基于CSM模型的硬岩TBM滚刀磨损预测方法

为解决硬岩TBM在掘进时滚刀磨损检测难的问题,以岩石断裂力学为理论基础,深入分析了TBM滚刀的破岩机理,并基于Colorado school of mincs(CSM)模型提出了一种新的滚刀磨损预测方法。通过滚刀与岩石相互作用的力学模型,利用刀盘比能预测了滚刀的磨损。结合秦岭隧道工程实例,对滚刀磨损水平进行了量化研究,预测结果与实际情况相符,从而验证了模型的有效性。     

Thrust and Torque Characteristics Based on a New cutter-head Load Model

Full face rock tunnel boring machine(TBM) has been widely used in hard rock tunnels, however, there are few published theory about cutter-head design, and the design criteria of cutter-head under compl...     

Fragmentation Energy-Saving Theory of Full Face Rock Tunnel Boring Machine Disc Cutters

Attempts to minimize energy consumption of a tunnel boring machine disc cutter during the process of fragmentation have largely focused on optimizing disc-cutter spacing, as determined by the minimum specific energy required for fragmentation; however, indentation tests showed that rock deforms plastically beneath the cutters. Equations for thrust were developed for both the traditional, popularly employed disc cutter and anew design based on three-dimensional theory. The respective energy consumption for penetration, rolling, and side-slip fragmentations were obtained. A change in disc-cutter fragmentation angles resulted in a change in the nature of the interaction between the cutter and rock, which lowered the specific energy of fragmentation. During actual field excavations to the same penetration length, the combined energy consumption for fragmentation using the newly designed cutters was 15% lower than that when using the traditional design. This paper presents a theory for energy saving in tunnel boring machines. Investigation results showed that the disc cutters designed using this theory were more durable than traditional designs, and effectively lowered the energy consumption.     

Experimental Study on Wear Behaviors of TBM Disc Cutter Ring in Hard Rock Conditions

ABSTRACT

To improve the wear resistance of disc cutters for tunnel boring machines (TBMs), this study is devoted to investigating the effects of rocks and cutter ring properties on the wear behaviors of disc cutters and the matching characteristics between the cutter ring properties and hard rocks. Cutter–rock wear tests were performed and the results show that the cutter ring properties and rock types significantly affect the cutter ring wear. The mass losses of cutter ring samples sliding against different types of hard rock are different and vary with the cutter ring properties because of the discrepancies in loads, vibrations, rock properties, and transition of the wear mechanisms. Finally, matching characteristics between the cutter ring properties and hard rocks are revealed.     

Disc cutters’ layout design of the full-face rock tunnel boring machine (TBM) using a cooperative coevolutionary algorithm

In rock TBM design the disc cutters’ layout design of the full-face rock tunnel boring machine (TBM) is one of the key technologies. However, there are few published papers in literatures for various reasons. In this paper, based on the engineering technical requirements and the corresponding cutter head’s structure design requirements, a nonlinear multi-objective disc cutters’ layout mathematical model with complex constraints and the corresponding multi-stage solution strategy are presented, in which the whole disc cutters’ layout design process is decomposed into the disc cutters’ spacing design and the disc cutters’ plane layout design. A numerical simulation method based on the FEM theory is adopted to simulate the rock chipping process induced by three TBM disc cutters to determine the optimal cutter spacing. And a cooperative coevolutionary genetic algorithm (CCGA) is adopted to solve the disc cutters’ plane layout design problem. Finally, a disc cutters’ layout design instance of the TBM is presented to demonstrate the feasibility and effectiveness of the proposed method. The computational results show that the proposed method can be used to solve the disc cutters’ layout design problem of the TBM and provide various layout schemes within short running times for the engineers to choose from.     

基于多个隧道掘进机工程数据回归分析的滚刀磨损评价方法

为了评价不同隧道工程围岩对隧道掘进机(TBM)滚刀磨损的影响,解决滚刀磨耗难以准确预测的问题,基于北疆供水二期、吉林引松供水、陕西引汉济渭、大瑞铁路高黎贡山、深圳地铁10号线等多个隧道(洞)工程T MB滚刀磨损数据,选取岩石单轴抗压强度、岩石等效石英含量、岩石磨蚀性指标、岩体完整性指标、滚刀破岩体积磨损速率等参数进行数...     

新型TBM螺旋槽滚刀破岩性能及接触行为研究

全断面隧道掘进机(TBM)是用于长大隧道建设的关键装备,在川藏铁路等国家重大战略工程中发挥着重要作用。但TBM在硬岩地层施工中仍然面临所需推力大、掘进速度慢、滚刀损耗严重等问题,亟待解决。尝试探索基于滚刀表面结构设计调控刀-岩接触的可行性,设计了一种新型螺旋槽盘形滚刀。使用直线切割破岩实验研究不同贯入度和岩石种类下新型滚刀的破岩性能,并利用颗粒流离散元数值仿真对其破岩机理进行阐释。结果表明,滚刀表面的螺旋槽设计可以显著地降低破岩时切削力,而对生成的岩石碎片总体积无明显影响,因此可以显著减小滚刀做功,降低破岩比能,提高破岩过程的能量利用效率。其机理在于螺旋槽有效地优化了岩石内应力分布,使得同一滚刀前后相邻的刃齿在沟槽下方岩石中形成拉应力区,该部分岩石未与滚刀直接接触形成岩石粉末,而是由拉裂纹互相贯通形成岩石碎片,即减少了岩石粉末数量、缓解了岩石过度破碎程度,最终达到了降低切削载荷和破岩能耗的效果。     

PDC钻头切削断面对破岩效率的影响

基于弹塑性力学和岩石力学,以Drucker-Prager 准则作为岩石的本构关系,采用剪切失效准则,在验证岩石模型及PDC齿破岩建模方法可行性的基础上,建立了PDC齿切削3种典型断面岩石的三维有限元模型,并针对井底不同围压,研究了切削断面的面积、切削齿的后倾角及侧转角对破岩效率的影响。结果表明：不论何种围压,减小切削断面的面积有利于岩石的破碎,且应多采用宽切削断面进行PDC钻头径向布齿;切削齿后倾角对岩石破碎效率影响大于切削齿的侧转角对岩石破碎效率影响,切削齿最优破岩后倾角在低围压下为5°,在高围压下为20°。     

隧道掘进机刀群与盘体支撑筋耦合布置设计

刀盘是全断面隧道掘进机(Tunnel boring machine,TBM)的关键部件,TBM刀盘系统设计直接关系掘进效率和可靠性。刀盘系统设计的关键是复杂岩石边界下刀群布置设计与刀盘盘体结构设计,二者相互耦合,相互影响。分析刀群与盘体支撑结构之间空间位置耦合以及支撑结构与刀盘强度刚度之间的非线性耦合关系,建立刀群与盘体支撑结构耦合布置优化模型,提出多子系统协同进化的刀具适应性布置与盘体结构耦合设计方法。以引洮工程为例进行验证,结果表明：支撑筋初始安装角与刀盘强度、刚度之间存在非线性函数关系,多子系统协同进化方法求解出的刀群与支撑筋耦合布置方案的最大等效应力、最大变形量、不平衡力矩、不平衡力、顺次角度等指标相比原方案降低了30%以上,以此证明提出的耦合优化模型及其求解方法的可行性和有效性,可为TBM刀盘系统设计提供一定的借鉴与方法支撑。     

铣削TC4钛合金的刀具磨损对比试验

TC4钛合金是典型难加工材料之一,极易造成工具磨损。本文通过铣削TC4钛合金试验,跟踪铣削过程中铣刀每个齿的磨损量及磨损形态,比较了不同细晶粒硬质合金铣刀的磨损过程。结果表明,铣刀切削刃发生崩刃会直接缩短铣刀的使用寿命。     

异形PDC齿切削破岩提速机理研究

在室内切削实验基础上基于有限元二次开发建立了异形齿切削及全钻头破碎非均质花岗岩的三维数值仿真模型,研究了12种形状聚晶金刚石复合片(PDC)齿切削非均质岩石过程中的切向力、法向力、岩屑、破岩比功,并研究了齿形对全尺寸钻头破岩效率的影响。研究结果表明：锥形齿的切向力最小,破岩比功最高,对应的锥形齿钻头的进尺也最小;三平面齿的法向力和切向力均为最大;破岩比功最低的齿为双曲面齿;进尺最大的全钻头齿形为更易吃入岩石的鞍形齿、双曲面齿以及斧形齿。     

TBM刀盘支撑筋布置优化

综合考虑刀盘支撑筋支撑和出碴的功能，建立了以刀盘强度和刚度为优化目标的刀盘支撑筋布置优化设计模型，基于Workbench平台采用神经网络拟合方法建立了刀盘强度和刚度与刀盘支撑筋位置之间的映射关系，进而采用NSGA多目标优化方法进行了有效求解。结果表明：在3种岩石边界和极限工况下，优化求解的方案在刀盘强度和刚度方面均优于原始方案，为TBM刀盘支撑筋结构设计提供了一种新的思路。     

盘形刀具安装角与切入角的一种计算方法

利用空间曲线相切条件导出了用于计算盘形刀具安装角和切入角的条件;该方法具有以下优点:无需知道工件齿形,可同时获得刀具宽度、半径等参数。     

Swept area modeling and cutter wear study in turn-milling

In turn-milling machining, we found the cutter wear concentrated on a small section around the corner of the cutter and affect the cutter life. In this paper, the idea of swept area is proposed firstly based on the analyses for cutter wear, and it can indicate the cutter wear. Balance of swept area will lead to balanced wear along cutting edge, and expressions of swept areas of infinitesimal elements on the cutting edge are given. Secondly, the cutting depth and cutting angle, which are the key parameters in calculating the swept area, are analyzed based on different contact situations between the cutter and workpiece, and the detailed calculating method is given. Then, the optimization model to balance swept areas along the cutting edge is established, and the cutting parameters including cutter offset and machining length are optimized. Finally, the orthogonal turn-milling machining experiments with different cutting parameters are conducted; the result shows that turn-milling with optimized parameters can actually balance the cutter wear and increase the cutter life.     

Numerical study of rock-breaking performance of cutters in heterogeneous sand cobble ground

Further research into tunneling performance in heterogeneous sand cobble ground demands an accurate numerical model of actual formation. In this paper, the ground model composed of spherical sand and ellipsoidal cobble was constructed to study the rock-breaking performance by using the discrete element method. The shape and physical parameters of sand and cobble were obtained on the basis of field test data. Then, the ground model was constructed to simulate the rock-breaking process of the cutterhead. The results show that the center cutter has a high flat wear percentage. With the decrease in cobble content (CC), the cracks between cutters are not connected effectively, thereby resulting in lower rock-breaking quantity. Finally, the influences of CC on the optimal parameters and crack propagation were analyzed. The results indicate that the rock-breaking performance in the ground with a low CC can be improved by increasing penetration and reducing cutter spacing.

     

硬质合金圆盘刀分切硅钢片的磨损形态及机理研究

分析了圆盘剪分切加工过程中圆盘刀的受力,利用硬质合金圆盘刀进行了硅钢片的分切加工试验,研究了硬质合金圆盘刀的磨损,对比分析了圆盘刀刃口磨损前后的表面形貌、微观结构和钴元素含量的变化,探讨了其磨损形式及机理。结果表明,硬质合金圆盘刀磨损主要在刃口两侧形成磨损带,随着磨损的发生,圆盘刀切削刃过渡圆弧半径增大、刃口变钝,刀具的磨损形式主要表现为WC硬质颗粒裸露脱落及材料的黏结撕裂,磨损机理主要为硬质合金黏结相钴元素的流失、疲劳磨损和黏结磨损。     

基于库仑-莫尔准则的盘形滚刀破岩力预测研究*

盘形滚刀破岩力是全断面掘进机设计的关键参数,为准确预测盘形滚刀破岩力,以被压岩石为研究对象,以岩石断裂力学为理论基础,综合考虑岩石、滚刀及施工工艺等参数,采用微元积分法,针对圆刃滚刀建立一种综合的滚刀破岩力预测模型。同时根据滚刀实际破岩过程应用库仑-莫尔破坏准则,提出二次派生推力的概念,推导出二次派生推力计算模型,修正滚刀破岩力预测模型使其符合实际情况。在此基础上,应用科罗拉多矿业学院数据对修正后里理论模型进行分析验证,并与线性切割模型和CSM理论模型对比,结果表明本文模型预测精度比已有模型要高。通过模型理论分析和设计三因素三水平正交试验分析得到岩石、滚刀及施工工艺等参数对滚刀破岩力的影响规律,这为全断面掘进机刀盘整体设计和实际施工提供一定的理论参考。     

An Enhanced DFM Model for Shaper Cutters

This paper presents a systematic CAD/CAM based geometric modelling technique for enhancing the manufacturing accuracy of general straight-tooth shaper cutters. The proposed modelling technique systematically computes and improves on the shape of general shaper cutters using a five-step procedure. In the first modelling step, the significant geometric parameters of shaper cutters which including tooth profile, rake and clearance angles, offsets, and backlash are estimated using criteria associated with the practical requirements and the theory of gearing, differential geometry, and motion theory. In the second modelling step, the precise cutting-edge curve model of the shaper cutter is constructed. The theoretical involute or cycloidal cutting-edge curve on the plane perpendicular to the motion axis of the shaper cutter is first computed and is then projected onto the conic surface of the shaper cutter which has both the rake and the clearance angles. In the third modelling step, the convoluted sectional profile of the diskshaped generating cutter required for producing the cuttingedge profile is established using the theory of gearing and the relative motion relationship between the grinder and the cutter in the manufacturing process. In the fourth modelling step, a simple procedure to obtain the profile shift coefficient of the shaper cutters from various given process parameters is presented. Shaper cutters of various shapes can thus be designed and produced. In the last modelling step, a practical working example for producing the precise disk-shaped generating cutter and associated shaper cutter is presented to illustrate the effectiveness of the proposed modelling approach. The results of numerical modelling indicate that the proposed approach is systematic, accurate and reliable for producing shaper cutters of various shapes.     

Mathematical modeling for the design of a generic custom-engineered form mill

This paper presents a mathematical model for the geometric design of a custom-engineered form milling (CEFM) cutter and develops an accurate 3D surface-based generic definition of the form mill. The proposed geometric definition of the CEFM cutter is developed in terms of biparametric surface patches using newly defined 3D rotational angles rather than the conventional 2D angles. The non-uniform rational B-spline curve fairing and sweep surface approaches are used to design the cutting edge and flank surface, respectively, of the cutter. To validate the methodology, an interface is developed that converts the proposed 3D parametric definition of the cutter into an intermediate neutral CAD format and then renders the cutter model in any CAD modeling environment. The accuracy of the mathematical model is verified by evaluating the deviation plot between the surfaces of the proposed cutter model and the surfaces developed using digitized data of an existing actual CEFM cutter. The satisfactory comparison verifies the shape design methodology for custom cutters presented in this paper. The method described here offers a simple and intuitive way of generating shape design of custom cutters for possible use in machining process simulations, finite element analysis, and other applications.     

Optimal disc cutters plane layout design of the full-face rock tunnel boring machine (tbm) based on a multi-objective genetic algorithm

Improving of the quality of the disc cutters’ plane layout design of the full-face rock tunnel boring machine (TBM) is the most effective way to improve the global performance of a TBM. The plane layout design of disc cutters contains multiple complex engineering technical requirements and belongs to a multi-objective optimization problem with multiple nonlinear constraints. Based on analysis of the technical requirements of the plane layout problem, an optimizing mathematical model was built. To obtain a set of design schemes for engineers to choose from, a multi-objective genetic algorithm (MOGA) was applied to carry out the optimization of the mathematical model. A constraint-domination principle was utilized to handle the constraints, and a nondominated sorting method was adopted to obtain Pareto solutions. Simulation results showed that the proposed method was efficient and accurate in obtaining the Pareto layout solutions.