卸荷条件下花岗岩破裂面粗糙度特征及成因分析试验研究  

Experimental study on roughness characteristics and genesis analysis of granitefracture surface under unloading condition

作　　者：胡宝文[1,2,3] 南博文 吕聪瑞 宿辉 宋金科[1] 李江哲 李世奇 HU Baowen;NAN Bowen;LYU Congrui;SU Hui;SONG Jinke;LI Jiangzhe;LI Shiqi(College of Water Conservancy and Hydropower,Hebei University of Engineering,Handan056038,Hebei,China;Hebei Key Laboratory of Intelligent Water Conservancy,Handan056038,Hebei,China;Beijing Key Laboratory of Urban Underground Space Engineering,Beijing100083,China;School of Civil and Resources Engineering,University of Science and Technology Beijing,Beijing100083,China)

机构地区：[1]河北工程大学水利水电学院,河北邯郸056038 [2]河北省智慧水利重点实验室,河北邯郸056038 [3]城市地下空间工程北京市重点实验室,北京100083 [4]北京科技大学土木与资源工程学院,北京100083

出　　处：《水利水电技术（中英文）》2024年第2期180-192,共13页Water Resources and Hydropower Engineering

基　　金：河北省自然科学基金项目基础研究专项(E2020402087);河北省自然科学基金资助项目(E2019402256);国家重点研发计划“超大型深井矿山高效绿色开采技术与智能装备”(2022YFC2904100);佛山市科技创新专项资金项目(BK22BE024)。

摘　　要：【目的】为探究工程岩体在高应力下加卸载过程中的断裂形貌变化及成因,【方法】以粗糙度作为描述形貌几何特征的重要参数,定量表征形貌变化,以拉剪比作为描述断裂特征的重要参数,定量表征断裂模式变化,选取两类花岗岩,开展加卸载力学试验,通过数字图像技术对破裂面粗糙度及成因进行分析。【结果】结果显示:在高应力卸荷条件下,初始围压、卸围压速率及矿物粒径均对花岗岩破裂面粗糙程度起负相关影响;超景深显微观察发现,粗糙程度越低的花岗岩,其断口出现剪切断裂占比越高;在围压卸荷破坏过程中,30 MPa围压卸荷,岩石破裂面以沿晶拉伸断裂为主,40 MPa围压卸荷,以沿晶和穿晶拉剪复合型断裂为主,50 MPa围压卸荷,以穿晶剪切断裂为主;随着矿物粒径和卸围压速率的增大,破裂面均呈现剪切断裂占比增加的趋势。【结论】结果表明,高围压卸荷下岩石破裂时张拉断裂占比越高,其破裂面越粗糙,相反剪切占比高,其破裂面粗糙度越低。[Objective]In order to explore the changes and causes of fracture morphology of engineering rock mass during loading and unloading under high stress.[Methods]The roughness is used as an important parameter to describe the geometric characteristics of the morphology,and the morphology change is quantitatively characterized.The tensile-shear ratio is used as an important parameter to describe the fracture characteristics,and the fracture mode changes are quantitatively characterized.This paper selects two types of granite to carry out loading and unloading mechanical tests,and analyzes the roughness and causes of the fracture surface by digital image technology.[Results]According to the result,Under the condition of high stress unloading,initial confining pressure,unloading confining pressure rate and mineral particle size have a negative correlation effect on the roughness of granite fracture surface.The result of microscopic observation of ultra-depth of field show that the lower the roughness of granite,the higher the proportion of shear fracture in the fracture.In the process of confining pressure unloading failure,30 MPa confining pressure unloading,rock fracture surface is mainly intergranular tensile fracture,40 MPa confining pressure unloading,mainly intergranular and transgranular tensile shear composite fracture,50 MPa confining pressure unloading,mainly transgranular shear fracture.With the increase of mineral particle size and unloading confining pressure rate,the proportion of shear fracture increases.Under high confining pressure unloading,the higher the proportion of tensile fracture is,the rougher the fracture surface is.[Conclusion]On the contrary,the higher the proportion of shear is,the lower the roughness of the fracture surface is.

关 键 词：花岗岩 卸荷试验 粗糙程度 断裂形貌 拉剪比 力学性能 影响因素 

分 类 号：TU452[建筑科学—岩土工程]