Mark J. Farrow. P.E.1, Nasir H. Syed2 and Ben Y. Lee3

The Texas Ranger Amphitheater structure to be constructed at THE BALLPARK AT ARLINGTON required a deep excavation into pervious water bearing granular soils. The amphitheater will be surrounded by a large lake with a 22 foot tall floodwall surrounding the lowest level. By design, the lake level can rise to the top of the floodwall during a flash flood within Johnson Creek. Various alternatives were considered to protect the lower levels of the amphitheater against excessive buoyant hydrostatic uplift forces that would develop beneath the structure due to water impoundment behind the floodwall. One alternative included a sophisticated dewatering system containing relief wells. The design of this system required pressure wave modeling of short term hydrostatic forces that develop beneath the structure during a flash flood. The wave modeling was based on geotechnical parameters related to the permeability of the aquifer soils, seepage velocities and variable hydraulic gradients that develop during a flash flood. This paper presents an overview of the hydrostatic pressure wave modeling used for this project.