复合地层中盾构机滚刀寿命预测研究

刀具磨损严重制约盾构施工效率,为了准确预测滚刀的磨损量和寿命,根据磨粒磨损机理,建立了正面滚刀的磨损速率、线磨损速率和滚刀寿命预测模型;通过深圳地铁7号线某区间正面滚刀磨损数据进行验证。结果表明,滚刀磨损预测模型准确率较高,所建立的预测模型也能够较准确地反应滚刀的实际磨损;所建立的滚刀寿命预测模型可用于预测不同安装半径滚刀的最大掘进距离,可为换刀提供理论依据;并且给出了滚刀寿命与滚刀安装半径、滚刀线磨损速率、贯入度的定量关系;但该模型仅适用于正面滚刀的正常磨损预测,对于中心刀还需考虑偏磨,边缘滚刀还需考虑二次磨损。     

基于破岩弧长的全断面掘进机滚刀磨损的研究

针对全断面掘进机滚刀的破岩弧长对其磨损进行了研究。推导了滚刀破岩弧长公式,并在此基础上研究了刀具安装半径、切深、滚刀直径以及刀间距等参数对滚刀磨损的影响,为滚刀的布置及相关施工参数的优化提供了参考。     

高强度围岩隧洞TBM刀具磨损规律研究

刀具磨损是影响TBM掘进效率的重要因素,该文以北疆供水二期工程XEVIII标段隧洞为依托,开展高强度围岩条件下刀具磨损规律研究。该标段已掘进段围岩强度最大为160MPa,平均为120MPa。根据掘进过程中的刀具磨损统计资料,分析不同刀位的刀具磨损值、围岩强度和掘进参数对刀具磨损的影响以及不同掘进参数对刀具磨损的敏感度,结果表明：中心滚刀和正面滚刀的累计磨损量随安装半径增大呈指数式增长,边缘滚刀累计磨损量受安装角度影响,随安装半径增大先增大后减小;边缘滚刀的单刀磨损量最大,正面滚刀次之,中心滚刀最小;随着围岩强度提高,中心滚刀和正面滚刀每延米磨损量呈指数型增长,边缘滚刀每延米磨损量呈二次函数型增长,所有刀具每延米累计磨损量呈线性增长;围岩强度不变时,随着刀盘转速、刀盘扭矩、推力、贯入度增大,刀具每延米磨损量均呈二次函数型变化,先增大后减小,随着掘进速度增大,刀具每延米磨损量呈二次函数型变化,先减小后增大;刀具磨损对刀盘扭矩和推力最为敏感,为减小磨损,建议施工中将刀盘扭矩控制在1100～1300kN·m或2100～2400kN·m,将推力控制在9000～11000kN或15000～16000kN。     

海底岩溶地层盾构刀盘刀具设计及应用

针对海底岩溶破碎带复杂地层,大直径泥水盾构施工过程中存在刀具易异常损坏、带压换刀作业效率低风险大、刀盘振动和结构偏载受力频繁等问题,结合大连地铁5号线跨海隧道,通过分析隧道穿越地层情况,针对性选型设计一种12m级全断面滚刀及刮刀常压更换新型复合刀盘,中心滚刀采用了较小刀间距布置,正面及边缘采用19寸双轴双刃滚刀,加强了常压滚刀刀座及刀具抗冲击设计,并通过有限元对刀盘结构强度刚度进行校核验算。工程应用表明,刀盘刀具具有较好的地质适应性,可为类似越江跨海隧道地层盾构刀盘刀具选型设计提供一定参考。     

TBM滚刀刀圈装配最优过盈量研究

研究TBM滚刀在动态载荷作用下,刀圈内孔与刀毂外表面接触应力分布规律,利用数值模拟对刀圈、刀毂之间过盈量分析计算,确定刀圈、刀毂最优的配合过盈量;对于优化滚刀刀圈、刀毂加工工艺,提高刀圈掘进性能和使用寿命,降低施工成本具有重要意义。     

盘形滚刀破岩力预测及试验研究

盘形滚刀破岩力是全断面掘进机施工过程的关键参数,是刀盘设计的重要依据。深入分析了盘形滚刀刀圈与围岩相互作用的过程,提出了以被压岩石为研究对象,对被压围岩应力分布函数进行积分推算,建立滚刀刀圈破岩力的预测模型;运用库仑-莫尔准则构建了滚刀刀圈切向力模型。通过设计盘形滚刀单刀线性破岩试验,经过试验结果对比和误差分析,验证了所构建的滚刀破岩力预测模型的准确性和有效性,为TBM刀盘结构设计优化提供一定的理论依据,可为实际施工提供科学指导。     

围压下掘进机多滚刀顺次破岩机理数值模拟研究

基于统计力学与细观损伤数值模型,运用RFPA^2D建立三把滚刀顺次侵入岩石的计算模型,并展开系列数值试验,模拟了岩石在不同围压、不同加刀次序下裂纹萌生、扩展以及破碎的全过程,并从能量的角度出发对刀间距的优化问题展开了探讨。研究结果表明,滚刀相位角的存在对岩石的破碎模式和破碎效率有着重要的影响;滚刀顺次加刀优于同时加刀;围压增大,裂纹向深部扩展能力降低。相同围压下顺次加载时存在最优刀间距。同时加载时,随着围压的增加,最优刀间距逐渐增加。研究结果可为地下工程岩石破碎理论与隧道掘进机刀盘布置提供依据。     

盾构隧道施工盘形滚刀推力分布规律研究

 盾构掘进时,刀盘由油缸推压到工作面上,滚刀与岩石之间产生相互作用。为研究各滚刀推力分布规律,分析影响滚刀与岩石相互作用的影响因素,指出掘进过程中滚刀推力分布主要与岩石刚度有关。假设滚刀与岩石弹性点接触,建立刀盘与岩石相互作用的三维弹性支点力学模型并进行了简化,运用有限元方法对其进行分析与比较。研究表明,刀盘上各滚刀的推力分布并不均匀,滚刀布置稀少处的推力较高,面刀推力均比边刀推力高出40%～60%。相同的刀盘形式,滚刀布置方式不同,其推力分布差异较大。最后,运用蒙特卡罗有限元方法,分析岩石刚度变化对滚刀推力分布的影响,岩石越软,滚刀推力分布越均匀;反之,滚刀推力分布的均匀性越差。在硬地层中掘进时,个别推力高的滚刀磨损严重,换刀频繁,影响了施工进度。因此,该部位的滚刀布置值得进一步研究。     

全断面岩石掘进机盘形滚刀螺旋线布置理论及应用分析

全断面岩石掘进机刀盘上盘形滚刀的布置规律一直是领域学者研究的难题和热点。通过对刀盘上已有盘形滚刀的布置形式分析,发现盘形滚刀在刀盘上的布置基本是均匀分布或是以刀盘旋转中心为中心的中心对称分布;以刀盘受力平衡方程为基础,建立刀盘上盘形滚刀的螺旋线布置理论,给出按此理论布置盘形滚刀的实施程序,并定义刀盘上的不平衡量,进而探讨螺旋线条数和螺旋线条数一定条件下的螺旋线螺旋角度对刀盘上不平衡量的影响。研究结论可为全断面岩石掘进机刀盘的理论研究和应用研究提供借鉴。     

盾构刀具布置对滚刀破岩效能影响

针对硬岩地层滚刀磨损严重的问题,采用数据回归的方法,以某工程硬岩段盾构滚刀磨损数据和刀盘布置参数为对象,分析在地质类同、滚刀磨损量相同的条件下,不同滚刀破岩量变化趋势,深入研究滚刀安装半径及刀间距对滚刀破岩效能的影响,根据分析结果为类似地层盾构合理刀盘设计提供参考。     

Disc cutter wear prediction for a hard rock TBM cutterhead based on energy analysis

Disc cutter wear is a crucial problem that influences the working efficiency and security of hard rock tunnel boring machines (TBMs). This wear results from friction energy accumulation and conversion. In this study, the process of hard rock TBM disc cutter wear is identified and analyzed by quantifying the collective energy change. This study starts with an analysis of the friction process between the disc cutter and hard rock. The relationship between the rolling force work and thrust force work of the disc cutter is examined. As a result, the disc cutter energy equation is determined, and the meaning of the upper and lower bounds of this equation are discussed. Based on the above results, the hard rock TBM cutterhead energy equation is then deduced. A method to identify the friction work is developed. According to the energy wear theory, the cutter wear law on hard rock for a TBM cutterhead is revealed, and a method for predicting disc cutter wear for a hard rock TBM cutterhead is advanced. Furthermore, the validity of this prediction method is confirmed by utilizing data from project cases.     

Theoretical prediction of wear of disc cutters in tunnel boring machine and its application

Predicting the cutter consumption and the exact time to replace the worn-out cutters in tunneling projects constructed with tunnel boring machine (TBM) is always a challenging issue. In this paper, we focus on the analyses of cutter motion in the rock breaking process and trajectory of rock breaking point on the cutter edge in rocks. The analytical expressions of the length of face along which the breaking point moves and the length of spiral trajectory of the maximum penetration point are derived. Through observation of rock breaking process of disc cutters as well as analysis of disc rock interaction, the following concepts are proposed: the arc length theory of predicting wear extent of inner and center cutters, and the spiral theory of predicting wear extent of gage and transition cutters. Data obtained from 5621 m-long Qinling tunnel reveal that among 39 disc cutters, the relative errors between cumulatively predicted and measured wear values for nine cutters are larger than 20%, while approximately 76.9% of total cutters have the relative errors less than 20%. The proposed method could offer a new attempt to predict the disc cutter's wear extent and changing time.     

An experimental research on the rock cutting process of the gage cutters for rock tunnel boring machine (TBM)

This paper proposed an experimental method to investigate the rock cutting process of TBM gage cutters based on the full-scale rotary cutting machine (RCM). The key point of this method is to reconstruct the RCM by inserting three wedges with angles of 10°, 20° and 30° respectively into the space between the cutter base and cutter box. As a result, the rock cutting process of gage cutters with tilt angles of 10°, 20° and 30° can be proceed. Using this method, rock cutting experiments were conducted with penetrations of 2 mm, 4 mm, 6 mm and 8 mm respectively. The testing results were analysed on the rock cutting force, rock debris dimension, specific energy and cutting surface profile, and it was found that: (1) the cutting forces and specific energy of the gage cutter were lower than those of the normal cutter respectively; and (2) the depth of the rock broken zone was smaller than the cutting depth. The testing results can also be used to validate corresponding numerical models and design the layout of gage cutters.     

Analysis on the damage behavior of mixed ground during TBM cutting process

Accurate prediction of rock cutting forces of disc cutters is especially significant for the design and construction of tunnel boring machine (TBM). Through the analysis of motion trajectory of TBM disc cutters, a three-dimensional model of rock breaking process of disc cutters is established. In terms of the rock strain which is resulted from the interaction between disc cutters and rock during the process of rock breaking, a three-dimensional cutting forces model is proposed with disc cutters set at certain parameters and in certain sizes. Subsequently, the equation of contacting forces between rock and disc cutter is derived. Moreover, a new method has been presented for the study of the rock breaking theory of the disc cutter and it also provides guidance for the design and application of TBM in tunnel excavation. The three-dimensional model for the rock breaking mechanism is used for predicting the cutting force for the situation of mixed ground.The damage field and the rock failure zone induced by disc cutter for mixed ground are also discussed in this study. In detail, the rock damage zones are divided into two parts, one is the left damage field which located in the outside of disc cutter. The other is the right damage field which located in the outside of disc cutter. The influence of the rock ground dip on the rock failure zone was also studied by parameter analysis.     

Mechanical performance of TBM cutterhead in mixed rock ground conditions

The mechanical performance of TBM cutterhead including thrust, torque, eccentric force and overturning moment was calculated and analysed in different mixed rock ground conditions. The calculation model was built by identifying the rock type under each cutter using a ray intersection algorithm and calculating the cutting forces of each cutter using the CSM model. The mixed rock ground conditions were simplified as rock type distribution and rock strength classification. In the present paper, the rock distributions of the Layer-Banded Rock (LBR) and Random-Distributed Rock (RDR) types were considered. The influences of rock strength (Uniaxial Compressive Strength: UCS, Brazilian Tensile Strength: BTS), rock locations and number of rock layers were studied. For verification, a boring experiment was designed and conducted using an experimental cutterhead with 14 disc cutters. The rock box was poured with concrete C20, C40 and C60 layer by layer to prepare the LBR condition. The average torque and thrust of the calculation model and experiment were in good agreement. Some conclusions were drawn from the study on the rock strength, rock locations, area percentages of different rock layers and number of rock layers. And hence, some suggestions were proposed to enhance the tunnelling efficiency and reduce damage to the cutterhead.     

基于协同破岩的TBM刀盘优化策略

岩石隧道掘进机工作时的刀具受力情况是影响刀盘破岩性能的关键。为了分析滚刀之间的协同破岩效应,提出3种基本的协同破岩模式,并将多把滚刀协同破岩过程等效为3种破岩模式的组合。不同破岩模式下,滚刀切割岩石的先后顺序不同,结合线性切割试验,证实了不同模式下3种滚刀力等级的大小关系。以引汉济渭岭北隧洞TBM工程为背景,研究得出名义磨损量与破岩模式的叠加效应具有较强的相关性,其中,由内而外模式占比与滚刀名义磨损量具有明显的正相关性,据此提出了考虑刀具磨损量的TBM刀盘刀具优化策略。     

TBM滚刀破岩动态特性与最优刀间距研究

在对实际工况合理简化的基础上,从岩土细观角度出发,采用颗粒离散元法建立滚刀侵入岩体的二维模拟模型,研究双滚刀作用下岩体的动态响应机制,找出滚刀侵入过程中岩体裂纹、贯入度以及切削力三者的关系。在此基础上,通过数值模拟对常见切深下滚刀最优刀间距问题进行分析,得到不同切深下比能耗与刀间距的规律,并通过试验对双滚刀破岩过程中岩体动态特性以及最优刀间距问题进行验证,最后以工程实例验证研究结论。研究表明：仿真过程中,切削力随贯入度的变化与岩体的跃进破碎特性相一致,岩体破坏服从格里菲斯理论;较小切深下岩体为剪切破坏,较大切深下岩体发生拉应力破坏;切深为10 mm时比能耗有明显拐点,此时刀间距为100 mm;切深为6 mm时,60 mm刀间距下比能耗最小;切深小于2 mm时,实际工况下岩体不能产生贯穿裂纹。     

土压平衡盾构刀盘扭矩计算方法与多因素量化分析

 刀盘扭矩是设计刀盘驱动的关键参数,是设计经济型盾构、决定盾构是否高效率掘进必不可少的参数之一。以土压平衡盾构为背景,在充分理解刀盘与土体相互作用的基础上,分析影响刀盘扭矩的7个因素,并基于现场测试和理论分析分别推导出各因素的计算模型。同时,以土耳其伊兹密尔地铁和伦敦机场隧道为例,通过与实际测得的刀盘扭矩对比分析,验证理论模型的准确性,所构建的计算模型可适用于黏性土和非黏性土地层中。对各影响因素进行量化分析,分析表明刀盘各面与地层的摩擦阻力扭矩约占总扭矩的80%,其中刀盘与土体的摩擦角、刀盘直径、土体的黏着力以及土仓内的土压支撑强度都是影响刀盘扭矩大小的重要参数。