Soil Mechanics and Foundation Engineering (Part-2) (General Engineering) (SSC JE)

For well graded soil coefficient of curvature lies between 1 to 3.

 Allowable bearing capacity–
• It is the maximum net intensity of loading that can be imposed on soil with no possibility of shear failure or settlement failure.
• In IS : 6403 allowable bearing pressure named as allowable bearing capacity.

Ultimate bearing capacity– The max gross pressure intensity of the loading that the soil can support before its soils in shear.

Net safe bearing capacity– • It is the maximum net intensity of loading that the soil can safely support without the risk at shear failure.

Test to fined liquid limit (Cassagrande test)-
• Sieve size = 425 µ
• Wt. of soil = 120 gm
• Water content corresponding to 25 no. of blow called liquid limit.
Groove    Cassagrande tool
Bottom width     2 mm
Top width    11 mm
Height    8 mm

Ultimate bearing capacity–
• Minimum gross pressure intensity of the loading at which soil fails in shear is termed as ultimate bearing capacity.
OR
The maximum gross pressure intensity of the loading that the soil can support before its fails in shear called ultimate bearing capacity.

Nuclear gauges– The nuclear measuring gauges that incorporate a radioactive source. These nuclear gauges provide and inexpensive, yet highly reliable and accurate method of measuring the thickness, density, moisture content or make-up of a wide variety of material or surfaces.
There are two types of nuclear gauges–
(i) Fixed
(ii) Portable

Sensitivity     Soil
<1                 Insensitive
2–4             Normal sensitive
4–8             Sensitive
8–16            Extra Sensitive
> 16             Quick Sensitive