干湿循环对龙游石窟泥质粉砂岩蠕变特性影响的试验研究  

EXPERIMENTAL STUDY ON THE INFLUENCE OF DRY-WET CYCLE ON CREEP CHARACTERISTICS OF ARGILLACEOUS SILTSTONE IN LONGYOU GROTTOES

作　　者：李紫怡 周剑 张德宇 张路青[3,4] 曾庆利 杨志法[3,4] 傅燕 LI Ziyi;ZHOU Jian;ZHANG Deyu;ZHANG Luqing;ZENG Qingli;YANG Zhifa;FU Yan(College of Architecture and Civil Engineering,Beijing University of Technology,Beijing 100124,China;Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education,Beijing University of Technology,Beijing 100124,China;Key Laboratory of Shale Gas and Geoengineering,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Institute of Earth Sciences,Chinese Academy of Sciences,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;Zhejiang Longyou Grottoes Research Institute,Quzhou 324000,China)

机构地区：[1]北京工业大学建筑工程学院,北京100124 [2]北京工业大学城市与工程安全减灾教育部重点实验室,北京100124 [3]中国科学院地质与地球物理研究所,中国科学院页岩气与地质工程重点实验室,北京100029 [4]中国科学院地球科学研究院,北京100029 [5]中国科学院大学地球与行星科学学院,北京100049 [6]浙江省龙游石窟研究所,衢州324000

出　　处：《工程地质学报》2024年第6期2003-2016,共14页Journal of Engineering Geology

基　　金：国家自然科学基金项目(资助号:42277144,41972287)。

摘　　要：龙游石窟,这一千年古迹,受长期侵蚀风化及人类活动影响,出现显著变形破坏。本研究针对龙游石窟围岩-泥质粉砂岩,通过模拟雨季与旱季交替变化环境下的干湿循环试验,结合SEM扫描电镜分析、单轴压缩和单轴压缩蠕变试验探究含水状态、干湿循环次数对泥质粉砂岩的短期力学特性和长期力学特性的影响。研究结果表明:干湿循环作用会加剧岩石内部结构劣化,内部孔洞增多并连通,结构变得松散。随着循环次数增加,无论是干燥还是饱水状态,岩石的峰值应变和强度均逐渐降低,且饱水状态损伤更为严重,干燥岩石的单轴抗压强度呈负指数函数降低。根据蠕变曲线发现,随着干湿循环次数的增加,瞬时应变和总蠕变量逐渐增大,水对瞬时应变的影响尤为显著。长期强度随着干湿循环次数增加而降低,饱水试样的长期强度是干燥试样的46%~51%。通过Burgers模型分析,发现干燥试样的瞬时弹性模量E_M约为饱和状态下的1.91~2.32倍,干湿循环次数越高,瞬时弹性模量E_M越小,但到达稳态蠕变所需时间参数T_d和黏滞系数η_M与应力水平的相关性不明显,难以全面反映干湿循环及水对岩石的综合影响。本研究为理解龙游石窟岩石劣化机制及评估石窟长期稳定性提供了重要参考。Longyou Grottoes,a 1000-year-old historical site,has been significantly deformed and destroyed by long-term erosion and weathering and human activities.Aiming at the surrounding rock of Longyou Grottoes-argillaceous siltstone,this study explores the influence of water-bearing state and the number of dry-wet cycles on the short-term mechanical properties and long-term mechanical properties of argillaceous siltstone by simulating the dry-wet cycle test under the alternate changing environment of rainy season and dry season,combined with SEM analysis,uniaxial compression and uniaxial compression creep test.The results show that the dry-wet cycle will aggravate the deterioration of the internal structure of the rock,increase and connect the internal holes,and make the structure loose.With the increase of the number of cycles,the peak strain and strength of rock gradually decrease in both dry and saturated state,and the damage in saturated state is more serious,and the uniaxial compressive strength of dry rock decreases in a negative exponential function.According to the creep curve,it is found that with the increase of dry-wet cycles,the instantaneous strain and total creep increase gradually,and the influence of water on the instantaneous strain is particularly significant.The long-term strength decreases with the increase of dry-wet cycles,and the long-term strength of saturated samples is 46%~51%of that of dry samples.Through Burgers model analysis,it is found that the instantaneous elastic modulus E M of dry samples is about 1.91~2.32 times that of saturated samples.The higher the number of dry-wet cycles,the smaller the instantaneous elastic modulus E M.However,the correlation between the time parameter T d and the viscosity coefficientηM required for steady-state creep and the stress level is not obvious,so it is difficult to fully reflect the comprehensive influence of dry-wet cycles and water on rocks.This study provides an important reference for understanding the rock deterioration mechanism of Longyou Gro

关 键 词：龙游石窟 泥质粉砂岩 干湿循环 蠕变 力学特性 

分 类 号：P642.3[天文地球—工程地质学]