豫南燕山期花岗岩蠕变特性及非线性蠕变损伤模型  

Creep Characteristics and Nonlinear Creep Damage Model of Yanshanian Granite in Southern Henan

作　　者：唐志强 吉锋[1] 许汉华 冯文凯[1] 何萧 TANG Zhi-qiang;JI Feng;XU Han-hua;FENG Wen-kai;HE Xiao(State Key Laboratory of Geological Disaster Prevention and Geological Environment Protection, Chengdu University of Technology, Chengdu 610059, China;Kunming Prospecting Design Institute of China Nonferrous Metals Industry Co., Ltd., Kunming 650051, China;Yunnan Key Laboratory of Geotechnical Engineering and Geo-hazards, Kunming 650051, China)

机构地区：[1]成都理工大学地质灾害防治与地质环境保护国家重点实验室,成都610059 [2]中国有色金属工业昆明勘察设计研究院有限公司,昆明650051 [3]云南省岩土工程与地质灾害重点实验室,昆明650051

出　　处：《科学技术与工程》2022年第16期6421-6429,共9页Science Technology and Engineering

基　　金：国家自然科学基金(41977237)。

摘　　要：豫南信阳地区燕山期高钾钙碱性I型花岗岩分布广泛,岩石性质对深埋地下洞室围岩开挖及支护设计具有重要影响。以豫南某大型水电站地下厂房区花岗岩为研究对象,在对其地质分布情况及矿物成分调查测试基础上,进行三轴压缩蠕变试验,揭示了围岩蠕变特性及加载过程中的损伤演化性质,采用等时曲线法进行花岗岩蠕变长期强度分析。考虑蠕变过程中岩石发生的损伤累积,建立变黏性系数的黏壶元件,并代替传统西原正夫模型中Newton黏壶,构建了能够描述加速蠕变阶段的蠕变损伤模型。结果表明:在整个蠕变过程中,花岗岩的总变形量以瞬时弹性变形为主,最终的蠕变破坏表现出脆性剪切破坏的特征;围压对剪切裂缝的扩展具有主要抑制作用;长期强度随围压增大而减小,与常规三轴试验结果相比,长期强度分别下降6.37%和21.0%;采用Levenberg-Marquardt优化算法+通用全局优化算法对非线性蠕变损伤模型进行参数辨识及拟合,理论值与试验值吻合较好,验证了非线性蠕变损伤模型对于岩石全过程蠕变特征描述的合理性及适用性。研究成果对保障豫南燕山期花岗岩地区的工程建设优化设计和安全建设具有重要意义。Yanshanian high potassium calc alkaline I-type granite is widely distributed in Xinyang area,Southern Henan.The rock properties have an important impact on the surrounding rock excavation and support design of deep underground caverns.Taking the granite in the underground powerhouse area of a large hydropower station in southern Henan as the research object,based on the investigation and test of its geological distribution and mineral composition,the triaxial compression creep test was carried out,the creep characteristics of surrounding rock and the damage evolution properties during loading were revealed,and the long-term creep strength of granite was analyzed by isochronous curve method.Considering the damage accumulation of rock in the process of creep,a clay pot element with variable viscosity coefficient was established,and a creep damage model which can describe the accelerated creep stage was constructed instead of the Newton clay pot in the traditional Masao Nishihara model.The results show that in the whole creep process,the total deformation of granite is mainly instantaneous elastic deformation,and the final creep failure shows the characteristics of brittle shear failure.Confining pressure has a main inhibitory effect on the propagation of shear cracks.The long-term strength decreases with the increase of confining pressure.Compared with the results of conventional triaxial test,the long-term strength decreases by 6.37%and 21.0%respectively.Levenberg-Marquardt optimization algorithm+general global optimization algorithm were used to identify and fit the parameters of the nonlinear creep damage model.The theoretical values are in good agreement with the experimental values,which verifies the rationality and applicability of the nonlinear creep damage model for describing the creep characteristics of rock in the whole process.The research results are of great significance to ensure the optimal design and safety construction of engineering construction in Yanshanian granite area in southern Henan.

关 键 词：豫南地区 花岗岩 三轴压缩蠕变试验 蠕变损伤模型 参数辨识及拟合 

分 类 号：P642[天文地球—工程地质学] TU458[天文地球—地质矿产勘探]