Effect of construction methods on the magnitude of forces on thin single-anchor retaining walls

Conclusions

• 1. Forces in flexible wall anchors depend on the method of construction. When constructing such walls, it should be borne in mind that changing the designed procedure of construction can cause dangerous overstresses in the anchor fastenings and unloading of the span part of the wall.

• 2. In case a change in the designed sequence of the wall construction is unavoidable (i.e., when carrying out a subsequent excavation) it is necessary to increase the sections of the anchor rods, distributing beams, and bolt connections. At the same time, if there is confidence in the rigidity of the anchor suports (of the girders, wall anchors, pile “framing,” etc.) one should redesign the sheet piles substituting a lighter section.

• 3. The results obtained in the studies should be taken into account when designing wall elements with rigid anchor fastenings by introducing coefficients for the change in magitude of the maximum bending moments in the span and of the anchor forces.

Based on an analysis of the results of these studies, the following coefficients are proposed as preliminary recommendations: a) for the reduction of moment in the span of a flexible wall, ξ_d = 0.8–09; b) for increase of active anchor force, the coefficient α_d = 1.35–1.5. Increases of the forces in walls without subsequent excavation can be determined according to earlier published studies by the authors. It is recommended that the smallest value of the coefficient ξ_d and the greatest value of α_d be used for a very firm, rigid anchor support and short anchor rods.