For Type A soils, what is the sloping ratio acceptable if the excavation will be open for less than 24 hours and is less than 12 feet in depth?

For Type A soils, which are characterized as cohesive and stable, the acceptable sloping ratio when an excavation will be open for less than 24 hours and is less than 12 feet deep is indeed ½:1. This ratio indicates that for every 1 foot of vertical height, the excavation should extend 2 feet horizontally. This is a remarkably safe approach, as Type A soils are considered the most stable classification and can support a gradual slope.

The rationale behind the ½:1 slope requirement is to balance safety and practicality in short-term excavations. Since the excavation will be open for less than 24 hours, there's a reduced risk of soil destabilization due to weather or other external factors, allowing for this less steep slope compared to what might be required for longer or deeper excavations.

This specific slope ensures that workers remain safe from a cave-in while still allowing for a more efficient excavation process, as steeper slopes could hinder access or productivity. Understanding the characteristics of Type A soils and the factors influencing excavation stability is crucial for ensuring a safe working environment in construction sites.