Field vs Laboratory Soil Tests: What Is the Difference

Field soil tests give foundation parameters in natural occurrence; laboratory tests give them on samples taken from a borehole. They are not competing methods: the designer needs both, but in different volumes. The mistake is to order only a laboratory suite “for expert review” and never check how the ground works under load on the site. In Aktau and across Mangystau Region this shows up clearly: saline, weak and locally collapsible soils change properties when they are sampled, dried and transported.

This article is for anyone writing a brief for geotechnical surveys: which methods sit in the field and laboratory suites, what each measures, and when a report cannot be submitted without field tests.

The Real Difference

Laboratory tests are run on intact blocks and disturbed samples. The geologist takes soil from a borehole, packs it and sends it to a soils laboratory. The lab determines grain-size composition, moisture, density, Atterberg limits, permeability, shear strength and compressibility. The output is a table of parameters by geotechnical element.

Field tests are performed on the site, without taking the sample out of the mass. A plate, static and dynamic probing, and a pressuremeter work the soil at its natural moisture, density and stress state. That is why the deformation modulus and bearing capacity obtained in the field sit closer to how the foundation, tank or pile field will actually behave.

The regulatory frame is the same across Kazakhstan: the survey composition is set by SP RK 1.02-102-2014 “Engineering-geological surveys for construction”, probing methods by GOST 19912-2012, plate and pressuremeter tests by GOST 20276-2012, soil classification by GOST 25100-2020. Which methods enter the programme is the geologist’s call from site complexity and structure type — not a “standard package”.

We covered which surveys you need before a foundation design in the article on engineering geology for foundations.

What Field Tests Measure

GeoProGlobal runs field tests with its own fleet: Izyskatel 600 and Izyskatel 5000 plates, a static CPT spread, dynamic probing (DPT) and a PEV-89MK pressuremeter.

Method	What it measures	When it is used
Plate bearing	Deformation modulus from the load–settlement curve	Critical foundations, weak soils, checking design settlements
Static CPT	Continuous qc and fs profile with depth	Pile foundations, layer boundaries, sites without coarse inclusions
Dynamic probing (DPT)	Blows per 10 cm of penetration	Dense sands, gravelly and coarse soils, embankment control
PEV-89MK pressuremeter	Deformation modulus at borehole depth, Ø 89 mm	Pile and piled-raft foundations where a surface plate cannot work

Static CPT does not replace drilling: it does not give a lithological log or samples. One CPT profile does, however, cover the section more densely than a sparse borehole grid. A dedicated write-up of the method is in the article on static cone penetration testing.

What the Laboratory Measures

The laboratory suite answers questions the field cannot close.

• Soil identification. Sand, loam or clay, void ratio, organic content. Without this a layer cannot be assigned to a geotechnical element under GOST 25100-2020.
• Physical properties. Moisture, density, plasticity limits, degree of salinity. For Caspian soils in Mangystau, salinity is not a footnote — it drives aggressiveness to concrete and steel.
• Strength and compressibility on the sample. Triaxial compression, oedometer, shear. These data enter the foundation calculation together with the field deformation modulus.
• Permeability and groundwater chemistry. Needed for drainage, waterproofing and concrete grade.

The laboratory’s limit is the same on every site: the sample is already disturbed. Even a careful block loses structure when it leaves the borehole. On saline and collapsible soils around Aktau this distorts the deformation modulus more than on a rock base.

When the Laboratory Is Enough — and When It Is Not

A minimum laboratory set is appropriate for simple Category I sites: a private house on a relatively uniform subgrade, modest load, no weak layers. Even then drilling and sampling are mandatory — there is no such thing as “a laboratory without boreholes”.

Field tests are added when at least one of the following holds:

• the structure is critical (tank, rack, multi-storey building, industrial hall);
• the section contains weak, fill, saline or collapsible soils;
• piles are designed and the calculation uses resistance with depth;
• the designer explicitly requires a plate or pressuremeter modulus for settlement;
• the site is linear (road, pipeline) and soils change along the route.

On industrial pads in Mangystau Region the typical programme is drilling + laboratory + CPT and/or a plate. A single method “just in case” will not pass expert review if the brief specifies a full suite.

The testing programme and report contents are described on the field soil testing service page.

What the Client Receives

The field stream produces protocols and graphs: load–settlement for the plate, qc/fs profiles, pressuremeter diagrams. The laboratory stream produces tables of physical-mechanical properties and chemistry. Both blocks go into the technical survey report together with borehole logs and foundation recommendations. That package goes to the designer and to state expert review.

FAQ

Can field tests be replaced with a laboratory suite to save money? No, if the designer needs the mass deformation modulus or a pile calculation from probing. The laboratory tests a sample; the field tests the subgrade.

Can we order only a plate or only CPT? Yes. The suite is selected from the brief: one method or a combination.

How long do field tests take? On a private plot inside Aktau — usually 1–2 days plus office processing. Remote pads at Zhanaozen and Beyneu add mobilisation of the rig and CPT unit.

Conclusion

Field soil tests show how the subgrade works on the pad. Laboratory tests show what it is made of and what physical-mechanical properties the sample has. For expert review and a correct foundation in Kazakhstan both streams are needed; in Aktau and Mangystau Region the field block matters especially because of saline and weak soils.

GeoProGlobal performs drilling, laboratory testing and the field suite (plate, CPT, DPT, pressuremeter) in Aktau and across Kazakhstan. To match a programme to your site, submit a request on the quote page — we will prepare a commercial proposal within one working day.