摘要
为了分析花岗岩在热冲击作用下的细观破坏特征及孔隙率变化规律,基于太原理工大学原位改性采矿实验室研发的热冲击试验平台对花岗岩进行不同温度的热冲击试验,采用高精度显微CT扫描系统对热冲击后的花岗岩进行扫描,并利用自制的CT图像分析系统对扫描得到的图层作二值化处理,然后进行三维重建,最终得到花岗岩立方体的数字模型。通过从数字模型提取其孔隙、裂隙的图像,同时计算不同温度热冲击下花岗岩的孔隙率,从而得到花岗岩的热冲击破坏规律。研究结果表明,花岗岩的热冲击作用随加热温度升高而明显变化,随着加热温度的升高,花岗岩表面裂隙逐渐发育,孔隙率变大;花岗岩热冲击破坏的温度阈值为400℃,当花岗岩试件热冲击温度为300℃时,岩芯内部孔隙有所增加,但孔隙并未连通形成裂隙;当热冲击温度为400℃时,岩芯内孔隙明显增大,并开始出现裂隙;当热冲击温度为500℃时,孔隙开始贯通形成裂隙,并急剧发育。此外,研究还发现,热冲击作用下,花岗岩在热破裂过程中发生不均匀热破裂,且破坏首先发生在岩石的表面。
In order to analyze the meso-fracture characteristics and porosity change laws of granite under thermal shock,based on the thermal shock test platform developed by the in-situ modified mining laboratory of Taiyuan University of Technology,thermal shock tests on granites at different temperatures were conducted.A high-precision micro-CT scanning system was used to scan the granite after thermal shock.And the CT image analysis system developed by the research group was used to perform three-dimensional reconstruction of the scanned layers after binarization,and finally a digital model of the granite cube was obtained.By extracting images of pores and cracks from the model,and calculating the porosity of granite under thermal shock with different temperatures,the failure laws of granite were obtained.The research results demonstrate that the thermal shock of granite changes significantly with the increase of heating temperature.With the increase of heating temperature,cracks on the surface of granite gradually develop,and the porosity of granite increases.The temperature threshold for thermal shock damage of granite is 400℃.When the thermal shock temperature of granite specimen is 300℃,the pores in the core increase,but does not connect to form cracks.When the thermal shock temperature is 400°C,the pores in the core increase significantly and begin to crack.When the thermal shock temperature is 500°C,the pores begin to penetrate to form cracks and develop rapidly.In addition,the study also finds that due to under the action of thermal shock,uneven thermal cracks occur in the thermal cracking process of granite,and the damage first occurs on the rock surface.
作者
李晓雪
郤保平
何水鑫
成泽鹏
辛国旭
LI Xiaoxue;XI Baoping;HE Shuixin;CHENG Zepeng;XIN Guoxu(College of Mining Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China;Key Laboratory of In-situ Property Improving Mining of Ministry of Education,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China)
出处
《矿业研究与开发》
CAS
北大核心
2021年第5期67-73,共7页
Mining Research and Development
基金
国家自然科学基金面上资助项目(51874207)
山西省自然科学基金项目(201701D21131).
关键词
热冲击
花岗岩
显微CT
孔隙率
三维重建
Thermal shock
Granite
Micro-CT
Porosity
Three-dimensional reconstruction
作者简介
李晓雪(1996-),女,山西太原人,硕士研究生,主要研究高温岩石力学,E-mail:1500627414@qq.com;通信作者:郤保平(1976-),男,山西太原人,博士,教授,主要从事岩石力学与干热岩地热开发利用方面的教学与研究工作,E-mail:xibaoping@163.com.
