Point Load Test

Point load test is a laboratory test used to determine the strength of rocks, and is widely used in geotechnical and mining engineering. The test is performed on cylindrical rock specimens of standard size (typically 50 mm diameter and 100 mm length), and the maximum compressive force required to break the specimen is measured. This force is used to calculate the point load index, which is an index of the rock strength.

The point load test provides valuable information about the mechanical properties of rock, such as its compressive strength, tensile strength, and shear strength. The results of the test are used to classify rocks into different categories based on their strength, which is useful for engineering design and analysis.

The point load test is performed according to the Indian Standard Code (IS: 9143-1979), which provides guidelines for the preparation of rock specimens, the arrangement of testing equipment, and the procedures for performing the test. The code also specifies the minimum number of tests to be conducted, based on the size and type of rock, to obtain a representative result.

The point load test is a relatively simple and quick test, and provides a good estimate of the strength of rocks, particularly in cases where core samples or full-scale rock tests are not possible. However, it is important to note that the results of the point load test are not always representative of the in-situ strength of rocks, as the test is performed under laboratory conditions, and does not take into account the effects of natural stress and strain.