风积沙地基工程性质及其输电线路基础抗拔设计  

Property of Aeolian Sand and Design of the Uplift Bearing Capacity for the Sand Foundation of Transmission Line Structures

作　　者：鲁先龙[1] 程永锋[1] 丁士君[1] 

机构地区：[1]中国电力科学研究院输变电工程力学研究所,北京市100055

出　　处：《电力建设》2010年第7期46-50,共5页Electric Power Construction

基　　金：国家电网公司科技项目(SGK[J2007]441)

摘　　要：沙漠风积沙地基工程性质及其输电线路杆塔基础抗拔设计是当前我国电网建设中的关键研究课题之一。通过对我国不同沙漠风积沙地基的物理力学性质的试验及其研究成果的统计,分析了我国沙漠地区风积沙地基的颗粒级配组成及其分类,给出了其含水性、容重、孔隙性、相对密度、内摩擦角等典型物理力学特性参数的平均值。基于我国沙漠风积沙地基的工程特性,介绍了沙漠风积沙地基输电线路杆塔基础抗拔稳定性"土重法"设计方法及其正确性。研究并分析了宁夏毛乌素沙漠4个斜柱扩展基础上拔水平力组合荷载试验、新疆塔克拉玛干沙漠4个装配式基础上拔水平力组合荷载试验、内蒙库布齐沙漠1个直柱扩展基础和2个混凝土拉线盘基础抗拔试验成果,得到了我国典型沙漠风积沙地基极限上拔角标准值为16.9°;在考虑地基抗拔承载力分项系数为1.65的基础上,得到风积沙地基上拔角设计值为10.3°。由于该上拔角设计值综合考虑了风积沙地基的区域特征、基础类型、基础几何尺寸、基础荷载工况等不同影响因素,可作为我国沙漠地区输电线路基础设计的依据。The properties of aeolian sand and design of the uplift bearing capacity of this kind of foundation is one of the key issues that need to be studied for power grid engineering construction in China.Based on a statistical analysis of the testing data of various desert aeolian sands in China,the mean values of their main physical and mechanical property parameters are obtained,such as the grain size and gradation,water content,unit weight,specific gravity of soil particles,porosity,relative density,internal friction angle.An introduction is made in this paper of a new design method for uplift bearing capacity,the earth cone method,in which the uplift angle of aeolian sands is a decisive and key parameter for determining the uplift bearing capacity of the aeolian sand foundations.Based on the available data of 11 in-site prototype uplift tests carried out in various desert aeolian sand foundations for power transmission lines in China,including four tests of uplift combined with horizontal loads performed on pad and chimney foundations in the Mu Us Desert in Ninxia,four tests of uplift combined with horizontal loads performed on assembly foundations in the Taklimakan Desert in Xinjiang,and one test on flexible concrete foundation and two tests on anchoring plate foundation in the Hobq Desert in Inner Mongolia,the obtained nominal value of ultimate uplift angle of aeolian sand is 16.9°.According to the specification of some codes in China that the differential coefficient of uplift bearing capacity of subgrade foundation soils is 1.65,the design uplift angle of 10.3° is thus obtained for aeolian sand foundations.With a comprehensive consideration of various influential factors of aeolian sand foundations,including the differences of regions,foundation types,foundation geometry sizes and loading conditions,this value can be used as a basis for design of transmission line foundations in various desert regions in China.

关 键 词：风积沙 输电线路杆塔基础 抗拔承载力 土重法 上拔角 土性参数 

分 类 号：TM753[电气工程—电力系统及自动化] TU47[建筑科学—结构工程]