Patent Publication Number: US-2023135570-A1

Title: Tunnel boring machine

Description:
The invention relates to a tunnel boring machine according to the preamble of claim  1 . 
     Such a tunnel boring machine is known from CN 107 607 082 A. This previously known tunnel boring machine has a shield skin extending in a longitudinal direction and a sensor unit equipped with distance sensors for detecting convergences. To carry out a continuous measurement method, the distance sensors work with a continuous spring force and are in constant contact with the surrounding rock mass during the excavation. 
     Another tunnel boring machine is known from the technical article by D. Harding entitled “Difficult Ground Solutions (DGS): Mew TBM Solutions carve a Path to Success”, published in Proceedings of the World Tunnel Congress 2017—Surface challenges—Underground solutions, Bergen, Norway. In this previously known tunnel boring machine, which has a shield skin extending in a longitudinal direction, a sensor unit is provided in the form of a hydraulic cylinder, which is installed on the shield skin near the cutting wheel in the ridge area, with this hydraulic cylinder, the thickness of the annular gap at the tunnel crown can be measured in order to record convergences. 
     A tunnel boring machine with a shield skin extending in a longitudinal direction and with a sensor unit having a number of laser rangefinders, which are attached to the inside of the shield skin in the longitudinal and circumferential direction, is known from CN 207379337 U. 
     The object of the invention is to specify a tunnel boring machine of the type mentioned at the outset, which is distinguished by reliable measurement of an annular gap present between the shield skin and the rock mass. 
     In a tunnel boring machine of the type mentioned at the outset, according to the invention this object is achieved with the characterizing features of claim  1 . 
     Due to the discontinuous work created in the present invention during breaks in excavation and the recording of distance values at measuring distances determined by tubbings to be installed, on the one hand the location accuracy in the position of the distance sensors is very reliably and easily ensured in terms of measurement technique and it is also guaranteed that the distance sensors will not be damaged in the extremely rough environment during phases of excavation. In addition, it has been found that by advancing the probes into the annular gap in the radial direction, larger moving components such as pieces of rock can also be displaced, resulting in a relatively high measurement accuracy. 
     Due to the fact that the sensor unit in the tunnel boring machine according to the invention has at least two, expediently more than two hydraulic distance sensors with an extendable probe with extension path measurement and arranged in the longitudinal direction at at least one measuring distance and expediently also in the circumferential direction if there are more than two distance sensors, it is possible to determine and evaluate by the central unit convergences in the area of the shield skin in changing distance values as the excavation progresses. 
     Further expedient embodiments of the invention are the subject matter of the dependent claims. 
     Further expedient embodiments and advantages of the invention result from the following description of exemplary embodiments with reference to the figures of the drawing. 
    
    
     
       In the figures: 
         FIG.  1    shows a side view of an exemplary embodiment of a shield shin of a tunnel boring machine with a sensor unit which has a number of distance sensors in a longitudinal direction, 
         FIG.  2    shows a sectional view through a shield skin of a tunnel boring machine of an exemplary embodiment of the invention in the ridge area, 
         FIG.  3    shows a block diagram of an exemplary configuration of a sensor unit and a central unit with further components in an exemplary embodiment of a tunnel boring machine according to the invention, and 
         FIGS.  4  to  7    show sectional views of another exemplary embodiment of a tunnel boring machine according to the invention in the area of a shield skin in various stages of an excavation. 
     
    
    
       FIG.  1    shows a sectional side view of an exemplary embodiment of a tunnel boring machine in the area of a shield skin  106  for boring a tunnel into a rock mass  103 . A number of feeding jacks  109  are attached to the shield skin  106 , which act in a longitudinal direction of the shield skin  106  and are supported on tubbings  112  of a ring construction for lining a tunnel during the excavation. On the front side of the tunnel boring machine opposite the tubbings  112  in the direction of excavation, there is a cutting wheel not shown in  FIG.  1   , by virtue of which a tunnel cavity can be created in the rock mass  103 . 
     The tunnel cavity created by the mining action of the cutting wheel has a diameter which is larger than the diameter of the shield skin  106 , so that an annular gap  115  is formed between the rock mass  103  and the outside of the shield skin  106 . The annular gap  115  is usually at least partially filled with liquid and solid, granular components from the mining operation. However, as shown in  FIG.  1   , convergences of the rock mass  103  usually lead to the annular gap  115  narrowing in the longitudinal direction of the shield skin  106  pointing away from the cutting wheel in the direction of the tubbings  112 . Therefore, if the convergence is too pronounced and the rock mass  103  comes into contact with the shield skin  106 , there is a risk that the tunnel boring machine will be jammed. 
     To detect convergence of the rock mass  103  via changes in the dimensions of the annular gap  115 , the exemplary embodiment of  FIG.  1    includes a sensor unit  118 , which has a number of hydraulic distance sensors  121 , which are arranged in the longitudinal direction of the shield skin  106  at a measuring distance and preferably also along the circumference of the shield skin  106  at regular intervals. Each distance sensor  121  has a probe  124 , which can be advanced in the radial direction into the annular gap  115  and is set up as a distance value as part of an extension path measurement to measure the distance between the shield skin  106  in the area of the relevant distance sensor  121  and the rock mass  103 . 
       FIG.  2    shows a cross section of the shield skin  106  in the ridge area in the exemplary embodiment according to  FIG.  1   . It is evident from  FIG.  2    that the sensor unit  118  also has distance sensors  121  arranged along the circumference of the shield skin  106  in addition to distance sensors  121  arranged at a measuring distance in the longitudinal direction of the shield skin  106 . In the arrangement according to  FIG.  2   , the distance sensors  121  arranged along the circumference of the shield skin  106  are positioned essentially symmetrically to a central vertical axis  203 . The angle of the distance sensors  121  to the central vertical axis  203  is expediently between approximately 15 degrees and approximately 45 degrees, preferably in the range of approximately 30 degrees. In a development that is not shown, it is provided that distance sensors  121  are also arranged in the middle of the ridge area on the middle vertical axis  203 . 
       FIG.  3    shows a block diagram of the sensor unit  118  with the distance sensors  121  which are connected to a measurement data memory  303  for storing the distance values obtained via the distance sensors  121 . A timer  306  and a position sensor  309  are also connected to the measurement data memory  303 . Time data can be generated with the timer  306 , which can be linked in the measurement data memory  303  with the distance values obtained at the relevant time. The position sensor  309  can be used to generate position data of the shield skin  106 , which can also be linked to the distance values obtained at specific positions of the shield skin  106 . 
     In this way, the distance values of the various distance sensors  121  are available in a time profile and in a location profile. 
     The measurement data memory  303  is connected to a central unit  332 , by virtue of which the distance values with the linked time data and position data can be evaluated so that convergences of the rock mass  103  can be evaluated in particular so that it can be determined whether certain minimum distance values between the rock mass  103  and the shield skin  106  are maintained. The central unit  312  can furthermore generate a forecast of the convergences to foe expected, particularly in the area facing away from the cutting wheel and adjacent to the tubbings  112 , based on the distance values resolved in terms of time and location, in order to ensure as far as possible that there is no risk of the tunnel boring machine getting stuck. 
     A signal generator  315  and a display  318  are expediently connected to the central unit  312 . The signal generator  315  is set up to emit a warning, for example in the form of a signal tone or a visual warning signal, when critical distance values are reached between the rock mass  103  and the shield skin  106 . The display  318 , in turn, is set up to graphically display the temporal and spatial progression of the distance values recorded by the distance sensors  121  and of predicted distance values. 
     The central unit  312  further has excavation data representing the trajectory of the tunnel boring machine, which can be taken into account when evaluating the convergences with regard to critical values such that an annular gap  115  that decreases in a controlled manner due to a curved trajectory does not lead to false alarms. 
       FIGS.  4  to  7    show a sectional side view in accordance with  FIG.  1    of a further exemplary embodiment of a tunnel boring machine in the area of a shield skin  106  in various phases of the excavation. 
       FIG.  4    shows the arrangement in accordance with  FIG.  1    after completion of a ring of tubbings  112  with a ring width B with retracted feeding jacks  109  and retracted probes  124  of in this case two distance sensors  121  in the longitudinal direction. The distance sensors  121  are arranged at a measuring distance D. Starting with the arrangement according to  FIG.  4   , an excavation cycle begins, which will be completed with the installation of a next ring of tubbings  112 . 
       FIG.  5    shows the arrangement according to  FIG.  4    with fully extended feeding jacks  109  shortly before installing tubbings  112 . The excavation is interrupted in this phase, so that the probes  124  of the distance sensors  121  are extended and in contact with the rock mass  103 , as shown in  FIG.  5   , displacing pieces of rock if necessary. The distance values obtained at this point in time and at this position of the shield skin  106  can be fed into the measurement data memory  303 . 
       FIG.  6    shows the next phase of the excavation, beginning after the installation of the next ring of tubbings  112 , in which the probes  124  of the distance sensors  121  are retracted again and remain retracted until the end of this phase of the excavation. 
       FIG.  7    shows in accordance with  FIG.  5    the feeding jacks  109  once again in the maximum extended position with the probes  124  of the distance sensors  121  extended again to obtain distance values. 
     The sequence of  FIGS.  4  to  7    also clearly shows that in this exemplary embodiment, the measuring distance D between the two distance sensors  121  in this case corresponds to the ring width B of the tubbings  112 . This ensures that each measuring point on the rock mass  103  is detected twice, or multiple times if more than two distance sensors  121  are provided, each at a corresponding measuring distance D, in terms of its distance from the shield skin  106 . As a result, the convergences can be determined very precisely and, moreover, reliable forecasts can be made for the rear area of the shield skin  106  in the direction of excavation.