Investigation of Seismic Footing Settlement due to Subsidence for the Sand Aquifer with Pumping Wells using PLAXIS

Abstract

Using PLAXIS to evaluate land subsidence due to the extraction of groundwater (i.e., pumping) has long been of interest to researchers. Similarly, the effect of earthquake on land subsidence is an issue worth considering. This study mainly focuses on the effect of groundwater extraction through wells while the site is exposed to seismic forces. The acceleration time series are from two real earthquake cases, one representing small quakes that happen more frequently and the other representing large and extreme quakes. The results showed that a small earthquake with a magnitude of 4.4 has little effect on footing subsidence while a very strong earthquake with a magnitude of 8.8 will increase footing subsidence by one time as compared to the subsidence from a small earthquake. In the meantime, the contribution of the groundwater pumping to the land subsidence is not significant. However, the combination of groundwater pumping and earthquake activity leads to a larger degree of subsidence than other scenarios.