Ground Improvement with Mechanically Stabilized Earth and Steep Surcharge Slopes near Existing Structures

Surcharging to improve compressible soils was the most attractive foundation option for constructing new structures for a large scale expansion of a wastewater treatment plant in Virginia Beach, VA. This required tall and steep embankments in close proximity of existing operating plant structures and utilities. Such tall (up to 40 feet (12m) high) and steep (up to 4V:1H) embankments were designed as mechanically stabilized earth (MSE). A detailed geotechnical investigation was performed to adequately characterize the site stratigraphy and soil properties. A significant volume (over one million cubic yards) of temporary borrow material was procured from adjacent areas where it was returned after completion of the surcharge program which demonstrated sustainability in use of natural resources. A geotechnical investigation in the borrow area was also performed. A monitoring program was implemented to measure the vertical and lateral movements and pore pressures during the surcharging program.