Mitigation Strategies and Engineering Solutions for Infrastructure at Risk from Earth Fissures

Abstract

Land subsidence can severely impact infrastructure and alter existing floodplain designations by changing ground elevation, ground slope (gradient), and through the development of ground cracks, known as earth fissures, that can erode into large gullies. Mitigation strategies and engineering solutions for infrastructure at risk from earth fissures are not widely available in existing literature, however many examples exist. Guidance on mitigation strategies intending to reduce the level of risk associated with the infrastructure exposed to earth fissure hazards has been developed for several sites in Arizona. The options are intentionally flexible so that the owner and design team can develop solutions that conform to the risk tolerance of stakeholders. The guidance is as follows: High Hazard Areas (earth fissures known to be present). Avoidance and/or significant engineered mitigation solutions. Moderate Hazard Areas (earth fissures could be present or develop in the future). Consider avoidance or implement engineered mitigation efforts such as structural elements and/or subsidence and earth fissure monitoring. Low Hazard Areas (earth fissures unlikely to be present or to develop in the future). Typical safety monitoring and maintenance for the infrastructure type.