颗粒级配对粒状材料不排水力学特性的影响  

Influence of grain gradation on undrained mechanical behavior of granular materials

作　　者：刘映晶[1,2,3] 李罡 尹振宇[1,2] 夏小和[1] 王建华[1] 

机构地区：[1]上海交通大学船舶海洋与建筑工程学院土木工程系,上海200240 [2]南特中央理工大学土木与力学学院,法国南特44300 [3]上海市隧道工程轨道交通设计研究院,上海200235 [4]中交第三航务工程勘察设计院有限公司,上海200032

出　　处：《岩土力学》2015年第2期423-429,共7页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.41240024;No.41172251;No.41372285;No.51161130523;No.41002095;No.41272317);欧盟玛丽居里行动计划(No.PIAPP-GA-2011-286397);高等学校博士学科点专项科研基金(No.20110073120012);上海市浦江人才计划项目(No.11PJ1405700)

摘　　要：为了研究颗粒级配对粒状材料不排水力学特性的影响，采用两种形状自相似度很高的材料（玻璃球和Hostun砂）进行了一系列传统三轴不排水压缩试验。对于每种材料，保持相近的相对密实度制作了6个不同颗粒级配（不均匀系数Ca=1．1～20）的试样，然后进行剪切。试验结果表明，颗粒级配对粒状材料的不排水力学性能存在明显影响：两种材料试样的偏应力水平随着不均匀系数的增加而降低，抗剪强度随着材料的不均匀系数Cu的增加而降低，并在Cu〉5后呈现出趋稳势态。基于不排水剪切试验中颗粒集合体二阶功的演化规律，对材料受荷载过程中出现不稳定性的条件进行分析。结果表明，在相同密实度下，粒状材料的静态液化潜能随着材料不均匀系数Cu的提高而增强，高不均匀系数的材料变得不稳定。This paper studies the influence of grain gradation on the undrained mechanical behavior of granular materials. A series of conventional undrained triaxial compression tests is carried out on two different materials （glass balls and Hostun sand）, which have high degree of shape self-similarity. For each material, 6 samples with similar relative density and different gradations （ Cu = 1.1-20） are prepared, and then the samples are sheared. Test results show that the grain gradation has an obvious impact on the undrained mechanical behavior of granular material： both deviatoric stress level and undrained shear strength of two material samples decreases as the coefficient of uniformity （ Cu ） of the material increases, their variations tend to converge as coefficient of uniformity Cu surpasses 5. Based on the evolution of the value of the second-order work of the granular assembly during undrained triaxial loading, potential instability for the selected granular materials is also analyzed. The results demonstrate a significant influence of the grain gradation on stability： the higher of coefficient of uniformity （Cu ）, the larger of the potential of static liquefaction and the unstabler of materials.

关 键 词：颗粒级配 三轴不排水试验 不稳定性 相对密实度 粒状材料 

分 类 号：TU411[建筑科学—岩土工程]