U100 Sampling Systems
Open tube driven-in soil samplers, for sampling clay and other cohesive soils. Sample tubes are 18″ (457mm) long and are driven into the ground using a sliding hammer with attached drive head. The drive head incorporates an overdrive space and a ball valve to allow air to be released from the upper part of the sample tube as it is driven into the ground.
A cutting shoe is screwed onto the lower end of the sample tube, and a corecatcher (optional) fits between the sample tube and the shoe. The corecatcher has four hinged flaps around its circumference. These flaps prevent the sample escaping from the tube when the apparatus is raised from the borehole.
We presently supply 3 different systems, all producing nominal 100mm (4”) diameter samples:
U100 Standard System
Comprises a steel or aluminium sample tube, cutting shoe and core catcher. Shoes may have either a plain edge or a serrated edge.
U100 Plastic Liner System
The sample tube is replaced with a “Body Tube” that contains arigid plastic liner. The liner containing the soil sample can be quickly removed from the body tube and replaced with an empty liner after each sampling event. Shoes and core catchers are made from a thicker wall material than those of the standard system. A spacing ring is required to fit inside the recess of the cutting shoe when the corecatcher is being used.
UT100 Thin-wall System
The standard U100 system and plastic liner systems do not deliver truly undisturbed samples. The UT100 is a thin-walled system designed to fully comply with BS EN ISO 22475-1: 2006 (Eurocode 7 Part 2) and is capable of producing quality Class 1 samples. The materials used for the sample tube, corecatcher and shoe are thinner than those in the standard and plastic liner systems; therefore the UT100 causes less sample disturbance as it is driven into the ground (Refer to table below).
However, it should be noted that, due to the use of thinner materials, the UT100 is not always sufficiently robust to withstand damage, especially when sampling in the presence of stony materials and dense gravels (e.g. glacial till). Under these circumstances a variety of alternative sampling methods should be employed.
Requirements of BS EN 22475-1:2006
UT100 thin-wall system
U100 standard system
|U100 plastic liner system|
|Edge taper angle (degrees)||should not exceed 5||5||10||7|
|Area ratio, Ca %||should be less than 15||14.97||29.4||47.1|
|Inside clearance ratio, Ci %||should be less than 0.5||0.19||1.34||1.27|
Key to Main Parts of U100 Assembly
Complete sampling system consists of:
1. Drive Head / Bell housing
2. Adaptor for Drive Head (UT100 only)
3a. Sample Tube (UT100)
3b. Sample Tube (U100 Standard system)
3c. Body Tube (U100 Plastic liner system)
4a. Corecatcher (UT100)
4b. Corecatcher (U100 Standard system)
4c. Corecatcher (U100 Plastic liner system)
5a. Cutting Shoe (UT100)
5b. Cutting Shoe (U100 Standard system)
5c. Cutting Shoe (U100 Plastic liner system)
5d. Cutting Shoe – Serrated type (U100 Plastic liner system)
6. Spacing Ring (U100 Plastic liner system)
7. Plastic liner (U100 Plastic liner system)
8. Caps for sample tube (not shown)