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研究地铁车站在地震中的响应对于地铁建设和安全运营非常重要。针对北京地区的地质条件和典型的地铁车站结构进行了大型振动台试验,对动土应力时程进行了分析,得出如下结论:埋深小于结构顶板和埋深大于结构底板的土中动土应力不随输入波强度与埋深变化而变化;在输入波强度低时,侧墙上各点的动土压力相等;在输入波强度高时,侧墙上各点的动土压力随输入波强度的增高而逐渐增大,且动土压力变化幅值随埋深增加而不断增加。通过以上分析,说明在地震强度小时,地下结构对土的水平向动应力影响很小,在地震强度大时,因地下结构的修建进行的开挖削弱了土体,其对土的水平向动应力影响变大。作者还对对结构底板的水平向动切应力进行了拟合,发现:底板的动切应力呈梯形分布,中点处最大,两个端点处最小;底板各点的动切应力随地震波强度的增加呈指数函数增加。为应用方便将底板中点的动切应力与地震波加速度峰值之间的关系简化为:当地震波峰值加速度不大于0.4 g时,峰值切应力为常数;当地震波峰值加速度大于0.4 g时,峰值切应力为直线分布。
Studying the response of subway stations to earthquakes is very important for subway construction and safe operation. According to the geological conditions in Beijing area and the typical metro station structure, a large-scale shaking table test was conducted to analyze the earth-moving stress time-history. The conclusions are as follows: the soil depth less than the structural roof and buried depth is greater than that The input earth wave intensity and the depth of the change changes; the input wave intensity is low, the lateral wall of each point of the earth pressure equal; input wave intensity is high, the lateral wall of each point of the earth pressure gradually increases with the input wave intensity gradually Increase, and the earth pressure changes with the increase of buried depth increases. Through the above analysis, it shows that the underground structure has little influence on the horizontal dynamic stress of the soil when the earthquake intensity is small. When the earthquake intensity is large, the excavation due to the construction of the underground structure weakens the soil and its horizontal movement to the soil The effect of stress becomes larger. The authors also fit the horizontal dynamic shear stress of the structural slab. It is found that the dynamic shear stress of the slab is trapezoidal, with the maximum at the midpoint and the minimum at the two ends. The dynamic shear stress at each point of the slab varies with the seismic intensity Increase exponential function increases. For the convenience of application, the relationship between the dynamic shear stress at the midpoint of the bottom plate and the peak acceleration of seismic wave is simplified as follows: the peak shear stress is constant when the peak acceleration of the seismic wave is not greater than 0.4 g; and the peak shear stress For a straight line.