In addition to many years of experience in geotechnical construction works, KARST d.o.o. holds experience in testing quality of executed geotechnical elements.
The tests we perform are closely related to the mentioned works, namely:
- Standard penetration test (SPT)
- Sampling of disturbed (DS) and undisturbed soil samples (UDS)
- Registering and measuring of groundwater level (GWL)
- Permeability tests by the Lugeon and Lefranc method
- Core determination / classification and determination of the degree of rock mass fracture (rock quality designation RQD)
- Dynamic penetration test (DPH, DPM, DPL)
- Static pile load tests
- Pile Integrity (PIT / PET)
- Testing of trial and working anchors (pre-stressing of anchors)
- Camera for prospection of boreholes/wells (up to 300 meters in depth)
- Static and dynamic water level measurement (DIVER)
- Sampling and testing of water in accredited laboratories
- Pumping tests (most commonly in well structures), by various methods, more commonly known are „step test” and “constant rate pumping test”
Standard penetration Test (SPT), sampling of disturbed (DS) and undisturbed samples (UDS), monitoring and measuring of ground water levels (GWL), permeability tests by Lugeon/Lefranc method, as well as core determination/classification and degree of rock mass fracture (RQD) are described in detail in the chapter “GEOTECHNICAL INVESTIGATION WORKS”.
Dynamic Penetration/Probing Test (DP) is also a part of soil investigations, respectively geomechanics (geotechnical investigation works), but it can be performed as an autonomous test, independent of drilling as opposed to the above-mentioned tests. Testing determines the resistance of soils and soft rocks in situ to the dynamic penetration of cone, which is located on the rods of a certain length and weight. Depending on the mass of the hammer used for driving the rods and the cone into the ground we have a division into following procedures: DPH, DPM and DPL. DPH (Dynamic probing heavy) – heavy dynamic probe or hammer mass of 50kg, Dynamic probing medium (DPM) – medium dynamic probe or hammer mass of 30kg, DPL (Dynamic probing light – lightweight dynamic probe or hammer mass of 10kg, there is also DPSH (Dynamic probing super heavy) – super-heavy dynamic probe, hammer mass weighing 63.5 kg.
In order to determine quality of executed foundation elements which are implemented up to several tens of meters deep in the ground, to test the deep foundations, micropiles and piles, we use two methods. One is a static pile load test, while the other and non-invasive method is PIT.
The static pile load test includes a massive load (defined by calculations) by a hydraulic press onto the executed pile and settlements measurement at the load, in order to assess whether the executed pile can hold the designed loads. This is a very expensive procedure and is rarely performed.
Pile Integrity test (PIT, Pile integrity test or PET, Pile echo test) is performed with our M.A.E. equipment and software for data processing. It is a non-invasive method that, based on the reflection of sound, sonic/acoustic waves through the pile, determines whether there are discontinuities/defects or a pile is whole. Particularly important when executing piles in materials where the risk of material debris falling is high or there is a justified fear of segregation of concrete.
The anchors are a very important element, either in landslides improvement, pit protection or slope stabilization, whether they are active or passive, it almost always comes to the same, which is tightening (inserting force into the anchor) at the designed force. To have the anchors tightened to a certain force or to perform anchor control, there are trial and working anchors, we use our calibrated hydraulic presses, micro gauges and cylinders. Depending on the type of a press, either manual or automatic, we test anchors to different forces, and the most up to 1.000 kN.
In the chapter “WATER INVESTIGATION WORKS” more or less the following tests are described: camera for prospection of boreholes/wells (up to 300 meters in depth), static and dynamic water level measurement (DIVER), sampling and testing of water in accredited laboratories, pumping tests (most commonly in well structures) by various methods, more commonly known are „step test”, and “constant rate pumping test”.
It should be noted once again that when an obstacle in the borehole happens or simply there is a need to check what is happening at the certain depth in some well, we own a “PASI” camera with which we conduct video prospection up to 300m deep. After the performed works, the report is prepared together with the ‘’video clip’’ of the recorded borehole/well.