Final answer:
The productivity of a CAT 329D excavator in digging a rock trench can be estimated by considering the effective capacity of the bucket per cycle and the number of cycles per hour. With a heaped capacity of 1.25 m³, a bucket fill factor of 0.8, and a load factor of 0.75, the effective bucket capacity is 1.33 BCM. Assuming a 2-minute cycle time, productivity is approximately 39.9 BCM/hour.
Step-by-step explanation:
To calculate the productivity of a CAT 329D excavator when digging a trench in a rock ledge, we need to consider the dimensions of the trench, the load factor of the material, the bucket capacity, the fill factor, and the operational capabilities of the excavator.
The trench is 1.5 m wide and 6 m deep. The bucket has a heaped capacity of 1.25 m3 and a fill factor of 0.8, so the effective capacity of the bucket when digging rock will be 1.25 m3 × 0.8 = 1.0 m3. The load factor for the rock is 0.75, hence each bucket load will contain 1.0 m3 / 0.75 = 1.33 bank cubic meters (BCM) of rock.
The productivity, as the number of buckets filled per hour, can be estimated by the cycle time of the excavator, which typically includes digging, swinging to the spoil pile, dumping the load, swinging back to the trench, and positioning for the next dig. Without specific cycle time provided, the estimation can only be general. As an example, if a complete cycle takes 2 minutes (which is a common estimate for this kind of operation), the hourly productivity would be 60 min/hour divided by 2 min/cycle × 1.33 BCM/bucket = 39.9 BCM/hour.
This is a broad estimation and actual productivity can vary based on efficiency, operator skill, and site-specific conditions (such as proximity to the spoil pile and any obstructions).