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| Study on Chaos of Discontinuities Distribution in Rock Mass |
| YU Guo-xin, XU Zhao-yi |
| Bejing Jiaotong University, Beijing 100044，China |
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Abstract Research purposes： The distribution of discontinuities is very complex and the traditional method of analyzing it is based on hypothesis of random, by which the mixed characteristic of dis. continuities could not be analyzed. The purposes of this paper are to show chaotic features existing in distribution of discontinuities and offer a new way of studying distribution of discontinuities through studying chaotic feature parameters.
Research methods： By bulding up the sequences of space , dip-direction and dip, the parameters of chaotic features for three sequences can be obtained by calculation. Whether the sequence of discontinuities is chaotic one or not can be judged according to the calculation result. Besides, the chaos features of the sequence of discontinuities can also be judged by negative power in power spectrum and inclination in PCA diagram. Phase space could be reconstructed by embedding dimension and space delay.
Research results :Kolmogorov entropy is more than zero , lyapunov exponents tend to zero，correlation dimension is real number of more than 3，negative power appears partially in power spectrum in lower frequency and the FCA diagram as certain inclination. The calculatulon result of embedding-dimension-and space delay show that discontinuities could be spreaded into multidimensional space, and embedding dimension is suitable for being 15 to 19 and space delay for 2 to 6. Reconstruction of phase space represents puckering and distorting of its distribution.
Research conclusions: Discontinuities has chaos features when it presents space distribition located in chaos edge. The correlation dimension of discontinuities reflects the distribition situation of discontinuities like fractal dimention. It shows there is more discontinuity, the distribution is more complicated and the rock mass is more broken when the correlation dimention of space sequnce becomes larger. And it also shows the change of emerged status of discontinuity is larger and there is more directional preponderance when the correlation dimension of the sequnce of the same emerged status becomes larger.
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Received: 10 March 2006
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2007, Vol. 24 
