scholarly journals Prediction of load on the cutting tools in tunnel boring machines

2020 ◽  
pp. 444-452
Keyword(s):  
Neural Network ◽  
Cutting Tools ◽  
Circular Cross Section ◽  
Tunnel Boring Machine ◽  
Correct Identification ◽  
Tunnel Boring Machines ◽  
Tunnel Boring ◽  
Cutting Insert ◽  
Boring Machines ◽  
Network Type

A tunnel boring machine (TBM) is a machine that is used to excavate tunnels with a circular cross-section. TBMs can bore through a variety of ground conditions. Tunnel boring machines are used as an alternative to drilling methods. TBMs have the advantages of limiting the disturbance to the surrounding ground. Predicting the load on cutting tools in tunnel boring machines is important for the mining process. The article presents a proposal for a method of forecasting the load on mining machinery tools. This paper presents current trends in hard rock tunnelling, including the directions of research on automated excavation processes. Particular emphasis is put on the aspects of predicting load variations in the cutterhead tools, which is of vital importance for machine power selection and mining process control, among others. The problem of predicting the load and wear of excavation tools plays an important role in designing and maintaining cutterheads. The effective monitoring of the operation of multi-tool cutterhead knives and their replacement time depend on correct identification of the type and condition of the excavating tool cutting insert. A neural network with a multilayer perceptron structure was used as a prediction tool. The concept of this network type is based on the arrangement of neurons in successive layers. This neural network type is treated as an input-output model. Its parameters include weights and threshold values.

scholarly journals Influence of geology on tunnel boring machine performance: A review

2020 ◽  
Vol 56 (1) ◽  
pp. 1-14
Author(s):  
P.K. Pandey ◽  
A.K. Raina ◽  
S. Deshmukh ◽  
R. Trivedi ◽  
R. Vajre ◽  
...  
Keyword(s):  
Dynamic Properties ◽  
Circular Cross Section ◽  
Tunnel Boring Machine ◽  
Intact Rock ◽  
Joint Spacing ◽  
Tunnel Boring Machines ◽  
Tunnel Boring ◽  
Machine Performance ◽  
Geological Conditions ◽  
Boring Machines

Tunnel boring machines are used for excavating a variety of soils and rocks for circular cross-section tunnels. Several published studies examined the role of rockmass in determining the cutting and advance rate of tunnel boring machines. A comprehensive review of literature was conducted to ascertain the influence of geological conditions on the performance of tunnel boring machines and revealed that different rock characteristics were used to define the tunnel boring machine performance. The progress of the tunnel boring machine was ascribed to the inherent properties of the rockmass, intact rock properties, and surrounding geological conditions. Several authors found that extreme geological conditions strongly influence the advance of the machine. The review revealed that joint spacing, angle between plane of weakness and tunnel axis, rock quality designation, and number of joint sets were the most important variables that influenced the advance rates of the tunnel boring machine. At least 12 intact rock variables were used to define tunnel boring machine performance with one to seven such variables used in combination. The compressive strength, tensile strength, and brittleness index emerged as most crucial intact properties. Rockmass classifications or indices of tunnel boring machine performance were used by different authors to predict their performance and even to define their selection methodology. Use of dynamic properties of rock/rockmass was identified as a grey area for future research by scientists.

Creation of 25kV AC Neutral Section in Bored/Round Tunnel of Delhi MRTS

2020 ◽  
Author(s):  
Om Hari Pande ◽  
Ashok Tewari ◽  
Sanjeev Kumar ◽  
Rajesh Kumar Singh
Keyword(s):  
Power Supply ◽  
Circular Cross Section ◽  
Cost Effective ◽  
Tunnel Boring Machines ◽  
Overhead Lines ◽  
Tunnel Boring ◽  
Space Saving ◽  
Boring Machines ◽  
Traction System ◽  
Neutral Section

Abstract Delhi metro uses 25kV single phase AC traction electric supply to power trains which is usually supplied through a continuous conductor running along the track such as overhead lines. Traction power is supplied from Traction sub stations which can cater a smaller portion of the line. Hence, AC traction system for one line comprises of different sections of suitable length being fed by different sub-stations. The electric power is generated in three phases with each having a phase shift of 120°, there is a possibility of two different traction sections being fed by different phases of power supply. In such condition, to avoid the risk of supply mixing of different phases, there is need to keep these sections isolated from each other. Therefore, a specific arrangement of conductor is done and a neutral section is created, which is preferably an earthed section. A significant portion of metro lines runs underground therefore the neutral section in underground tunnels is provided in a box tunnel constructed through cut and cover method to maintain the required clearances for separation of different phase power supply. The cut and cover method involves temporary acquisition of land, massive excavation followed by a durable covering to support the overhead construction and subsequent restoration of excavated area which takes around 6–8 months in construction. Moreover, neutral section is to be located at a minimum distance of 250 meters from platform having tangent track, zero gradient, no stop signals. Accordingly, there is a need of developing improved and cost-effective technology for providing neutral sections in the AC traction system in underground to reduce the time taken for construction and abolish the present practice of constructing a cut & cover tunnel between two stations. The present invention provides a time and space saving method of incorporating neutral sections in the 25kV AC traction system within the round/bored tunnel by creating a niche in the soffit of tunnel which also ensures all the safety clearances required for making effective neutral sections. The tunnel with circular cross section is bored using tunnel boring machines. The bored tunnel is approximately 5.6m to 5.8m in diameter to house the track, metro train, overhead equipments for electrification. A neutral section is to be housed in the niche created in the ceiling of the round/bored tunnel during the boring process itself. The time spent in boring tunnel utilizing boring machines is considerably less than the time spent in cut and cover method of construction. This Paper present in detail the design concept prepared by DMRC for Creation of 25 KV AC neutral section in Bored/Round Tunnel of Propose Phase-IV of Delhi MRTS. DMRC has also filed a patent for the innovation with Indian Patent Authority.

scholarly journals Assessment of rate of penetration of a tunnel boring machine in the longest railway tunnel of Turkey

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Candan Gokceoglu
Keyword(s):  
Multiple Regression ◽  
Prediction Models ◽  
Tunnel Boring Machine ◽  
Regression Equations ◽  
Railway Tunnel ◽  
Tunnel Boring Machines ◽  
Rate Of Penetration ◽  
Tunnel Boring ◽  
Ann Models ◽  
Boring Machines

AbstractOne of the most important issues in tunnels to be constructed with tunnel boring machines (TBMs) is to predict the excavation time. Excavation time directly affects tunnel costs and feasibility. For this reason, studies on the prediction of TBM performance have always been interesting for tunnel engineers. Therefore, the purpose of the study is to develop models to predict the rate of penetration (ROP) of TBMs. In accordance with the purpose of the study, a new database including 5334 cases is obtained from the longest railway tunnel of Turkey. Each case includes uniaxial compressive strength, Cerchar Abrasivity Index, α angle, weathering degree and water conditions as input or independent variables. Two multiple regression models and two ANN models are developed in the study. The performances of the ANN models are considerably better than those of the multiple regression equations. Before deep tunnel construction in a metamorphic rock medium, the ANN models developed in the study are reliable and can be used. In contrast, the performances of the multiple regression equations are promising, but they predict lower ROP values than the measured ROP values. Consequently, the prediction models for ROP are open to development depending on the new data and new prediction algorithms.

Geotechnical risks, mitigation measures and performance of tunnel boring machine (TBM) tunnels for the Tuen Mun – Chek Lap Kok Link Project, Hong Kong

2019 ◽  
Vol 26 (4) ◽  
pp. 175-189
Author(s):  
Lucas Kwan Lok Chan ◽  
Alan Kwok Lun Kwong
Keyword(s):  
Hong Kong ◽  
Ground Improvement ◽  
Tunnel Boring Machine ◽  
Mitigation Measures ◽  
Face Stability ◽  
Tunnel Boring Machines ◽  
Tunnel Boring ◽  
Overall Performance ◽  
Boring Machines ◽  
And Performance

The Tuen Mun – Chek Lap Kok Link (TM-CLKL) project implemented latest innovation designs and ground improvement techniques in large slurry tunnel boring machines (TBM) tunnelling for constructing the sub-sea TBM tunnel in Hong Kong. Face stability, ground settlement, blow out, water ingress and ovalisation are always the major geotechnical risks for TBM tunnelling in the industry. This paper summarises the design considerations in terms of ground improvement and special arrangements of TBM tunnelling to mitigate the geotechnical risks and the improvement of the overall performance of TBM tunnelling under the TM-CLKL project. Field monitoring data such as surface settlement, ovalisation of segmental lining and ground improvement technique such as barrettes are presented.

scholarly journals Use of saturation diving technique for tunnel boring machine cutterhead intervention in the Tuen Mun–Chek Lap Kok Link Sub-sea Tunnel Project, Hong Kong

2021 ◽  
Vol 28 (1) ◽  
pp. 31-38
Author(s):  
A W Y Chan ◽  
Charles H C Yeung ◽  
A J Westmoreland ◽  
S W Fok ◽  
Conrad C W Ng ◽  
...  
Keyword(s):  
Hong Kong ◽  
Cutting Tools ◽  
Tunnel Boring Machine ◽  
Tunnel Boring ◽  
Tunnel Section ◽  
Decomposed Granite ◽  
Boring Machines ◽  
Mixed Ground ◽  
Tunnel Alignment ◽  
Ground Condition

The entire Tuen Mun–Chek Lap Kok Link (TM-CLKL) was commissioned on 27 December 2020 and it comprises a 9km-long dual 2-lane carriageway between Tuen Mun and North Lantau, Hong Kong. Construction of the 5km-long sub-sea tunnels was carried out by two 14m diameter Tunnel Boring Machines (TBMs). The tunnel alignment for the TM-CLKL sub-sea tunnel section is in mixed ground condition with the first 500 m in mixed geology of slightly to moderately decomposed granite and completely decomposed granite (CDG), followed by soft ground condition with CDG, alluvial sand, alluvial clay and marine deposit. This mixed ground geology requires regular TBM cutterhead interventions to change the worn-out cutting tools during the tunnelling operation. As the tunnel alignment is up to 55 m below the sea level with the deepest seabed level at -21 mPD, in order to maintain the cutting face stability during the intervention, the intervention pressure could be up to 6 bars. This paper describes different techniques used for TBM interventions under the sea such as trimix bounce mode and saturation mode that appears first time in Hong Kong under a high hyperbaric pressure to change the worn-out cutting tools at the TBM cutterhead.

Research on the Load on Cutter Head of Hard Rock Tunnel Boring Machine

2014 ◽  
Vol 684 ◽  
pp. 303-307 ◽  
Author(s):  
Xiao Xu Zhao ◽  
Ya Dong Gong
Keyword(s):  
Hard Rock ◽  
Rolling Force ◽  
Tunnel Boring Machine ◽  
Tunnel Boring Machines ◽  
Tunnel Boring ◽  
Particle Hydrodynamics ◽  
Boring Machines ◽  
And Performance ◽  
Rock Tunnel ◽  
Cutter Head

Study on the load exerted on cutter head is very useful for the design and performance prediction of hard rock tunnel boring machines. A composite model based on smoothed particle hydrodynamics and finite element method was carried out using AUTODYN software to study the rock fragmentation mechanism of constant cross-section disk cutters in cutter head. The normal force, rolling force and side force on the disk cutters with different cutter radius were researched in the numerical simulation study. The results were verified by historical literature data. To obtain the distribution of the forces with different cutter radius, the loading of cutter head of a Ф5.75 hard rock tunnel boring machine were analyzed. The result shows that it is useful for cutter head’s design and its layout optimization.

scholarly journals Study of the influence of face pressure on surface settlements by shield tunneling

2020 ◽  
Vol 61 (1) ◽  
pp. 31-40
Author(s):  
Do Ngoc Thai ◽  
Do Duc Toan ◽  
Keyword(s):  
Urban Areas ◽  
Ground Surface ◽  
Tunnel Boring Machine ◽  
Shield Tunnel ◽  
Shield Tunneling ◽  
Tunnel Boring Machines ◽  
Tunnel Boring ◽  
The Face ◽  
Boring Machines ◽  
Surface Settlements

In the mechanized excavation of subway tunnels, the shield tunnel boring machine (TBM) has been developed in recent decades for managing the instability of the excavation profile in complicated geotechnical conditions in urban areas. The paper presents a 3D simulation procedure for the detailed description of TBM (via the finite element code Abaqus) and quantifies the influence of TBM face pressure on ground surface settlements. The model is used to calculate ground surface settlements for different values of TBM face pressure. An additional aspect of the investigation is the determination of the critical value of TBM face pressure, which controls face instability in very weak ground. During the advancement of shield tunnel boring machines, the face-stabilizing pressure is one of the most important factors of critical. In tunneling by shield tunnel boring machines, high face pressure often leads to surface upheaval, whereas low face pressure leads to sudden collapse of the face and ultimately settlement of the surface. For the model condition, the maximum value was quantity 250 kPa and the minimum value obtained quantity 150 KPa.

scholarly journals A perspective of pipejacking works by tunnel boring machines in Hong Kong: part I – development, selection of design, operations and types of techniques

2021 ◽  
pp. 108-118
Author(s):  
Wilson W S Mok ◽  
Andrew S W Ng
Keyword(s):  
Hong Kong ◽  
Design Method ◽  
Tunnel Boring Machine ◽  
Tunnel Boring Machines ◽  
Tunnel Boring ◽  
Ground Conditions ◽  
History Of ◽  
Boring Machines ◽  
And Performance ◽  
Selection Of

In this paper, the history of pipejacking works by tunnel boring machines in Hong Kong, their development, selection of design method and tunnel boring machine (TBM), operations, length and alignment of a pipeline, types of techniques to suit different site constraints and ground conditions, and performance of the works are discussed. This paper should be read together with part II, which covers applications, problems encountered, cost and prospects.

Sign in / Sign up

Export Citation Format

Share Document