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Abstract Investigation of mechanical behavior of bedded salt rock is the scientific fundamental for constructing storage cavern in underground salt rocks. By means of an advanced testing system which can be used to observe real-time SEM images of samples under the condition of loading in situ，the evolution of cracks was investigated during bedded salt rock samples have being broken and the meso-mechanism is discussed based on the analysis of energy dissipation and energy release. It is observed that there exists large different between the meso-structure of rock salt and that of mud rock impurity in bedded salt rock，and such difference affect the micro mechanical behavior of bedded salt rock. Cracks never develop along the interface of rock salt and mud rock impurity，and they usually develop in rock salts or mud rock impurities. When cracks are developing in the mud rock impurity，energy dissipation plays an important role so that the path of cracks is irregular which fractal dimension is large than 1 and even branch out sometimes，and under this case the load-bearing capacity of bedded rock is weak so that it would rupture although the work of external load is still small. When cracks are developing in the rock salt，more elastic energy is released quickly so that the path of cracks is straight which fractal dimension is nearly equal to 1 and even open more large distance sometimes，and under this case the load-bearing capacity of bedded rock is strong so that it could absorb more energy due to the work of external load.
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Received: 28 September 2010
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2011, Vol. 30 
