WELWOOD LANDSLIDE STABILIZATION

Frisco (Dallas), Texas

The project was located in a high-end residential neighborhood in a suburb of Dallas , TX . An existing landslide had developed between the residence and a nearby lake. Soft weak soils consisting of clays overlying claystone bedrock were included in the landslide mass. Stabilization of the landslide was required to prevent continued movement of the earth slope adjacent to the residence, and to prevent additional movement of the portions of the residence founded on slabs and spread footings and to avoid continued lateral earth pressures on caisson foundations.

Lyman Henn provided a final evaluation of the cause and origin of the landslide mass, options for stabilizing the landslide mass, and final design and construction management/construction inspection services during stabilization construction activities. The stabilization design strategy included 100 kip soil and rock anchors comprised of a deformed steel bar with large concrete face plates. Individual anchors were designed to extend beyond the landslide mass failure surface and provide an anchor zone in the claystone bedrock.

Special project challenges included delimited working area between the residence and the shoreline of the lake, weak clayey soils and relatively weak claystone bedrock, and a difficult construction season during the winter months. Lyman Henn worked closely with Hayward Baker who provided the construction services for the project to develop specific and efficient means and methods for constructing the concrete face plates, drilling the required anchor holes, developing sufficient anchorage for each of the tieback anchors.