Optimization Inversion of the Ground Stress Field of Bohai Sea and Its Adjacent Area

Abstract

An optimization inversion model of the ground stress field of Bohai Sea and its adjacent area is established by combining Hooke-Jeeves optimization algorithm and finite element method. The study area was simplified into two 2D sections, a shallow and a deep section, for optimization inversion analysis in consideration of the spatial distribution of the measuring points. The main faults in the study area were simulated by 2D surface to surface contact model, in which the friction state between hanging wall and footwall was modeled by Coulomb friction model. The objective function is established by least squares method, according to the difference values between calculated ground stress data and measured ones. The results show that a plausible ground stress field distribution of Bohai Sea and its adjacent area can be obtained with less data by the optimization inversion method. When there are less measuring points, the optimization inversion result can be easily affected by the distribution of measuring points and the distance of each measuring point to the model boundary; when there are more measuring points, the inversion errors at the checkpoints can be obviously reduced and a more reasonable integrated inversion result can be obtained.