基于邻域均匀抽样Bootstrap方法的水泥土无侧限抗压强度演化规律研究

Study on evolution law of unconfined compressive strength of cement-soil based on neighborhood uniform sampling Bootstrap method

水泥土无侧限抗压强度的演化规律与水泥土的加固设计以及施工计划的安排和控制直接相关。为了得到在合理误差范围内且符合实际情况的水泥土无侧限抗压强度演化方程,本文首先大量挖掘现有文献的试验数据,获得水泥掺入比在10%~25%之间、龄期在3~90 d范围内的黏性土水泥土无侧限抗压强度(UCS)原始样本数据;然后提出一种新的邻域均匀抽样Bootstrap方法,对不同水泥掺入比的水泥土UCS值在不同龄期下的均值进行估计;再通过回归分析,得到各单一水泥掺入比下水泥土无侧限抗压强度的双曲线函数型演化方程;最后在回归分析获得演化方程参数a、b与水泥掺入比的经验公式的基础上,建立了综合水泥掺入比的水泥土UCS演化方程。研究结果表明,当龄期在0~90 d、水泥掺入比在10%~25%范围内,黏性土水泥土UCS演化方程中参数a、b的建议取值范围为:a=3.0~9.0,b=0.2~0.4,且它们在水泥掺入比较大时取较小值,反之取较大值。

The evolution law of unconfined compressive strength of cement-soil is directly related to the reinforcement design,the arrangement and control of construction scheduling of cement-soil.To obtain the evolution equation of unconfined compressive strength of cement-soil within a reasonable error range and in line with the actual situation,in this paper,the original sample data of unconfined compressive strength(UCS)of clay cement-soil with cement incorporation ratio of 10%to 25%and age of 3 to 90 days was obtained by mining a large number of experimental data from existing literture.Then,a new neighborhood uniform sampling Bootstrap method is proposed to estimate the mean UCS values of cement-soil with different cement ratios at different age.Through regression analysis,the evolution equations of unconfined compressive strength of cement-soil with each single cement ratio are obtained.Finally,the UCS evolution equation of cement-soil with cement ratio was established on the basis of regression analysis of the relationship between the parameters of the evolution equation and the cement ratio.The results show that when the age ranges from 0 to 90 days and the cement ratio ranges from 10%to 25%,the recommended values of parameters a and b in the UCS evolution equation of cementsoil are as follows:a=3.0-9.0,b=0.2-0.4.In addition,when the cement ratio is larger,the values of parameters a and b should be smaller;otherwise,they should be larger.