An evaluation of generated source signals from machinery in conventional tunnelling and their possible application in a tunnel seismic while drilling (TSWD) system

Author(s):  
Irene Hartl ◽  
Ingrid Schlögel ◽  
Robert Wenighofer ◽  
Jakob Gallistl

<p>Geological conditions and their uncertainties are a major risk factor in underground construction projects. To ensure a fast, smooth and save completion of the excavation, a prediction of the geological conditions in front of the working face during tunnelling is a topic of great importance.</p><p>Various geophysical methods for a prediction of the conditions ahead of the tunnel face have been developed over the past years, yet, most of them being seismic techniques, which require a short interruption of the excavation to minimise noise interference. However, there is also the approach with TSWD which uses the working TBM (Tunnel Boring Machine) as a source signal and can thus work simultaneously with the excavation. Up to now, this concept has been applied primarily in mechanised tunnelling and there are hardly any applications in conventional tunnelling.</p><p>In the course of several practical experiments at the “Zentrum am Berg” in Eisenerz (Austria), different concepts for a transfer of TSWD from mechanised to conventional tunnelling were developed and tested at scale in an underground research facility. Three machines were used for these tests, an excavator with a hydraulic hammer attached as well as two different drilling jumbos. The devices were equipped with an accelerometer to pick up the source signal at its origin (pilot signal). Different sensor positions were tested using a sledge hammer as a source and evaluated in detail. Moreover, omnidirectional geophones of different sensitivities (4.5 Hz and 27 Hz) were tested and compared as transducers in the adjacent rock mass.</p><p>An essential part of the experiment analysis consisted of the evaluation of the source characteristics as well as the generated spectral bandwidth of the source signal from typical construction machines in conventional tunnelling. Consequently, the outcomes will be another step forward in the development of a TSWD exploration system also applicable to conventional tunnelling projects.</p>

2012 ◽  
Vol 256-259 ◽  
pp. 1316-1319
Author(s):  
Feng Shan Hao ◽  
Gui Zhong Tian ◽  
Tu Long Wang

This paper was based on many pre-existing or being successful tunnel projects for study. Through in-depth investigation and analysis of the action mechanism on rock and the construction control under complex geological conditions, the author synthesized the technical advantages of the drilling-blasting method and tunnel boring machine technology into integration as a new drilling-blasting machine method applied in tunnel (lane) excavation. If this method intended by conventional process, it’s difficult to realize mechanized continuous excavating. In this problem, the author put forward two new technologies named helicoid tunnel face and shallow blasthole close blasting to improve. Respectively from the theory, economic, technology and safety, the paper demonstrates the feasibility of drilling-blasting machine method.


2018 ◽  
Vol 10 (1) ◽  
pp. 168781401875472 ◽  
Author(s):  
Wei Sun ◽  
Xiaobang Wang ◽  
Maolin Shi ◽  
Zhuqing Wang ◽  
Xueguan Song

A multidisciplinary design optimization model is developed in this article to optimize the performance of the hard rock tunnel boring machine using the collaborative optimization architecture. Tunnel boring machine is a complex engineering equipment with many subsystems coupled. In the established multidisciplinary design optimization process of this article, four subsystems are taken into account, which belong to different sub-disciplines/subsytems: the cutterhead system, the thrust system, the cutterhead driving system, and the economic model. The technology models of tunnel boring machine’s subsystems are build and the optimization objective of the multidisciplinary design optimization is to minimize the construction period from the system level of the hard rock tunnel boring machine. To further analyze the established multidisciplinary design optimization, the correlation between the design variables and the tunnel boring machine’s performance is also explored. Results indicate that the multidisciplinary design optimization process has significantly improved the performance of the tunnel boring machine. Based on the optimization results, another two excavating processes under different geological conditions are also optimized complementally using the collaborative optimization architecture, and the corresponding optimum performance of the hard rock tunnel boring machine, such as the cost and energy consumption, is compared and analysed. Results demonstrate that the proposed multidisciplinary design optimization method for tunnel boring machine is reliable and flexible while dealing with different geological conditions in practical engineering.


2019 ◽  
Vol 24 (4) ◽  
pp. 609-619
Author(s):  
Ao Song ◽  
Bin Song ◽  
Rongyi Qian

Geophysical technologies are used to mitigate geological hazard caused by adverse geological conditions in front of a tunnel face. The prevailing method for forward probing for tunnels constructed by a tunnel boring machine (TBM) for advance prediction is based on seismic detection. Conventional tunnel seismic prediction technology uses P- and S-waves with sources fired on the tunnel wall or face and layout receivers on the tunnel wall to acquire the reflected waves. However, the results show that most of these methods have different deficiencies that are in either low detection accuracy, short detection depth, and/or multiplicity in imaging. This paper proposes a new high resolution tunnel advance prediction technology on the face based on 3D seismic wave detection. It arranges the 3D high-density source and recording geometry on the tunnel face to receive reflected P-waves for 3D imaging. By using the 3D numerical simulation, we first analyze the energy distribution and propagation characteristics of the wave field, which proves that our method is feasible. Compared with the conventional technologies, the seismic energy propagating towards the tunnel face is stronger and produces rich reflected information. The reflected wave has the advantages of bandwidth, strong energy and little interferences from surface wave, so that the seismic phases are easy to be identified. On this basis, we present the high resolution true 3D prediction technology to obtain more comprehensive and abundant azimuth information. Our approach is further validated by an application experiment in a real-world engineering project of water conveyance tunnel. The results show that the new technique has a greater detection length, higher detection accuracy and more reliable imaging results.


2011 ◽  
Vol 103 ◽  
pp. 570-577
Author(s):  
Yue Qiang Li ◽  
Ya Ke Liu

With a large number of construction projects building in urban rail construction, it’s very necessary for researching on the construction axis. Construction axis of the subway is consisted of line segment, circular arc segment and transition curve. The paper introduces design models and algorithms of the tunnel boring machine (TBM) axis (DTA). By analyzing the DTA characteristics of each curve, summing up their general characters, we ultimately make a unified common algorithm and geodetic coordinate calculation model of the design axis in horizontal and vertical planes. It will be very useful for the process of underground construction.


2020 ◽  
Vol 25 (2) ◽  
pp. 189-198
Author(s):  
Lei Chen ◽  
Chao Fu ◽  
Xinji Xu ◽  
Lichao Nie

The seismic method is one of the main geophysical methods that are widely used to image the geology ahead of tunnels during tunnel construction. However, owing to the complex environment and limited observation aperture in a tunnel, symmetric false results (that appear in imaging results but not in the actual environment) frequently occur in imaging results. In a symmetric false reflection, false and true reflection points are axisymmetric around the tunnel axis. Such false results frequently cause errors in the interpretation of the geological conditions ahead of a tunnel face. To overcome this problem, a seismic method that uses adaptive polarization analysis was adopted to better image geological conditions. Based on an adaptive time window, the polarization characteristics of seismic signals were analyzed to calculate the main polarization direction. The symmetric false results in imaging results were suppressed by adopting a weighting coefficient based on the angle between the main polarization direction and ray direction. Numerical simulations revealed the superiority of the method when applied to synthetic data processing. Moreover, the method was applied to a diversion tunnel. The method successfully identified the fracture zones ahead of the tunnel face, thus significantly enhancing the safety of tunnel construction.


2020 ◽  
Vol 1 (1) ◽  
pp. 87-105
Author(s):  
Hongyuan Wang ◽  
Jingcheng Wang

PurposeThe purpose of this paper aims to design an optimization control for tunnel boring machine (TBM) based on geological identification. For unknown geological condition, the authors need to identify them before further optimization. For fully considering multiple crucial performance of TBM, the authors establish an optimization problem for TBM so that it can be adapted to varying geology. That is, TBM can operate optimally under corresponding geology, which is called geology-adaptability.Design/methodology/approachThis paper adopted k-nearest neighbor (KNN) algorithm with modification to identify geological conditions. The modification includes adjustment of weights in voting procedure and similarity distance measurement, which at suitable for engineering and enhance accuracy of prediction. The authors also design several key performances of TBM during operation, and built a multi-objective function. Further, the multi-objective function has been transformed into a single objective function by weighted-combination. The reformulated optimization was solved by genetic algorithm in the end.FindingsThis paper provides a support for decision-making in TBM control. Through proposed optimization control, the advance speed of TBM has been enhanced dramatically in each geological condition, compared with the results before optimizing. Meanwhile, other performances are acceptable and the method is verified by in situ data.Originality/valueThis paper fulfills an optimization control of TBM considering several key performances during excavating. The optimization is conducted under different geological conditions so that TBM has geological-adaptability.


2020 ◽  
Vol 56 (1) ◽  
pp. 1-14
Author(s):  
P.K. Pandey ◽  
A.K. Raina ◽  
S. Deshmukh ◽  
R. Trivedi ◽  
R. Vajre ◽  
...  

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.


1991 ◽  
Vol 28 (2) ◽  
pp. 239-254 ◽  
Author(s):  
F. Pelli ◽  
P. K. Kaiser ◽  
N. R. Morgenstern

A tunnel excavated by a tunnel boring machine was monitored extensively by means of extensometers installed near the tunnel face. Consequently, the three-dimensional state existing at the time of installation must be considered for the interpretation of the monitoring data. Results from three-dimensional finite element simulations are used to back-calculate rock mass strength and deformation properties. The purpose of this study was to establish and test various approaches of back-analysis. Results are compared with field and laboratory measurements. On the basis of these analyses, the paper provides guidance on how field data can be used for back-analysis purposes even when the ground behaves in a nonelastic manner. Key words: tunnelling, monitoring, tunnel boring, back-analysis, nonlinearity.


2012 ◽  
Vol 204-208 ◽  
pp. 2819-2823
Author(s):  
Tao Li ◽  
Kai Bin Liu ◽  
Wei Hong Yang ◽  
Bo Liu ◽  
Ying Chao Liu

The stability control of surrounding rock is a relatively important problem in tunnel boring machine (TBM) construction. The tunnel convergence deformation value was monitored in field while TBM passing weak and broken section of hydraulic tunnel. The correlation between tunnel convergence and surrounding rock stability is analyzed. The monitoring results show that: the characteristic of weak and broken Strata is closely correlated with some geological conditions, such as fault development, intrusive contact of orthophyre and lamprophyre veins. These supporting measures can well ensure the stability of surrounding rock in weak and broken section, such as sealing the inverted arch by using concrete of C25,reinforcing the inverted arch by steel arch of I10 and anchor construction in the roof. There is great difference between the properties of the weak and broken rocks on both sides, which is the main reason of the large tunnel convergence deformation. The monitoring results can provide reference for similar engineering in the future.


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