You are excavating a location for the vault shown below. The top of the walls shown are 1 foot below grade. All slopes of the excavation are 1 to 3/4 per OSHA regulations (assuming type A soil) to a toe 1 foot outside the base of the walls. The walls sit on a slab 1 foot in depth. Draw a sketch of the volume to be excavated, break it into components, and calculate the volume. The material from the excavation is to be used in a compacted fill. The front-end loader excavating the vault has an output of 200 bank cubic yards of common earth per hour. It loads a fleet of four trucks (capacity 18 loose cubic yards each) that haul the earth to a fill where it is compacted with a shrinkage factor of 10%. Each truck has a total cycle time of 15 minutes, assuming it does not have to wait in line to be loaded. The earth has a swell factor of 20%. How many hours will it take to excavate and haul the material to the fill?

a. What is the production of this system in cubic yards per hour, assuming the trucks carry 35 cubic yard per load?

b. Is the system working at, above, or below its balance point?

c. If there is probability of major delay on the travel elements to and from the fill of 7% and the mean value of delay is 5 minutes, what is the new system production?

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Wall thickness= 1 ft 9 20 -30- 45' T 3/4'