胀缩性土强度衰减曲线的函数拟合  

Function fitting on strength attenuation curve of swell-shrinking soils

作　　者：吕海波[1,2] 曾召田[1,2] 赵艳林[1,2] 葛若东[2] 陈承佑[2] 韦昌富[1] 

机构地区：[1]广西矿冶与环境科学实验中心(桂林理工大学),广西桂林541004 [2]广西大学土木建筑工程学院防灾减灾研究所,广西南宁530004

出　　处：《岩土工程学报》2013年第S2期157-162,共6页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(51169005;41272358);广西自然科学基金项目(2013GXNSFBA019233);广西自然科学基金重点项目(2011GXNSFE018004)

摘　　要：通过广西地区红黏土和膨胀土的室内干湿循环模拟试验,探讨了干湿循环条件下胀缩性土的强度衰减规律;在此基础上,建立了黏聚力衰减率与循环次数的关系;根据黏聚力衰减曲线变化特征,提出采用S型曲线函数进行拟合,并与其他类似的试验结果进行了拟合效果验证。研究结果表明:①胀缩性土的黏聚力随干湿循环次数增加而衰减,最终趋于稳定;干湿循环次数引起内摩擦角的波动变化极小,基本保持一稳定值。②S型曲线函数能很好地描述土体强度干湿循环衰减规律,反映土体干湿循环达到一定次数后土体强度趋于稳定的规律,克服了以往线性函数、多项式函数和指数函数拟合存在的不足。Experimental studies are performed on red clay and expansive soils from Guangxi area in order to establish the relationship between shear strength parameters of swell-shrinking soils and number of wetting-drying cycles. Then, the relationship between cohesive attenuation rate and cyclic number is found. Based on the characteristics of the cohesive attenuation curve, the S-shaped function is adopted for fitting. The results show that the cohesion of swell-shrinking soils decreases with the increasing number of cycles and finally reaches a constant state. However, the friction angle keeps stable under the influence of the wetting-drying effects. Furthermore, the S-shaped function can well describe the strength attenuation law, and it overcomes the shortcomings of the previous fitting with linear function, polynomial function and exponential function because it can reflect the law that the soil strength is close to a stable value after certain wetting-drying cycles.

关 键 词：胀缩性土 干湿循环 强度衰减 拟合曲线 

分 类 号：TU443[建筑科学—岩土工程]