1.3 Assumptions

(1) Reference is made to – EN 1990:2002, 1.3 and EN 1997-1:2004, 1.3.

(2) The provisions of this standard are based on the assumptions given below:

data required for design are collected, recorded and interpreted by appropriately qualified personnel;
structures are designed by appropriately qualified and experienced personnel;
adequate continuity and communication exist between the personnel involved in data-collection, design and construction;

1.4 Distinction between Principles and Application Rules

(1) Depending on the character of the individual clauses, distinction is made in EN 1997-2 between Principles and Application Rules.

(2) The Principles comprise:

general statements and definitions for which there is no alternative;
requirements and analytical models for which no alternative is permitted unless specifically stated.

(3) The Principles are preceded by the letter P.

(4) The Application Rules are examples of generally recognised rules which follow the Principles and satisfy their requirements.

(5) It is permissible to use alternatives to the Application Rules given in this standard, provided it is shown that the alternative rules accord with the relevant Principles and are at least equivalent with regard to the structural safety, serviceability and durability, which would be expected when using the Eurocodes.

NOTE If an alternative design rule is submitted for an application rule, the resulting design cannot be claimed to be wholly in accordance with EN 1997-2, although the design will remain in accordance with the Principles of EN 1997-1. When EN 1997-2 is used in respect of a property listed in an Annex Z of a product standard or an ETAG, the use of an alternative design rule may not be acceptable for CE marking.

(6) In EN 1997-2, the Application Rules are identified by a number in brackets e.g. as in this clause.

1.5 Definitions

1.5.1 Terms common to all Eurocodes

(1)P The terms used in common for all Eurocodes are defined in EN 1990.

1.5.2 Terms common to Eurocode 7

(1)P The terms specific to EN 1997 are defined in 1.5.2 of EN 1997-1:2004.

1.5.3 Specific definitions used in EN 1997-2

1.5.3.1 derived value

value of a geotechnical parameters obtained from lest results by theory, correlation or empiricism (see 1.6)

1.5.3.2 disturbed sample

sample where the soil structure, water content and/or constituents have been changed during sampling

1.5.3.3 measured value

value that is measured in a test

1.5.3.4 natural specimen

specimen made from the available (disturbed, undisturbed, remoulded) sample

1.5.3.5 quality class

classification by which the quality of a soil sample is assessed in the laboratory

NOTE For laboratory testing purposes, soil samples arc classified in five quality classes (see 3.4.1).

1.5.3.6 remoulded sample

sample of which the soil or rock structure is fully disturbed

1.5.3.7 remoulded specimen

fully disturbed specimen, at natural water content

1.5.3.8 re-compacted specimen

specimen forced into a mould with a rammer or under desired static stress state

1.5.3.9 reconstituted specimen

specimen prepared in the laboratory: for fine soils, it is prepared as a slurry (at or above the liquid limit) and then consolidated (sedimented); for coarse soils, it is either poured or pluviated in dry (dried) or wet conditions and compacted, or consolidated

1.5.3.10 re-consolidated specimen

specimen compressed in a mould or cell under static pressure while allowing drainage to take place

1.5.3.11 sample

portion of soil or rock recovered from the ground by sampling techniques

1.5.3.12 specimen

part of a soil or rock sample used for a laboratory test

1.5.3.13 strength index test

test of a nature that yields an indication of the shear strength, without necessarily giving a representative value

NOTE The results of such a test are subject to uncertainly.

expansion due to reduction of effective stress resulting from either reduction of total stress or absorption of (in general) water at constant total stress

NOTE Swelling includes the reverse of both compression and consolidation.

1.5.3.15 undisturbed sample

sample where no change in the soil characteristics of practical significance has occurred