基于门限自回归计算模型的软土扰动度评价

Assessment of Sampling Disturbance of Soft Clay by Use of Threshold Autoregressive Mode

采用基于门限自回归计算模型的修正体积压缩法,对连云港地区典型软土勘察中取/制样过程进行扰动度评价。研究表明:采用门限自回归模型可自动捕捉屈服点,评价指标的标准差均小于1%,数值拟合结果较好;薄壁原状土样平均扰动程度为22.0%,说明连云港地区软土结构性强,土样易受扰动。此外,分析了扰动度和屈服应力及十字板抗剪强度之间的关系,并探讨了取/制样扰动的恢复处理方法。

In this paper, corrected volume calculation model based on Threshold Autoregressive mode is used to evaluate soil disturbance degree of the typical soft clay in Lianyungang area. The results show that： Threshold Autoregressive model could automatically capture the yield point, the standard deviation of the index is less than 1%, fitting the numerical mode well. Average disturbance degree of the soft caly samples from the thin wall geotome is 22.0%, indicating that the soft clay can be easily disturbed with high structural properties. Besides, the relationship between the disturbance degree and yield stress and vane strength are discussed, and the pretreatment method of resuming natural stress status of samples are analysed.