BS 6031:2009 pdf free download – Code of practice for earthworks.
If the observational method is the design approach, certain requirements for the GI should be addressed at an early stage (see BS EN 1997-1:2004, CIRIA R185 [16]). However, the 61 and design process for earthworks projects should be responsive to ground conditions encountered, so there should always be an element of observation and response. Therefore, the 61 may be planned accordingly from an early stage, which can be advantageous, (e.g. position of instrumentation to ensure future use through the project).
The investigation of failed earthworks should be given special consideration when planning investigations. Of paramount importance are the on-going risks posed by the failed earthwork and the economic implications for the earthworks owner. The investigation should be designed to identify the failure mechanism and provide sufficient information to design an engineered solution to the problem.
Existing earthworks that will be subject to modification e.g. embankment widening should be given special consideration when designing a GI to take account of the potential for differential settlement, increased porewater pressures and reduced slope stability.
6.1.3 Testing
The testing regime, both in situ and within the laboratory, should form an integral part of any GI to enable site characterization and material classification for both design and construction purposes.
The choice of testing method to control the works should maximize the volume of usable material and minimize disruption to the works. The use of laboratory relationship testing (MCV: mc: dry density: strength) in advance of the works is advisable; this approach will often enable control of earthworks by MCV which minimizes disruption of the works.
Relationship testing to identify an acceptable range of moisture contents for the material to be used in earthworks should be undertaken under Category 2 and Category 3 projects. An adequate amount of soil should be recovered as bulk samples to enable a range of testing to be undertaken at a set of moisture contents, allowing an assessment to be made of the acceptable range of moisture content of the material for use in earthworks (see HA44/91 [17] and HA7O/94 [18] for details). An assessment may then be made for the appropriate treatment of marginal material falling outside of this acceptable moisture content range, or one of the other required material suitability criteria such as grading. Additional testing may be required as part of this assessment of marginal materials.
Table 2 provides a summary of the earthworks testing that is most commonly used to follow the SHW [1], and appropriate tests from Table 2 should be selected for the investigation and design stage.
COMMENTARY ON 6.1.3
The nature of soils tests undertaken for earthworks are detailed within 85 EN 1997-2:2007 and the various supporting documents. Experience has shown that more meaningful results can be obtained for earthworks by modifying tests to take account of local soils and conditions. This subcla use is provided to identify the tests most commonly recommended to control earth works (especially when following the SHW [1]) and to comment on some of the main issues that ought to be considered both during Gl and design of the earth works.