Experimental Model Construction and Stability Evaluation of Slope Instability Induced by Microearthquakes

Abstract:

To reveal the displacement response mechanism and stability evolution law of the high slopes on both sides of the Lixian Expressway under seismic action, a systematic investigation was conducted by combining model experiments with theoretical analysis. The focus was on quantifying the displacement characteristics of the high slopes under seismic conditions, and a physical model test platform was established to simulate the dynamic responses of the slopes under different seismic wave parameters (frequency ranging from 10 to 100 Hz, amplitude ranging from 0.05g to 0.60g). The finite element numerical simulation was combined for theoretical verification, and the stability coefficient was calculated using the Mohr-Coulomb criterion. The research process strictly followed the technical route of engineering geo-logical investigation-model construction-loading test-data collection-theoretical analysis, with a particu-lar emphasis on monitoring the displacement time history curves at the top, fault zone, and middle areas of the slopes. The research results show that the top of the slope, lacking lateral constraints, exhibits linear growth characteristics in horizontal displacement under the excitation of seismic waves, and signs of fatigue failure appear after more than 2 000 vibration cycles; the upper edge of the fault zone is the most sensitive to the release of seismic energy, and the displacement accumulation rate is exponentially related to the vibration cycle. The frequency of the seismic waves has a significant impact on the displacement response. The amplitude of the low-frequency band (≤40 Hz) has a larger displacement amplitude but a slower growth rate, while the high-frequency band (>40 Hz) is prone to resonance effects, causing a 15% to 30% increase in displacement. The stability coefficient analysis shows that the relationship between the seismic wave amplitude and the required vibration cycle is a logarithmic function.