD

15. LAP OF CAGE

17. SLUMP TEST

19. OVERFLOW OF CONCRETE

21. CONDUCTOR PIPE

22. 3.4 PROBLEMS IN SOFT GROUND In soft ground having undrained shear strength less than 15kn/m 2 causing the squeezing of the pile section near the head because lateral pressure of soil is more than the lateral pressure of concrete as shown in Fig. SQUEEZING OF THE PILE SECTION

23. CONCLUSIONS Full time supervision of pile construction should be carried out by an experienced Engineer which gives us the designed pile capacity

24. THANKS THANKS THANKS

25. ANY QUESTION?