双波导辐射对岩石裂纹扩展机理的影响  

Effect of Dual Waveguide Radiation on the Mechanism of Rock Crack Propagation

作　　者：温森[1] 杜林 王倩 张敏 邓珂 WEN Sen;DU Lin;WANG Qian;ZHANG Min;DENG Ke(School of Civil Eng.and Architecture,Henan Univ.,Kaifeng 475004,China)

机构地区：[1]河南大学土木建筑学院,河南开封475004

出　　处：《工程科学与技术》2024年第2期108-117,共10页Advanced Engineering Sciences

基　　金：国家自然科学基金项目(42307243);河南省科技攻关项目(232102321102);河南省高等学校青年骨干教师培养计划项目(2020GGJS035);河南大学研究生英才计划项目(SYLYC2022213)。

摘　　要：通过微波辐射能够使岩石迅速升温并产生扩展裂纹,从而大幅降低岩石强度,有助于解决全断面隧道掘进机(TBM)在破碎高强度硬岩地层时面临滚刀磨损严重、破岩效率低下、工程成本剧增等问题。为此,本文采用离散元软件PFC2D建立玄武岩的三相矿物(斜长石、橄榄石、辉石)模型,并进行双波导辐射模拟,探究波导间距(60、70、80、90及100 mm)、辐射时间(0、0.04、0.06、0.08及0.10 s)和围岩压力(5、10、15及20 MPa)对岩石损伤裂纹扩展的影响规律。结果表明:采用微波功率密度1×1010W/m3对玄武岩进行辐射加热时,为达到辅助破岩的效果,辐射时间不宜低于起裂时间(0.04 s)。微波辐射导致强吸波矿物(辉石)和弱吸波矿物(斜长石)间形成较大的温度梯度和热应力且最易产生损伤裂纹,所以裂纹产生的位置主要与岩石矿物的位置分布具有重要关系。在微波辐射岩石过程中,裂纹首先在辐射区域产生,继而在热膨胀和热应力作用下扩展延伸并在波导间的岩石区域形成裂纹贯通;随着波导间距的增加,波导间岩石裂纹贯通时所需要的微波辐射时间逐渐增加。围岩压力对裂纹的产生和扩展具有抑制和约束作用,其变化对岩样损伤裂纹的生成位置和扩展路径无明显影响,通过延长微波辐射的时间可以弥补因围压增加而减少的裂纹。The Full Face Rock Tunnel Boring Machine(TBM)is increasingly prevalent in China's tunnel construction.However,the significant wear of the disk cutter in extremely hard rock layers has resulted in low efficiency in rock-breaking,leading to project cost escalation and other contradictions.These challenges are increasingly prominent and hinder the TBM's normal usage.Microwave-assisted TBM disk cutter rockbreaking,a novel technology,is gaining attention from engineering researchers due to its advanced technology,safe and controllable nature,rapid heating,and environmental friendliness.In light of this,this study explores the damage mechanism of microwaves on rocks under various factors.Basalt from Chifeng,Inner Mongolia,was chosen as the study object.X-ray diffraction results revealed that the rock primarily consists of 65%plagioclase,23.9%pyroxene,and 11.1%olivine.The Particle Discrete Element PFC2D simulation software was employed to model the threephase mineral rocks by randomly distributing them based on mineral content ratios.To eliminate boundary effects and enhance simulation model efficiency,a mineral particle size of 1.7 mm to 2.0 mm and a rock model size of 400 mm×160 mm were selected.The rock model’s left and right sides act as confining pressure boundaries,the bottom is a fixed boundary,and the top(Tunnel face)is a free boundary,with the initial rock temperature set at 25℃.Simplifying the heating effect of microwave radiation on the rock,the heating area of microwave radiation on the rock,and the attenuation of microwave with depth,enables a more efficient and intuitive study of the microwave radiation’s influence mechanism.To validate the numerical model calculation’s rationality,a 90 mm×180 mm three-phase mineral rock model is established to analyze the microwave radiation rock cracks’change rule and expansion characteristics.The study utilizes a dual waveguide with a microwave power density of 1×1010 W/m3 to radiate the rock.The effects of waveguide spacing(60 mm,70 mm,80 mm,90 mm,100 mm),

关 键 词：微波辅助 PFC2D 裂纹 辐射时间 波导间距 围压 

分 类 号：TU45[建筑科学—岩土工程]