The PL-100V is a cost-effective portable point load tester used for determining the point load strength index for rock strength classification. Its digital readout unit comes with wide spread dis-play battery operated with a keyboard.
The PL-100V point load tester consists of a loading frame, a hy-draulic cylinder, a pump and a pressure gauge with digital readout unit for maximum load reading. An upper conical platen is fixed on the frame and a lower one on the cylinder piston. A graduated scale is fixed on the frame and indicates the specimen diameter.
Test Procedure
Three point load test configurations are used depending on the available rock specimens:
Diametrical – Axial – Irregular lump
The diametrical and axial tests use core specimens with length/diameter (L/D) ratios greater than 1.0 in the first case, and between 0.3 and 1.0 in the second case. Rock pieces of suitable irregular shapes are used when cores are not available.
The testing steps are the same for all configurations:
The specimen is positioned between the conical platens. The platens are then closed to make contact.
The distance “De” between the points of contact is read on the scale.
The load is increased such that failure occurs within 10 to 60 sec. and the failure load “P” is read and recorded.
| General specifications | |
| Maximum specimen size | 102 mm |
| Maximum load | 100 kN |
| Effective resolution | 18 bit (1/262’000 div) |
| Pressure gauge | |
| Range | 100 000 kPa |
| Accuracy | 1% F.S. |
| Available units | kN*, MPa, psi |
| Load measurement accuracy | 1 kN |
* Based on conversion factor determined at calibration
| Main frame assembly | |
| Height | 418 mm |
| Length | 200 mm |
| Depth | 200 mm |
| Weight | 14 kg |
| Pump assembly | |
| Height | 160 mm |
| Length | 798 mm |
| Depth | 310 mm |
| Weight | 8.3 kg |
Interpretation
The Point Load Tester allows users to determine an “Uncorrected Point Load Strength Index” (Is). This index must be corrected to a standard equivalent diameter (De) of 50 mm. It then becomes a unique property of the rock tested (Is(50)) which is most useful in rock strength classification.
Rock anisotropy is quantified by the “Strength Anisotropy Index” (Ia(50)). This index is the ratio of the greatest to least (Is(50)) index measured respectively perpendicular and parallel to the existing planes of weakness.
The uniaxial tensile (UTS) and compressive (UCS) strengths can be approximated from the Is(50) index. The UTS is about 1.25 times Is(50) and the UCS is normally between 20 and 25 times the Is(50) index.
Is is obtained from the following equation:
Is = P / De2 where:
The ISRM* “Suggested Method for Determining Point Load Strength” size correction procedure is used. Is(50) is obtained either graphically, mathematically or by testing 50 mm (maximum diameter) specimens.
*ISRM: International Society of Rock Mechanics.
The unit comes in a custom-made road case.
Accessoires disponibles
