Study On Macroscale Inversion Analysis Of Displacements And Discussion Of Its Multiscale Problems

Inversion analysis of measured displacements is used extensively in geotechnical engineering, structural engineering, information construction, and trauma diagnosis, etc. In this dissertation, parameters identification of original geostress and medium physical property in cavern, slope, tunnel and dam are taken as a cut-in point. Macroscale inversion analysis of displacements and numerical solutions of inverse problems of mechanics are researched profoundly. Scientific theories of multiscale problems are connected with numerical inversion approaches. And multiscale mechanical model of structural materials (rock, bone) and its inversion method are discussed preliminarily.Evolution and advance of generalized solutions and numerical inversion approaches of mechanics inverse problems are summarized in detail. That can be divided into four classes, based on the difficulties of numerical inversion. The first is linear, nonlinear and multiscale mechanics inversion problems. The second is mechanics inversion problems founded on three conditions of ill-poesed problem of statics and dynamics. The third is local optimum and global optimum mechanics inversion problems. The fourth is deterministic and non-deterministic mechanics inversion problems. Therefore, research about multiscale problems of mechanics and multiscale methods of inversion are predicted according to the development tendency of these generalized solutions and numerical inversion approaches.Macroscale inversion analysis of measured displacements in tunnel, slope and dam is studied detailedly according to inverse formulation method and direct formulation method. Aimed at inverse problem for identifying original geostress parameters and stru -ture modulus of rock, linear hypothesis for shear stress field of slope is proposed. Structural model of transversely isotropic medium is constructed. Inverse formulation method based on FE method is adopted. And the optimum of inversion parameters can be searched quickly. At the same time, optimum model and constrained inversion for multiparametric displacements back analysis are studied. A formula of optimum model for ordinary geostress field is proposed. Computation model for rock deformation under one step excavation and multi-step excavation is constructed. Constrained inversion algorithm based on FE method and constrained variable metric method is established. Thus, Inversion reliability and accuracy of multiparametric identification can be enhanced. Then, Based on the direct back analysis program DBAPM of Japan edition in construction forecast, the constrained optimization back analysis program COBAP is developed. And the more reliable and accurate inversion forecast can be obtained when COBAP is used in information construction and design in geotechnical engineering._ ___Uncertain factors of macroscale inversion analysis of displacements are summed up. Associated inversion model containing non-deterministic factors is proposed, i.e. "deterministic inversion of differential equation + systematic optimization technique = non-deterministic inversion" . The systematic optimization technique includes direct operator optimization, direct numerical analysis optimization, measurement design optimization, measured data processing, in -ersion algorithm optimization, and inverse operator regularization, etc. When this associated inversion technique is used in displacements back analysis, uncertain factors can be processed Quantitatively. And reliability and accuracy of inversion results would be enhanced obviously. On the other hand, wavelet threshold optimization method for digital data processing and quantized monotonic denoising method for non-digital data processing are established. And multiscale denoising function and computation stability of these two methods are compared with each other.One of the difficulties in inverse problem studies is the quantitative evaluation of inversion results. A reliability evaluation method of displacements bac...