Research On Seismic Dynamic Response Characteristics Of Counter-tilt Rock Slopes Based On FLAC3D

Slope dynamic response characteristics are the basis of all problems about dynamic slope. Earthquakes occur frequently in our country in recent years, inducing thousands of landslides, the counter-tilt slope is one which large scale and strong damage, causing a lot of property loss and casualties. Analyze the factors of slope dynamic response characteristics based on a lot of information on counter-tilt slope, then a further study on seismic dynamic response characteristics of counter-tilt rock slopes affected by these factors such as slope height, slope angle, strata dip, soft rock underlying, seismic wave frequency, and amplitude with the acceleration amplification coefficient by the methord of Flac3 D. At the same time, select a typical counter-tilt rock landslide---the Guantan Landslide induced by Wen Chuan Earthquake as the research object, study the seismic dynamic response characteristics with the acceleration amplification coefficient, displacement, shearing stress, principal stress, plastic zone. Research achievements as follows:1. Slope seimic dynamic response characteristics under different seismic wave frequency and amplitude.(1) When the seismic wave frequency close to or equal to the natural frequency of slope, the slope response is severe. The counter-tilt slope deformation and failure will happen within a certain range of the interior of the slope, the closer the frequency, the greater the range.(2) When the seismic wave amplitude value is small, seismic amplitude has a greater influence on the value of acceleration of the slope while amplitude value is large, it has small influence on the value of acceleration and the acceleration distribution. The counter-tilt slope deformation and failure will happen within a certain range of the interior of the slope, The greater the amplitude, the bigger the range.2. The seimic dynamic response characteristics of counter-tilt slope with different height, slope angle, strata dip.(1)The acceleration amplification coefficient value of extremum will increase then decrease with the increase in slope height, it will increase with the increase in slope angle and it will decrease with the increase in strata dip.(2)The counter-tilt slope deformation and failure will happen within a certain range of the interior of the slope, the larger the slope angle, the greater the range; the higher the height, the greater the range; the larger the strata dip, the greater the range.3. The seimic dynamic response characteristics of counter-tilt slope with soft rock at the bottom.When seismic wave energy is smaller, the soft rock underlying of the counter-tilt slope exerts a positive effects on stability of the slope. While seismic wave energy is large, the soft rock plays a negative role; the soft rock underlying will produce compression while the trailing edge rock of slope will produce cracking under the earthquake.4. The seimic dynamic response characteristics of Guantan slope.Slope failure did not occur under the earthquake, under the influence of the earthquake, the slope rock mass strength is weakened, tensile failure produced in hard rock where at the shallow site of trailing edge of the slope and the surface of soft rock, shear failure produced at the deep soft rock where at the bottom of the slope. The tension crack is conductive to the water to the lower part of the slope. Water soften rock, make pore water pressure increased, which leading to the effective stress decreases, these are harmful to the stability of the slope, it created the conditions for the occurrence of slope instability under the heavy rain.