Abstract
Abstract. Land subsidence and earth fissures are phenomena related to groundwater withdrawal in a sedimentary basin. If the rock basement or basin lithology is irregular, both vertical and horizontal displacements can be induced due to differential settlement and tensile stresses appearing in the soil mass. If the differential settlement is of sufficient magnitude, earth fissuring can occur within tensile zones. The magnitudes of compaction and fissure geometry are closely related to the thickness and skeletal compressibility of fine-grained sediments within the aquifer system. Land subsidence and earth fissuring were modeled by employing a two-dimensional (2-D) coupled seepage and stress-strain finite element analysis. The basin bedrock geometry, lithological variation, measurements of surface displacements, and changes in hydraulic head were the critical input parameter for the subsidence modeling. Simulation results indicate that strain had exceeded the approximate threshold for fissure formation of 0.02 to 0.06 % in the area of the identified fissures. The numerical model was used to predict future subsidence and potential earth fissures for flood control structures within the metro Phoenix area.
Highlights
Land subsidence due to groundwater withdrawal in alluvial basins in the southwest region of USA is a process of differential compaction of deep sediments
Numerical models have been developed by the authors (Panda, 2007; AMEC, 2003, 2013) to assimilate both interferometric synthetic aperture radar (InSAR) and historic subsidence data for prediction of subsidence and earth fissure due to groundwater withdrawal
The earth fissures resulting from ground subsidence due to the withdrawal of groundwater were modeled using coupled flow and deformation finite element models
Summary
Land subsidence due to groundwater withdrawal in alluvial basins in the southwest region of USA is a process of differential compaction of deep sediments. The application of interferometric synthetic aperture radar (InSAR) to characterize the distribution and rate of land subsidence provided invaluable detail into the probable positioning of tensile ground stresses and earth fissuring (AMEC, 2003). The differential rates and magnitudes of subsidence over relatively short distances, cause horizontal strains due to tensile stresses and eventually can become sufficient to cause earth fissuring. Jachens and Holzer (1982) concluded that most fissuring occurred at horizontal tensile strains in the range of 0.02 to 0.06 %. Numerical models have been developed by the authors (Panda, 2007; AMEC, 2003, 2013) to assimilate both InSAR and historic subsidence data for prediction of subsidence and earth fissure due to groundwater withdrawal
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Proceedings of the International Association of Hydrological Sciences
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
