| The research on the dynamic response of slope and retaining structure under seismic action has always been a hot topic.Most scholars use relatively simple sine wave to guide the design.However,the waveform of actual earthquake is irregular and the frequency component is complex.The size and law of engineering response under actual earthquake may be inconsistent with that of sine wave,which leads to improper engineering design.Therefore,it is very important to study the difference between the dynamic response of retaining structure and slope under sine wave and actual seismic wave.In this paper,based on the key research and development project of Sichuan Province “Study on the evaluation method of service state of typical retaining structures in high-intensity seismic zone after earthquake”,the shaking table test of high and steep slope supported by anti-slide piles is designed.Combined with three-dimensional simulation,the difference in the dynamic response of slope and anti-slide piles under the action of sine wave and EL wave and the reasons for the difference are emphatically analyzed.The main contents are as follows:1.The sine wave frequency is only 5Hz;EL wave band is widely distributed,and the predominant frequency is mainly located in 0～10 Hz.The strength of Arias contained in sine wave is about 4.60 times that of EL wave,and the maximum displacement of structure caused by sine wave is about 5.60 times that of EL wave.2.The dynamic response of the slope and the anti-slide pile under sine wave and EL wave conditions is compared and analyzed by shaking table model test.It can be found that the spatial distribution of the response caused by the two seismic waves is basically the same.The response at the upper 1/3 height of the slope is large,and the pile body is subjected to large forces near the sliding surface.These areas are the key areas of seismic design.There is a numerical difference in response,and the ratio of slope PGA amplification coefficient obtained by EL wave and sine wave gradually approaches 1 with the increase of acceleration.The sine wave will cause greater slope deformation and pile force,and the difference of horizontal residual displacement at the top of the two piles reaches 0.29 mm when 0.60g;when the micro-strain of pile is 0.60 g,the maximum difference is 35.680 e-6;when the soil pressure before and after the pile is 0.50 g,the maximum difference is 3.242 k Pa and2.268 k Pa,respectively.3.The frequency domain analysis reveals that the difference of response values between sine wave and EL wave is due to the difference of frequency and energy.Under the sine wave condition,the reconstructed signal of the first frequency band of the soil pressure at the measuring point is closer to the original signal.Under the EL wave condition,the first frequency band occupies the main role,and the second frequency band is followed.The maximum earth pressure of the reconstructed component in the first frequency band of sine wave is about 1.5 times of that in the first frequency band of EL wave.4.The FLAC3 D three-dimensional simulation software is used to calculate the actual slope.The results show that the residual displacement difference of the slope after horizontal earthquake reaches 0.97 m under the action of 0.40 g sine wave and EL wave.The response ratio of PGA amplification factor of slope under the action of EL wave and sine wave is basically maintained at around 1.The sine wave causes larger pile response,and the maximum difference of horizontal displacement,shear force and bending moment reaches52.24mm、13.42MN、48.38 MN×m when 0.40 g,respectively.5.Due to their different characteristics,sine wave and EL wave have different responses.For seismic research on slopes and retaining structures,measured natural seismic waves should be used for research. |
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