A New System to Evaluate Comprehensive Performance of Hard-Rock Tunnel Boring Machine Cutterheads

The accurate performance evaluation of a cutterhead is essential to improving cutterhead structure design and predicting project cost. Through extensive research, this paper evaluates the performance of a tunnel boring machine(TBM) cutterhead for cutting ability and slagging ability. This paper propose cutting efficiency, stability, and continuity of slagging as the evaluation indexes of comprehensive cutterhead performance. On the basis of research of true TBM engineering applications, this paper proposes a calculation method for each index. A slagging efficiency index with a ratio of the maximum di erence between the slagging amount and average slagging is established. And a slagging stability index with a ratio of the maximum slagging fluctuation and average slagging is presented. Meanwhile, a cutting efficiency index by the weighed average value of multistage rock fragmentation of a cutter’s specific energy is established. The Robbins and China Railway Construction Corporation(CRCC) cutterheads are evaluated. The results show that under the same thrust and torque, the slagging stability of the CRCC scheme is worse, but the slagging continuity of the CRCC scheme is better. The cutting ability index shows that the CRCC cutterhead is more efficient.

A Closer Look at the Design of Cutterheads for Hard Rock Tunnel-Boring Machines

The success of a tunnel-boring machine （TBM） in a given project depends on the functionality of all components of the system, from the cutters to the backup system, and on the entire rolling stock. However, no part of the machine plays a more crucial role in the efficient operation of the machine than its cutterhead. The design of the cutterhead impacts the efficiency of cutting, the balance of the head, the life of the cutters, the maintenance of the main bearing/gearbox, and the effectiveness of the mucking along with its effects on the wear of the face and gage cutters/muck buckets. Overall, cutterhead design heavily impacts the rate of penetration （ROP）, rate of machine utilization （U）, and daffy advance rate （AR）. Although there has been some discussion in commonly available publications regarding disk cutters, cutting forces, and some design features of the head, there is limited literature on this subject because the design of cutter- heads is mainly handled by machine manufacturers. Most of the design process involves proprietary algorithms by the manufacturers, and despite recent attention on the subject, the design of rock TBMs has been somewhat of a mystery to most end-users. This paper is an attempt to demystify the basic concepts in design. Although it may not be sufficient for a full-fledged design by the readers, this paper allows engineers and contractors to understand the thought process in the design steps, what to Look for in a proper design, and the implications of the head design on machine operation and life cycle.

Numerical simulation of freezing effect and tool change of shield machine with a frozen cutterhead

A shield machine with freezing function is proposed in order to realize tool change operation at atmospheric pressure. Furthermore, the transformation project of freezing cutterhead and tool change maintenance method are put forward. Taking the shield construction of Huanxi Power Tunnel as an example, a numerical analysis of the freezing cutter head of the project was carried out. The results show that when the brine temperature is-25 °C, after 30 d of freezing, the thickness of the frozen wall can reach 0.67 m and the average temperature drops to-9.9 °C. When the brine temperature is-30 °C, after 50 d of freezing, the thickness of the frozen wall can reach 1.01 m and the average temperature drops to-12.4 °C. If the thickness of the frozen wall is 0.5 m and the average temperature is-10 °C, as the design index of the frozen wall, the brine temperature should be lower than-28 °C to meet the excavation requirements in 30 d. Analyzing the frozen wall stress under 0.5 m thickness and-10 °C average temperature condition, the tensile safety factor and compressive safety factor are both greater than 2 at the most dangerous position, which can meet the tool change requirements for shield construction.

Real-time analysis and prediction of shield cutterhead torque using optimized gated recurrent unit neural network

An accurate prediction of earth pressure balance(EPB)shield moving performance is important to ensure the safety tunnel excavation.A hybrid model is developed based on the particle swarm optimization(PSO)and gated recurrent unit(GRU)neural network.PSO is utilized to assign the optimal hyperparameters of GRU neural network.There are mainly four steps:data collection and processing,hybrid model establishment,model performance evaluation and correlation analysis.The developed model provides an alternative to tackle with time-series data of tunnel project.Apart from that,a novel framework about model application is performed to provide guidelines in practice.A tunnel project is utilized to evaluate the performance of proposed hybrid model.Results indicate that geological and construction variables are significant to the model performance.Correlation analysis shows that construction variables(main thrust and foam liquid volume)display the highest correlation with the cutterhead torque(CHT).This work provides a feasible and applicable alternative way to estimate the performance of shield tunneling.

On the Loads for Strength Design of Cutterhead of Full Face Rock Tunnel Boring Machine

Cutterhead loads are the key mechanical parameters for the strength design of the full face hard rock tunnel boring machine(TBM).Due to the brittle rock-breaking mechanism,the excavation loads acting on cutters fluctuate strongly and show some randomness.The conventional method that using combinations of some special static loads to perform the strength design of TBM cutterhead may lead to strength failure during working practice.In this paper,a three-dimensional finite element model for coupled Cutterhead–Rock is developed to determine the cutterhead loads.Then the distribution characteristics and the influence factors of cutterhead loads are analyzed based on the numerical results.It is found that,as time changes,the normal and tangential forces acting on cutters and the total torque acting on the cutterhead approximately distribute log normally,while the total thrusts acting on the cutterhead approximately show a normal distribution.Furthermore,the statistical average values of cutterhead loads are proportional to the uniaxial compressive strength(UCS)of cutting rocks.The values also change with the penetration and the diameter of cutterhead following a power function.Based on these findings,we propose a three-parameter model for the mean of cutterhead loads and a method of generating the random cutter forces.Then the strength properties of a typical cutterhead are analyzed in detail using loads generated by the new method.The optimized cutterhead has been successfully applied in engineering.The method in this paper may provide a useful reference for the strength design of TBM cutterhead.

Optimal design of structural parameters for shield cutterhead based on fuzzy mathematics and multi-objective genetic algorithm

In order to improve the strength and stiffness of shield cutterhead, the method of fuzzy mathematics theory in combination with the finite element analysis is adopted. An optimal design model of structural parameters for shield cutterhead is formulated,based on the complex engineering technical requirements. In the model, as the objective function of the model is a composite function of the strength and stiffness, the response surface method is applied to formulate the approximate function of objective function in order to reduce the solution scale of optimal problem. A multi-objective genetic algorithm is used to solve the cutterhead structure design problem and the change rule of the stress-strain with various structural parameters as well as their optimal values were researched under specific geological conditions. The results show that compared with original cutterhead structure scheme, the obtained optimal scheme of the cutterhead structure can greatly improve the strength and stiffness of the cutterhead, which can be seen from the reduction of its maximum equivalent stress by 21.2%, that of its maximum deformation by 0.75%, and that of its mass by 1.04%.

Load Sharing Performance of the Main Drive System in the Shield Machine and Improvement of Control Method

Shield machine is the major technical equipment badly in need in national infrastructure construction. The service conditions of shield machine are extremely complex. The driving interface load fluctuation caused by geological environment changes and multi field coupling of stress field may lead into imbalance of redundant drive motors output torque in main driving system. Therefore, the shield machine driving synchronous control is one of the key technologies of shield machine. This paper is in view of the shield machine main driving synchronous control, achieving the system＇s adaptive load sharing. From the point of view of cutterhead load changes, nonlinear factors of mechanical transmission mechanism and the control system synchronization performance, the authors analyze the load sharing performance of shield machine main drive system in the event of load mutation. The paper proposes a data-driven synchronized control method applicable to the main drive system. The effectiveness of the method is verified through simulation and experimental methods. The new method can make the system synchronization error greatly reduced, thus it can effectively adapt to load mutation, and reduce shaft broken accident.

Evaluation of TBM Cutterhead’s Comprehensive Performance Under Complicated Conditions

A comprehensive performance evaluation method for the tunnel boring machine(TBM)cutterhead is proposed in this paper.The evaluation system is established on strength and vibration.Based on fracture mechanics theory,fatigue strength evaluation indices are determined under critical crack length.The concept of crack regions division is proposed to evaluate fatigue strength more accurately and specifically.In addition,the velocities in three directions of critical locations are obtained with dynamics equations.Then,the root-mean-square values of velocities are taken as the vibration severity indices.Taking the cutterhead of Jilin diversion engineering as an example,the evaluations of each index are completed;then,the vibration of the TBM cutterhead is measured and compared with the theoretical calculation results.There are similar change laws between the theoretical calculation results and the testing results of the cutterhead acceleration,which proves that the method of calculation of the vibration index is effective,the reliability of the cutter saddle welding should be paid attention to when the TBM is working,and the condition of vibration severity of the TBM cutterhead meets the requirements but needs to be improved.

Evaluation Method for Tunneling Stability of TBM Cutterhead

In the process of tunneling of tunnel boring machine (TBM), different geological conditions often correspond to different working conditions, and the randomness of geological conditions also causes the order of occurrence of each working condition to be different. Under the conversion of different working conditions, this makes the vibration of different types of cutterheads different. How to choose the appropriate type of cutterhead according to different geological conditions is very important for saving engineering cost and increasing cutterhead life. In view of the above situation, this paper proposes a stability evaluation method during the TBM tunneling process to select the appropriate cutterhead type. Firstly, the corresponding relationship between geology and working conditions is established according to different geological conditions, and the input loads corresponding to geological conditions are obtained. Then, it is substituted into the dynamic model of the cutterhead system, the vibration response boundaries of each degree of freedom are obtained by solving. And the average value of the maximum boundary amplitude of each degree of freedom is taken to represent the extreme vibration of the cutterhead under the corresponding working conditions. Finally, by comparing the fluctuation of the ultimate vibration amplitude of each type of cutterhead in the process of working condition conversion, the results are as follows: when the transition between homogeneous strata and composite strata is normal and there is no large turning and deviation correction, the vibration response of the two-part cutterhead is the smallest, and the two-part cutterhead is the best choice. Otherwise, the five-part cutterhead is the best choice, while the stability of the integrated cutterhead is the worst.

A Prediction Method for TBM Cutterhead Dynamic Tunneling Performance under Typical Composite Geological Conditions

The cutterhead system is a core component of TBM equipment,which works in the extremely severe environment,and the strong impact loads result in severe vibration,crack,damage failure and other engineering failures.Accordingly,the key for cutterhead system structure design and parameter matching is to evaluate and predict cutterhead tunneling per-formance reasonably.In this paper,a prediction method for TBM cutterhead dynamic tunneling performance is pro-posed under the typical composite geological conditions,based on the CSM model of multi-cutters and cutter loads field test data.Then an actual TBM cutterhead of a water conservancy project is taken as an example,a spatial three-dimensional separation zone model for cutterhead tunneling is established under the typical geological condition,and the parameters influence rules of cutterhead tunneling performance are analyzed.The results show that,the cutter-head loads and specific energy change rules with different parameters are basically similar.Moreover,under the condi-tion of penetration p=10mm,the cutterhead bending moment coefficient of variation magnitude exceeds 20%,which is the maximum,and the normal cutter spacing optimal value is 95mm.Also,when the normal cutter spacing is kept constant in 85mm,the penetration has a greater influence on the torque and specific energy coefficient of variations,which is increased from 2mm to 10mm,and the two indexes decrease by about 73%.It is indicated that proper increase of pene-tration is beneficial to reduce the vibration fluctuation degree of torque and specific energy.The proposed method of TBM cutterhead dynamic tunneling performance and the analysis results can provide theoretical basis and design refer-ence for TBM cutterhead layout and tunneling parameters matching.

浅埋富水地层特大断面矩形顶管隧道掘进参数分析

为保障特大断面矩形顶管隧道在浅覆土、小净距下的安全高效掘进,依托世界上首个直径15 m级3车道矩形顶管隧道工程,对顶管多刀盘开挖系统、减摩注浆系统、三螺机出渣系统进行针对性优化设计。通过对顶管主要掘进参数及地层沉降监测结果进行统计分析,得到以下结论:1)本工程采用的减阻措施有效降低了管节受到的地层摩擦阻力,实际总推力为理论值的40%左右;2)刀盘直径和安装高度对刀盘转矩影响较大,多数刀盘转矩均值小于额定转矩的一半,说明刀盘额定转矩有较大的优化空间;3)顶管掘进过程中盾壳受到较大的地层挤压力,土舱内渣土压力也显著大于地层侧向土压力,停机后上述压力均有较大幅度降低;4)顶管掘进后地表横向沉降槽呈“盆”状,隧道两侧0.5倍开挖宽度内的地层沉降较大。

盾构刀盘系统掘进性能评价方法研究

研究刀盘系统掘进性能评价方法有助于刀盘设计方案的优选,对于提高盾构掘进效率,降低施工成本和提高施工安全性具有重要意义。文章将仿真分析与模糊评价方法相结合,提出一种根据刀盘掘进性能优劣来确定最优刀盘设计方案的模糊综合评价方法。文章首先提出了刀盘的掘进性能指标,建立了刀盘系统掘进的离散元仿真模型和掘进性能指标的获取方法;其次以五个刀盘掘进性能指标为评价因素,根据专家评分法确定因素的重要程度,以仿真和分析数据确定评价因素的等级指标和评价矩阵,并采用广义模糊合成算法对刀盘掘进性能进行模糊综合评价;最后以北京地铁砂卵石地层盾构隧道施工为例,采用模糊综合评价法得出辐条式盾构刀盘掘进性能优于辐板式盾构刀盘的结论。

面向掘进性能的盾构刀盘系统设计方法研究

提出了盾构刀盘系统设计和评价方法的理论框架,重点阐述了刀盘系统设计流程。采用经验公式和理论分析的方法,面向刀盘系统的排土率、掘进面稳定性、刀具寿命、刀盘功率和结构性能,给出了刀盘系统设计的流程。以北京地铁4号线角门北路站—北京南站区间路段为背景,设计出相适应的刀盘结构参数、刀具布置和操作控制参数。该设计结果与实际使用刀盘结构相似,说明设计流程可行。

TBM刀盘系统多自由度耦合振动响应灵敏度研究

研究冲击载荷作用下TBM刀盘的振动特性。在已有TBM刀盘系统耦合动力学模型的基础上,运用直接导数法推导动态响应灵敏度的表达式,建立适用于TBM刀盘强迫振动响应的灵敏度分析方法。以辽西北引水工程项目的刀盘系统参数为例,采用协同数值求解方法计算刀盘振动响应及其灵敏度,并分析刀盘质量分布对响应的影响。研究结果表明:刀盘振动响应对分体质量的灵敏度最大,且各方向灵敏度均不为0,说明质量参数的变化会影响刀盘各方向振动,而刀盘支撑刚度仅影响其相关联的振动,刀盘轴向振动响应对轴向支撑刚度的灵敏度约为倾覆方向的2倍;刀盘分体质量分数控制在13%~14%区间时,结构振动最小。

TBM刀盘系统多自由度耦合固有特性及敏感度

综合考虑时变啮合刚度、轴承刚度、综合传递误差、阻尼等影响因素,建立了TBM刀盘系统的平移-扭转-倾覆多自由度耦合动力学模型.基于实际工程项目的刀盘系统参数求解固有频率和振型,并研究系统参数对固有频率的影响及敏感度问题.研究结果表明,刀盘系统低阶固有频率为57和61 Hz,对应振型分别为电机和小齿轮的纯扭转振动及刀盘和大齿圈平移倾覆耦合振动,刀盘分体的切向支撑刚度和质量的敏感区间分别为3~4 GN/m和19~23 t.

多点分布载荷下TBM刀盘系统振动响应分析

刀盘系统是全断面隧道掘进机(tunnel boring machine,TBM)装备的核心部件,其工作环境极端恶劣,系统振动剧烈,导致关键构件发生异常失效,影响整机掘进效率。为此,有必要研究TBM刀盘系统的动态特性,分析不同参数对结构振动响应的影响,为系统设计及参数匹配提供理论基础。基于已有的TBM刀盘系统动力学模型,以某供水工程TBM刀盘系统为研究对象,对空间多点分布载荷下刀盘振动响应的参数影响规律进行了分析。研究结果表明,刀盘的分体质量比例控制在13%~14%时,刀盘轴向振动最小;刀盘转速高于2r/min时,其径向及扭转振动波动较明显,且得到了一系列峰值突变的转速点;驱动小齿轮均匀布置时,刀盘径向振动最小,振动幅度比非均匀布置时小近30%。分析结果可为刀盘的结构设计及系统参数匹配提供指导。

TBM刀盘系统动态特性及参数影响

隧道掘进机刀盘在掘进过程中承受高强度冲击载荷,振动十分剧烈,导致关键构件过早损伤失效,有必要在设计阶段研究刀盘系统的振动特性及其参数影响。为此,在已有TBM刀盘系统多自由度耦合动力学模型的基础上,通过求解各阶固有频率和振型,得到各构件的模态能量分布,进一步区分各阶模态振型,识别模态敏感参数,并分析了敏感参数对前10阶频率的影响。研究结果表明,刀盘系统模态振动主要集中在中间阶,且纯扭转振型对应的固有频率为57 Hz;模态能量能够区分各阶振型,且和常规的振型分析结论一致;第2～10阶固有频率主要受小齿轮转动惯量和输入端扭转刚度的影响,且这两个值分别取原始方案的1.1倍和1.3倍时,系统振动特性较稳定。

TBM试验台刀盘混合驱动系统设计与仿真分析

针对全断面硬岩隧道掘进机(TBM)在施工时因驱动扭矩不足引发的刀盘卡死情况,提出了由变频电机和泵控马达混合驱动的方案.采集电机转矩跟随主从控制系统下的电机速度信号,叠加一个预设的常量来实时调节变量泵的排量,利用比例溢流阀溢流多余流量实现对马达工作压差的比例调节,从而实现泵马达系统对电机系统的转速跟随和扭矩可调,并基于○/2.5mTBM实验台的刀盘驱动系统指标要求完成了设计选型.在AMEsim仿真平台上搭建了负载敏感变量泵控系统(LSCS)、流量反馈比例变量泵控系统(FFPCS)和变量缸位移反馈比例变量泵控系统(DFPCS)的模型,分析对比了不同系统在同一电机系统速度信号下泵的压力和流量响应,并对比了不同比例控制策略下变量泵的效率.结果表明:LSCS无法响应电机系统转速跳变,且不适用于闭式系统,FFPCS和DFPCS均能较好地跟随电机系统的转速变化,尽管FFPCS有着更高的控制精度和效率,DFPCS的高可靠性、模块化和低成本优势更符合实际施工要求.

TBM刀盘驱动系统单神经元模糊同步控制

针对全断面硬岩隧道掘进机(TBM)刀盘多电机并联驱动由于载荷突变和传动系统磨耗所引起的电机偏载甚至过载,提出基于单神经元模糊自适应PI速度调节器的转矩主从控制策略.搭建电机闭环矢量控制模型,推导多齿轮齿圈并联系统的数学模型并使用S函数加以描述,在Simulink环境下将两者连接,对比分析转速并联和转矩主从控制策略下,电机对外在载荷和机械磨耗的黏性和刚性啮合响应及其机理,将单神经元模糊PI速度调节器应用于转矩主从策略消除扭矩超调.仿真结果表明,基于单神经元模糊PI速度调节器的转矩主从控制策略能够适应传动系统的参数变化,消除电机在负载变化时的扭矩超调和偏载,并能提高系统的精度和响应速度.

盾构刀盘液压驱动系统

刀盘驱动液压系统是盾构液压系统的重要组成部分。本文简要介绍电比例功率自适应控制和变频驱动控制两种刀盘液压系统及其工作原理和特点。该驱动系统与阀控系统相比,具有结构简单、技术先进、性能可靠等特点,特别是节能效果明显。