加载路径对粗粒土非共轴性影响的试验研究  

Experimental study on effect of loading path on non-coaxiality of granular materials

作　　者：蔡燕燕[1,2] 俞缙[1,2] 余海岁 郭力群[1] 

机构地区：[1]华侨大学岩土工程研究所,福建厦门361021 [2]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221008 [3]诺丁汉大学岩土力学研究中心

出　　处：《岩土工程学报》2012年第6期1117-1122,共6页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(51109084);福建省自然科学基金项目(2011J01317);中国矿业大学深部岩土力学与地下工程国家重点实验室开放基金项目(SKLGDUEK1012;SKLGDUEK1111);重庆交通大学(桥梁)结构工程重点实验室开放基金项目(CQSLBF-Y11-2);华侨大学侨办基金项目(09QZR03)

摘　　要：采用空心圆柱扭转仪,对Portaway砂进行排水试验,研究粗颗粒砂土主应力和主应变增量的非共轴性,以及应力路径(历史)对砂土非共轴性的影响规律。试验分两个系列,系列1中试件在排水固结后直接沿着固定的主应力方向进行加载,系列2中试件在排水固结后先进行轴向压缩,再沿着与系列1同样的加载路径剪切。试验进一步验证了颗粒材料的非共轴特性。试验结果显示:非共轴度与材料的加载方向密切相关,加载历史对于非共轴度有一定的影响;随着试件接近破坏状态,主应力和主应变增量趋于共轴。The non-coaxiality between the major principal stress and the principal strain increment directions is found to be an important feature of granular materials. The conventional constitutive models are based on the theory of coaxiality without considering the effect of non-coaxiality. A hollow cylinder apparatus is used to investigate the non-coaxiality between the axes of the major principal stress and principal strain increment and the effects of loading history on the degree of non-coaxiality. Two series of drained tests are carried out on Portaway sand. In the first series, the specimens are sheared along the fixed principal stress directions. In the second one, the specimens are compressed along the vertical direction before shearing along the same paths of the first series. The results show further evidence of the non-coaxiality. The degree of non-coaxiality has dependence on the loading directions as well as the effect of loading history. It is also found that the degree of non-coaxiality will reduce when the specimen approaches failure.

关 键 词：非共轴 粗粒土 空心圆柱扭转仪 排水试验 

分 类 号：TU411[建筑科学—岩土工程]