循环荷载作用下钙质砂地基土压力分布特征研究

Study on earth pressure distribution characteristics of calcareous sand foundation under cyclic loading

钙质砂颗粒性形状不规则,且存在咬合作用,对地基土压力传递有较大影响。通过开展循环荷载作用下不同密实度钙质砂地基土压力动力响应的模型试验,揭示了钙质砂地基土压力的响应特征和衰减规律。试验结果表明:循环荷载作用下的近端各点土压力动力响应明显,随埋置深度的增加,各点的土压力峰值呈指数递减,距中轴线水平距离越远的土体,受波动影响越小。方形荷载面以下4倍荷载宽度处土压力衰减殆尽,而震动频率大小对于近端土压力的波动峰值有一定影响,对远端土压力的影响并不明显,且加载前后距荷载中心50 cm外土体密实度变化较小。增大整体试样密实度后,土体颗粒间紧密咬合,减少了承载时的相对运动,增大了循环荷载的波动影响深度。

The calcareous sand particles have irregular shapes and are interlocked, which has a greater impact on the transmission of earth pressure. This paper carried out a model test on the dynamic response of earth pressure of the calcareous sand foundation with different degrees of compaction under cyclic loading, and revealed the response characteristics and attenuation law of the earth pressure of the calcareous sand foundation under the cyclic loading. The test results show that the dynamic response of earth pressure at each point near the end under cyclic loading is obvious. As the embedment depth increases, the peak earth pressure at each point decreases exponentially. The farther the horizontal distance from the central axis, the smaller the impact from dynamic response. The attenuation of earth pressure at 4 times of the load width below the square load surface is attenuated, and the vibration frequency has a certain effect on the peak earth pressure at the near end, but the effect on the far end is not obvious, and the relative densities of soil 50 cm away from the load center before and after loading show small variation. After increasing the relative density of sample, the soil particles are tightly interlocked, reducing the relative movement during loading, and increasing the impact depth of cyclic loading.