Geotechnical Engineering

DHARM

544 GEOTECHNICAL ENGINEERING

values in their code of practice ‘‘IS: 1904–1986 Code of practice for structural safety of Build-
ing Foundations—Second Revision”. Excerpts of these recommendations are given below:

Table 14.1 Safe bearing capacity (IS: 1904–1986 revised)

S. No. Type of rock or soil Safe bearing capacity

kN/m^2 (t/m^2 )

Remarks

1. Rocks without laminations and
   defects—e.g., granite, trap,
   diorite

3240 (330)

2. Laminated rocks, e.g., sand-
   stone and limestone, in sound
   condition

1620 (165)

3. Residual deposits of shattered
   and broken bed rock and hard
   shale, cemented material

880 (90)

I. ROCKS

4. Soft Rock 440 (45)
   II. COHESIONLESS SOILS


5. Gravel, sand and gravel, com-
   pact and offering high resist-
   ance to penetration when exca-
   vated by tools

440 (45) See note 2

6. Coarse sand, compact and dry 440 (45) Dry means that the
   GWL is at a depth not
   less than width of the
   foundation below the
   base of the foundation.


7. Medium sand, compact and dry 245 (25)


8. Fine sand, silt (dry lumps eas-
   ily pulverised by fingers)

150 (15)

9. Loose gravel or sand-gravel mix-
   ture; loose coarse to medium
   sand, dry

245 (25) See note 2

10. Fine sand, loose and dry 100 (10)
    III. COHESIVE SOILS


11. Soft shale, hard or stiff clay, dry 440 (45) Susceptible to long-
    term consolidation set-
    tlement

(Contd.)...