考虑岩石破碎程度的数字化钻进单齿推力模型  

Normal indentation force model considering the degree of rock breakage for digital drilling

作　　者：杨宏伟 韩凤岩 唐晖 李慧臻 刘文杰 黄林冲 陈瑜 YANG Hongwei;HAN Fengyan;TANG Hui;LI Huizhen;LIU Wenjie;HUANG Linchong;CHEN Yu(School of Civil Engineering,Sun Yat-sen University,Guangzhou 510275,China;State Key Laboratory for Tunnel Engineering,Guangzhou 510275,China;School of Civil Engineering,Central South University,Changsha 410075,China;China Railway Communications Investment Group Co.,Ltd.,Nanning 530219,China)

机构地区：[1]中山大学土木工程学院,广东广州510275 [2]隧道工程灾变防控与智能建养全国重点实验室,广东广州510275 [3]中南大学土木工程学院,湖南长沙410075 [4]中铁交通投资集团有限公司,广西南宁530219

出　　处：《铁道科学与工程学报》2024年第8期3262-3273,共12页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(52174101);广东省基础与应用基础研究基金资助项目(2023A1515011634);广东省“珠江人才计划”引进创新创业团队项目(2021ZT09G087)。

摘　　要：数字化超前钻探依赖于建立随钻参数与围岩特征之间的定量关系,如何定量分析围岩破碎程度对于推力的影响是个重要难题,对于预测不良地质地层具有重要意义。提出一个基于小孔扩张理论的单齿推力理论模型,模型采用HoekBrown破坏准则和非关联流动法则,描述岩石破碎程度对于岩石强度的影响。基于弹塑性力学,推导小孔扩张模型的应力场和位移场,并将模型应用到岩石贯入试验中,建立单齿贯入岩石过程中贯入深度与无量纲塑性区半径的定量关系。该理论模型考虑了刀头形状参数、岩石破坏程度和围压等重要参数对于推力的影响,并可以得到单齿贯入岩石过程中贯入深度与贯入力的定量关系。为验证模型的准确性,开展2种不同地质强度指标的楔形探头贯入岩石试验,试验结果与模型曲线趋势及数量级一致。将模型预测结果与文献中试验数据相对比,进一步验证了模型的可靠性,且表明本文模型在实际工程利用贯入力预测掌子面围岩破碎程度时更趋于安全。参数分析研究表明,岩石破坏程度、围压和岩石强度参数对于推力影响较大,推力与地质强度指标呈负相关关系,与围压和楔形刀头倾角呈正相关关系。结合钻头中单齿分布情况,该理论模型可以用来探讨实际工程推力参数与围岩参数的关系,推进实现数字化超前钻探。Digital advanced drilling relies on quantitative relationships between measurement-while-drilling parameters and rock characteristics.Yet,quantifying the effect of rock fracture on thrust-one of the key measurement-while-drilling parameters that is pivotal in digital drilling,remains largely unexplored.This paper proposed a cavity expansion theory based on the theoretical model to predict thrust considering the fracture effect on rock strength degradation.The degradation of rock strength by fractures was accounted for by the Hoek-Brown constitutive model.In addition,the model took into account the effect of confining pressure on thrust.The similarity between the indentation process and expansion of simplified cavity shapes was exploited,and the stress and displacement fields were approximated during indentation.This led to quantitative relationships between cutter shape parameters,rock strength parameters,and results from indentation tests including penetration depth and indentation force.To verify the proposed quantitative relationship,two wedge-shaped probes with different geological strength indices were carried out to penetrate the rock,and the test results were consistent with the trend and order of magnitude of the model curve.The reliability of the model was further verified by comparing the prediction results of the model with the experimental data in the literature,and the model in this paper tended to be safer when using penetration force to predict the degree of fracture of the surrounding rock of the tunnel face in actual engineering.Subsequent parametric analysis demonstrated that rock fracture and confinement have opposite effect on the thrust,which necessitates consideration of rock fracture on prediction of thrust.The proposed model serves as a start point to discuss the relationship between the thrust recorded in the field and rock strength parameters thus promoting the realization of digital advanced drilling.

关 键 词：小孔扩张理论 单齿推力模型 岩石破碎 HOEK-BROWN准则 围压 

分 类 号：TU452[建筑科学—岩土工程]