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Constructing backbone grid is important means of carrying out differential planning to improve power system’s ability of resisting natural disasters. A searching method of core backbone grid with the target of the smallest total lines and nodes and the largest integrated survivability index based on the index system of survivability was put forward with constraint conditions of network connectivity and power grid’s safe operation. The biogeography-based optimization algorithm was introduced to search for the optimal core backbone grid. Compared with particle swarm optimization (PSO), binary ant colony algorithm (BACA), genetic algorithm (GA), the proposed method is accurate and effective, and it has the merits of better convergence speed and convergence precision.

According to the analysis of the current chloride ion eroding model, it has been known that diffusion coefficient and chloride ion concentration on the concrete’s surface are random variables. Meanwhile the concrete protective thickness is also random variable because of manufacturing error and other reasons. So the diffusion process is the random process in fact. The random calculation model of chloride ion concentration in concrete has been deduced from the current model with the help of mathematical knowledge in this paper. Moreover, a satisfied effect has been achieved after comparing the calculated values with the test values. The calculation model is proved to be useful for life prediction and assessment of concrete structures.

The means of current experimental study on expansive soil dilatancy primarily count on triaxial apparatus and compression apparatus. The narrative revealed in the article is in relation with expansive soil trial by means of CBR test, with outcome linked to regulation among swelling amount rating with time, initial moisture content, and dry density, which leads to high value associated with implication for predicting expansive soil deformation with moisture.