Straightening A Stone Wall

A system of horizontal kickers and diagonal braces bearing against 6x6 posts driven deep into the soil - one of which is visible just to the right of the traffic beacon - held the wall in position during excavation of the poorly drained original backfill.

Closed-cell foam injected between the uneven stone wall and the shoring planks ensured consistent contact, eliminating areas of localized stress that could have caused the wall to fracture when straightened. A 4-mil poly slip sheet kept the foam from bonding to the stone.

A heavy wood block strapped to the excavator's bucket distributed the pressure across a 4-foot section of shoring as the wall was eased upward. Though relatively little lifting force was needed, only a large machine could supply the necessary reach across the excavation.

The wall's battered configuration - wider at bottom than top - increased its stability in the fully upright position.

Helical soil anchors furnished tieback points for fixing the reinforced wall to the hillside. The anchor sub was familiar with retaining-wall design and recommended an appropriate depth and spacing for the anchors.

An improvised stand supports the coring drill used to bore 3-inch-diameter holes for the wall tiebacks. To provide an aiming point, a length of white closet rod - visible at top left - was inserted in the previously drilled vertical holes extending from top to bottom of the wall.

Strands of epoxy-coated rebar pin the repositioned upper wall to the undisturbed portion below grade.

A foam plug prevented grout from leaking out of the 3-inch-diameter horizontal holes.

The protruding ends visible here were later cut off flush with the top of the wall. The clevis removed from the bottom of the turnbuckle forms a strong mechanical connection with the rebar.

The grouted wall pins and hardware are mechanically fastened to the exposed ends of the helical soil anchors.

The inner face of the wall is covered with a dimpled drainage mat and the excavation is filled with stone.

The restored section of the wall stands perfectly straight. To save the mature plantings visible at rear, repairs were limited to the most severely affected section; parts of the original wall remain several inches out of plumb.

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