Laboratory tests have the limitations like variability and sample disturbance. Also, testing is done on small specimens and extrapolation of the measured properties for the entire site is often challenging.

In contrast, insitu test provide the response of a larger mass under natural insitu condition. The limitation includes poorly defined boundary condition, cost and time, approach and site condition, non-uniform and high strain rates imposed during testing and inability to control drainage condition etc. Despite these limitations insitu tests are most acceptable and essential part of any geotechnical site investigation and design. Large scale insitu tests are necessary for design consideration of major projects because laboratory tests invariably lead to an overestimate of the properties of rock mass. Geotechnical investigation and design in rock mass always insists insitu tests. Some important requirements of insitu tests,

• Test should affect a rockmass to the extent that it represents the behaviour of the affected rockmass or zone.
• Cost should be low without compromising quality.
• Equipment used should be simple and compact.
• Nearest to actual stress condition•As per theory on which the test is based.
• Load should be applied in the direction representing actual anticipated direction.

Type and number of insitu tests usually depends upon the type of structure and its importanceand the rock strata condition. Insitu tests can be put in general following categories,

• Shear test.
• Deformability tests.
• Strength tests.
• Tests for internal stresses.