Civl2410 - determine the settlements when a stress of 150

Question

Individual Projects

For each project the aims are

- to show the effect that the sub-layer thickness has on the calculation of the settlement
- to determine the maximum differential settlement under the foundation
- to discuss the accuracy of the settlement calculations

To determine the initial void ratio assume G_s = 2.65. Assume also that settlements of any sand and gravel layers can be ignored

A. A square building (15 m x 15 m in plan) is to be constructed on a site where the soil profile consists of 3 m of clay with an over-consolidation ratio of 5 overlying a 5 m thick layer with an over-consolidation ratio of 1, which overlies rock. The soil properties are C_c = 0.35, Cr = 0.07 and γ_sat = 20 kN/m³ for both clays, and the water table is 1 m below the soil surface. Determine the settlements when a stress of 100 kPa is applied by the building.

B. A building is to be constructed with a ring beam foundation on a site where the soil profile consists of 3 m of dense sand overlying a 5 m thick layer with an over-consolidation ratio of 1, which overlies rock. The soil properties of the clay are C_c = 0.25, C_r = 0.05, γ_sat = 18 kN/m³, for the sand γ_sat = 18 kN/m³, and the water table is 2 m below the soil surface. Determine the settlements when a stress of 100 kPa is applied by the building. Determine the differential settlement between the centre line of the ring beam and under the centre of loaded area of the beam. The inner and outer radii of the ring beam are 8 m and 12 m respectively

C. A rectangular building is to be constructed on a site where the soil profile consists of 5m of clay with an over-consolidation ratio varying linearly from 2 at the surface to 1 at 5 m, overlying a 7 m thick layer with an over-consolidation ratio of 2, which overlies rock. The soil properties are C_c = 0.3, C_r = 0.08 and γ_sat = 20 kN/m³ for both clays, and the water table is 1 m below the soil surface. Determine the settlements when a stress of 125 kPa is applied by the building over an area of 12 m × 7 m on the soil surface.

D. Figure 1a shows the elevation of a site where a building applying a uniform stress of 100 kPa over a 12 m square foundation is to be demolished. An old brittle pipe carrying critical infrastructure lies 4 m beneath one edge of the building as shown in the plan view in Figure 1b. The soil profile consists of 2 m of dense gravel with γ_dry = 17.2 kN/m³ which overlies a 6 m thick clay deposit. The water table is 2 m below the surface, level with the top of the clay layer. The clay layer has properties C_r = 0.04, C_c = 0.4, OCR = 1, γ_sat = 17.75 kN/m³. The clay is underlain by impermeable rigid rock.

Determine the settlement of the pipe at points X and Y when the building is demolished and the stress of 100 kPa is removed. It may be assumed that the pipe moves with the surrounding soil.

E. A circular grain silo is to be constructed on a site where the soil profile consists of 20m of clay overlying rock. The over-consolidation ratio varies linearly from 5 at the surface to 1 at the base of the clay layer. The clay properties are C_c = 0.25, C_r = 0.04 and γ_sat = 18.5 kN/m³, and the water table is 1.5 m below the soil surface. Determine the settlements when a stress of 150 kPa is applied by the tank which is 12 m in diameter.

Attachment:- Assignment.pdf