Please answers questions 65 and 610 64 PROBLEMS 61 A concent

6-4 PROBLEMS 6-1. A concentrated load of 200 kips is applied to the ground surface. What is the vertical stress increment due to the load at a depth of 15 ft directly below the load? 6-2. A concentrated load of 200 kips is applied to the ground surface. What is the vertical stress increment due to the load at a point 15 ft below the ground sur- face at a horizontal distance of 10 ft from the line of the concentrated load? 6-3. A 10-ft by 7.5-ft rectangular area carrying a uniform load of 5000 lb/ft2 is applied to the ground surface. Determine the vertical stress increment due to this uniform load at a depth of 12 ft below the ground surface by the approx imate method (ie, 2:1 slope method) 6-4. A rectangular area 2 m by 3 m carrying a uniform load of 195 kN/m2 is applied to the ground surface. Determine the vertical stress increment due to the uniform load at (a) 1, (b) 3, and (c) 5 m below the area by the approxi- mate method. 6-5 A circular area carrying a uniform load of 4500 lb/ft2 is applied to the ground surface. The area\'s radius is 12 ft. What is the vertical stress increment due to this uniform load (a) at a point 18 ft below the area\'s center and (b) at a point 18 ft below the ground surface at a horizontal distance of 6 ft from the area\'s center? 6-6. Soil with a unit weight of 16.38 kN/m3 is loaded on the ground surface by a uni- formly distributed load of 250 kN/m2 over a circular area 3 m in diameter Determine (a) the vertical stress increment due to the uniform load and (b) the total vertical pressure at a depth of 3 m under the edge of the circular area. 6-7. An 8-ft by 12-ft rectangular area carrying a uniform load of 6000 lb/ft2 is applied to the ground surface. What is the vertical stress increment due to the uniform load at a depth of 15 ft below the corner of the rectangular loaded area? -A 6-8. A 12-ft by 12-ft square area carrying a uniform load of 5000 bft2 is applied to the ground surface. Find the vertical stress increment due to the load at a depth of 25 ft below the center of the loaded area. 6-9. A 2-m by 2-m square footing is located 1.8 m below the ground surface and carries a load of 1000 kN. Determine the net vertical stress increment due to the uniform load at a depth of 4 m below the center of the footing (see Figure 6-17) -6-10. The l-shaped area shown in Figure 6-18 carries a 2000-b/ft2 uniform load. Find the vertical stress increment due to the structure load at a depth of 24 ft (a) below corner A and (b) below corner E. 6-11. The square area ABCD shown in Figure 6-19 carries a 2500-lb/ft2 uniform load. Find the vertical stress increment due to the exerted load at a depth of 12 ft (a) below point G and (b) below point J 6-12. Soil with a unit weight of 19.65 kN/m3 is loaded on the ground surface by a strip load 1.5 m wide. The strip load is 365 kN/m of wall length. Determine

Solution

6.5 a. formula; stress = (1-(1/(1+(R/z)²))^1.5)*q

where R=12ft; z= 18ft; q=4500lb/ft²   Ans: 1908 lb/ft²

b. There is no straight away formula in order to find out the stress hence we use the concept of isobar

s. Vertical stress at z=18ft=1.5R

                               r=6ft=0.5R

Which will approximately give the stress as 0.45q = 0.45*4500=2025 lb/ft²

Please excuse me, I want to submit in the form of image but it is not supporting sorry for the inconvinence.