Foreword

This document (EN ISO 22476-2:2005) has been prepared by Technical Committee CEN/TC 341 "Geotechnical investigation and testing", the secretariat of which is held by DIN, in collaboration with Technical Committee ISO/TC 182 "Geotechnics".

This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by July 2005, and conflicting national standards shall be withdrawn at the latest by July 2005.

EN ISO 22476 Geotechnical investigation and testing — Field testing has the following parts:

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard : Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

1 Scope

This document specifies requirements for indirect investigations of soil by dynamic probing as part of geotechnical investigation and testing according to EN 1997-1 and EN 1997-2.

This document covers the determination of the resistance of soils and soft rocks in situ to the dynamic penetration of a cone. A hammer of a given mass and given height of fall is used to drive the cone. The penetration resistance is defined as the number of blows required to drive the cone over a defined distance. A continuous record is provided with respect to depth but no samples are recovered.

Four procedures are included, covering a wide range of specific work per blow:

  • dynamic probing light (DPL): test representing the lower end of the mass range of dynamic equipment;
  • dynamic probing medium (DPM): test representing the medium mass range of dynamic equipment;
  • dynamic probing heavy (DPH): test representing the medium to very heavy mass range of dynamic equipment;
  • dynamic probing super heavy (DPSH): test representing the upper end of the mass range of dynamic equipment.

The test results of this document are specially suited for the qualitative determination of a soil profile together with direct investigations (e.g. sampling according to prEN ISO 22475-1) or as a relative comparison of other in situ tests. They may also be used for the determination of the strength and deformation properties of soils, generally of the cohesionless type but also possibly in fine-grained soils, through appropriate correlations. The results can also be used to determine the depth to very dense ground layers e.g. to determine the length of end bearing piles, and to detect very loose, voided, back-filled or infilled ground.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

EN 10204, Metallic products — Types of inspection documents

prEN ISO 22475-1, Geotechnical investigation and testing — Sampling by drilling and excavation methods and groundwater measurements — Part 1: Technical principles for execution (ISO/DIS 22475-1:2004)

3 Terms and definitions

For the purpose of this document, the following terms and definitions apply.

3.1

dynamic penetrometer

cone and drive rods

3.2

dynamic probing equipment

penetrometer and all equipment necessary to drive the penetrometer

3.3

anvil or drive head

portion of the drive-weight assembly that the hammer strikes and through which the hammer energy passes into the drive rods

3.4

cushion; damper

placed upon the anvil to minimise damage to the equipment

3.5 hammer

portion of the drive-weight assembly which is successively lifted and dropped to provide the energy that accomplishes the penetration of the cone

3.6

height of fall

free fall of the hammer after being released

3.7

drive-weight assembly

device consisting of the hammer, the hammer fall guide, the anvil and the drop system

3.8

drive rods

rods that connect the drive-weight assembly to the cone

3.9 cone

pointed probe of standard dimensions used to measure the resistance to penetration (see Figure 1)

3.10

actual energy; driving energy

Emeas

energy delivered by the drive-weight assembly into the drive rod immediately below the anvil, as measured

3.11

theoretical energy

Etheor

energy as calculated for the drive weight assembly,

Etheor = m× g × h

where

m is the mass of the hammer;

g is the acceleration due to gravity;

h is the falling height of the hammer.

3.12 energy ratio

Er

ratio of the actual energy Emeas and the theoretical energy Etheor of the hammer expressed in percentage

3.13

Nxy-value

number of blows required to drive the penetrometer over a defined distance x (expressed in centimetres) by the penetrometer y

3.14

specific work per blow

value calculated by

En = m× g × h/A = Etheor/A

where

m is the mass of the hammer;

g is the acceleration due to gravity;

h is the falling height of the hammer;

A is the nominal base area (calculated using the base diameter D);

Etheor is the theoretical energy.

ISO 22476-2:2005 Field testing — Part 2: Dynamic probing