Research On Dynamic Response Rules And Stability Of High Rock Slope Under Explosion

There are many high rock slopes in the expressways which are built in the mountainous terrain and hilly land in China. People pay attention to the stability of the above slopes all the time. And the vibration effect of the blasting construction, as one of the external factors affecting the stability of slope, has caught more and more attention from people. The fierce blasting vibration effect would result in serious consequences such as the collapsing of the slope, the landslide or even the debris flow. However, there are little researches on dynamic response rule of rock slope at home and aboard. So it has profound realistic meaning to study the dynamic response rule of rock slope under explosion and to explore the effect on the stability of slope by the blasting vibration.Combined with the blasting construction and the field blasting vibration test in the cutting high rock slope in Guanghe expressway, the paper uses FLAC-3D to establish a blasting dynamic numerical model of the rock slope to study the dynamic response rule and stability of the rock slope under explosion, thus getting some preliminary rules. The main achievements of the paper are as follows:On base of discussing mechanisms of the rock breaking of blasting and the blasting seismic wave propagation, the field blasting vibration test data is used to summarize the rationality of the blasting parameters in the test and some data is analyzed with classified statistics to get the characteristics of the blasting vibration velocity of the slope. With the regression analysis of the data, the peak velocity attenuation rule of blasting vibration of test slope is obtained. And the measures of reducing vibration,which is for the field blasting construction, are put forward.Basing on the fast lagrange method and FLAC-3D, the input of blasting load, boundary condition, constitutive model and damping setting are analyzed and discussed to establish the blasting dynamic model of field test slope. Through the numerical simulation, the paper analyzes the dynamic response of the slope under explosion and gets the characteristics of peak velocity of particles of the slope, proving the elevation amplification effect and getting the conclusion that particles on the slope surface have larger velocity than those in the internal of the slope. The distribution maps of stress in different times are obtained to find that vertical direction stress changes little but the horizontal direction stress and shear stress change a lot. And the displacement time-history curves of particles are got to find that the biggest displacement of particle does not have obvious rules and the particles on the slope surface have larger displacement than those in the internal of the slope.Combining with the strength reduction method which is based on the numerical simulation and sarma method which is based on time-history method, the paper analyzes the stability of the test slope under the explosion and get the time-history curves of dynamic safety coefficient of the slope under different blasting charge weight, thus judging that the slope is stable under explosion and getting the safe critical blasting charge weight of the slope .