This set of Construction Materials Assessment Questions and Answers focuses on “Bearing Capacity of Soil”.
1. _________ is used to indicate the maximum load per unit area which the soil will resist safely without displacement.
a) Bearing power
b) Maximum safe bearing capacity
c) Strength of soil
d) Allowable bearing pressure
Explanation: The Load of the structure is ultimately coming on the soil and hence it is of utmost importance to know the strength and behaviour of the soil. Dividing the ultimate bearing power of soil by a factor of safety, the safe bearing capacity of soil is obtained.
2. The term _________ on soil is used to indicate the maximum pressure which can be exerted on soil while taking into account shear failure, settlement and the ability of structure to resist settlement.
a) Bearing capacity
b) Net pressure intensity
c) Allowable bearing pressure
d) Maximum safe bearing capacity
Explanation: The value of Allowable Bearing Pressure on soil depends on the nature of ground and the type of building. The maximum safe bearing capacity of soil is generally more than the allowable bearing pressure on soil.
3. The maximum differential settlement should not exceed _____ mm in case of foundation on sandy soil.
Explanation: The total amount of settlement should be generally limited between 40 mm and 100 mm. The term differential settlement indicates the relative settlement of the adjacent portion of the structure.
4. The maximum differential settlement should not exceed ____ mm in case of foundation on clayey soil.
Explanation: For ordinary frame structures of concrete, the permissible angular distortion is 1/500 i.e. one horizontal to 500 vertical and the desirable value is 1/1000 i.e. one horizontal to 1000 vertical. The term angular distortion is used to indicate the deformation of the structure in a vertical plane.
5. The maximum safe bearing capacity of hard rocks with defects and lamination such as granite, diorite and trap is _____ kN/m2.
Explanation: The term maximum safe bearing capacity of soil is used to indicate the maximum pressure that is soil can be here without any risk of shear failure only, irrespective of any settlement that may occur.
6. The maximum safe bearing capacity of very soft, wet, pasty or muddy clay is ____ kN/m2.
Explanation: As the given soil is very soft, wet, muddy clay, the soil possess very least minimum safe bearing capacity. This is because, this soil possess very less intermolecular attraction between the molecules hence it has low bearing capacity.
7. In case of non-cohesive soils such as sand and gravel, ___% reduction in allowable bearing capacity of the soil should be applied, if the water table is situated below or near the bearing surface of the soil.
Explanation: However, if water table is situated below the bearing surface of the soil at a depth equal to the width of the foundation trench, no such reduction should be applied. But in this case, 50% reduction is applied. For intermediate depths of the water table, the proportion and percentage reduction should be applied.
8. Identify the method given below for the determination of the bearing power of soil.
a) Plate load test method
b) Electrical resistivity method
c) Seismic refraction method
d) Geophysical method
Explanation: Plate load test method is one of the methods of determination of bearing power of soil. Plate load test method is the improved point method and it is widely used for determination of the bearing capacity. Other methods for determination are: method of loading, method of dropping a weight, analytical methods and Presumptive method.
9. In which method, a square steel plate is used to determine the bearing power of soil.
a) Plate load test
b) Method of loading
c) Analytical method
d) Penetration test
Explanation: In method of loading, a square steel plate is used whose size depends on practical conditions and it generally varies from 3000 mm2 to 7500 mm2. The plate should have sufficient thickness to with stand the maximum bending stresses due to probable loading.
10. The bearing capacity of soil is calculated in ______ units.
Explanation: The bearing capacity of soil is calculated as the maximum load divided by the total area of steel plate i.e. Bearing Capacity = max. Load ÷ area of steel plate and the unit is N/m2 or kN/m2.
Sanfoundry Global Education & Learning Series – Construction and Building Materials.
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