EP0300159B1 - Method and device for lining a tunnel with concrete cast in situ - Google Patents

Description

The invention relates to a method for lining a tunnel with in-situ concrete behind a tunneling machine having a trailing shield jacket, the in-situ concrete through a front formwork which is longitudinally movable relative to the shield jacket and to the inner formwork and which is adjacent to the inner jacket surface of the shield jacket and to the inner formwork while simultaneously advancing the Forehead formwork is pressed against the inner formwork between the mountains and the inner formwork, the forehead formwork being acted upon by the pressure of the in-situ concrete supplied in a controlled manner depending on the relative position of the forehead formwork to the shield casing and by acting on a hydraulic spring arrangement with a compensation force corresponding to that between the forehead formwork and the Shield jacket and the internal formwork of the frictional forces. In addition, the invention relates to a device for carrying out such a method, in which the front formwork has an outer jacket seal that is in contact with the inner jacket surface of the shield jacket and an inner jacket seal that is in contact with the outer jacket surface of the inner boarding, is connected to an in-situ concrete pump via a movable in-situ concrete delivery line and via the adjustable, the frictional force compensating hydraulic spring arrangement is coupled to the shield casing and the face formwork and the shield casing is interposed with a displacement measuring device which is assigned as an input element to a control device having the in-situ concrete pump as an actuator.

As part of the known measures of the type mentioned (DE-PS 34 06 980) should by setting the hydraulic spring assembly the in-situ concrete compressive force and the frictional forces can be brought into the relevant relationship; how this setting is to be carried out in detail is left open. The control device merely serves to hold the front formwork in a predetermined area of the shield casing and consequently has a cylinder piston arrangement, via which the shield casing is coupled to a propulsion unit of the tunneling machine, and the in-situ concrete pump as actuators. However, these measures do not meet the requirements. Experience with jacking shields in the diameter range of 6 to 7 m has shown that the required compensation forces can fluctuate between 400 and 1400 kN. This leads to correspondingly large fluctuations in the concrete pressure required for the forward movement of the forehead formwork, with the correspondingly negative consequences for the quality of the tunnel lining, in particular in the loose soil and below the water table. The pressure fluctuations that occur must be reduced in order to obtain a qualitatively perfect in-situ concrete lining. The concrete pressure in the formwork must be kept above the existing earth and water pressure as well as a safety value.

In another device for driving a tunnel (DE-PS 31 27 311) it is also known to enable low-friction longitudinal adjustment by using jacket sliding bearings on the side of the front formwork facing the shield jacket and to ensure with the aid of a stabilization device that Face formwork always maintains its position perpendicular to the machine direction. The currently prevailing and varying frictional forces are not taken into account here.

The invention has for its object to reduce the amount of harmful pressure fluctuations when feeding the in-situ concrete in the context of the measures described above.

In procedural terms, this object is achieved according to the invention in that the frictional forces between concreting sections of a predetermined length by pulling the front formwork over the stationary shield casing and the inner formwork by means of the spring arrangement with interrupted in-situ concrete supply by a predetermined distance in which the front formwork does not differ from the last supplied in-situ concrete dissolves, as well as being determined by measuring the forces required for this, and that during the subsequent concreting, the face formwork is additionally subjected to a constant force corresponding to the forces determined in the direction of advance and the amount of in-situ concrete supplied increases if the front formwork remains behind the shield jacket and if the front formwork leads ahead the shield mantle is lowered. The device-based solution is characterized in that the hydraulic spring arrangement is also connected as an actuator to the control device and consists of parallel hydraulic cylinder piston arrangements, the cylinder chambers facing away from the front formwork are connected via a hydraulic line to a gas pressure accumulator arrangement and the cylinder chambers facing the front formwork are connected via a hydraulic line to a proportional pressure valve arrangement are, and that the cylinder chambers can be acted upon by the proportional pressure valve arrangement until it moves forward by a predetermined distance when the shield casing and the in-situ concrete pump are at a standstill, and the corresponding pressure ratios can be stored by the control device and can be adjusted via the proportional pressure valve arrangement when the in-situ concrete is supplied.

The invention is based on experiences gained in the course of lining tunnels with in-situ concrete. The variable frictional forces acting on the movable face formwork cannot be determined practically during operation. To ensure pressure-stable concrete paving with only slight fluctuations in the concrete pressure, it is therefore necessary to record the frictional forces at regular intervals and to change a supporting force that acts continuously when feeding the in-situ concrete so that the change in supporting force corresponds to the amount of the frictional force, but in the opposite direction in the direction of action is directed. This adjustment of the supporting force causes the front formwork to be moved forward in the driving direction solely by the concrete compressive force of the in-situ concrete that exceeds the supporting force, and any frictional forces that occur are eliminated in their effect by the compensation forces additionally introduced into the system.

There are several possibilities for the further configuration within the scope of the invention. From a procedural point of view, there is the possibility of imparting the frictional forces along the circumference of the face formwork independently at several points; Accordingly, it is also possible to apply different compensation forces to the front formwork in the circumferential direction.

The invention is explained in more detail below with the aid of a drawing representing an exemplary embodiment.

The single figure shows a device for lining a tunnel with in-situ concrete behind a tunnel boring machine with a trailing shield jacket 1. In this case, a front formwork 2 is used, which has an outer jacket seal 3 lying against the inner surface of the shield jacket 1 and an inner jacket lying against the outer jacket surface of an inner formwork 4 Has jacket seal 5. Through the face formwork 2, 7 in-situ concrete is pressed via a movable in-situ concrete delivery line 6 with an in-situ concrete pump; this is only hinted at in the figure. The front formwork 2 is coupled to the shield casing 1 via an adjustable hydraulic spring arrangement 8 that compensates for the frictional forces. In addition, the face formwork 2 and the shield casing 1 are assigned a displacement measuring device 9 as an input element of an electrical control device 10.

Said hydraulic spring arrangement 8 is connected as an actuator to the control device 10 and the control device 10 is set up for storing the setting of the hydraulic spring arrangement 8 when determining the frictional forces; this will be explained in more detail below. The hydraulic spring arrangement 8 consists of a plurality of parallel hydraulic cylinder piston arrangements 11, only one of which is shown. The cylinder chamber 12 facing away from the front formwork 2 is connected via a hydraulic line 13 to a gas pressure accumulator arrangement 14. This is designed so that practically the same pressure is always exerted on the piston of the hydraulic cylinder piston assembly 11 regardless of its position. The cylinder chamber 15 of the hydraulic cylinder piston arrangement 11 facing the face formwork 2 is connected via a hydraulic line 16 to a proportional pressure valve arrangement 17 with a hydraulic pump 18. With the aid of the proportional pressure valve arrangement 17, a constant hydraulic pressure can be maintained in the cylinder chamber 15. The in-situ concrete pump 7 is connected as a further actuator to the control device 10 in order to control the concrete volume flow as a function of the path. For this purpose, when the front formwork 2 is deflected relative to the shield casing 1 around the operating point Xm in the + x direction, the concrete volume flow to be introduced through the front formwork 2 is reduced, when the Xm direction is deflected in the -x direction, the concrete volume flow is increased, and when the front formwork 2 is not deflected, the supplied concrete volume flow rate is reduced kept constant or not changed. The working point can be provided with a path tolerance.

When the support is switched on, standing face formwork 2 and standing shield casing 1, the unpressurized cylinder chambers 15 of the hydraulic cylinder piston arrangement 11 are continuously pressurized with increasing pressure in that hydraulic fluid from the hydraulic pump 18 is pumped into the cylinder chamber 15. The concrete flow control and the concrete supply are interrupted. The hydraulic quantity fed in is dimensioned such that, after a certain pressure is exceeded, the front formwork 2 is pulled off at a low speed in the + x direction. The displacement measuring device 9 registers a change in displacement, from which the electronic control device 10 determines a change in speed of the front formwork 2. This change in speed is the signal for the end of the hydraulic feed. The resulting pressure is stored in the control device and optionally provided with a correction factor to be determined by calibration. The forces shown (supporting force F _s , concrete pressure force F _b , earth and water pressure force) are in equilibrium. With a slight and sufficiently slow movement of the front formwork 2, the pressure conditions in the concrete room change only slightly, since the volume changes are absorbed as if by an elastic membrane.

wobei F_Speicher = F_Beton und F_Reibung = F_Kompensation ist. Für den praktischen Einsatz wird F_Kompensation so gewählt, daß eine leichte Unterkompensation von F_Reibung erreicht wird. Dieses bedeutet, daß der Betondruck etwas überhöht angesetzt wird. Wird der Betondruck jetzt um einen gewissen Wert dF_b gesteigert, so setzt sich die Stirnschalung 2 in Richtung der auf sie einwirkende Betondruckkraft in Bewegung, da ein Ungleichgewicht der Kräfte entsteht.For the compensation operation, the proportional pressure valve arrangement 17 is brought to a setting corresponding to the last measured and corrected value and the cylinder chamber 15 of the hydraulic cylinder piston arrangement 11 is pressurized. Ideally, the following applies to the state of equilibrium

${\text{F}}_{\text{Storage}}{\text{+ F}}_{\text{friction}}{\text{= F}}_{\text{concrete}}{\text{+ F}}_{\text{compensation}}\text{,}$

where F _storage = F _concrete and F _friction = F _compensation . For practical use, F _compensation is chosen so that a slight under _compensation of F _{friction is} achieved. This means that the concrete pressure is set too high. If the concrete pressure is now increased by a certain value dF _b , the face formwork 2 starts to move in the direction of the concrete pressure force acting on it, since an imbalance of the forces arises.

When the forehead formwork 2 moves in the + x direction with the inner formwork 4 standing and a higher forehead formwork speed than the shield casing 1, the forces that inhibit the movement are almost optimally compensated for. In the normal case, the compensation force remains constant until a certain distance, e.g. B. 20 cm, is concreted. The control device 10 is equipped with all path information required for determining the concreting path. When the intended distance is reached, the compensation operation is terminated and a new friction force determination is carried out automatically. A higher reserve of the concrete pressure than would be necessary according to the static framework conditions serves as a safety reserve as well as the low undercompensation of the friction force, as a result of which an increase in the concrete pressure is necessary. The deflection of the face formwork 2 leads to the onset of the concrete volume flow control. The concrete volume flow is reduced. For practical reasons, the working point X _{m can be provided} with a tolerance field x 1> x _m > x _o . If the face formwork is within this distance, the concrete volume flow remains constant.

When the forehead formwork moves in the + x direction with the inner formwork 4 stationary and a lower forehead formwork speed compared to the shield casing 1, the displacement measuring device 9 registers a deflection in the -x direction. As a result, the concrete volume flow is increased. The increased concrete volume flow leads to an increase in pressure in the annular space and finally to a movement of the front formwork 2 in the direction + x at a speed which is greater than that of the shield casing 1. The frictional force acting on the front formwork 2 between the shield casing 1 and the front formwork 2 changes direction and possibly their amount. In order to take into account the resulting change in the resulting frictional force, the compensating force is reduced until the relative speed between the front formwork 2 and the shield jacket 1 is no longer negative. As a result of the deflection, the concrete volume flow is increased. The increased concrete volume flow leads to an increase in pressure in the formwork and finally to a movement of the front formwork 2 in the direction + x at a speed which is greater than that of the shield casing 1. Failure to achieve the relative movement between the shield casing 1 and the front formwork 2 does not lead to a substantial incorrect compensation as long as the direction of the frictional forces between the inner formwork 4 and the front formwork 2 and the shield casing 1 and the front formwork 2 have the same direction. If the direction of the frictional force between the shield casing 1 and the front formwork 2 is reversed, the total frictional force is reduced and, in extreme cases, can reverse its direction. The design of the control device 10 provides that the operator is made aware of the case described; the operator can then take appropriate steps to "troubleshoot" if necessary. If the front formwork 2 stops, the control device 10 is designed such that that the operation is interrupted immediately with a friction compensation, ie the cylinder chamber 15 of the hydraulic cylinder piston assembly 11 is vented. It is possible to restart the compensation operation after the fault has been rectified.

In a modification of the described embodiment, it is of course also possible to determine and compensate the frictional forces, to change the support pressure in the gas pressure accumulator arrangement 14. It is also possible to use further proportional pressure valve arrangements instead of the single proportional pressure valve arrangement 17 shown, for example to use a separate proportional pressure valve arrangement 17 for each hydraulic cylinder piston arrangement 11.

Claims (3)

1. A process for the lining of a tunnel with cast-in-situ concrete behind a tunnel-driving machine possessing a trailing shield jacket (1), in which, through a front shuttering (2) fitting closely against the inner jacket surface of the shield jacket (1) and against the outer jacket surface of an inner shuttering (4) and longitudinally movable relatively to the shield jacket (1) and the inner shuttering (4), the cast-in situ concrete is pushed between the rock face and the inner shuttering (4) with simultaneous movement forward of the front shuttering (2) relatively to the inner shuttering (4), in which the front shuttering (2) is moved forward by the pressure load of the cast-in-situ concrete, the supply of which is controlled in accordance with the relative positions of the front shuttering (2) and the shield jacket (1), and by loading from a hydraulic spring device (8) with a compensation force corresponding to the frictional forces occurring between the front shuttering (2), the shield jacket (1), and the inner shuttering (4), characterized in that the frictional forces between concreting sectors of specified length are determined with the cast-in-situ concrete supply interrupted, by pulling forward the front shuttering (2) relatively to the stationary shield jacket (1) and the inner shuttering (4) by means of the spring device (8) over a specified distance in which the front shuttering (2) does not separate from the last-supplied cast-in-situ concrete and by measuring the forces necessary for this, and that in the subsequent concreting the front shuttering (2) is constantly additionally loaded in the direction of advance in accordance with the determined forces and the quantity of cast-in-situ concrete supplied is increased when the front shuttering (2) lags behind the shield jacket (1) and is reduced when the front shuttering (2) moves ahead of the shield jacket (1).
2. A process according to Claim 1, characterized in that the frictional forces around the circumference of the front shuttering (2) are determined at several points independently of one another.
3. An equipment to perform the process according to Claim 1 or 2, in which the front shuttering (2) has an outer jacket seal (3) fitting against the inner jacket surface of the shield jacket (1) and an inner jacket seal (5) fitting against the outer jacket surface of the inner shuttering (4), is connected to a cast-in-situ concrete pump (7) by a movable cast-in-situ concrete conveyor pipe (6) and is coupled to the shield jacket (1) by the adjustable hydraulic spring device (8) compensating for the frictional forces, and a distance-measuring instrument (9) is interposed between the front shuttering (2) and the shield jacket (1), that as input unit is associated with a control equipment (10) having the cast-in-situ concrete pump (7) as output unit, characterized in that the hydraulic spring device (8) is also connected to the control equipment (10) as an output unit, and consists of parallel hydraulic piston-cylinder systems (11) the cylinder chambers (12) of which that face away from the front shuttering (2) are connected to a gas-pressure storage system (14) by a hydraulic pipe (13) and the cylinder chambers (15) of which that face towards the front shuttering (2) are connected to a proportional pressure valve system (17) by a hydraulic pipe (16), and that when the shield jacket (1) and cast-in-situ concrete pump (7) are stationary the cylinder chambers (15) can be loaded by means of the proportional pressure valve system (17) until there has been movement forward through a specified distance, and the corresponding pressure data can be stored by the control equipment (10) and are adjustable via the proportional pressure valve system (17) during the supply of cast-in-situ concrete.

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