Experimental Study of Bridge Foundation Reinforced with Front and Back Rows of Anti-Slide Piles on Gravel Soil Slope under El Centro Waves

Featured Application The research conclusions could be used as the reference for engineering designs, especially for the seismic reinforcement design of a bridge foundation reinforced with front and back rows of anti-slide piles on a gravel soil slope. The supposed method of two-dimensional equipotential maps used in model test analysis are visual and convenient. Abstract A shaking table test for a bridge foundation reinforced with the front and back rows of anti-slide piles on a gravel soil slope was designed. The test results were obtained by loading El Centro waves with different peak accelerations. It was not an advantage for the deformation of bridge pile foundation while the distance between the front-row anti-slide piles and pier was large. The back-row anti-slide piles played a major role in seismic reinforcement, and the peak bending moment of the pile shaft and the peak earth pressure behind the pile had a triangular distribution. The distance from the crack to the sliding surface of the anti-slide pile was approximately one fifth of the length of the anchoring section. As the crack propagated, the bearing capacity of the pile shaft decreased gradually. Since the influence of pier inertia force and soil horizontal thrust, a peak negative bending moment and a peak positive bending moment were observed near the pile top and the sliding surface respectively. The rate of attenuation of the bending moment from the top of the pile along its depth was related to the resistance of the soil around the pile. The stress-induced deformation of the pile foundation behind the pier was larger than that in front of the pier. The peak ground acceleration (PGA) amplification factor of the slope had a vertical amplification effect and a layered distribution. The acceleration responses of the sliding section and the steep slope section were strong, while the acceleration responses of the region between the bridge pier and the back-row anti-slide piles were weak. With the increase in the vibration intensity, the soil damping ratio increased and the PGA amplification factor decreased. The feasibility of analyzing the acceleration response of the slope model by the two-dimensional equipotential map was experimentally verified.