基于PFC2D的单齿直线切削破岩过程分析  

Analysis of rock breaking process of single tooth straight cutting based on PFC2D

作　　者：柳洪杰 凌雪 马俊涛 范自立 刘宝林[1] LIU Hongjie;LING Xue;MA Juntao;FAN Zili;LIU Baolin(China University of Geosciences(Beijing),Beijing 100083,China;Coal Mine Grouting Technology Innovation Base,Beijing 100040,China)

机构地区：[1]中国地质大学(北京),北京100083 [2]煤矿开采注浆技术创新基地,北京100040

出　　处：《钻探工程》2023年第S01期156-162,共7页Drilling Engineering

基　　金：国家自然科学基金资助面上项目“真空无水低功耗条件下碎岩机理研究”(编号:41672365);国家863计划“自动化智能化岩心钻探技术与设备研制”(编号:2014AA06A614)。

摘　　要：在石油钻井、隧道开挖等领域经常遇到关于岩石切削的问题,岩石切削问题的研究成为提高机械开采效率的重要突破口。针对钻井过程中锥形齿切削岩石的塑-脆性破碎机理这一科学问题,以提高钻进效率为最终目的,通过实验测试岩石力学参数和离散单元法(PFC2D)建立了锥形齿平行切削岩石的数值模拟,研究岩石切削过程中在不同切削深度下的切削形貌、切削力、破岩比功等。结果表明:(1)岩屑先产生宏观剪切裂纹形成半脱落岩屑,后于薄弱处发生张拉失效导致岩屑弹出,并且在切削深度较浅时产生小尺寸岩屑,在切削深度较深时产生大尺寸岩屑。(2)研究了不同切削深度下产生岩屑时的切削峰值力,发现与Nishimatsu的峰值力模型更加符合,与切削深度呈线性增长的趋势。(3)切削力的峰值基本对应裂纹的激增,随着切削深度的增加裂纹图中台阶数会随之减少;破岩比功与切削深度在一定范围内呈正相关,并可以根据MSE2D与logd的关系图将切削过程划分出塑性破坏阶段、小碎屑阶段、脆性破坏3个阶段。Problems about rock cutting are often encountered in the fields of oil drilling and tunnel excavation.The research of rock cutting problems has become an important breakthrough to improve the efficiency of mechanical mining.Aiming at the scientific problem of plastic‑brittle fracture mechanism of rock cut by conical teeth during drilling,the numerical simulation of parallel rock cut by conical teeth was established through experimental testing of rock mechanics parameters and discrete element method(PFC2D)to study the cutting morphology,cutting force and rock break specific energy of rock cut at different cutting depths during rock cutting.The results show that:(1)the macro‑shear crack is first generated in the cuttings to form semi‑shedding cuttings,and then the tensioning failure occurs in the weak area to cause the cuttings to pop out,and the small size cuttings are generated when the cutting depth is shallow,and the large size cuttings are generated when the cutting depth is deep.(2)The peak cutting force that generates rock chips at different cutting depths was studied and found to be better in agreement with Nishimatsu’s peak force model,showing a linear increase trend with cutting depth.(3)The peak value of cutting force corresponds to the surge of cracks,and the number of steps in the crack chart will decrease with the increase of cutting depth.The specific energy of rock breaking is positively correlated with the cutting depth in a certain range,and the cutting process can be divided into plastic ductile stage,fragmentation stage and brittle failure stage according to the relationship diagram of MSE2D and logd.

关 键 词：岩石切削 离散元 岩屑 破岩比功 钻进效率 

分 类 号：P634.1[天文地球—地质矿产勘探] TU45[天文地球—地质学]