A site is to be developed for construction of a one-story steel structure. The site is underlain by 20 ft of soft clay (GWT at ground surface), which in turn is underlain by impervious rock Five feet of freely draining fill is to be placed on the site to raise the ground surface. The structure is relatively flexible and can withstand several inches of differential settlement. It is decided early in the design phase that the maximum allowable total settlement is 2 inches. The fill has a total unit weight of 120 pcf. The soft clay is normally consolidated with the following properties (= 100 pcf, S = 100%, Gs=2.7, Cc = 0.78, C₂=0.09). Assume that the water table stays at the interface between the clay and fill during consolidation and assume that the weight of the building is negligible compared to the weight of the fill. (a) Compute the total settlement of the soft clay caused by placement of the 5 ft of fill. Use one clay layer in your calculation. (b) Calculate the time required until only 2 inches of consolidation settlement remains. The coefficient of consolidation for the clay (c) is 0.35 f/day. Assume that the clay layer is free draining only at its top. 58 20 Draining Fill Clay Layer 3-130 g 7 Point of Interest 10 71-100 pdf Impervious Rock Fig. 2 Soil Profile in Question 4

What are the main factors affecting the expansion and contraction deformation of expansive soils?

To determine whether the surface zone of the natural soil is adequate for supporting the compacted fill, the area can be “proofrolled.” Explain what is Proofrolling?

Please explain and solve the question

A twenty-story hospital building with a 400 ft x 200 ft footprint is to be built on a site underlain by fill over glacial sands. The building will have a 25-ft deep basement and will probably be supported on either a mat foundation located 5 ft below the bottom of the basement, or a deep foundation extending about 100 ft below the bottom of the basement. The groundwater table is about 30 ft below the ground surface and bedrock is about 120 ft below the ground surface. There are no accessibility problems at this site. (a) How many exploratory borings will be required as per NYC Code, and to what depths should they be drilled? (b) How would you obtain groundwater data? Explain your answer.

Define the following terms: a) Fine sand (according to AASHTO) b) Silt fraction (according to AASHTO) c) Screenings d) Pit run

A compressible, normally consolidated clay layer is 7 ft thick and the slope of its field consolidation line is 0.27. If the initial void ratio is 0.09 and the effective overburden pressure is 2.7 tons/ft^2, what is the primary consolidation at midheight of the clay layer if the additional pressure from the building is 2.6 tons/ft^2? Give an answer in inches to 3 decimal places. Type your answer...