8.5 Driving of the sheet piles
8.5.1 The driving method, equipment and assistance shall be selected on the basis of comparable experience and shall comply with the design of the section according to 7.2.1.
8.5.2 When comparable experience does not exist or is considered to be insufficient, driving tests or a mathematical analysis of the driving process should be adopted in order to select the correct driving method (see annex C).
8.5.3 When pressing the sheet piles into the ground, it shall be shown that the capacity of the press and the holding capacity of the previously driven sheet piles (which must deliver the necessary reaction forces) are sufficient. This can be demonstrated either by comparable experience or by tests or analysis on the basis of soils data.
- a top
- b toe
- c set back
A set back on top of the sheet pile for installation with a driving cap is often necessary. The size of the set back should comply with the shape and dimensions of the cap.
8.5.4 All piling equipment shall comply with EN 996:1995.
8.5.5 It should be verified, either by tests or analysis, that the selected driving method does not cause damage to adjacent buildings and installations (see annex C).
8.5.6 Jetting, pre-drilling or blasting techniques applied to assist driving, shall be carried out in such a way that damage to adjacent buildings, installations and services and to the work itself is unlikely to occur (see annex D).
8.5.7 A suitable driving method shall be selected which ensures that the requirements of the design with respect to the tolerances of the sheet pile wall after driving, will be obtained.
NOTE The following aspects are important:
- achieving the required toe level;
- keeping the plan position and verticality in accordance with 8.6;
- avoiding significant damage to sheet piles and interlocks (de-clutching);
- obtaining the required coefficient of permeability;
- ensuring that the driving forces act along the neutral axis of the sheet piles and the primary elements;
- maintaining the sequence of driving the primary elements for a combined wall;
- obtaining the required vertical bearing capacity, if applicable;
- specifying templates for combined walls and straight web piles, (see also annex D).
8.5.8 Sheet piles should be guided at one or more levels during driving.
8.5.9 Guide frames should be stable and robust and positioned at such levels so as to ensure the horizontal and vertical alignment of the piles during driving. The guiding system should be designed to avoid damage to the coating on the sheet piles (for example by using guide rolls).
8.5.10 The piles in the driving rig or the guide frame shall be positioned with an accuracy which ensures that the specified tolerances are complied with.
8.5.11 In the case of a closed sheet pile wall, special care shall be taken of the plan position and the verticality of the closing sheet piles.
8.5.12 The sequence for driving primary elements should be selected so that the elements will meet the conditions of 8.6.1.
8.5.13 Driving caps should fit closely the profile of the pile. Cushion fillings should be checked regularly in accordance with manufacturers recommendations or the proven experience with the applied materials.
8.5.14 If lubricants or bentonite are used to facilitate driving, the local environmental regulations shall be followed.
8.5.15 Because of the possible considerable reduction of the interlock tensile strength of straight web piles, lubricants shall not be used.
8.5.16 If lubricants are used in the interlocks, they shall be in accordance with the design (see 7.2.2).
8.5.17 In the case of sheet piles having tongue and claw type interlocks, the sheet pile should be driven with the tongue at the leading end (see figure 11).
- a claw
- b tongue
- c driving direction