Study on Chaos Dynamic Parameters of Surrounding Rock Displacement of Underground Grave

Abstract

It is an important to evaluate surrounding rock stability and analyze surrounding rock stress-strain for engineering and constructing, and the most direct way is to analyze the measuring displacement of underground powerhouse. Combining measuring displacement, dynamic characteristics of displacement of are studied. G-P method is improved by setting Theiler window w, by which effectively eliminating bad effect of time series relativity, and can avoid taking non-convergent correlation dimension wrongly as finite dimension, and C(r) is calculated and determined by setting w to obtain relatively impersonal correlation dimension D through fitting definition linear region. Many analysis methods, as is G-P method, C-C method and multiple autocorrelation method, have been synthetically analyzed to obtain optimum correlation dimension m and delay time t. The maximum Lyapunov exponents are calculated after phase space is reconstructed through the optimized values of m, t. Results show most of the displacements have chaos features. So most of displacement take chaos feature, and correlation dimension D is greater than zero and fractal, optimize values of m, t are obtained and maximum Lyapunov exponents λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> is greater than zero; While data of crown and those of abutment within 30m depth don't have chaos dynamic feature with D equal to zero. The study provides with a new method for similar practice, and a new thought for prediction the surrounding rock displacement of underground powerhouse.