This British Standard is published by BSI and came into effect on 31 December 2009. It was prepared by Technical Committee B/526, Geotechnics. A list of organizations represented on this committee can be obtained on request to its secretary.
This British Standards supersedes BS 6031:1981, which is obsolescent.
NOTE It was considered important to make the information on timber support and other largely historic advice available through the previous edition, which is still available from BSI.
Relationship with other publications
The standard has been completely re-written to bring it into line with both UK earthworks practice and the framework that is created by the Eurocodes. The aim was to reduce the size of the document and wherever possible include cross references to other existing documents.
This revision of BS 6031 reflects the widespread UK practice of using the Specification for Highway Works (SHW) 600 series  for the construction of earthworks. Within this standard, the SHW has been set as the default approach for earthworks specification that applies unless the designer details an alternative form of specification/earthworks management system.
Cross references are included within this standard to various other documents, to link into the existing information sources available. However, it remains the responsibility of the designer of the earthworks for a project to assess whether a reference is relevant to the particular project.
Use of this document
As a code of practice, this standard takes the form of guidance and recommendations. It should not be quoted as if it were a specification and particular care should be taken to ensure that claims of compliance are not misleading.
Any user claiming compliance with this standard is expected to be able to justify any course of action that deviates from its recommendations.
It has been assumed in the preparation of this standard that the execution of its provisions will be entrusted to appropriately qualified and experienced people, for whose use it has been produced.
The provisions in this standard are presented in roman (i.e. upright) type. Its recommendations are expressed in sentences in which the principal auxiliary verb is "should".
Commentary, explanation and general informative material is presented in smaller italic type, and does not constitute a normative element.
Contractual and legal considerations
This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.
Compliance with a British Standard cannot confer immunity from legal obligations.
Section 1: General
The structure for this document reflects the actual processes that might be followed on a typical project to deliver the earthworks. In practice earthworks design is an iterative process where design decisions are often taken by various parties (employer, consultant, main contractor, sub-contractors and construction validation team). To reflect this situation BS 6031:2009 includes some subjects in more than one clause.
This revision of BS 6031 reflects the widespread UK practice of using the Specification for Highway Works (SHW) 600 series  for the construction of earthworks. Within this standard, the SHW has been set as the default approach for earthworks specification that applies unless the designer details an alternative form of specification/earthworks management system. Guidance on the use of the SHW can be found in Notes for Guidance to the Specification for Highway Works .
Earthworks are commonly associated with transport infrastructure, but there are many other important applications:
- platforms for industrial, commercial and residential buildings;
- water engineering, flood defence and coastal protection works;
- other civil engineering projects.
BS 6031 is intended to be an all-encompassing code of practice; the document has been developed to enable it to cover all earthworks projects, with the exception of dams. In this regard it is relevant to note the following.
a) Embankment dams are constructed either to retain water or for waste impoundments and, while some aspects of the design, construction and maintenance of such embankments are similar to those pertaining to infrastructure embankments, those features which relate specifically to their function as dams are not within the scope of this standard. Note that since 1930 reservoir safety in Great Britain has been regulated by Act of Parliament. A guide to the Reservoirs Act 1975 1)  describes the application of current legislation and An engineering guide to the safety of embankment dams in the United Kingdom  provides some relevant information on earthworks.
b) Substantial earthworks can take place for the purpose of providing a suitable landform for building development. Typically this can involve:
- 1) backfilling old pits and quarries with engineered fill;
- 2) cut and fill operations on natural slopes to provide terraces for building.
In the former situation the major hazard to be guarded against is long-term settlement of the fill occurring subsequent to building development; in the latter situation slope instability can also be a significant hazard. While most of the technical background of highway earthworks (as captured within the SHW ) is also relevant to this type of application, two significant differences have to be recognized where structures are built on fill:
- i) settlement criteria can be much stricter than those normally acceptable for general earthworks; the designer has to consider whether the SHW  criteria are sufficient for the project; and
- ii) the engineering environment in which the earthworks are carried out does influence the approach that is applicable to earthworks; this is particularly relevant on comparatively small scale projects where the designer might need to modify the approach to earthworks.
This standard has been drafted to include sufficient flexibility to allow for these scenarios.
This standard is aligned with Eurocode BS EN 1997-1:2004. Advice on using BS EN 1997-1:2004 is provided in Thomas Telford Designers' Guide to EN 1997-1 Eurocode 7: Geotechnical Design – General Rules , local government guide A designer's simple guide to BS EN 1997 , and CIRIA C641, Eurocode 7: implications for UK practice . These publications help highlight differences between BS EN 1997-1:2004 and previous traditional practice.
The foreword to BS EN 1997-1:2004 states that "BS 6031 is to be withdrawn", which is an error; it has been agreed since the publication of BS EN 1997-1:2004 that BS 6031 will remain as part of the system of earthworks standards in UK.
The style adopted within BS 6031:2009 is to cross reference BS EN 1997-1:2004 (not repeat it), summarize the aspects of BS EN 1997-1:2004 that form the overall framework for undertaking an earthworks project, include an interpretation of certain key points that are relevant/important to earthworks (e.g. selection of partial factors to be used at design stage) and add additional information that is relevant to earthworks (i.e. add some commentary to the "dry rules" set out in BS EN 1997-1:2004). The overall aim is for BS 6031 to be non-conflicting complementary information (NCCI) to BS EN 1997-1:2004.
This edition of BS 6031 is set out in clauses to reflect the overall earthworks process: where earthworks are planned, designed, constructed, adopted/approved following construction, and then the earthworks moves into an asset management process. This cycle is only broken when the earthworks reach the end of their useful life and are decommissioned. This cycle is illustrated in Figure 1. This standard recognizes that construction of new earthworks and the remediation or repair of existing earthworks are activities that have similarities and significant differences. Wherever possible, clauses cover both construction and remediation activities, which need to be taken into consideration as appropriate.
NOTE 1 Recommendations for each stage are given in the clauses numbered in the figure.
NOTE 2 During the asset management phase, if problems are identified that require construction work, the cycle has to begin again.
This standard gives recommendations and guidance for unreinforced earthworks forming part of general civil engineering construction, with the exception of dams. This standard also gives recommendations and guidance for temporary excavations such as trenches and pits.
NOTE Reinforced earthworks are covered in BS 8006-1 and BS 8006-2.
This document applies to earthworks classified as Geotechnical Category 1, 2 and 3 structures as defined in BS EN 1997-1:2004.
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.
BS 812-109, Testing aggregates – Methods for determination of moisture content
BS 1377 (all parts), Methods of test for soils for civil engineering purposes 2)
BS 1924-1, Stabilized materials for civil engineering purposes – Part 1: General requirements, sampling, sample preparation and tests on materials before stabilization
BS 1924-2, Stabilized materials for civil engineering purposes – Part 2: Methods of test for cement-stabilized and lime-stabilized materials
BS 5607, Code of practice for the safe use of explosives in the construction industry
BS 6164, Code of practice for safety in tunnelling in the construction industry
BS EN 474 (all parts), Earth-moving machinery – Safety
BS EN 500-4, Mobile road construction machinery – Safety – Part 4: Specific requirements for compaction machines
BS EN 791, Drill rigs – Safety
BS EN 1990:2002+A1:2005, Eurocode 0 – Basis of structural design
BS EN 1998-5, Eurocode 8: Design of structures for earthquake resistance – Part 5: Foundations, retaining structures and geotechnical aspects
BS EN 12111, Tunnelling machines – Road headers, continuous miners and impact rippers – Safety requirements
BS EN 13331-1, Trench lining systems – Part 1: Product specifications
BS EN ISO 14688-1:2002, Geotechnical investigation and testing – Identification and classification of soils – Part 1: Identification & description
BS EN ISO 14688-2:2004, Geotechnical investigation and testing – Identification and classification of soils – Part 2: Classification principles
BS EN ISO 14689-1, Geotechnical investigation and testing – Identification and classification of rock – Part 1: Identification and description
NA to BS EN 1990:2002+A1:2005, UK National Annex for Eurocode – Basis of structural design
NA to BS EN 1997-1:2004, UK National Annex to Eurocode 7 – Geotechnical design – Part 1: General rules
NA to BS EN 1997-2:2007, UK National Annex to Eurocode 7 – Geotechnical design – Part 2: Ground investigation and testing
Other normative references
 Manual of Contract Documents for Highway Works, Volume 1 – Specification for Highway Works, Series 600 – Earthworks. Highways Agency. (www.standardsforhighways.co.uk)