Sampling of Stabilized Clay by Use of Kiso-Jiban GP-Tr Sampler-Paper

Paper

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The paper evaluates the Kiso-Jiban Gel Push Triple (GP-Tr) sampler for collecting high-quality samples of lime-cement-stabilized clay, a brittle material that is difficult to sample using conventional piston methods. The sampler uses a gel polymer to reduce friction between the sample and its liner, and can operate with a standard geotechnical drilling rig.<br /><br />Field trials were conducted at two Norwegian sites, where stabilized clay columns were sampled at depths of up to 8 m. Most samples were continuous and showed no obvious cracking or damage when inspected. Laboratory testing—including uniaxial compression, triaxial, oedometer and direct simple shear tests—was successfully performed on the samples. Measured shear strengths ranged from 60 to 310 kPa; the lowest results were associated with samples disturbed during handling or testing.<br /><br />Some samples broke during extrusion or transport. Because stabilized clay is highly brittle, the cause may include the sampling process, vibration, sealing, extrusion, or weak zones within the columns. Careful handling is therefore essential. Preparing samples for testing also required reducing their diameter, which could itself cause disturbance; ideally, laboratory equipment would accommodate the sampler’s original sample diameter.<br /><br />Overall, the trials indicate that the GP-Tr sampler can retrieve representative stabilized-clay samples from considerable depths and enable advanced laboratory assessment of material properties. Although sampling takes time, the equipment’s compatibility with a standard drilling rig offers practical advantages. Further investigation is needed to identify and reduce sources of sample disturbance.

Keywords

Kiso-Jiban Gel Push Triple

GP-Tr sampler

lime-cement-stabilized clay

brittle material

geotechnical sampling

Norwegian field trials

sample disturbance

uniaxial compression

triaxial testing

direct simple shear