Numerical Simulation Research On Dynamic Response Rules Of High Rock Slope Under Explosion

Along with the increasing invest having been put into our country's infrastructure, a great deal of cutting high rock slopes have appeared in high grade roads built in mountainous terrain and hilly land. During the construction course, more and more attention have been paid to the seismic effect, which is an outer factor influencing the slopes' stability, caused by the exploding excavation.By consulting a large numbers of documents home and abroad, this paper summarizes the development of the researches on dynamic issues of rock slope, and finds out that the researches are mostly focused on the calculating methods and the safety evaluation of slope's dynamic stability, and there are quite a number of related documents. However, there are not so many researches on dynamic response rule of rock slope, most of which are researches on dynamic response of rock slope under the natural seismic dynamic action. And the research on dynamic response rule of rock slope under the exploding seismic action is almost blank. Therefore, further researching on dynamic response rule of cutting high road slopes to the explosion quake has profound realistic meaning and applicable prospect to the exploration of how to reduce the explosion quake's influence to the stability of slopes and the security during the roads' construction and the ambient geologic environment.Combined with the technology program subject of Guangdong province (20064050002) , the paper uses ANSYS to establish a great deal of single rock slope models, by simulating the action of explosion seismic waves to slopes, that is respectively applying two acceleration time history curves from x and y directions to the lateral base of slope, and taking velocity maximum of each sloping surface particle on x and y directions as the observation indexes, and finally coming to the dynamic response rule of high rock slope under the explosion action. There are several points:(1) As the explosion is close to the slope's corner, it has great influence on the slope's corner, and forms a stress concentration mainly effected field within a certain altitude of the slope's corner. Through a lot of analysis of numerical simulation ,it has been found that the critical altitude of this area is related to the breadth value of the input stress wave.(2)Finding that the high rock slope under the explosion action, outside the stress concentration mainly effected field, will appear low slope dynamic effect and high slope dynamic effect, which is very similar to the dynamic response rule of slope under natural seismic action.(3)It is discussed that, under the explosion action, some factors affecting the critical height of the high slope dynamic effect appears. Through the simulation experimentation, finding that under the action of explosion wave, the critical height "H_thre" of slope is not a fixed value, but related to the material's property of slope and predominant frequency of input seismic wave. By a lot of analysis of numerical simulation results and formula derivation, a experience formula of critical height is gained, is H_thre = (0.155 - 0.2)λ.According to varying law of velocity's maximum in x direction,λis P wave's wavelength; and according to the varying law of velocity's maximum in y direction,λis S wave's wavelength.