Segmental retaining walls and steep slopes reinforced with PVA geogrids in the energy polo of Massa Martana
This work concerns the construction of segmental retaining walls and steep slopes reinforced with PVA geogrids in the Energy Polo for the Production of Renewable Energy, located in Massa Martana (PG), Italy. The industrial area is rectangular and is located along a hillside, therefore was necessary the construction of retaining walls at the upstream of the mountainside, along the lateral sides and at the downstream side of the whole area, in order to obtain a wide horizontal surface. For this purpose, 3.700 sqm of Segmental Retaining Walls (SRW) reinforced with geogrids up to 11.6 m high were constructed, while in an outskirts area was built about 1.500 sqm of a Steep Reinforced Slope (SRS), up to 12 m high, with vegetated facing. This method of construction has been decisive for the choice of this type of solution, because the execution of the walls started simultaneously with the construction of the total energy plant, then the system chosen must minimize interferences with other multiple processes and allow a reduction of working time.
The choice of SRW and SRS as retaining walls proved to be a valid solution from technical and aesthetic points of view: a) excellent behaviour against earthquakes, b) easy and fast construction, c) versatility to follow any shape and topographic irregularities, d) environmentally friendly, e) production of blocks with customized colour. Thanks to good chemical resistance in alkaline environments of PVA geogrids (pH > 12) it was possible to use, as filling material for SRW and SRS, the clayey soil present in site through a suitable lime stabilization. The geogrid reinforced retaining walls technique allowed to optimize the execution time. The construction of the walls has been done simultaneously without interfering with earthworks and the construction of other buildings. Furthermore, with these systems, there’s no need to wait for the curing of the concrete before laying the backfill and putting under load, as happens with traditional concrete walls.