What are the bearing capacity values of different types of soils such as clay, sand, gravel, rocks etc.?
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Follwoing are the values of safe bearing capacity as per IS:1904–1978 –
a) hard sound rock – 330 t/m2 or 3240 KN/m2
b) leminated rock – 165 t/m2 or 1620 KN/m2
c) residual deposit of shattered and broken rocks- 90 t/m2 or 880 KN/m2
d) soft rock – 45 t/m2 or 440 KN/m2
Non Cohesive Soil (sand & gravel ) –
a) compact gravel, sand and gravel – 45 t/m2 or 440 KN/m2
b) compact and dry coarse sand – 45 t/m2 or 440 KN/m2
c) compact and dry medium sand – 25 t/m2 or 245 KN/m2
d) find sand – 15 t/m2 or 150 KN/m2
e) loose gavel or sand – 25 t/m2 or 245 KN/m2
f) loose and dry fine sand – 10 t/m2 or 100 KN/m2
Cohesive soil –
a) hard or stiff clay, soft shale – 45 t/m2 or 440 KN/m2
b) medium clay – 25 t/m2 or 245 KN/m2
c) moist clay and sand clay mixture – 15 t/m2 or 150 KN/m2
d) soft clay – 10 t/m2 or 100 KN/m2
e) very soft clay – 5 t/m2 or 50 KN/m2
f) black cotton soil , peat – by soil investigation
This is bit difficult to state like this. Generally, in fields, we deal with layered soil systems where in you need to work out settlement of each layer and then compare the same to allowable settlement of the subject structure. The allowable settlement for each structure in different and hence the criterion changes all the time.
More than shear criteria, the settlement criteria generally governs the safe bearing capacity of a soil. So, it is difficult to standardize the bearing capacity values in case of soils. May be, in the case of rock, you can standardize the values as the rock does not settle more than 3–4 mm.
For the different values of bearing capacity factor under the application of general shear failure, values are shown in the above table.
Where Nc, Nq and Ny are the factors of Terzaghi’s bearing capacity.
Different soil SBC are as follow
In actual site, we conduct several test to find out SBC.
Is it always correct to utilize smaller value of SBC even though the kind of material is loose of soft clay and yet within this value the structure is still safe and sound.
Regards and thanks.
The bearing capacity values for different types of soil are-
Of course these are indicative values and do not substitute for soil testing by a specialized laboratory.
Can I get step by step on how to find out SBC if cohesion=0.36 kg/cm²,angle of internal friction=13,Field dry density=1.603,fmc=12%.
1 kg = 10 N, so, 1000 N = 100 kg = 1 kN. So, value of column 2 is divided by 100 to obtain value in kN/m2.
Review the Gopal first column, it’s wrong, the correct value must be: the tabla value divided by 10000
Following table shows maximum bearing capacity values of different types of soils:
Bearing capacity of soil is the maximum load per unit area. This is the ultimate bearing capacity of soil shown in table. Dividing the ultimate soil bearing capacity by a safety factor we get the maximum safe bearing capacity of soil for design of foundations.
Dear Gopal, thankyou for this informative. I have an additional query. How does one deduce the soil type (among the above mentioned types) by visual inspection or simple field tests ?