Generation Of Spatial Correlation Ground Motion And The Study Of Inconsistency Motivation About Underground Pipeline

The generation of artificial ground motion is an important aspect of structural seismic research. The two aspects had been studied about the time domain method and frequency domain method in the generation of artificial earthquake. In the time-domain method to generate artificial ground motion. one separation method had been used to decompose the power spectrum matrix, which is Imaginary-Real separation method. The results found that the calculation method is fast, accurate and feasible. In addition, a series of research had been carried out to solve the contradiction between the amplitude convergence and local convergence. At last, the both convergence in the two aspects had been achieved, and one kind of reasonable input model had been prived for study of structure anti-seismic.In the generation of artificial ground motion with frequency domain method, the traditional method can’t refrect the traveling wave effect, so a traveling wave effect factor had been introduced to this paper for the first time. On one hand, wich made the "liquidity" characteristic just like the natural vibration wave, when wave transmited from one end to another. On the other hand, the traveling wave effect factor can reproduce the single phase information to form a phase angle matrix, so it solved the difficulty of directly obtaining so many ground motion records which are spatial correlated.Due to differences in local site conditions, and the different input requirements about structure seismic research, the artificially ground motion generated by above method usually cannot be directly as one kind of sesmic input, before being detailed analysised, adjusted and fitted with design response spectrum. Therefore, studies had been on over the five aspects, the select of input model, the analysis of time-frequency characteristics about the input wave, the adjustment of spectrum components, the generation of coupling similar waves, and the target response spectrum fitting. So a kind of ideal input mode had been formed.It is the research emphasis that pipeline type structure responsed under the ground motion input, the concept of coupling wave pattern similarity was been first putted forward in this paper, and had been combined with inconsistency incentive research of pipe structure. Through two kinds of comparative analysis means, such as the oretical analysis and experimental verification, we found that this two research results had good consistency and a series of research laws were obtained.When earthquakes occur, the amplification effect about free field directly affects the strength of the pipeline structure nonuniformity incentive, so it is an indispensable part of pipeline structure seismic safety research. Using the time-frequency analysis method, this paper focuses on the amplification effect about each frequency component in the different soil layer. The results showed that:in different soil layer, there is a big difference about the time-frequency information existed in the time history curve. Even in the same soil layer, the amplification effect of spectrum is different. These differences relate to the height of the soil, the soil physical properties and different position (whether in the free surface) in the soil layer that the study particle was located.