大主应力方向及中主应力系数对重塑黄土小应变刚度特性影响试验研究  

Influence of principal stress direction and intermediate principal stress parameter on the small strain stiffness of reconstituted loess

作　　者：林清辉[1] 严佳佳[2] 董梅[2] 朱剑锋[3] LIN Qing-hui;YAN Jia-jia;DONG Mei;ZHU Jian-feng(l. College of Architecture and Civil Engineering, Taizhou Vocational ＆ Technical College, Taizhou, Zhejiang 318000, China;College of Architecture and Civil Engineering, Zhejiang University, Hangzhou, Zhejiang 310058, China;Faculty of Architectural, Civil Engineering and Environment, Ningbo University, Ningbo, Zhejiang 315211, China)

机构地区：[1]台州职业技术学院建筑工程学院,浙江台州318000 [2]浙江大学建筑工程学院,浙江杭州310058 [3]宁波大学建筑工程和环境学院,浙江宁波315211

出　　处：《岩土力学》2018年第4期1369-1376,共8页Rock and Soil Mechanics

基　　金：广东省产学研合作院士工作站(No.2013B090400024);同济大学岩土及地下工程教育部重点实验室开放基金项目(No.KLE-TJGE-B1501);国家自然科学基金项目(No.51409142;No.51608477);the Program of Guangdong Academician Workstation(2013B090400024);the Open Fund of Key Laboratory of Geotechnical and Underground Engineering;Ministry of Education;Tongji University(KLE-TJGE-B1501);the National Natural Science Foundation of China(51409142;51608477)

摘　　要：利用配备高精度应变传感器的空心圆柱扭剪仪对重塑黄土开展了一系列定向剪切试验,剪切过程中保持平均主应力p、大主应力方向角?以及中主应力系数b不变。共完成了包括3组不同大主应力方向角和1组不同中主应力系数的4组试验,共21个试样。对定向剪切条件下重塑粉土的应力-应变-强度以及小应变(<0.1%)刚度特性进行了研究,分析了不同大主应力方向角及中主应力系数的影响。试验研究结果表明,重塑黄土存在显著的强度各向异性特性,沿?=0°方向的强度最大,而最小强度方向因中主应力系数的不同而不同。?=0°时,b=0.25的强度最大,此时试样接近平面应变条件。小应变条件下重塑黄土的剪切刚度也因剪切时?和b的不同而不同,剪应变小于0.02%和大于2%时,刚度基本保持不变,初始剪切刚度很大,当剪应变大于0.02%后,随着剪应变的增加而迅速衰减,衰减曲线可以采用指数函数进行较好的拟合。A series of tests was carried out on reconstituted loess with a hollow cylinder apparatus equipped with high precision strain sensors with fixed principal stress direction. The mean principal stress p, principal stress direction a and intermediate principal stress coefficient b were constant during shearing. A total of 21 specimens in 4 groups of experiments, including 3 groups with different main stress direction angles and 1 group with main stress coefficients, were completed. The stress, strain, strength, and small strain（0.1%） stiffness behavior of reconstituted loess under fixed directional shearing was studied. The test results indicated anisotropy strength for reconstituted loess, with the maximum strength at a =0°, while the direction of minimum strength varied with the value of b. Highest shear strength was observed under plain strain condition a =0° and b=0.25 specimen. The small strain stiffness of reconstituted loess varied with α and b. Stiffness was almost constant when shear strain was 0.02% and 2%. The initial stiffness was higher at the beginning of shearing and decreased quickly with the increasing of shear strain when shear strain 0.02%. Stiffness varying with shear strain could be simulated accurately with the exponential function.

关 键 词：重塑黄土 大主应力方向角 中主应力系数 小应变刚度 

分 类 号：TU433[建筑科学—岩土工程]