Disc Cutter Wear Research Articles

Stress and Wear Analysis of the Disc Cutter of Rock Tunnel Boring Machine

Full face rock tunnel boring machine is one of the main machineries and equipments for underground engineering, and the failure of its disc cutter is the main failure form of this machinery. In order to find out the factors of wear of disc cutters and improve the rock breaking efficiency, a lot of research has been done. In this paper, the methods of theoretical research, simulation analysis and engineering application are used. The laws of wear of disc cutters on the cutter head are researched at the process of cutting migmatitic gneiss, and its influence factors are analyzed. The results show that the wear on the edge of disc cutter is serious. The main factor for the wear of disc cutters is its stress from the rocks, and its variance is continual. And wear rate of the disc cutters is proportional to the integrality index of the rocks. With the increase of the amount of wear, the area of contact between a disc cutter and the rock gets bigger, and their extrusion strength gets lower on the contrary. These results are very helpful to the structure optimization of the disc cutter and the improvement of working efficiency.

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.

Analysis on the Rock–Cutter Interaction Mechanism During the TBM Tunneling Process

The accurate prediction of rock cutting forces of disc cutters is crucial for tunnel boring machine (TBM) design and construction. Disc cutter wear, which affects TBM penetration performance, has frequently been found at TBM sites. By considering the operating path and wear of the disc cutter, a new model is proposed for evaluating the cutting force and wear of the disc cutter in the tunneling process. The circular path adopted herein, which is the actual running path of the TBM disc cutter, shows that the lateral force of the disc cutter is asymmetric. The lateral forces on the sides of the disc cutter are clearly different. However, traditional solutions are obtained by assuming a linear path, where the later forces are viewed as equal. To simulate the interaction between the rock and disc cutter, a simple brittle damage model for rock mass is introduced here. Based on the explicit dynamic finite element method, the cutting force acting on the rock generated by a single disc cutter is simulated. It is shown that the lateral cutting force of the disc cutter strongly affects the wear extent of disc cutter. The wear mechanism is thus underestimated by the classical model, which was obtained by linear cutting tests. The simulation results are discussed and compared with other models, and these simulation results agree well with the results of present ones.

TBM performance and disc cutter wear prediction based on ten years experience of TBM tunnelling in Iran

AbstractAccurate estimation of rate of penetration (ROP), daily rate of advance (AR), and cutter cost/life is necessary for the justification and successful use of a TBM on any tunneling project. Various models have been introduced over the years to provide such estimates. In many cases, these models have been successful with pin point accuracy, and in other instances off by a wide margin. Improving the accuracy of performance prediction models for hard rock TBMs has been the subject of many studies, some yielding project‐based models and some more universal models that can be used elsewhere. This paper will discuss the latest version of a new empirical model for estimating penetration rate and disc cutter life for hard rock TBM tunneling based on recent tunneling projects, constructed during the period 2002–2009. The new model was then applied to predict TBM performance and disc cutter wear in different mechanized tunneling projects under construction since 2009. Accuracy and validity of the model for prediction of ROP were checked by comparing predicted and measured values of TBM performance in 24 km of newly bored tunnel. The results indicate that despite some minor deviations in estimates in some tunnel sections, reasonable agreement can be observed between predicted and actual ROP of TBMs.

Wear analysis of disc cutters of full face rock tunnel boring machine

Wear is a major factor of disc cutters’ failure. No current theory offers a standard for the prediction of disc cutter wear yet. In the field the wear prediction method commonly used is based on the excavation length of tunnel boring machine(TBM) to predict the disc cutter wear and its wear law, considering the location number of each disc cutter on the cutterhead(radius for installation); in theory, there is a prediction method of using arc wear coefficient. However, the preceding two methods have their own errors, with their accuracy being 40% or so and largely relying on the technicians’ experience. Therefore, radial wear coefficient, axial wear coefficient and trajectory wear coefficient are defined on the basis of the operating characteristics of TBM. With reference to the installation and characteristics of disc cutters, those coefficients are modified according to penetration, which gives rise to the presentation of comprehensive axial wear coefficient, comprehensive radial wear coefficient and comprehensive trajectory wear coefficient. Calculation and determination of wear coefficients are made with consideration of data from a segment of TBM project(excavation length 173 m). The resulting wear coefficient values, after modification, are adopted to predict the disc cutter wear in the follow-up segment of the TBM project(excavation length of 5621 m). The prediction results show that the disc cutter wear predicted with comprehensive radial wear coefficient and comprehensive trajectory wear coefficient are not only accurate(accuracy 16.12%) but also highly congruous, whereas there is a larger deviation in the prediction with comprehensive axial wear coefficient(accuracy 41%, which is in agreement with the prediction of disc cutters’ life in the field). This paper puts forth a new method concerning prediction of life span and wear of TBM disc cutters as well as timing for replacing disc cutters.

Introduction of an empirical TBM cutter wear prediction model for pyroclastic and mafic igneous rocks; a case history of Karaj water conveyance tunnel, Iran

One of the main cost items in tunneling projects using tunnel boring machines (TBMs) in rock and soil is the cost of changing of damaged or worn cutting tools. Cutter change is a time consuming activity which can have a major impact on the daily advance rate (AR) and therefore, on the time and cost of constructing the tunnel. Accurate estimation of TBM performance and related completion time and cost requires reliable assessment of disc cutter wear by using appropriate methods. This study introduces a new empirical model for predicting cutter wear in moderate to very strong pyroclastic and mafic igneous rocks based on data collected from a long tunnel constructed by mechanized method in Iran. This includes monitoring and analysis of field data including cutter wear, geological parameters, and operational data from Karaj water conveyance tunnel project. The field data compiled in a database was subjected to statistical analysis for development of relationships between disc cutter life and geological parameters. Results of the analyses indicated reasonable correlations between intact rock parameters and tool wear. Some empirical equations are offered for predicting disc cutter wear in similar geological conditions. These equations were developed based on data from very blocky to blocky pyroclastic rocks and blocky to massive mafic igneous rocks with a UCS range of 30 to more than 150MPa.

A comparative study on the TBM disc cutter wear prediction model

A comparative study on the TBM disc cutter wear prediction model

Design theory of full face rock tunnel boring machine transition cutter edge angle and its application

At present, the inner cutters of a full face rock tunnel boring machine (TBM) and transition cutter edge angles are designed on the basis of indentation test or linear grooving test. The inner and outer edge angles of disc cutters are characterized as symmetric to each other with respect to the cutter edge plane. This design has some practical defects, such as severe eccentric wear and tipping, etc. In this paper, the current design theory of disc cutter edge angle is analyzed, and the characteristics of the rock-breaking movement of disc cutters are studied. The researching results show that the rotational motion of disc cutters with the cutter head gives rise to the difference between the interactions of inner rock and outer rock with the contact area of disc cutters, with shearing and extrusion on the inner rock and attrition on the outer rock. The wear of disc cutters at the contact area is unbalanced, among which the wear in the largest normal stress area is most apparent. Therefore, a three-dimensional model theory of rock breaking and an edge angle design theory of transition disc cutter are proposed to overcome the flaws of the currently used TBM cutter heads, such as short life span, camber wearing, tipping. And a corresponding equation is established. With reference to a specific construction case, the edge angle of the transition disc cutter has been designed based on the theory. The application of TBM in some practical project proves that the theory has obvious advantages in enhancing disc cutter life, decreasing replacement frequency, and making economic benefits. The proposed research provides a theoretical basis for the design of TBM three-dimensional disc cutters whose rock-breaking operation time can be effectively increased.

The energy method to predict disc cutter wear extent for hard rock TBMs

Prediction of disc cutter wear extent is a critical factor for improving the working performance of tunnel boring machines (TBMs). In this study, three TBM working performance parameters are demonstrated to be directly influenced by disc cutter wear and selected as factors that predict disc cutter wear extent; new equations that describe the specific energy (SE) requirement of all disc cutters on the cutterhead are developed, and the SE rule is revealed based on mechanical analysis of the disc cutters as they cut hard rock. Two particular project cases are analysed to verify the above research results. The SE rule varies with disc cutter radius, while the change in disc cutter radius directly reflects the cutter wear extent. Consequently, the cutter wear extent can be predicted utilising the SE rule. Furthermore, the wear mechanism is investigated for the prediction of disc cutter wear extent. Lastly, a novel energy method is established that is based on the SE rule and the wear mechanism. In application, the average wear extent of all disc cutters on the cutterhead can be calculated using the SE equations, and the wear extent of each cutter can be predicted according to wear mechanism and the layout of the disc cutters on the cutterhead. To illustrate the applicability of this energy method, data from on-site Qinling tunnel boring are analysed in detail as an example. The establishment of this method is based on mechanical analysis of the disc cutter as it cuts hard rock; the parameters used in this method reflect rock mass properties and vary from moment to moment as disc cutter wear changes. Therefore, this method is well founded and can be used for real-time prediction of disc cutter wear for hard rock TBMs.

Kinematics Modeling and Analysis of TBM Disc Cutter Based on D-H Matrix

The objective of this paper was to study tool wear condition and to guide the cutter configuration by studying the movement of the disc cutter of all-section rock Tunneling Boring Machine(TBM).Through the analysis of rock destruction process by disc cutter based on spatial geometry theory and D-H matrix, the kinematic model of work cutter in rock destruction process was established and the movement law of cutting-tool is concluded, which are beneficial for the research on wear of disc cutter, structural design and optimization design of cutting tool configuration.

A Mechanical Model to Estimate the Disc Cutter Wear of Tunnel Boring Machines

A Mechanical Model to Estimate the Disc Cutter Wear of Tunnel Boring Machines

Characteristics Analysis of TBM Disc Cutter Ring

Disc cutter is the key part in Tunnel Boring Machine (TBM). Wear and tear of disc cutter is the main reason of low efficiency and high cost of this machine. Forces and deformations of disc cutter ring are foundation for its design and assembly. In this paper, the analysis of stress and deformation are carried to study their distribution; Wear mechanism of disc cutter ring is presented; modal analysis is carried to study the vibration of disc cutter ring. The results show the yield strength and rigidity of disc cutter ring is very high; disc cutter ring can avoid resonance and meet the engineering requirement. The results are very helpful for digital design of disc cutter ring used in different geology conditions.

飛騨トンネル本坑ＴＢＭにおけるカッタの摩耗と破損

飛騨トンネル本坑ＴＢＭにおけるカッタの摩耗と破損

An Integrated Approach to Penetration, Advance Rates and Disc Cutter Wear for Hard Rock TBM Drives

AbstractTunnel boring machines (TBM) are increasingly used for excavating subsurface infrastructure such as road and railway, water supply and sewer tunnels, to name a few applications. When designing a hard rock TBM drive it is necessary to appreciate all interactions of the rock mass to be tunnelled with the TBM. This paper deals specifically with these interactions and suggests an integrated approach in estimating hard rock TBM performance, such as the penetration rate, the advance rate and the disc cutter wear.

Factors Influencing Disc Cutter Wear

AbstractDisc cutter wear in mechanised tunnelling has a strong influence on costs and performance in hard rock and soil materials. Wear is affected by several geological and technical factors. Several aspects have been considered in prediction models and case studies. In this paper the essential technical influences are presented in a systematic way and are further analysed based on jobsite experience. Modifications in the operation of a TBM like adjustments of the cutterhead rotation or thrust lead to less disc cutter wear at comparable advance. A geological mapping during the tunnelling process, regular cutterhead inspections and tool wear measurements in combination with penetration tests will improve the work and results in a more economic tunnelling process.

開発機械 ディスクカッタの摩耗特性と寿命向上法

In order to improve disc cutter life on TBMs, a series of studies, which consistedof investigation on wear characteristics of disc cutters in situ, construction of a wear model for disc cutters and suggestion of a method for disc cutter life improvement, were conducted.From the examination and analysis of disc cutter wear on TBMs in two tunneling sites, it was shown that disc cutter life is dependent on its position (cutting radius) on the cutter head. Rolling distance per unit wear of disc cutters near the center of the cutter head is extremely shorter than ones in the other positions. The edge shape of a worn cutter is also dependent on its position.These characteristics can be explained well by the model based on skid between a disc cutter and rock. In cutters near the center of a cutter head, the life is much shorter and the wear on the outside face of the disc is outstanding because lateral skid is much predominant.As a method to decrease the wear induced by skid, the offset arrangement of disc cutters was suggested and the equation for the optimum offset condition was derived. It was calculated that the cutter life might be elongated up to twice by the optimum offset arrangement.

Rock abrasivity test with a modified schmidt hammer

Ideally, an abrasivity test should be physically similar to the real cutting process of a drag bit or roller cutter and should generate a force of a few tonnes. The note describes how an m-type Schmidt hammer was modified and used as a portable in-situ tester. The indentation tool is a replaceable hardened steel cylinder, inclined at 45 degrees giving a typical penetration in hard rock of 2 to 3 mm. The test consists of between 20 and 50 separate impacts in the rock formation and measurement of total weight loss of the tool. Abrasivity is measured as the weight loss for a given total impact energy in mg/kj. Typical readings of weight loss are 15 mg after 20 impacts on granite or 7 mg after 40 impacts on hard sandstone. Because of the difficulty of comparing Schmidt data with actual readings from tunnels, Schmidt abrasivity data have been compared to laboratory tests with a miniature disc cutter on samples of the same rock. Reasonable correlation was obtained between the wear of the miniature disc cutter and the wear of the indentation of the Schmidt hammer. (TRRL)

Bluntness and wear of rolling disc cutters. 13F, 5R : Rad, PF; Clemson Univ. S. Carolina, USA Int. J. Rock Mech. Min. Sci. Geomech. Abstr, V12, N4, Apr. 1975, P93–99

Bluntness and wear of rolling disc cutters. 13F, 5R : Rad, PF; Clemson Univ. S. Carolina, USA Int. J. Rock Mech. Min. Sci. Geomech. Abstr, V12, N4, Apr. 1975, P93–99