Rosyida, HawmarFerry, FatnantaAgus, Nugroho Soewignjo2013-03-302013-03-302013-03-30rio andikahttp://repository.unri.ac.id:80/handle/123456789/2710Soil investigations are carried out in the field to get a true geotechnical analysis. Various kinds of testing tools are designed to simplify the work of investigation, one of which is the Mackintosh Probe. However, the use of Mackintosh Probe is less popular in Indonesia. The device has advantages, such as easy to use, light, requires no calibration, and requires a relatively low cost when compared to other soil strength testing. However, it also has drawbacks. Data obtained from the test results are in the form of number of blows and depth, making it difficult to be applied in further calculation of soil. This research was conducted to determine the shear strength value of soft soil based on Mackintosh Probe testing, by creating correlation value between Mackintosh Probe testing with shear strength (cu, φ) from triaxial testing and Mackintosh Probe with field vane shear test (Su). The tests were carried out in 35 points. Field trials were conducted in Siak District, Riau, with locations spread out in several villages located not far from the river. Based on the research conducted, test results show that the value of Mackintosh Probe testing is directly proportional to the value of Su, if the value of Mackintosh Probe is great, then the value of Su is also increasing. Whereas the correlation value between Mackintosh Probe testing and cu and φ reveals no positive data connection.othersoil investigationMackintosh Probeshear strengthstudent Paper Post Degree