Abstract
SummaryThe accurate modelling of gravity is of crucial importance for a variety of issues including, but not restricted to, the identification of buried objects. Gravity is an unbounded problem, which causes challenges when applying numerical models, i..e.., it results in computational difficulties when specifying the relevant boundary conditions. In order to address this, previous research has tended to generate artificial boundary conditions, e.g., truncating the simulated domain and adding many unrealistic zero‐density layers, which introduces more unknown parameters and unnecessarily excessive computational time. In order to overcome such inaccuracies, this paper proposes an innovative development of the finite element modelling technique, which represents a step change in the field of gravity forward modelling. A comprehensive formulation of an infinite element to reproduce the far‐field boundary effect using only one layer of infinite elements is presented. The developed model considerably reduces the computational time while obtaining high degrees of accuracy. The model is validated against the exact solution of the problem, and its results show an excellent performance. The proposed method can significantly improve the postprocessing and interpretation stages of data analysis relevant to micro‐gravity sensors. The new method is applied to subsurface civil engineering although its applicability is manifold.
Highlights
Forward modelling of gravity data is the process of calculating gravity from a specific density distribution
This paper presents a detailed formulation of boundary infinite elements in a 3D classical finite element analysis for forward modelling of gravity data
In order to validate the results of the developed infinite element boundary, synthetic gravity data were generated using the closed-form solution of the right rectangular prism (Equation (17)) presented in Li and Chouteau.[37]
Summary
Forward modelling of gravity data is the process of calculating gravity from a specific density distribution. Butler and Sinha[24] used the Comsol Multiphysics Package for gravity forward modelling and compared different boundary conditions including infinite elements They simulated a simple model consisting of a cylinder with a radius of 1000 m and a density contrast of 100 kg m−3 with the surrounding material. Gharti et al[26] showed the application of SIEM, developed by Gharti and Tromp,[25] for computing gravity anomalies using MeshAssist[29] and Trelis/CUBIT30 to prepare their models While this approach resolved the features accurately, it should be mentioned that the details of the infinite element shape functions used by Gharti and Tromp[25] and Gharti et al[26] were not presented in their work. To assess the suitability of the developed approach, it is tested on a subsurface civil engineering–related application of a shallow multi-utility tunnel with input from field gravity observations as a practical example
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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 call
