Ground investigations

Undisturbed sampling

Silt, sand and gravel

Geofrost provides undisturbed samples by the Geofrost Coring method. We provide undisturbed samples also from pure frictional soils like silt, sand and gravel which can be tested in the laboratory to find in-situ strength and deformation properties as well as degree of compaction and permeability.

Geofrost Coring is the method providing the best quality of undisturbed samples of frictional soils.

Talus and moraine

Geofrost Coring gets core samples from mixed soils containing cobbles, stones and more or less fines in-between. The coarser particles are not torn out of the surface, but accurately cut.

Fill

Geofrost Coring obtains undisturbed samples also in fills, which often are mixed soils. As long as it is possible to drill, undisturbed samples are achievable.

Transition from soil to rock

Geofrost Coring penetrates stones and rock and at the same time captures the fines, enabling undisturbed samples of the transition from soil to rock. In the laboratory, closer examination of the transition may be done to both find the degree of rock weathering and whether critical amount of soft soil is left behind after a complete mass replacement.

Rock fracture filling

With Geofrost Coring all fracture fillings are captured, even empty cavities and water filling.

With conventional core sampling the filling is often washed away.

Contamination

With Geofrost Coring all phases of the content present are locked in place in situ, making the samples showing exact level or position of the different contaminations. This is the method to capture both the liquid and the gas phase, in addition to contamination i the solid phase.

Natural frost

In areas with seasonal frost, sampling by Geofrost Coring through the layers potentially containing ice lenses, may add new knowledge to the frost heave process and how different temperature variations affect the buildup of ice lenses in the different ground conditions.

In permafrost areas, Geofrost Coring provides undisturbed samples of good quality. Even for marine permafrost sediments, with pore water containing salt, the Geofrost Coring method provides good quality samples without surface destruction.

Laboratory testing

Frozen sample

With Geofrost Coring the ground is frozen before samples are cored. The samples may be tested directly to find in-situ frozen strength parameters as well as thermal properties. Complicated preparatory build-in and freezing procedures to recreate the in-situ conditions in the frozen ground are avoided.

Thawed sample

The exceptional good quality of the samples received by Geofrost Coring, enables performing laboratory testing on frictional material as it was in situ. The undisturbed frozen samples are robust and can easily be handled for preparation in the test apparatus. In-situ confining pressure is applied to the sample before it thaws. Then the desired test is run.

Geofrost Coring provides samples with actual structure and compaction, instead of being artificially built into a mold. This makes it possible to find strength and deformation properties for both frictional soils and mixed soils, as well as finding actual permeability properties through critical layers.

Classification

Geofrost provides complete classification and description of the layers, also for inhomogenous frictional soils, because nothing is lost or disturbed during Geofrost Coring.

Porosity and density determination is possible where one previously could only do qualified guessing.