Numerical inversion method of nonlinear stress field

The invention discloses a numerical inversion method for a nonlinear stress field, and the method comprises the steps: selecting a research range, and constructing a three-dimensional geologic model; dispersing the boundary surface of the three-dimensional geologic model into a plurality of surface elements, assigning a nonlinear variation coefficient to each surface element, and generating a nonlinear variation coefficient of the boundary surface of the model; according to a crustal stress measured value, determining a stress component which has a great influence on a research area as a linear boundary condition applied to the model; performing nonlinear coefficient adjustment on the linear boundary condition to obtain a nonlinear boundary condition; according to the nonlinear boundary condition, determining a stress component calculation value of the actual measurement point under the preset working condition; according to the stress component measured value and the stress component calculated value, determ