饱水-失水循环条件下红层泥岩蠕变特性及本构模型研究  

RESEARCH ON CREEP CHARACTERISTICS AND CONSTITUTIVE MODEL OF RED BED MUDSTONE UNDER SATURATED-DEHYDRATED CYCLE

作　　者：李安润 邓辉[1] 王小雪 罗杰[1] 张君[1] LI Anrun;DENG Hui;WANG Xiaoxue;LUO Jie;ZHANG Jun(State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]地质灾害防治与地质环境保护国家重点实验室(成都理工大学),中国成都610059

出　　处：《工程地质学报》2021年第3期843-850,共8页Journal of Engineering Geology

基　　金：国家自然科学基金资助项目(资助号:41272332).

摘　　要：滇中地区红层软岩分布广泛,且具有显著的流变特性,为研究饱水-失水循环条件下红层泥岩的蠕变特性,以龙川江河谷泥岩为研究对象,借助YZJL-300型岩石剪切流变仪,分别进行饱水-失水循环次数30次、50次和100次剪切蠕变试验,通过分析不同循环次数下的剪切蠕变特征,提出了饱水-失水循环条件下泥岩蠕变的本构模型。试验结果表明:(1)随着饱水-失水循环次数的增加,极限瞬时蠕变速率由0.273 mm·h^(-1)、0.365 mm·h^(-1)、0.452 mm·h^(-1)逐渐增加,长期强度逐渐降低;(2)相同剪切荷载下,循环次数越多,泥岩黏弹性模量越低;相同循环次数,剪切荷载越大,泥岩黏弹性模量小;(3)通过Matlab拟合分析提出了黏弹性模量E(n)与循环次数和时间的函数关系式E(n,t),并引入一个非线性黏塑性体建立了龙川江倒虹吸泥岩剪切蠕变本构模型(LCJN);(4)以1stOpt软件基于BFGS算法和通用全局优化法对LCJN模型辨识参数,并验证了模型的准确性和适用性。The red bed soft rocks in central Yunnan are widely distributed and have significant rheological properties.In order to study the creep properties of red bed mudstones under saturated-dehydration cycle conditions,Longchuan River valley mudstones are used as research objects.YZJL-300 rock shear rheometer performs 30,50,and 100 shear creep tests on saturated-dehydration cycles.A constitutive model of mudstone creep is proposed by analyzing the shear creep characteristics of mudstone.The test results show that:(1)the limit instantaneous creep rate gradually increases 0.273 mm·h^(-1),0.365 mm·h^(-1),and 0.452 mm·h^(-1) as the number of saturated-dehydrated cycles increases and the long-term strength gradually decreases;(2)under the same shear load,the greater the number of cycles,the lower the viscoelastic modulus of mudstone;the same number of cycles,the larger the shear load,the smaller the viscoelastic modulus of mudstone.The function of the number of cycles and time is E(n,t).A non-linear viscoplastic body is introduced to establish the shear creep constitutive model(LCJN)of the inverted siphon mudstone of the Longchuan River and a general global optimization method to identify parameters of LCJN model,and verify the accuracy and applicability of the model.

关 键 词：泥岩 饱水-失水循环 剪切蠕变 LCJN模型 

分 类 号：P642.3[天文地球—工程地质学]