潮汐应力对滑坡的触发机理研究

DAILY SUCCESSIVE VARIATION AND TRIGGERING MECHANISM OF TIDAL STRESS TO LANDSLIDE

已有的滑坡统计数据和研究成果显示,滑坡发生的时间具有明显的周期分布规律特征,除了与降雨季节相关的因素外,受日月引力潮的影响也较明显。本文对一定数量的滑坡发生的历史数据进行统计分析,得到滑坡的发生时间在1d内呈明显的分布特征。然后从固体潮理论出发,推导简化弹性地球模型地表的潮汐应力表达式,阐述了固体潮汐作为滑坡日周期因子对滑坡的影响。并通过岩体破坏判据剖析潮汐应力触发滑坡的机理。最后以南京某典型平面滑动的岩质边坡作为算例,在安全系数表达式中将潮汐应力的作用考虑进去,得到坡体的稳定性系数随时间的变动特征,以定量的方式加强对滑坡发生时间分布的日周期性及固体潮汐的触发机理的阐述。

Landslide statistics and research findings have shown that the occurrence time of landslides has the feature of evident period distribution.In addition to rainfall,the moon and sun gravitational tide is recognized as another apparent factor.In this paper,the statistical diagram of landslides in days is gained by analyzing the data of a certain number of slides.Further efforts is made on the deduction of the formulas of tidal stress at surface of the Earth,by modifying a simplified elastic earth model based on the earth tide theory.The mechanism of landslide triggered by tidal stress is discussed in further.Moreover,a rock slope in Nanjing is taken as a example,based on the planar failure surface method,to discuss the correlation between tidal stress and time,and how the safety factor of stability change with time.The results show that,the tidal stress and the factor of slope stability change with time at daily period.Therefore,the characteristic with daily successive variation of landslides and the mechanism triggered by earth tide are elaborated quantitatively.