Three dimensional analytical study of landsubsidence due to groundwater overpumping
Date Issued
2009
Date
2009
Author(s)
Tseng, Chung-Min
Abstract
Besides regulating and reducing the pumping of groundwater, the Taiwan government has also been conducting related researches, such as developing and using new models to better understand potential landsubsidence areas. Because the simulation results do provide valuable trend information for the implementation of prevention measures, these models play vital roles in the decision-making process. s abovementioned, not only these models which couple groundwater flow with soil body are not yet perfected, most models still use the time-consuming and highly complex numerical methods to find the solution. However, such method still cannot output realistic data because land conditions and other key parameters still cannot be quantified. As results, the research in this paper aims to develop a practical and easy-to-use model which can find the fast solution for the value of landsubsidence due to groundwater overpumping in large land area. Consequently, the model will become helpful in managing groundwater resources and conservation of land and water.his research first coupled the 3D water flow with the soil control equation, and then deduces the complete uncoupled equation using only pore water pressure and soil displacement. Furthermore the research uses the compressibility of solids and obtains the simplified analytical method for calculating the value of land subsidence in real time. The results show that the control equation is very similar to Stokes flow, which means singularity of the flow with no Reynold’s Number can be introduced into the equation to find the condition of landsubsidence when groundwater is over-pumped. Validated by using the boundary integral method, water being pumped underground is a stokeslet. In the end, the research looks into confined and unconfined aquifers, analyzes and validates the model using different case studies, and demonstrates that the model is both practical and easy-to-use.his research entails the following breakthroughs in providing solutions for 3-D land subsidence problem:.A model that finds the fast solution for normal land subsidence problem..The proof for land subsidence control equation can be deduced to the form of Stokes’ flow.Water being pumped out of the aquifer can be regarded as a stokeslet in the laminar flow with no Reynold’s Number.Water conductivity in the ground, K, is not a constant. It changes as the displacement of soil body changes. As observed, the variation of K is inversely proportional to distance (r).
Subjects
landsubsidence
overpumping
coupled
uncoupled
Type
thesis
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