Method | Advantages | Limitations |
Relief (Overcoring) | Most developed technique in both theory and practice. Operated at 10−3 - 10−2 m3 rock volume. | Scattering due to small rock volume. Requires drill rig. Only 2D. |
Doorstopper | Works in jointed and high stressed rocks. | Only 2D. Requires drill rig. |
Flat jacking | Direct measurement of the compressive stress present. Both 2D/3D within the masonry. Useful for determining stress gradients within a masonry wall or column. Operated at 0.5 - 2 m3 rock volume. | Requires the cutting of a slot in the masonry, which may cause damage to the structure. Can be time-consuming and labor-intensive. Requires specialized equipment and trained personnel to perform the test. |
Hydraulic fracturing (HF) | Measurements in existing hole. Low scattering in the results. Involves a fairly large rock volume. Quick. Operated at 0.5 - 50 m3 rock volume. | Only 2D. The theoretical limitations in the evaluation of σh. Disturbs water chemistry. Only 2D. |
HTPF | Measurements in existing hole. Can be applied when high stresses exist and overcoring and hydraulic fracturing fail. Both 2D/3D. Operated at 1 - 10 m3 rock volume. | Time-consuming. Requires existing fractures in the hole with varying strikes and dips. |