检索规则说明:AND代表“并且”;OR代表“或者”;NOT代表“不包含”;(注意必须大写,运算符两边需空一格)
检 索 范 例 :范例一: (K=图书馆学 OR K=情报学) AND A=范并思 范例二:J=计算机应用与软件 AND (U=C++ OR U=Basic) NOT M=Visual
作 者:亓帅 马伟 索智 汪晶 刘锦辉 QI Shuai;MA Wei;SUO Zhi;WANG Jing;LIU Jinghui(School of Civil and Transportation Engineering,Beijing University of Civil Engineering and Architecture,Beijing 100044;Beijing Urban Transportation Infrastructure Construction Technology Research Center,Beijing 102616)
机构地区:[1]北京建筑大学土木与交通工程学院,北京100044 [2]北京城市交通基础设施建设工程技术研究中心,北京102616
出 处:《北京建筑大学学报》2024年第5期66-73,共8页Journal of Beijing University of Civil Engineering and Architecture
基 金:国家自然科学基金项目(52108295);北京建筑大学“建大英才项目”(JDYC20220811)。
摘 要:黏土是一种常用的路基填料。现场施工中,受降雨、蒸发等的影响,黏土路基填料通常在宽含水率范围下(包括最优含水率及其干湿侧)完成压实,形成情况各异的微观骨架,动力荷载作用下呈现出不同刚度特性。对5种压实含水率的黏土路基填料开展了动力回弹模量和微观结构研究,结果表明:当土体在最优含水率w_(opt)及其干侧压实时,土骨架为团粒-团粒接触结构,孔隙分布呈现双峰特性;当土体在最优含水率w_(opt)湿侧压实时,土骨架为颗粒-颗粒接触结构,孔隙分布呈现单峰特性。回弹变形ε_(1r)和回弹模量Mr在不同压实含水率下随振次的变化规律相近,在加载初始阶段呈现迅速变化(减小/增大)的趋势,后随加载次数增加逐步趋于稳定。ε_(1r)和Mr随压实含水率的增大分别呈现“倒钟型”和“钟型”的曲线变化趋势;特征含水率w_(-cha)定义于曲线转折点处,将ε_(1r)和Mr的变化分为2个阶段:当w_(opt),w增大导致ε_(1r)下降和Mr上升;当w≥w_(opt),w增大导致ε_(1r)上升和Mr下降,该规律可归因于团粒和基质吸力的变化。土体刚度在w_(opt)干侧和湿侧均小于w_(opt)的对应值,为保证路基良好的刚度性能,工程现场过湿和过干的压实含水率均需采取措施调整。Clay soils were always used in the construction of road subgrade.During in-situ compaction,under the effects of the factors such as rainfal and evaporation,clay subgrade soils were usually compacted under a wide range of remoulding water content(optimum water content as well as its wet and dry sides).Thus,the microstructure of the compacted clay soils could change,leading to variations in stiffness property under cyclic loadings.The dynamic behavior and microstructure of compacted subgrade clay soils at various remoulding water contents were investigated.Results showed that:when compacted at w_(opt) and its dry side,soil fabric was characterized by aggregate-aggregate contact structure with pore size distribution(PSD)exhibiting a bi-modal feature,while at wet side of w_(opt),soil fabric was characterized by particle-particle contact structure with an uni-modal PSD.The variations of resilient deformationε_(1r) and resilient modulus Mr with remoulding water content were similar,which varied rapidly at the initial loading stage and then tended to stabilize.The variations ofε_(1r) and Mr with remoulding water content exhibited“inverted bell”and“bell”shapes,respectively.A characteristic remoulding water content was defined at the turning point of the curve,defining two stages of the variations ofε_(1r) and Mr:when w<wcha,w increment led to a decrease inε_(1r) and an increase in Mr,while when w<wcha,w increment led to an increase inε_(1r) and a decrease in Mr.This phenomena could be attributed to the variations in aggregate and matric suction.The soil stiffness at wet and dry sides of the wcha was smaller than the value at wcha.Thus,the too wet or too dry case should be handled to guarantee the dynamic performance of the road subgrade.
正在载入数据...
正在载入数据...
正在载入数据...
正在载入数据...
正在载入数据...
正在载入数据...
正在载入数据...
正在链接到云南高校图书馆文献保障联盟下载...
云南高校图书馆联盟文献共享服务平台 版权所有©
您的IP:216.73.216.33