3 Terms and definitions

For the purposes of this European Standard, the following terms and definitions apply:

3.1

displacement pile

pile which is installed in the ground without excavation or removal of material from the ground except for limiting heave, vibration, removal of obstructions or to assist penetration

3.2

prefabricated (displacement) pile

pile or pile element which is manufactured in a single unit or in pile segments before installation

3.3

cast in place (displacement) pile

pile installed by driving a closed ended concrete shell or permanent or temporary casing, and filling the hole so formed with plain or reinforced concrete

3.4

combined pile

pile made up of two or more types or sizes of piles joined together. The connection between the components is designed to transmit load and to prevent separation during and after construction. (= composite pile) See Figure A.8 of annex A

3.5

screw pile

pile in which the pile or pile tube comprises a limited number of helices at its base and which is installed under the combined action of a torque and a vertical thrust. By the screwing-in and/or by the screwing-out, the ground is essentially laterally displaced and virtually no soil is removed. See Figure A.10 of annex A

3.6

jacked pile

pile pressed into soil by means of static force

3.7

grouted pile

prefabricated pile fitted with an enlarged shoe to create along a part or the full perimeter of the pile a space which is filled during driving with grout, mortar or microconcrete. See Figure A.11 of annex A

3.8

post grouted pile

pile where shaft and/or base grouting is performed after installation through pipes fixed along or incorporated in the pile. See Figure A.12 of annex A

3.9

casing

steel tube used temporarily or permanently to support shaft walls during the construction of a pile. In permanent situation the casing can act as a protective or load bearing unit

3.10

drive tube

steel tube used to displace the ground during the formation of a driven cast in place pile. Drive tube is withdrawn during concreting

3.11

liner, lining

a tube, generally of thin steel plate, forming part of the shaft of a pile, e.g. used for the protection of pile shafts in soft or aggressive grounds or to reduce negative skin friction

3.12

pile joint

means of joining lengths of pile elements either by welding or by mechanical joints (examples see Figures A.7, A.8 and A.9 of annex A)

3.13

pile shoe

shoe or point fitted to the base of a pile or drive tube to form the toe (examples see Figures A.4a to A.4h and A.13 of annex A)

3.14

wings

shaft enlargements to steel piles formed by welding steel sections to the pile. (see example in Figure A.2j of annex A)

3.15

leader

steel sections used for guiding driving equipment and/or pile during driving. See Figure A.6 of annex A

3.16

impact hammer

tool of construction equipment for driving piles by impact (striking or falling mass)

3.17

vibrator (vibrating hammer)

tool of construction equipment for driving or extracting piles, drive tubes or casing by the application of vibratory forces

3.18

helmet

device, usually steel, placed between the base of the impact hammer and the pile or drive tube so as to uniformly distribute the hammer impact to the top of the pile. See Figure A.6 of annex A

3.19

hammer cushion

device or material placed between the impact hammer and the helmet to protect the hammer and the pile head from destructive direct impact. The hammer cushion material shall have enough stiffness to transmit hammer energy efficiently into the pile. See Figure A.6 of annex A

3.20

pile cushion

material, usually softwood, placed between the helmet and the top of a precast concrete pile. See Figure A.6 of annex A

3.21

follower

a temporary extension, used during driving, that permits the driving of the pile top below ground surface, water surface, or below the lowest point to which the driving equipment can reach without disengagement from the leaders

3.22

mandrel

a steel core for driving that is inserted into a closed-end tubular pile. After installation the mandrel is withdrawn

3.23

driving

method to bring the piles into the ground to the required depth, such as hammering, vibrating, pressing, screwing or by a combination of these or other methods

3.24

driven pile

pile which is forced into the soil by driving, the soil being displaced by the pile or drive tube

3.25

driving assistance

method used to assist a pile to penetrate the ground e.g. jetting, preboring, preblasting, predriving

3.26

coring

removal of soil by core sampler (e.g. to mitigate the effects of heave by pile driving)

3.27

jetting

use of pressurised water to facilitate the driving of a pile by means of hydraulic displacement of parts of the soil

3.28

preboring (preaugering, predrilling)

boring through obstructions or materials too dense to penetrate with the planned pile type and driving equipment

3.29

grouting

injection of a fluid cementitious mixture (e.g. cement grout, mortar, micro concrete)

3.30

restrike

a single hammer blow to a prefabricated pile that is monitored for energy input and measurement of pile strain/acceleration and/or pile set are made, to allow assessment of pile bearing resistance

3.31

redrive (1)

an additional series of hammer blows used to drive the prefabricated pile to re-establish the required driving resistance

3.32

redrive (2)

method used to form an enlarged shaft on a temporarily cased driven cast in place pile

3.33

initial pile

first working pile on construction site

3.34

test pile

pile to which a load is applied to determine the resistance deformation characteristics of the pile and surrounding ground

3.35

trial pile

pile installed to assess the practicability and suitability of the construction method for a particular application

3.36

preliminary pile

pile installed before the commencement of the main piling works or section of the works for the purpose of establishing the suitability of the chosen type of pile, driving equipment and/or for confirming the design, dimensions and bearing capacity

3.37

driving criteria

driving parameters used to be fullfilled when driving a pile

3.38

set

mean permanent penetration of a pile in the ground per blow measured by a series of blows

3.39

monitoring

the passive role of checking the technical quality of the piling process

3.40

supervision

the active role of overseeing or directing the piling operations

3.41

recording

to make a permanent record of the facts relating to the piling operations and aspects monitored

3.42

maintained load pile test

static loading test in which a testpile has loads applied in incremental stages, each of which is held constant for a certain period or until pile motion has virtually ceased or has reached a prescribed limit (ML – test)

3.43

constant rate of penetration pile load test

static loading test in which a test pile is forced into the ground at a constant rate and the force is measured (CRP – test)

3.44

dynamic pile load test

loading test where a pile is subjected at the pile head to a dynamic force for analysis of its load bearing capacity

3.45

sonic test, low strain integrity test

integrity test where a series of waves is passed between a transmitter and a receiver through the concrete of a pile and where the characteristics of the received waves are measured and used to infer continuity and section variations of the pile shaft

3.46

sonic coring

sonic integrity test of pile concrete carried out from core drillings in a pile shaft or from a pre-placed tube system

3.47

working level

level of the piling platform on which the piling rig works. See Figure A.13 of annex A

3.48

casting level

final level to which the concrete is cast. It is above the cut off level by a margin depending on the execution procedure. See Figure A.13 of annex A

3.49

cut off level

prescribed level to which a pile is cut or trimmed back to before connecting it to the superstructure. See Figure A.13 of annex A

3.50

toe level

lowest level of pile. See Figure A.13 of annex A

3.51

pile top

upper area of pile. See Figure A.13 of annex A

3.52

pile head

upper part of pile. See Figure A.13 of annex A

3.53

pile shaft

the body of the pile between the head and the base. See Figure A.13 of annex A

3.54

pile bottom

lower part of a pile. See Figure A.13 of annex A

3.55

pile base

bottom area of pile. See Figure A.13 of annex A

3.56

cathodic protection

a means of protecting steel piles from corrosion by providing a consumable anode or by applying an external electrical potential

3.57

stray current

direct current that is induced in the soil which can cause corrosion of a pile

3.58

initial set

stage after mixing concrete when it turns from liquid to solid

3.59

second choice

prefabricated section originally manufactured for other purposes but accepted as suitable for use as a pile e.g. steel pipe for oil

3.60

heave

upward movement of ground or pile

3.61

brooming

separation of fibres at the toe or head of a timber pile

NOTE In EN 1536 annex A there is an explanation of common piling terms.

EN 12699:2001 Execution of special geotechnical work – Displacement piles