What is the ground slope angle and a splinter wedge?

A splinter wedge is a fragment of a slope that can collapse due to its own weight or a force applied from the outside. The splinter wedge is located between the slip or fall surface and the slope slope.

Safety of earthworks

The basic safety rules for carrying out earthworks with construction machines require the designation of a zone in the area that is dangerous for the operation of an excavator, grader or other equipment. The danger zone is the length of the greatest reach of the machine extended by 6 m. In addition, the machine should be at least 0.6 m beyond the wedge of the natural fracture for a specific type of soil. When extracting spoil from the excavation and storing it for dumping, care must be taken that the distance between the foot of the dump slope and the upper edge of the excavation is: not less than 3 m for permeable soils and not less than 5 m for impermeable soils.

Natural ground slope angle

Each soil category has natural properties that influence its behavior during earthworks. Soils are susceptible to falling at an angle, which we call the natural slope angle. The natural slope angle is the greatest angle at which the ground is able to stay balanced on a slope. Slopes that are inclined at a greater angle than their natural angle may collapse. We are dealing then with a fragmentation wedge.

How to calculate the splinter wedge?

The fracture wedge for construction equipment is calculated using the following formula: l = (h * coefficient) + 0.6 m; where:

l – safe distance
h – digging depth
a – fracture wedge reach (h * coefficient)
Coefficient for a given soil category:

I – 1.5
II – 1.25
III – 1.0
IV – 0.5
Depending on the soil category, a safe distance for setting the construction machine should be determined.

References:
https://pl.wikipedia.org/wiki/Klin_od%C5%82amu
https://osom.pl/badania/publikacje/kat-stoku-naturalnego-gruntu-i-klin-odlamu
https://asystentbhp pl/bezpieczenstwo-prac-ziemnych-klin-odlamu-gruntu/
https://uprawnienia-budowlane.com/blog/wykopy-budowlane-zabezpieczenie-klin-odlamu/