METHOD AND DEVICE FOR STABILIZING A TRACK

Abstract

A method for stabilizing a track having sleepers supported on a track ballast and rails secured to the sleepers, includes using a stabilizing unit which is connected to a machine frame that can be moved on the rails and has a vibration exciter and rollers that can roll on the rails. The vibration exciter generates in particular horizontal vibrations which run transversely to the track longitudinal direction. The course of a force exerted onto the track by the stabilizing unit is recorded over a vibration path during a vibration cycle by sensors. At least one parameter is derived from the course by an evaluation device and is used to evaluate the stabilizing procedure and/or the quality of the track ballast. A device for implementing the method is also provided.

Claims

1-15 (canceled)

16. A method for stabilizing a track having sleepers supported on track ballast and rails fastened on the sleepers, the method comprising: providing a machine frame being mobile on the rails; connecting a stabilizing unit to the machine frame, the stabilizing unit including a vibration exciter and rollers configured to roll on the rails; using the vibration exciter to generate vibrations running transversely to a longitudinal direction of the track; using sensors to record a course of a force acting from the stabilizing unit on the track over an oscillation path during a vibration cycle; and using an evaluation unit to derive at least one parameter from the course and to evaluate at least one of a stabilizing procedure or a quality of the track ballast.

17. The method according to claim 16, which further comprises using the vibration exciter to generate horizontal vibrations.

18. The method according to claim 16, which further comprises specifying the parameter as a parameter for controlling the stabilizing unit.

19. The method according to claim 16, which further comprises rotating at least two eccentric masses with phase positions matched to one another and with a prescribed angular frequency, during an activation of the vibration exciter.

20. The method according to claim 19, which further comprises determining an excitation force from the rotating masses, an eccentricity of the rotating masses and the angular frequency of the rotating masses.

21. The method according to claim 16, which further comprises deriving a slope of the course as a first parameter for determining stiffness conditions.

22. The method according to claim 21, which further comprises deriving a curvature of the course as a second parameter for determining damping conditions.

23. The method according to claim 16, which further comprises determining a circumscribed area as dynamically transmitted work by circle integration over each excitation period, for at least one course of a force acting from the stabilizing unit on the track over an associated oscillation path.

24. The method according to claim 16, which further comprises: using the evaluation device to specify a modal mass of the stabilizing unit; determining a force acting on the rails by taking into account a product of the modal mass times an acceleration of the stabilizing unit; and determining the course of the force acting on the rails over the oscillation path of the stabilizing unit.

25. The method according to claim 16, which further comprises: using the evaluation device to specify a modal mass of the vibrating sleepers; determining a force acting on the track ballast by taking into account a product of the modal mass times an acceleration of the sleepers; and determining the course of the force acting on the track ballast over the oscillation path of a sleeper.

26. The method according to claim 25, which further comprises using the evaluation device to specify the modal mass of the vibrating sleepers with a vibrating section of the rails.

27. The method according to claim 16, which further comprises storing in the evaluation device a mechanical model of the stabilizing unit and of the track section set in vibrations, and using the model to compute soil-mechanical parameters.

28. The method according to claim 16, which further comprises carrying out the recording of the course of the force over the oscillation path while the stabilizing unit is operated in a stationary manner.

29. A device for stabilizing a track having sleepers supported on track ballast and rails fastened on the sleepers, the device comprising: a stabilizing unit fastened to a machine frame being mobile on the rails, said stabilizing unit including a vibration exciter and rollers configured to roll on the rails, said vibration exciter generating vibrations running transversely to a longitudinal direction of the track; sensors disposed on the device for recording a course of a force acting from said stabilizing unit on the track over an oscillation path during a vibration cycle; and an evaluation device receiving measuring signals of said sensors, said evaluation device configured for determining a parameter derived from the course to evaluate at least one of a stabilizing procedure or a quality of the track ballast.

30. The device according to claim 27, wherein said vibration exciter generates horizontal vibrations.

31. The device according to claim 29, which further comprises at least one path measurement sensor.

32. The device according to claim 29, which further comprises a device control coupled to said evaluation device for controlling said stabilizing unit in dependence on the parameter.

33. The device according to claim 29, wherein said evaluation device includes a memory storing modal masses of said stabilizing unit and of the track to be stabilized.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The invention will be described below by way of example with reference to the accompanying drawings. There is shown in a schematic manner in:

[0029] FIG. 1 a track maintenance machine having stabilizing units

[0030] FIG. 2 a cross-section of a track with a stabilizing unit

[0031] FIG. 3 a top view of a track with stabilizing units

[0032] FIG. 4 a cross-section of a track with dynamic force introduction by means of the stabilizing unit

[0033] FIG. 5 work diagrams

[0034] FIG. 6 a dynamic model for describing the dynamic interaction of stabilizing unit and ballasted track

DESCRIPTION OF THE EMBODIMENTS

[0035] The device 1 shown in FIG. 1 is configured as a track maintenance machine (dynamic track stabilizer DTS) and comprises a machine frame 2 which, supported on on-track undercarriages 3, is mobile on rails 4 of a track 5. The rails 4 are fastened to sleepers 6 and, together with these, form a track grid which is supported on track ballast 7. Advantageously, two stabilizing units 8 are movably connected to the machine frame 2 to transmit oppositely directed vibrations to the track 5. In simple embodiments, only one stabilizing unit 8 is provided.

[0036] The stabilizing unit 8 comprises flanged rollers 9 and clamping rollers 10 for gripping the track grid. Specifically, the gripping of the rails 4 by the clamping rollers 10 takes place by means of a clamping mechanism 11. Advantageously in this, the flanged rollers 9 are pressed against the rails 4 from inside by means of locked telescopic axles 12. The stabilizing unit 8 sets the track grid locally in vibrations which are transmitted by the track grid into the track ballast 7. The vibrations have the effect that the grains in the granular structure become mobile, allow displacement and assume a denser packing. In the case of new track ballast 7 without an appreciable portion of fine parts, the ballast 7 may start to flow which additionally enhances the consolidation effect. As a result of the consolidation of the track ballast 7, the bearing capacity and stiffness of the same are increased, and the settlement accompanying the consolidation are anticipated in a controlled way.

[0037] FIG. 2 shows a cross-section through a railway embankment with the stabilizing unit 8 acting on the track 5. FIG. 3 shows a corresponding top view. The stabilizing unit 8 is dynamically excited in a horizontal direction transversely to the track axis 14 by means of a vibration exciter 13 (directed vibrator). Via the clamping rollers 10 and the flanged rollers 9, these horizontal vibrations 15 are transmitted to the rails 4 and, via the rail fastenings 16, to the sleepers 6. The respective sleeper 6—optionally by way of a sleeper sole pad 17—transmits the vibrations thus produced to the track ballast 7 which is to be consolidated.

[0038] In an exemplary embodiment, the vibration exciter 13 comprises rotating eccentric masses (imbalances) with phase positions synchronized with one another. Preferably, the eccentric masses rotate in opposite directions, wherein the eccentric forces cancel one another in vertical direction and amplify one another in horizontal direction. By changing the respective phase position or the eccentricity, the effect of the eccentric masses can be adjusted. In order to determine the size of the effective eccentricity, the frequency and the phase position of the dynamic excitation, the positions of the rotating eccentric masses are continuously recorded metrologically. In the case of alternative vibration exciters 13, the recording of the dynamic excitation takes place in a correspondingly suitable way.

[0039] According to the invention, a course 21 of a force F, F.sub.S, F.sub.B acting by way of the stabilizing unit 8 on the track 5 over a vibration path y.sub.DGS, Y.sub.s (horizontal displacement) is recorded during a vibration cycle by means of sensors 18, 19, 20 arranged on the stabilizing unit 8. In the arrangement according to FIG. 2, a sensor 18 measures the motion of the stabilizing unit 8, and a sensor 19 measures the position of the rotating eccentric masses of the vibration exciter 13. For example, an acceleration ÿ.sub.DGS is determined first by means of an acceleration sensor 18 and, by way of integration in each case, a vibration speed {dot over (y)}.sub.DGS and the vibration path y.sub.DGS of the stabilizing unit 8 and thus also of the rail heads is determined.

[0040] Advantageously, the state of motion of the sleepers 6 in the effective direction of the stabilizing unit 8 is determined by means of a contact-less sensor 20. This is, for example, a camera with automatized image evaluation which is aimed at the sleeper 8 set in vibration. In this manner, the displacement or the vibration path y.sub.S of the respective sleeper 8 is recorded.

[0041] Preferably arranged in the track maintenance machine for on-line evaluation is an evaluation device 22 to which sensor signals or data recorded by means of the sensors 18, 19, 20 are fed. This is, for example, an industrial computer with a memory device. In the memory device, structural data of the device 1 and the treated track 4 as well a dynamic model are stored. A software is installed in the evaluation device 22 by means of which work diagrams are compiled and evaluated. Additionally, measuring results of a path measuring sensor 23 are fed to the evaluation device 22 in order to link the work diagrams of the individual vibration cycles to a respective position on the track 5. In another embodiment, the evaluation device 22 is arranged in a central, wherein a data transmission is set up between the track maintenance machine and the central.

[0042] With reference to FIG. 4, path—displacement relationships (work diagrams) are explained which are compiled on the basis of the measurements according to the invention. The force F of the excitation of the stabilizing unit 8 by means of the vibration exciter 13 is the product of the effective eccentricity (eccentric mass m times eccentricity e) and the square of the excitation circuit frequency ω multiplied by the sinus of the product of excitation circuit frequency ω and time t:

F=m.Math.e.Math.ω.sup.2.Math.sin(ω.Math.t)

[0043] Both amplitude and phase position are known from the measurements. The metrologically determined phase position serves as reference for the further phase positions and is thus set to zero in the calculation.

[0044] As a rule, the measurements take place in a work-integrated way during operation of the moved stabilizing unit 8, but they can also be carried out during a stand-still for calibration- or testing purposes in order to track the consolidating course at a fixed point.

[0045] The horizontal displacement y.sub.DGS of the stabilizing unit 8 and the derivations thereof with the related phase positions are known from the measurement. The mass M.sub.DGS of the stabilizing unit 8 and the modal mass M.sub.S of the excited sleepers 6 are known based on the design. The mass of the rail heads can be added modally to the mass M.sub.DGS of the stabilizing unit 8, and that of the rail bases to the modal mass M.sub.S of the excited sleepers 6.

[0046] If the respective mass inertia forces of the components are deducted from the excitation force F, then the excitation force F.sub.s on the sleeper 8 and the excitation force F.sub.B on the track ballast 7 can be determined

F.sub.B=F−ÿ.sub.DGS.Math.M.sub.DGS−ÿ.sub.S.Math.M.sub.S

F.sub.S=F−ÿ.sub.DGS.Math.M.sub.DGS

[0047] The work diagrams shown in FIG. 5 can be compiled from the relationships between these forces F, F.sub.B, F.sub.S and the associated vibration paths or displacements y.sub.DGS, y.sub.S in the effective direction. They give information about the stiffness relationships (inclination of the line) and damping relationships (curvature) as well as the work introduced into the system per excitation cycle (circumscribed area A.sub.1 and A.sub.2).

A.sub.1=F.sub.B.Math.dy.sub.s

A.sub.2=F.sub.S.Math.dy.sub.DGS

[0048] The amplitude relationships {circumflex over (F)} of the forces F, F.sub.B, F.sub.S and the amplitude relationships ŷ of the vibration paths y.sub.DGS, y.sub.s in the system can also be read out.

[0049] To determine the dynamic characteristics of the system components by way of the amplitudes and phase positions established from the measurements and the analysis thereof, a mechanical model according to FIG. 6 is used. In this, relevant system components for mechanical modelling are switched in series.

[0050] The metrologically known dynamic excitation force F acts on the modal mass M.sub.DGS of the stabilizing unit 8 which undergoes the displacement y.sub.DGS. The stabilizing unit 8 is connected via the rails 4 and the rail fastenings 16 to the sleepers 6 (modal mass M.sub.S and displacement y.sub.S). In this, the resilience of the rails 4 and rail fastenings 16 is modelled by means of a Kelvin-Voigt element (spring k.sub.S and damper c.sub.S arranged in parallel).

[0051] The sleepers 6 rest on the track ballast 7 which is modelled as a friction element r.sub.B, optionally of a resonating mass M.sub.B and a Kelvin-Voigt element (spring k.sub.B and damper c.sub.B arranged in parallel). In this, the friction element r.sub.B describes the dynamic transverse displacement resistance.

[0052] Via soil-mechanical principles, the spring constant k.sub.B, the damping coefficient c.sub.B and the resonating mass M.sub.B stand in relation to the shear modulus G.sub.B of the track ballast 7 which can be determined by retroactive calculation. Besides the information from the work diagrams (FIG. 5), the shear modulus G.sub.B of the track ballast 7 is one of the most important parameters for assessing the ballast stiffness and thus the state of consolidation of the track ballast 7. It is determined continuously by way of the process-related measurements (FIG. 2) by back-calculation with the aid of the mechanical model (FIG. 6).

[0053] If two or more stabilizing units 8 are working one behind the other in a track maintenance machine, then the described measuring principle can be applied to each of these stabilizing units 8. The results, determined independently of one another, are set in relation to one another, as a result of which additional information about track ballast condition, compactibility, development of carrying capacity, course of settlement, etc. is available and can be applied. Therefore, it is advantageous if several stabilizing units 8 are arranged one behind the other and if the measuring signals of the sensors 18, 19, 20 associated with the stabilizing units 8 are fed to a common evaluation device 22.