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What is soil bearing capacity?

What is soil bearing capacity?

All the civil engineering structures whether buildings, dams, bridges, etc. are built on soils. A base is required to transmit the load of the structures on a large area of soil. The base of the structure should be designed so that the ground below will not fail in the shear nor will there be an excessive settlement of the structure. The conventional method of foundation design is based on the concept of load capacity. The soil is considered by the engineer as a complex material produced by the weathering of solid rock. The soil is the most important material used for the construction of civil engineering structures. Among all the parameters, the load capacity of the soil to support the load over unit area important. There are several methods to calculate the soil carrying capacity presented by the specialist. The main factors that influence the ultimate load capacities are the type of soil, the foundation width, the weight of the soil in the cutting area and the surcharge. Structural rigidity and contact voltage distribution do not greatly influence the load capacity. The analysis of the load capacity assumes a uniform contact pressure between the foundation and the underlying soil. With other factors unchanged, the type of soil failure, the depth of foundation and the effect of groundwater table control the bearing capacity of the soil.

 

soil bearing test

 

When a soil is stressed due to loading, it tends to deform. The resistance to soil deformation depends on factors such as water content, bulk density, internal friction angle and the way the load is applied to the ground. The maximum load per unit area that the earth or rock can transport without yielding or moving is called bearing soil capacity. Soil properties, such as cut resistance, density, permeability, etc., affect the load capacity of the soil, dense sand will have more load capacity than loose sand as a unit of weight dense sand is more than loose sand. If the carrying capacity of the ground at shallow depth is sufficient to safely take the load of the structure, a surface foundation is provided for a shallow foundation, isolated foundations, combined footings or shoe bases can be used. Deep foundations are provided when the ground immediately below the structure does not have the capacity of adequate load, piles, springs or wells are the options for deep foundations. The foundations of mat or raft are useful for soils that are subject to settlement or where there is a large variation in the load between adjacent columns.

 

soil testing

 

Methods of bearing capacity

 

There are various methods of computing the bearing capacity listed as follows

1: Presumptive Analysis

2: Analytical Methods

3: Plate Bearing Test

4: Penetration Test

5: Modern Testing Methods

6: Centrifuge Test

What is meant by Geotechnical Engineering and what does they do?

What is meant by Geotechnical Engineering and what does they do?

Geotechnical engineering

 

Geo technical engineering is a branch on civil engineering that deals with soil and rock behaviour. This also involves to assess the slope stability and the risk of landslides, rock falls and avalanches. The word geotechnical refers to the geological components of the earth like the earth, soil and also the groundwater. They also assess the risks posed by the site conditions. Geo technical engineering is also applicable in Military, mining and petroleum along with other engineering disciplines like construction that is done on the surface or within the ground.

 

What does they do?

 

 

Geotechnical engineering helps in determining the physical, mechanical and chemical properties of soil and rocks. A geotechnical engineer skills are used for drilling wells, transporting petroleum products, construction of production and storage facilities and also examining ground water flow. Geotechnical engineers plays a crucial role in all civil engineering projects, Before commencing any construction work it is very important to do a site investigation.  Because if the investigation is not carried out properly it can be very expensive and can carry negative consequences also.

Geotechnical engineers guard and maintain the earth's physical environment during the development of major projects. They also combine there expertise in civil engineering, construction and design which enables them to safely investigate and analyse the project sites and determine  their present and future stability. Geotechnical engineers provide analysis and mapping of technical results obtained from seismic surveys and investigate subsurface conditions and materials to determine their properties and risks. They also design pitwalls, mine waste dumps & dam structures used in oil sands mining and analyses the slope stability .

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