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Hyperspectral image change detection can provide timely change information on the surface of the earth, which is essential for urban and rural planning and management. Due to the higher spectral resolution, hyperspectral images are often used to detect finer changes. Aiming at the problem of change detection by using hyperspectral image, a hyperspectral change detection method based on collaborative sparsity and nonlocal low-rank tensor is proposed. This method first obtains hyperspectral differential image at different time points, and then extracts different nonlocal similar block tensor clusters according to the nonlocal distribution characteristics of the image blocks in the differential image. Then, based on collaborative sparse regularization and low-rank regularization, a change detection model using collaborative sparsity and non-local low-rank tensor is established, and the representa-tion coefficient is obtained by solving the model using the alternating direction method of multipliers. Finally, the projection residuals of the tensor in different categories are obtained according to the representation coefficients, and then the projection residual minimization criterion is judged whether the tensor has changed. Experiments on Farm-land and Urban area in San Francisco City datasets demonstrate that the proposed method can achieve much better changes detection accuracy.

Dynamic caustic experimental method and numerical simulation method were used to study the crack propagation rules and the tension/compression damage zone at the end of boreholes in the planar model.The results show that the effect of different length-diameter ratios on the crack propagation was significant.As the length-diameter ratio increasing,the crack propagation lengths increased and the expansion angles decreased.When the length-diameter ratio was 5/5,the crack propagation angle was about 90°.When the length-diameter ratio increased to be 20(30/1.5),the crack propagation angles decreased to be 40°.As the length-diameter ratios increased again,the crack propagation angled didn’t change any more.The numerical results are in good agreement with the experimental results,and Numerical simulation shows that small area of compression damage area formed in the area of the column hole,and “X” type tensile damage zone formed at the end of the hole,which lead to the formation of explosive crack easily at the end of the borehole.The radius of the tensile damage zone was approximately 5 times the radius of the compression zone around the borehole.