摘要
从现有文献可以发现,含砾量、制样方法、相对密度和固结比等因素对饱和砂砾土动强度CRR的影响已有较多研究,但鲜有文献涉及细粒含量FC对砂砾土CRR的影响。通过一系列不排水循环三轴试验,研究了FC对细粒–砂粒–砾粒混合料CRR的影响。基于颗粒接触状态理论,将细粒–砂粒–砾粒混合料分为类粗粒土、类细粒土和中间性态土;引入"循环流动"和"循环液化"描述类粗粒土和类细粒土的循环破坏过程,提出了适用于混合料的循环破坏标准。试验结果表明:随着FC的增大,混合料的CRR呈现出先降低后增大的特征,当FC=30%时,混合料的CRR最低。通过分析发现,细粒–砂粒–砾粒混合料的CRR随骨架孔隙比e_k的增大而降低,且当FC<25%或FC>35%时,两者有较好的指数关系,说明e_k是合理地表征细粒–砂粒–砾粒混合料CRR的一个物理指标。
In the available researches on the cyclic resistance ratio （CRR） of saturated sand-gravel mixtures, the factors such as gravel content, sample preparation method, relative density and consolidation stress ratio have been considered. However, because of some reasons, the fines content （FC） has rarely been studied. The influences of the fines content on CRR of fines-sand-gravel mixtures are studied based on a series of undrained cyclic triaxial tests. According to the theory of particle contact state, the fines-sand-gravel mixtures are divided into coarse-like soils, fines-like soils and in-transition soils. ＂Cyclic mobility＂ and ＂cyclic liquefaction＂ are introduced to describe the cyclic failure process of coarse-like soils, fines-like soils and in-transition soils, and the criteria for the evaluation of cyclic failure of mixtures are proposed. The test results show that CRR of mixtures decreases with the increase of FC when FC is less than 30%, thereafter, it starts to increase, and CRR is the weakest when FC is 30%. Also, the analysis shows that CRR of mixtures decreases with the increase of ek, when FC 〈 25% or FC 〉 35%, ek can serve as a proper index to uniquely evaluate CRR of fines-sand-gravel mixtures, and an exponential relationship between the decrease in CRR and the increase in ek is then obtained.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2017年第6期1038-1047,共10页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(41172258
51438004)
国家重点基础研究发展计划("973"计划)项目(2014CB047005)
国家科技重大专项项目(2013ZX06002001-09)
