Vertical uplift resistance of two closely spaced horizontal strip anchors embedded in cohesive–frictional weightless medium

摘要

The vertical uplift resistance of two closely spaced horizontal strip plate anchors has been investigated by using lower and upper bound theorems of the limit analysis in combination with finite elements and linear optimization. The interference effect on uplift resistance of the two anchors is evaluated in terms of a nondimensional efficiency factor (η_c). The variation of η_c with changes in the clear spacing (S) between the two anchors has been established for different combinations of embedment ratio (H/B) and angle of internal friction of the soil (φ). An interference of the anchors leads to a continuous reduction in uplift resistance with a decrease in spacing between the anchors. The uplift resistance becomes a minimum when the two anchors are placed next to each other without any gap. The critical spacing (S_(cr)) between the two anchors required to eliminate the interference effect increases with an increase in the values of both H/B and φ. The value of S_(cr) was found to lie approximately in the range 0.65B–1.5B with H/B = 1 and 11B–14B with H/B = 7 for φ varying from 0° to 30°.