Earth Pressure & Slope Failure on Route A16

Traffic disruption due to displaced slopes and rock movements.

Traffic on route A16 between the cities of Iquique and Alto Hospicio was interrupted as a result of several slopes displacements and rock falls. This route is of strategic importance for regional economy, and following the earthquake, an 80 m long section descended 40 cm displacing over 2500m³ of soil. In addition, rock falls on the hillside caused major traffic delays, until the flow was partially restored two days after the earthquake.

Figure 1. Slope Failure on route A16. Avg. displacements: Vertical 40cm, Horizontal 10cm. Slope dipping: 20.

Earth Retaining Structures

Overall, basement walls, bridge abutments, and retaining walls performed well as expected for the measured ground accelerations (PGA < 0.3g). Nevertheless, the cantilever walls of Cerro Dragon in Iquique sustained significant rotations (Δ/H~1%-8%) due to the insufficient size of the footing and the lack of moment connections. Many of these walls were previously damaged during the M_w=7.8 Tarapacá Earthquake (2005) and the M_w=7.7 Tocopilla Earthquake (2007).