发泡球粒粒径对混合轻量砂强度影响试验研究  

TEST FOR INFLUENCE LAW OF EXPANDED POLYSTYRENE(EPS) PARTICLE SIZE ON STRENGTH CHARACTERISTICS OF MIXED LIGHT-WEIGHT SAND

作　　者：谢书萌[1,2] 徐光黎[2] 叶三霞[3] 胡焕忠[2] 

机构地区：[1]贵州省交通规划勘察设计研究院股份有限公司,贵州贵阳550001 [2]中国地质大学岩土钻掘与防护教育部工程研究中心,湖北武汉430074 [3]中国水电顾问集团成都勘测设计研究院,四川成都610072

出　　处：《岩石力学与工程学报》2013年第S2期3056-3063,共8页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(41072218)

摘　　要：为确定发泡球粒粒径对混合轻量砂的强度影响规律,采用三轴固结不排水试验系统研究发泡颗粒混合轻量砂在不同配比下(2~6 mm范围内4种不同发泡颗粒平均粒径,水泥掺入比13%和20%,发泡颗粒体积比为1.8)的强度特性。试验结果表明:发泡颗粒混合轻量砂是一种结构性土体,其应力–应变关系曲线具非线性、多阶段性、应变硬化和应变软化特性。Mohr破坏包络线有折线形和直线形2种表现形式,取决于自身结构强度和所选取的固结压力。变形模量和抗压强度具有可调节性,随水泥掺入比增大而增大。配比一定时,随发泡颗粒粒径增大,变形模量线性减小,抗压强度呈指数递减。黏聚力和内摩擦角均随着发泡颗粒粒径的增大而呈递减的趋势,但内摩擦角减小的幅度较小。水泥含量对黏聚力影响较大,对内摩擦角影响不明显。发泡颗粒粒径在2~5 mm范围内增大时,单价降低率远远大于强度衰减率,继续增大优势不明显,粒径为5~6 mm时,制样难度大大增加。综合考虑,推荐采用4~5 mm粒径的发泡颗粒进行工程设计。A series of triaxial tests were carried out to investigate the influence law of expanded polystyrene size(EPS) on strength characteristics of light-weight sand(4 kinds of EPS sizes in range of 2-6 mm),cement mass ratio is 13% and 20%,EPS volume ratio is 1.8). Results show that the light-weight sand is a kind of structural soil,nonlinearity,multi-stage,strain hardening and strain softening are the properties of its stress-strain relation curves. Broken line and straight line are the two different types of Mohr failure envelope,which depends on the structural strength and consolidation pressure. Deformation modulus and compressive strength are adjustable,both growing with the increase of cement mixed ratio. For a certain mixed ratio,with the increase of EPS size,deformation modulus decreases linearly and compressive strength decreases exponentially. Cohesive strength and internal frictional angle decrease with the increase of EPS size,but the reduction of internal frictional angle is smaller. The cement mixed ratio has a big influence on the cohesive strength and little influence on the internal frictional angle. The reduction rate of unit price is far more greater than that of strength,with the increase of EPS size from 2 to 5 mm,but the advantage is not obvious when the EPS size continues to grow. The difficulty of sample preparation is highly increased when the EPS particle sizes are 5-6 mm. Take all factors into consideration,4-5 mm particle sizes of EPS are recommended in practical engineering.

关 键 词：土力学 轻量砂 发泡颗粒 粒径 抗压强度 变形模量 三轴试验 

分 类 号：TU521.1[建筑科学—建筑技术科学]