Our solution protects the roadway in El Nido, Palawan, Philippines from falling rocks
El Nido, Palawan is one of the top tourist destinations in the Phillipines. Recent years have seen a dramatic increase in the number of domestic and foreign tourists visiting the area. Accessible by road from Puerto Princesa, the road journey time takes just over four hours travelling through lush tropical forests and steep sided valleys.
The Department of Public Works and Highways (DPWH) Region 4B regularly addresses the issue of falling debris and boulders onto the road. Cleanup is time consuming and there is the ever-present risk of danger to motorists using the road. To this end, the DPWH determined the need to tackle one of the more problematic slopes and sought our advice.
The affected portion of roadway is overlooked by a 100-metre slope to the east with a 30-40-degree slope angle. Our engineers proposed a rockfall barrier bounding the tree-line some 20 metres up the slope and with SteelGrid HR and Macmat geomat on the cleared slope below to prevent detachment of rocks and boulders, surficial erosion and to promote vegetation.
DPWH engineers admitted that their original plan was to treat the whole slope with secured drapery however, budget constraints made our alternative solution using a rockfall barrier more attractive and resulted in over 25% cost reduction with the added advantage of faster installation.
The original project timescale was over six months. Commencing installation in February 2018, installing contractors completed the project in four months ahead of the rainy and typhoon seasons.
The contractors had worked with our rockfall solutions many times in the past and needed little support to proceed with the project. After clearing the slope, the SteelGrid HR and MacMat were installed followed by the installation of the dynamic barriers with posts spaced at 10-metre intervals and attached to pre-installed base plates. After the installation of support cables, ring net panels and double-twist mesh panels were attached.
Within a few short weeks of completion, the underlying slope was seen to be rapidly revegetating allowing for this installation to blend seamlessly into the natural environment.