SPT split spoon samplers, CPT cones and drive rods

SPT split spoon samplers, CPT cones and drive rods

Split tube assembly

Manufactured to BS EN ISO 22476-3, consisting of top adaptor, pair of split spoons and cutting shoe. The top adaptor contains a ball valve held in place by a threaded brass bush. The standard thread connection on the top is 11/2″ BSW or BW rod but any other thread can be incorporated. The split spoon is manufactured from high tensile alloy steel tube. The cutting shoe is specially case-hardened and tempered to give the optimum wear resistance.

Until recently BS 1377:Part 9:1990 has been the definitive standard in the UK for carrying out the standard penetration test (SPT). However, with the publication of a new edition incorporating Amendment 2 (Amd. No. 17229, 31 July 2007) this is no longer the case.

Amendment 2 removes all of the wording in Clause 3.3 relating to the SPT, replacing it with a single sentence: “The SPT method is given in BS EN ISO 22476-3”. This ISO standard, dated 2005, is a normative reference cited in BS EN 1997-2, ie Eurocode 7 Part 2, which was published in 2007 although the National Annex for this Standard is still in preparation and the committee might like to consider the comments in this paper.

The amended British Standard has not been given a new publication date, its designation remains BS 1377-9:1990. This raises the potential for confusion when referenced in specifications and other contract documents. However, as specifications usually state that the latest edition of any standard is deemed to apply it is the test method given in BS EN ISO 22476-3 which is now definitive. The question is whether this ISO standard by itself provides a satisfactory basis for carrying out SPT's in the UK. 

The standard SPT split tube assembly is 2″ (50.8 mm) O.D. x 13/8″ (34.9 mm) I.D. and the length of split tube is 24″ (610 mm). Other diameters and lengths, if required, are manufactured to order. Split tube samples can also be manufactured to order with stainless steel liners or made entirely from stainless steel tube.

Also available as illustrated is 60 degree solid nose cone for cone penetration test (CPT) and long solid CPT rod.

SPT drive rods

A purpose-manufactured drive rod is available for SPT sampler. The rod is manufactured from a thin, but high tensile, tubular section 54 mm O.D. with solid 11/2″ BSW male and female tool joints shrink welded to each end. The rod weighs only 8.8 kg per metre but is both stronger and stiffer than the BW rod (BS 4019), which can be used as an alternative drive rod for the standard penetration test. The rods are available in standard lengths of 3.0m, 1.5m and 0.75 m.