Soil mechanics is the study of the physical properties and utilization of soils, its behavior, and applications. For structures and subgrades for highways soil mechanics is especially used.
By French physicist the first scientific study of soil mechanics was undertaken and as the name soil mechanics implies the subject is concerned with the strength and deformation of bodies of soil and deals with the mechanical properties of the soil materials.
By soil mechanics study the type of construction, type of equipment to be used, and type of foundation, support material, and many other aspects of construction works are largely affected.
For resolving problems related to geology and geophysical engineering soil mechanics is one of the major sciences and for civil engineers soil mechanics studies are very important because engineering structures are constructed on the findings of soil mechanics studies.
Now we will discuss the major aspects of soil mechanics studies;
Formation of Soils:
Soil is the combination of organic elements and minerals that are in solid, aqueous, and gaseous form, and in their physical, mineralogical, and chemical properties the consisting particle layer in the soil is different from the original materials because of the interactions between the atmosphere and hydrosphere.
From broken rocks due to the chemical and environmental effects including weather and erosion, the particles of the soil are created and creating a soil formation that consists of pore spaces particles of soil that are filled loosely.
Soil formation modes study is important because it helps in determining properties of soil and knowing about the types of soil we have to deal with, cohesiveness, adhesiveness, the acidity of the soil, and other factors that can easily be determined. By conducting soil studies we cannot draw any concrete conclusions but by studying the basic characteristics of soil such as color, texture, and nature of the soil we can surely narrow our research parameters.
Soil structure is based on the arrangement of soil particles into small clumps and these clumps are called aggregates or peds and to form peds soil particles like sand, silt, clay, and organic matter bind together.
The ped has a specific shape depending on the composition and on the conditions in which the peds formed like getting wet and drying out, or freezing and thawing, etc.
Types of Soil:
There are two main types of soil as given below;
- Residual soils
- Transported soils
Residual soils are found at the location where they have been formed and from 5m to 20m the depth of residual soil varies.
In warm and humid regions chemical weathering rate is greater than cold and dry regions and residual soils take place as the rate of rock decomposition exceeds the rate of erosion. The presence of surface vegetation reduces the possibility of soil transportation in humid regions.
Residual soils comprise of a wide range of particle shapes, composition, and sizes.
To form transported soils weathered rock materials can be moved from their original site to new locations by one or more of the transportation agencies.
Based on the mode of transportation transported soils are classified;
- Alluvial Deposits; these are the soils that are carried and deposited by the river.
- Lacustrine Deposits; these soils are deposited by flowing water or surface runoff while entering a lake.
- Marine Deposits; In seawater if the deposits are made by rivers such soils are called marine deposits.
- Glacial Deposits; These types of deposits are formed by the melting of a glacier which causes deposits of all the materials.
Basic Characteristics of Soils:
- The basic characteristics of soils are an important aspect of soil mechanics. Soil consists of different phases of solid, gas, and liquid and on these phases and on the applied stress its characteristics depend and soil phase includes organic matter, clay, and non-clay minerals.
- From chemical spills, wastes, and groundwater the liquid phase is composed of water that contains organic compounds available while the gas phase is normally air and by mineralogy the size, form, chemical properties, compressibility, and load-carrying capacity of the soil particles are determined.
- The soil structure depends on the arrangement of particles, particle groups, composition, and pore spaces and these characteristics determine the type of structure to be built.
- An important factor that needs to be studied to make strong and durable structures is the consolidation of soils and this is a procedure by which the volume of soils is reduced. During the process of consolidation, the soil will bounce back and recover some of the volume lost with the removal of stresses.
- To determine the lateral earth pressure, bearing capacity of the soil, and slope stability analysis, soil mechanics studies are used and to design and construct batter structure soil mechanics studies always help a civil engineer. Soil mechanics studies also help in risk mitigation because if we know how the soil mass is going to behave we can take precautions at the time of construction.
All of the above discussion is the aspects of soil mechanics and in the study of soil mechanics, all things about the soils are available.