地震边坡动态临界加速度计算中抗剪强度参数概率分布分析

Probability Distribution of Shear Strength Parameters in Calculation of Dynamic Critical Acceleration of Seismic Slopes

基于动态临界加速度计算地震边坡永久位移的方法应用了边坡分布的不均匀性,不均匀分布程度影响着永久位移计算结果。研究Newmark滑块底部或潜在滑动面上抗剪强度参数的分布特征,有利于了解地震过程中临界加速度的分布和变化过程,为地震边坡永久位移计算参数选取提供依据。通过计算发现:边坡土体标准差的线性关系比较微弱,在缺乏实验数据时,仅可参考使用;黏聚力随机数个数达到200时所计算的永久位移数值不再有波动;黏聚力无论设置为正态分布还是对数正态分布均不影响永久位移计算结果;黏聚力标准差的数值大小对永久位移的大小和离散性影响很大。在地震边坡计算时,尽量将其设置为符合正态分布;尽量根据实测数据设定黏聚力标准差,若缺乏实测资料,可参考两者的线性关系并结合经验进行标准差设定。

The heterogeneity of cohesion distribution was applied in the calculation method of seismic slope permanent displacement based on dynamic acceleration,and the degree of uneven distribution affected the permanent displacement calculation results.Studying the distribution characteristics of shear strength parameters on the bottom of the Newmark sliding block or the potential sliding surface of slopes can clarify the distribution and change process of critical acceleration in seismic processes.Through calculation,it was found that the linear relationship between the standard deviation of cohesion and the cohesion of soil slope is weak and can only be used for reference in the absence of experimental data.When the random number of cohesive forces reached 200,the calculated permanent displacement values no longer fluctuated.Setting the cohesion as a normal distribution or lognormal distribution had no effect on the permanent displacement calculation result.The standard deviation of cohesion had a great influence on the value and dispersion of permanent displacement.During the seismic slope calculation,the cohesion should be set as normal distribution as possible,and the standard deviation of cohesion should be set according to the measured data as much as possible.If there is no measured data,the standard deviation can be set by referring to the linear relationship between the two.