Question

Topic: Construction - Soils

(Note: Briefly discuss in your own words, 2-3 paragraphs minimum, add reference if using any.)

Create a Technical report about "Soils conditions requiring drainage and drainage types and methods". Your report should include charts/tables and other tabulated information collected from your research of this topic.

Answer 1

Ans) Soil condition required drainage

A soil with high water table and water logging topography will require a drainage for the stability of the structure build on soil.Properties of soil will affect the drainage and play and important role in deciding type of drainage required

1) Permeability - Soil with low or very low permeability will require drainage especially when rainfall is high and the surface of soil is leveled .Also, if the level of groundwater table is high then the soil will require drainage.

2) Texture -Fine texture soil will require drainage whereas coarse texture may or may not require drainage.

3) Structure of soil - Clayey soil generally have poor drainage as compared to sandy soils and they requires drainage

4) Water table - Soil in area with high water table will require artificial drainage

5) Soil lying over impermeable layer - In such case, naturally water is not allowed to drain so if the soil lie over an impermeable layer it will require artificial drainage .

Types of artificial drainage

Surface drainage - Removing excess water from land in controlled manner as quickly as possible is known as surface drainage. It has the following advantages:

1) Draining large quantities of surface water quickly

2) Acting as collector system sub surface

Sub surface drainage - When the topography of land is flat and surface drainage is not possible then sub surface drainage will be used.Following are the types of sub surface drainage :

Random subsurface drainage - Drain files are laid randomly to drain and lateral or sub main line are connected further to main line

Herring Bone system - It consist of parallel sub lines that connect to main to either side at angle

Soil property	Drainage requirement
Permeability	Yes for low permeability and in some cases for high permeablity
Texture	Yes for fine grained
Structure	Yes for clay
Water table	Yes for high water table
Underneath layer	Yes for impermeable underlying soil layer