Table 4.

Suggested method for estimating F3 ‘Nature of defects’ (Table 3)

Separation*Joint Roughness Coefficient (JRC)
>128–104–8<4Smooth and/or slickensided
Tight, no separation11122
<1 mm11233
1–2 mm12344
2–5 mm23455
>5 mm34555
  • * If joint is in-filled with soil, or is weathered to UCS <1 MPa, assume in-fill and/or soil is eroded and use eroded opening as separation.

  • If joint walls have UCS 1–5 MPa, increase relative importance factor by 1, with a maximum of 5.

  • Joint Roughness Coefficient to be estimated from Barton & Choubey (1977).