Answer Happy

2. A contractor has a requirement to install 750 feet of new water lines as a part of her project. She plans to use a hydraulic backhoe to excavate the trench for the water line in an open trench (Slope ratio (H:V) - 1:2). The maximum digging depth of the backhoe is 7.55 feet, and the bucket capacity is 1.2 CY. The average swing is 60°. The soil to be excavated is hard tough clay. The trench to be excavated is illustrated in the figure below. The contractor estimates that the actual digging time will average 40 minutes per hour. Job site conditions are considered average. The cycle time for the excavator is 25 seconds. The swell and shrinkage for the excavated material are estimated to be 20% and 25%, respectively. Estimate the productivity of the excavator in linear feet of trench per hour. (16 points) 7 በ 5 ft