GCHM: Geotechnical Chemistry Testing

• Class: Samples, Amalgamated Specimens and Laboratory Test Scheduling

Heading	Unit	Type	Example	Description
LOCA_ID		ID	327-16A	Location identifier
SAMP_TOP	m	2DP	24.55	Depth to top of sample
SAMP_REF		X	24	Sample reference
SAMP_TYPE		PA	U	Sample type
SAMP_ID		ID	ABC121415010	Sample unique global identifier
SPEC_REF		X	1a	Specimen reference
SPEC_DPTH	m	2DP	24.55	Depth to top of test specimen
GCHM_CODE		PA	AS	Determinand
GCHM_METH		X	BS1377-3	Test method
GCHM_TTYP		PA	Solid_21 Water Extract	Test type
GCHM_RESL		U	14.23	Test result
GCHM_UNIT		PU	mg/l	Test result units
GCHM_NAME		X	Water Soluble Sulfate	Client/laboratory preferred name of determinand
SPEC_DESC		X	Grey slightly gravelly clay	Specimen description
SPEC_PREP		X	2:1 water/soil extract	Details of specimen preparation including time between preparation and testing
GCHM_REM		X		Remarks on test
GCHM_LAB		X	ACME Laboratories plc	Name of testing laboratory/organisation
GCHM_CRED		X	UKAS 0000	Accrediting body and reference number (when appropriate)
TEST_STAT		X	Checked	Test status
FILE_FSET		X	FS23	Associated file reference (eg test result sheets)

Notes - 8

• GCHM is used to report chemical testing carried out for geotechnical design. It is to be used for testing in accordance with BS1377-3:1990 (Amendment 1), testing for use in the assessment described in BRE Special Digest 1 (2005) and/or buried steel testing described in the Design Manual for Roads and Bridges; BD42/00 (Volume 2, Section 1, Part 2) and BD12/01 (Volume 2, Section 2, Part 6). Chemical testing for contamination or water quality testing is reported in ERES. Laboratory resistivity test results should be reported using the LRES Group.
• The GCHM_CODE abbreviations to report testing to BRE Special Digest 1 and BS 1377-3 would be:
• The GCHM_CODE abbreviations to report testing of buried steel would be:
• All GCHM_CODE abbreviations reported in this group are to be listed in the ABBR group.
• The GCHM_TTYP abbreviations would be limited to SOLID_21WAT, SOLID_ACID, SOLID_TOT and WATER to report testing to BRE Special Digest 1 and BS 1377-3.
• GCHM_UNIT is a REQUIRED field (Rule 10b) which enforces the inclusion of units for all test results. Where a test result has no unit, the GCHM_UNIT data shall be set to “-”.
• Units reported in GCHM_UNIT must be fully defined in the UNIT group (Rule 15). It is possible that units require conversion when the data is received and amalgamated into project databases to ensure that data are consistent across testing tranches and appropriate for the assessment.
• For a chalk content test carried out to BS1377-3, it would be good practice to report both a Carbonate content (as CO2) and the chalk content (as %CaCO3).