Clay soils, trees, vegetation and their influence on buildings

Question 1

Plasticity index

Answer 1

Question 2

Five main types of subsoil

Answer 2

• Rock such as granite, limestone and sandstone
• Granular soils such as sands and gravels
• Cohesive soils such as clays
• Organic soils such as pete and topsoil made ground

Question 3

Concrete strip foundation for compact sand and gravels

Answer 3

600 mm wide

Trench depth of 450 mm minimum but increased to 700 mm if there is a danger of frost heave

Question 4

Raft foundation

Answer 4

A slab of reinforced concrete spread over a large subsoil area often used above former underground mining areas

Question 5

Piled foundation

Answer 5

2 m down to 8 m or more which might support reinforced ground floor concrete slabs

Question 6

Common structural defects of foundations at construction stage

Answer 6

Question 7

Common structural defects of foundations at construction stage continued

Answer 7

Question 8

Subsidence

Answer 8

Cracks wider at the bottom

Question 9

Heave or hogging

Answer 9

Cracks wider at the top

Question 10

Differential settlement

Answer 10

Where separate parts of a building a subject independent movement e.g. a bay window rear annex

Question 11

Different types of retaining walls

Answer 11

Gravity retaining wall
Rubble retaining wall
Cantilever retaining wall
Anchored retaining wall
Steel reinforced wall
Sheet piling

Question 12

Strip foundation summary

Answer 12

Question 13

The foundation choice for various subsoil conditions

Answer 13