红层泥岩填料蠕变特性及分数阶五元件非线性蠕变模型研究  

Study of creep characteristics of red mudstone filling and fractional five-element nonlinear creep model

作　　者：余云燕[1] 杜乾中 罗崇亮 丁小刚 李永鹏 YU Yunyan;DU Qianzhong;LUO Chongliang;DING Xiaogang;LI Yongpeng(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;Transport Bureau of Gannan Tibetan Autonomous Prefecture,Gannan 747000,China)

机构地区：[1]兰州交通大学土木工程学院,甘肃兰州730070 [2]甘南藏族自治州交通运输局,甘肃甘南747000

出　　处：《中南大学学报（自然科学版）》2024年第4期1654-1664,共11页Journal of Central South University:Science and Technology

基　　金：甘肃省科技计划项目(21YF5GA050);甘肃省教育厅产业支撑计划项目(2021CYZC-28);甘肃省交通运输厅科技研发项目(2021-12)。

摘　　要：为揭示红层泥岩填料的蠕变力学特性,对甘肃红层泥岩填料开展分级加载三轴CU蠕变试验,分析不同含水率和偏应力水平下红层泥岩填料的轴向蠕变、蠕变速率、应力-应变等时曲线等蠕变特性。基于红层泥岩填料蠕变曲线特征分析,引入分数阶微积分,构建适用于甘肃红层泥岩填料的分数阶五元件非线性蠕变模型,并对模型参数进行辨识和分析。研究结果表明:甘肃红层泥岩填料存在明显的蠕变特性,呈非线性衰减蠕变,随含水率与偏应力水平增大,蠕变变形明显增大;应力-应变等时曲线呈现出非线性特征,存在明显拐点,甘肃红层泥岩填料的长期强度为瞬时强度的0.6~0.8;所构建的模型可以准确地描述甘肃红层泥岩填料的蠕变特性,对试验结果的拟合效果明显比Burgers和Merchant模型拟合效果好。In order to reveal the creep mechanical characteristics of red mudstone filling,triaxial CU creep test with graded loading of red mudstone filling in Gansu Province was carried out,and the creep characteristics such as the axial creep,creep rate and stress-strain isochronous curves of red mudstone filled with different moisture contents and stress levels were analyzed.Based on the characteristic analyses of creep curves of red mudstone filling,fractional calculus was introduced to construct a fractional five-element nonlinear creep model suitable for red mudstone filling in Gansu Province,and the model parameters were identified and analyzed.The results show that the red mudstone filling in Gansu Province has obvious creep characteristics,showing nonlinear attenuation creep,and the creep deformation increases significantly with the increase of moisture content and deflection stress.The stress-strain isochronous curves show nonlinear characteristics and obvious inflection point,and the long-term strength of the Gansu red mudstone filling is 0.6−0.8 times the instantaneous strength.The constructed model can accurately describe the creep characteristics of Gansu red mudstone filling,and the fitting effect on the experimental results is significantly better than those of the Burgers and Merchant models.

关 键 词：红层泥岩填料 三轴CU蠕变试验 蠕变特性 分数阶微积分 非线性蠕变模型 

分 类 号：TU446[建筑科学—岩土工程]