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Some useful construction tips to compute the sliding safety factor for cantilever retaining walls
This construction article is extracted from an exclusive article written by Javier Encinas, the renowned professional engineer Javier Encinas.
The article sheds light on how to compute the sliding safety factor for concrete or masonry cantilever retaining walls.
Retaining walls are specifically created to encircle soils among two dissimilar elevations. So, they have to primarily withstand the lateral pressures from the retained soil as well as any other surcharge. Cantilever walls are susceptible to sliding issues, specifically if constructed on inferior quality soils.
Pressures functioning on a retaining wall
Besides, to the retained backfill, retaining walls are dependent on surcharge loads at the top of retained mass. A surcharge belongs to a strip load. If the stem expands beyond backfill, the retaining wall has to withstand wind load. If the retaining walls are placed in seismic zones, the focus should also be given to seismic pressures.
The load has been used contains a definite effect on the wall. The backfill employs a triangular lateral pressure measured according to the equivalent earth pressure theory. The surcharge creates a constant rectangular pressure on the wall. The seismic pressure is trapezoidal, together with the greater pressure at the top. Due to the actions of these loads, a bearing pressure is created beneath the footing, as well as a passive pressure at the front of the wall.
Method for verifying the sliding failure mode
The wall will be moved to exterior by the horizontal pressures on the backfill side that will have a tendency to slide on its footing. The driving force from the assigned loads should be defied with an opposite friction force at the edge of the footing base and the foundational soil that is formed by the bearing pressure against the base.
Besides, the passive pressure against the front face of the wall and footing should also be taken into consideration. It will never happen that the natural soil will be unaffected throughout the construction, so usually the top portion of the soil cover for the passive force calculation is omitted.