EP0760419B1 - Method for surveying planned tunnel galleries - Google Patents

Abstract

A through pilot bore is produced with a bore head guided in the bore path along the planned tunnel course. Samples are removed from the pilot bore for geo-physical examination. The pilot bore is produced along the centre line of the planned tunnel course. In the production of the pilot bore, bore advance parameters are highlighted, which can then be related to the bore hole investigation. One or more of the following bore advance parameters are established: bore pressure, advance speed, abrasion of the bore head. Samples are taken from the flushing back flow of the pilot boring. Pre-investigation is enacted by geo-physical depth probing of the surface.

Description

The present invention relates to a method of exploration of planned tunnel routes.

In tunnel construction projects, the An engineering-geological report was prepared for the tunnel route be the exact information on the geological Contains the nature of the formation to be drilled. On Such a tunnel report should provide information about the Lithology, tectonics and the prevailing Have groundwater conditions so that when the Tunnel route no unforeseen complications occur. Such complications have occurred in the past Tunnel construction projects up to 50% more expensive.

So far, to explore a planned tunnel route from the surface of the formation from geological Deep soundings are carried out, with a variety of vertical test holes are required, some of which must also have a considerable depth. This is the known methods of exploring a planned one Tunnel route complex and expensive, in its coverage actual tunnel route, however, very inadequate (max. 5-10 % of the future tunnel route will be direct Acquisition).

FR-A-2 716 233 describes an apparatus for determining the geological structure with a device for transmitting signals (8A), a second device for detecting the signals (9A) and a built-in analysis device (10) for evaluating the Results. Above all, the device serves to remove obstacles or to detect voids and determine the course of a mine. The signal generator and signal receiver are on an exploratory spine mounted directly on the shield of the tunneling machine. The one with the Exploratory mandrel is drilled vertically or in one Angle to the strut executed. FR-A-2 716 233 represents the closest state of the art.

Japanese Patent Abstract JP-A-61 107157 describes one Device for exploring the geological structure with a Drilling device from which drilling fluid emerges and continuously loosened soil particles from the hole. From the analysis The structure of this flushed out substance can be determined. This type of drilling fluid investigation has long been used in petroleum and natural gas industry.

The specialist article Brückl et al., "Geophysics and the geological-geotechnical Preliminary exploration of rock structures ", Felsbau, No. 13, 1995, p. 256-261; describes the geophysical methodology of the preliminary exploration of Rock buildings. The methods used here and the. measurements to be used in geological and geotechnical exploration and monitoring of rock projects summarized. As can be seen from Table 1, one planned rail and road tunnels the geotechnical question of the Rock boundaries. Table 2 summarizes the answers to this question Using geophysical methods.

US Pat. No. 5,314,267 describes a drilling device for Create a pipeline based on a pilot well a large diameter pipeline is being drilled. Drilling fluid sampling is possible immediately before tunneling.

It is the problem underlying the present invention a method of exploring a planned tunnel route create the most suitable driveway can be determined.

This problem is solved by a method according to Claim 1, wherein under a substantially horizontal running tunnel section every tunnel section is understood which are predominantly at an angle of <45 ° to the horizontal runs.

According to the invention, the geology along the planned tunnel route to a pilot hole prepare. After going through this preliminary investigation first Information about the existing geology is preserved in a second step with one that is steerable in the course of the drilling A continuous drilling head along the planned tunnel route Pilot bore created. Eventually, the pilot bore Samples are taken and it becomes a petrographic, tectonic and geophysical exploration of the pilot well.

The method according to the invention results in considerable Advantages over conventional exploration methods. There according to the invention for the first time a continuous, essentially horizontal pilot hole can be created with With the help of this pilot hole, the entire tunnel section on their entire length can be explored. At the same time it is targeted and selective sampling along the entire tunnel route possible, whereby difficult mountain areas are recognized can. Since no long vertical holes are required and there is a very fast drilling without moving the equipment is possible, the inventive method is very fast and inexpensive and therefore efficient. Finally, through the inventive method the Exploration data can be obtained exactly at the point where the tunnel is to be drilled later, i.e. there is a 100% exploration of the future tunnel route.

A drill head that can be steered in the course of drilling to create continuous, essentially horizontal holes already known (cf. DE 40 16 965 A1). However, so far not yet proposed to explore such drill heads to use a planned tunnel route. Furthermore it was So far not possible, curved tunnel sections in terms of drilling technology to develop what is now technically with steerable drill heads is possible.

For tunneling, deformation measurements of the rock are in the Ahead of the actual opening of the tunnel, very important. So far, this has usually been done by creating Exploratory tunnels, which are very expensive, in the Voltage measuring devices are installed. Only after a measurement and During the observation period, a tunnel eruption is started. The measurement a pilot borehole saves considerable costs here. At long tunnels are still left after tunnel construction Deformation measurements during operation in specially created Side studs required. These can be omitted in the future because lateral, dead end-shaped from the pilot hole Branches for the installation of measuring tunnels are possible that deformation measurements here before, during and after the Tunnel driving is possible.

If the pilot bore does not later become the central axis of the future tunnels, but e.g. a side Supply line or a centrally arranged Supply route in double tunnels, or outside the Soil drainage profiles or ridge ventilation are used this can also be represented in terms of drilling technology. Also for subsequent supply routes to existing or Tunnel routes in need of expansion are pilot holes feasible. The same applies to escape routes or Ventilation tunnel that can be added or retrofitted must be installed.

There are also voltage measurement and hydrogeological ones Investigations possible for the tunneling and later Expansion of the tunnel provides crucial data. So the in the pilot hole is noticeable Sizing and the enemas of the Define tunnel drainage system while the voltage measurement data the outbreak cross section in the With regard to the adjustable, definable wall thickness requirement of the tunnel. Even during the advance Voltage measurements in the remaining part of the Pilot drill hole possible. This can be crucial Provide information about rising relief gaps, which are responsible for spontaneous burglary events. Such information from the ramp area was not yet available.

For example, to explore geology Borehole cameras, acoustic probes e.g. (Digital Acoustic Borehole Televiewer), borehole radar antennas, Resistivity imaging tool, microresistivity), gamma probes, ultrasonic probes, pulsed neutron probes etc. can be used. Another method is for example the so-called resistance depth probing, those used to determine vertical layer sequences horizontal storage of layers of different Thicknesses and specific resistances.

With deep resistance probing, two Electrodes inserted into the earth's surface through which a DC current from a power source flows. Two more Potential electrodes that are also in the earth's surface are used are connected to a voltage measuring device. By measuring the voltage at various points in the Earth's surface can be the specific electrical resistance determine the geological formation and leave it there conclusions about the geological structure of the formation achieve. By manually changing the The electrode configuration can be the measurement setup geological task, the petrophysical situation and be adapted to the geometric conditions. The distance the measurement profiles and the measurement points determine this Resolving depth probing.

Advantageous embodiments of the invention are characterized by Subclaims marked.

The pilot bore can advantageously essentially created along the center line of the planned tunnel route even if it should have a curved course. This will make exploration exactly in the area carried out, which removed when driving up the tunnel route must become. At the same time, the so created Pilot drilling in this case as a guide to Use driving up the tunnel section without further (expensive) position measurements must be made. There nowadays pilot bores are created with high accuracy can be through this advantageous embodiment the invention saved considerable costs and time that would otherwise be used to control the position of the Tunnel boring machinery are required.

After a further embodiment of the invention can already when creating the pilot hole, drilling progress parameters are recorded, which are then used for borehole exploration can be used. Because already when drilling the Pilot drilling from such drilling progress parameters valuable information on the nature of the piercing formation can be preserved according to the invention this information for exploring the borehole be used. For example, by measuring the Drilling pressure, the rate of advance or the Abrasion of the drill head on the strength, the structural bond, the chunkiness and other of the existing rock or Earth formation can be inferred.

According to a further embodiment of the invention, the sampling provided according to the invention Flush reflux from the pilot well used to sample refer to. This eliminates the need for time-consuming sampling and by relating drilling progress to the samples from the backwash of the pilot hole Analyze existing formation already advantageous.

According to a further advantageous embodiment of the Invention will be lateral when taking samples Test drilling carried out by the essentially vertical pilot bore. This procedure, that too basically known under the term "side wall coring" has not yet been associated with a horizontal pilot drilling proposed. At the same time this enables targeted and selective sampling along the entire tunnel route possible.

According to a further embodiment of the present invention can be used in well exploration in a conventional manner geophysical probes are pulled through the borehole. Such probes can, for example, downhole cameras, Acoustic probes e.g. (Digital Acoustic Borehole Televiewer), Borehole radar antennas, resistance probes (resistivity imaging tool, microresistivity), gamma probes, ultrasonic probes, Pulsed neutron probes etc.

Such geophysical probes are from the prior art Technology basically known. For example, describes EP 0 384 823 A1 a geoelectric probe in the form of a Measuring block, which is provided with a central electrode and in a test hole is drained. To focus the Test streams are active and passive Focusing system provided. However, so far has not been proposed such probes related continuous horizontal pilot holes.

According to a further particularly advantageous embodiment the invention is used in well exploration Electrode measuring string with at least six electrodes in the Pilot hole introduced. Here are the Electrodes on the measuring string under the same mutual Intervals arranged and the measuring string has several electrical connection lines on by at least one Lead the end of the measuring strand to the electrodes. Furthermore, at this advantageous embodiment, a current through two Electrodes of the measuring line passed, and it is between two other electrodes of the measuring string measured. Finally the electrodes are moved within the borehole, and current flows through two electrodes again and the voltage between two further electrodes is measured.

Such a measuring string can be used to make different ones Electrodes located on the measurement string from the end the measuring line so that it is not shifted or needs to be replaced. Achieving different Penetration depths can be done in the simplest way that electrodes of different distances from each other for the Measurement can be used. At the same time, with the measuring strand according to the invention the most varied Realize electrode arrangements without the electrodes themselves would have to be relocated.

Furthermore, the borehole for temperature measuring cables, for Humidity sensor cable, for voltage measuring devices and others Rock mechanical and hydrogeological instruments Surveillance can be used.

According to a further aspect of the present invention, a Method for driving a tunnel provided, in which first an exploration of the planned tunnel route after a the procedures described above. Then will the tunnel route opened, with an orientation of the Propulsion takes place on the pilot bore. As already mentioned has been mentioned nowadays with the help of drilling steerable drill heads, high-precision drilling is carried out, so that the actual tunnel course already through the Pilot drilling can be determined. Provided that when driving up of the tunnel section, the drilling machinery at the pilot hole oriented, i.e. follows the course of the pilot hole no further position measurements or corrections be made to make the tunnel the desired course contains.

The pilot hole can also be used for rod guidance Expanding holes, e.g. after the raise drilling process become. With a correspondingly large or multiple expansion hole In this way, the target tunnel cross-section can be achieved create.

After further training of this procedure can Driving up the tunnel section at the same time Apron drainage can be used. It can do this be advantageous to the pilot hole as free drainage use or with loose rock to a drainage line expand.

When driving up the tunnel can be after further training the pilot hole to an intrusion hole for mining Driveways will be expanded. The pilot hole can also during the tunnel construction for the laying of Communication lines and supply lines used become.

Apron drainage often turns into a hydraulic one Relaxation of the mountains needed, also to prevent water ingress to avoid during tunneling. Such Ingress of water can affect the overall advance and partially bring it to a standstill. Time-consuming rescheduling, Additional measures and time delays are the result.

However, drainage in Opposite direction to the advance. On Packer that can be moved according to the propulsion is called artificial watershed installed in the borehole at the opposite slope can be achieved by using a submersible pump Removal of the water rush to be taken care of.

If there is a lot of water, the pilot hole can be expanded to cover the cross-section To be able to absorb amounts of water.

Fig. 1

eine schematische Darstellung einer bergartigen geologischen Formation, in die eine horizontale Pilotbohrung eingebracht wird;

Fig. 2

eine schematische Darstellung der Formation von Fig. 1, wobei aus der Pilotbohrung Gesteinsproben entnommen werden;

Fig. 3

eine schematische Darstellung der Formation von Fig. 1, wobei in die Pilotbohrung ein Meßstrang eingeführt ist;

Fig. 4

eine schematische Darstellung der Formation von Fig. 1, wobei eine begonnene Tunnelauffahrung dargestellt ist; und

Fig. 5

einen Vertikalschnitt durch das Erdreich im Bereich einer geplanten Tunnelstrecke mit einer zusätzlichen Erkundungsbohrung im verformungshaften Gebirge.

The present invention is described below purely by way of example on the basis of advantageous embodiments with reference to the accompanying drawings. Show it:

Fig. 1

is a schematic representation of a mountainous geological formation into which a horizontal pilot hole is made;

Fig. 2

a schematic representation of the formation of Figure 1, rock samples are taken from the pilot hole;

Fig. 3

a schematic representation of the formation of Figure 1, wherein a measuring string is inserted into the pilot bore.

Fig. 4

is a schematic representation of the formation of Figure 1, showing a tunnel tunnel has begun; and

Fig. 5

a vertical section through the soil in the area of a planned tunnel route with an additional exploration hole in the deformed mountains.

Fig. 1 shows a mountainous geological formation, wherein Areas with different geological structures hatched differently.

To the pilot bore shown in Fig. 1 along a The planned tunnel route can be installed according to the first proposed methods along the geology planned tunnel route. This preview can in a conventional way by deep geoelectric sounding from the surface as described at the beginning has been. After through this preliminary investigation information about the basic structure of the formation has been preserved, a continuous pilot bore 12 is created. To do this a drilling apparatus 14 used, which with the help of an entire drill path of steerable drill head a pilot hole created along the planned tunnel route. Through the Information obtained during the preliminary investigation can be used to create the pilot hole Select the drill accordingly.

After the preliminary research and the creation of the continuous Pilot bore 12, samples are taken from the pilot bore, to continue exploring the planned tunnel route. This can by taking samples from the pilot well's backflow respectively. However, it can also start from the pilot hole 12 test holes in different places on the same side 16 can be performed (see FIG. 2), the result of these test bores to the end of the pilot holes becomes.

For further geophysical borehole exploration e.g. geoelectric probes are pulled through the borehole. It can also be one described at the beginning Electrode measuring string 18 in the pilot hole are introduced, which is shown in Fig. 3. The Measuring strand 18 has a plurality of electrodes 20, which on these are arranged at equal mutual distances, wherein electrical leads from one end of the Measuring strand are led to each individual electrode. On Such a measuring string 18 can be made after the borehole 12 by coupling to the drill pipe easily through the Borehole 12 are drawn.

To carry out geoelectric borehole exploration, two electrodes of the measuring string are connected as current electrodes (A _i , B _i ) and two further electrodes are connected as potential electrodes (M _i , N _i ). The geoelectric data can be obtained by measuring the resulting potential difference. In particular, by using the measuring string, it is possible to select the appropriate electrode arrangement by simply switching on other electrodes or by switching between the electrodes. Known arrangements can be used here, such as the Wenner arrangement (A _i , M _i , N _i , B _i ), the dipole arrangement (A _i , B _i , M _i , N _i ) or the Carpenter arrangement ( A _i , M _i , B _i , N _i ). The Wenner arrangement is primarily used for the investigation in areas with homogeneous layer formation and different inclinations. For the mapping of steeply inhomogeneities, such as faults and other, it is more favorable to carry out measurements with the dipole arrangement. The distance between the individual electrodes determines the depth of penetration, but can be chosen almost freely by using the measuring strand.

So-called geoelectric tomography can be carried out for an even more precise exploration of the tunnel route. For this purpose, as shown in FIG. 3, a measuring string 18 is introduced into the horizontal borehole 12 of the pilot bore, a large number of electrodes being arranged on the measuring string at regular intervals. The connecting lines of the individual electrodes of the measuring line are led to one end of the measuring line. The electrodes 20 (M ₁ , N ₁ , M ₂ , N ₂ or M _n , N _n ) are selected so that the rock complex to be examined can be completely "irradiated", ie flowed through. In order to be able to detect a "shadow formation" of a low-resistance interference body, a current electrode (not shown) is fixed at one point on the surface of the earth and a further current electrode (not shown) is attached to the ground at a distance from the measuring point. For the measurement, the potential electrodes are first moved along the distance of the borehole, which can be done by mechanical movement of the measuring string. However, it is simpler to use different electrodes of the measuring string. If a "shadow formation" appears, the measurement must be repeated from several current electrode positions to delimit the contours of the interfering body. The current electrode can then be moved to another location or, if a measuring string is also used for the current electrodes, the adjacent current electrode is activated and the measurement is repeated.

It can also use current electrodes and voltage electrodes be reversed, i.e. the electrodes inside the borehole are used as current electrodes, whereas those on the Electrodes located on the earth's surface as potential electrodes be used.

The geoelectric tomography described above is suitable excellent for localization of loosening zones and tectonic disturbances, for locating waterways and Water inclusions, and it can run between parallel Boreholes an inventory of existing lines on low or high-resistance areas are examined.

The measuring strand 18 shown only schematically in FIG. 3 has a plurality of annular electrodes 20 on the Measuring line at an equal distance of 100 cm are arranged. The annular electrodes 20 are in one Plastic hose incorporated so that the ring-shaped The outer circumference of the metal electrodes 20 remains free. The Connection lines for the respective electrodes 20 run inside the plastic tube and are shielded. Overall, the measuring string is flexible and can be easily operated wind up on a cable drum.

Two run within the measuring strand 18 Voltage lines that form a voltage bus, two Power lines that form a power bus and one bipolar signal line. Also for power supply a line is provided.

The measuring string has a switching device in its interior that includes a switch that electrode 20 optionally with the connecting cables of the power bus and the Voltage bus connects. This is within the Measuring strand a two-wire current bus and a two-wire Voltage bus provided. Through the two signal lines the respective electrodes can be put on the individual Switch bus lines so that any number of Electrodes controlled with only a few connecting lines can be.

When the switching device is activated via a at the end of the Measuring strand 18 arranged connecting device (not shown), the electrode 20 can be connected to any connecting line be switched. The switching device is connected to the Supply voltage connected and is via the Signal line activated. The response of the switching device takes place via a digital address, whereby via a provided digital code can be set to which Bus the assigned electrode 20 is to be switched. Of course, each electrode 20 is one Switching device assigned. The switching device exists from a small electronic circuit and is inside of the measuring strand added.

If each first electrode with one of the two Power lines and one of the two voltage lines is connectable and every other electrode with the other of the two power lines and the other of the two Voltage lines can be connected, the circuit complexity can be reduced. The Above mentioned switching device can preferably on the Signal line can be activated and digitally controlled. At the control device switches the assigned electrode to the desired wire of the power bus or the voltage bus. A shielding of the connecting line is advantageous in that the geoelectric measurements then not be disturbed.

The body of the measuring strand can also pass through the Connection lines are formed by the electrodes are surrounded in a ring. Such an embodiment is very inexpensive and easy to manufacture because only the annular electrodes at regular intervals on the Connection lines must be attached by the Electrodes are passed through. Furthermore, the Electrodes of the measuring string in a ring and in one Be plastic tube incorporated, inside which the Connection lines run. Such an embodiment is very robust and less prone to malfunction, because the Connection lines inside the plastic hose are protected.

The measuring string used according to the invention can have a length > 100 m, preferably> 400 m and can also be assume the length of kilometers, depending on the length of the tunnels to be created. Such a long measuring string in the The order of magnitude of 100 m or more enables geoelectric detection of a very large area, without, however, electrodes having to be moved.

The switchgear can be attached to everyone for increased safety Electrode can also be provided twice. Because the cost of one such switching device are small, is such Embodiment particularly advantageous because if one Switching device the measuring string is not inoperative, but the respective electrode by the second provided Switching device that has a different address, can be addressed.

A measuring system, not shown, has a current source as well a voltage measuring device, which is integrated in a computer are. A connector is at one end of the Measuring strand connected to its connecting lines, so that the Current source and the voltage measuring device with at least four any electrodes of the measuring string can be connected. The You can access the electrodes you want are program-controlled, with any measuring programs, i.e. Electrode distances can be selected. The measuring system and whose connecting device can preferably be from one Computer can be controlled. This gives you a fully automatic borehole detection system with not yet existing possibilities, the one within a very short time allows detailed recording of the geological formation, through which the tunnel is to be drilled, and at the same time works very inexpensively. The cost of such Systems are around a third of the cost of comparable seismic systems.

To perform geoelectric tomography, the Connection device with the connecting lines of a second Measuring strand connected to the surface of the earth, the electrodes with the help of the provided adapter in the Soil are plugged in. With such an arrangement measure the entire mountainous formation completely, being geological due to the great variety Profiles with an unprecedented Density of information can be recorded. Here you can any cuts made through the mountainous formation become.

Use of the measuring string in a horizontal borehole increases the in contrast to the classic borehole probes Depth of investigation considerably. This can depend on the drill hole length and the length of the electrode measuring string approx. 10 m, which is the previous penetration depth by far exceeds. At the same time, the electrode measuring string can also be used for the geoelectric tomography described above as a transmitter and can also be used as a receiver. This is the complete mountain range with an unprecedented Capture resolution and density of information.

With this new measuring method it is with the help of the measuring strand described above possible for the first time, detailed information about a geological formation in the immediate area of a planned tunnel route obtained, the depth of penetration by using different electrodes of the measuring string freely chosen can be. So it doesn't have to - as has been the case up to now the technology was the case - different probes in each vertical test holes with great depth are used.

A particularly advantageous variant of the above The method is achieved by moving the Electrodes inside the borehole are made in that other electrodes of the same measuring string can be used. This allows the geological structure along the entire hole, without the measuring string would have to be mechanically displaced or moved. At the same time the penetration depth can be determined by the relative distance of the Electrode dependent, by choosing the appropriate one Set electrodes freely. This allows for the first time large-scale geological formation "shine through" without that a variety of vertical test holes are drilled should be. At the same time, it is not necessary Electrode measuring string several times within the borehole to move mechanically.

Alternatively, electrodes are essentially in the one hand horizontal bore of the pilot hole introduced and additional electrodes are attached to the earth's surface become. This procedure uses at least two Potential electrodes inserted into the borehole. Next up Step, a current is passed through two current electrodes, which are attached to the surface. By measuring the The voltage between the two potential electrodes can be between the electrodes attached to the surface of the earth and the electrodes inside the borehole located rock complex "shine through" so that completely new information in an unprecedented Density of information can be obtained. By repeating the voltage measurement between the two potential electrodes within the borehole with each within the borehole offset electrodes can be between the borehole and Complete rock complex located on the earth's surface map using any cutting planes can, which is why this method is also called geoelectric Is called tomography.

Since the borehole is continuous, the electrode measuring string can after creating the drill hole on the drill pipe through the Borehole be drawn, so that a laying of the measuring string is possible within a very short time.

Even if the potential electrodes are moved within the Borehole through mechanical displacement of the measuring string can be achieved, the preferred procedure in it, only to map the rock formation other Electrodes of the measuring string as potential electrodes use. This can be done using the above measuring system according to the invention in the simplest way occur that other electrodes are activated or connected be so that the measuring technician from his measuring station, the entire geological formation along the borehole and can measure above the borehole without actually Electrodes would have to be mechanically offset. By using of computer-controlled measurement programs open up through the inventive method unexpected possibilities.

Another embodiment of the method described above is achieved in that not only within the Borehole electrodes are varied, but that also at least one of the current electrodes on the Earth's surface is displaced. This will resolve the measurements significantly increased.

If as a current electrode in the methods described above an electrode of a measuring string is used, that is described methods of geoelectric tomography still further improved, since in this case the relocation of the Electricity electrodes on the earth's surface also no longer must be done mechanically, but by choosing different ones Electrodes of the measuring string can take place. In this case it is advisable to use adapters that support the Extend electrodes like a rod. Such adapters, the one Introducing the measuring currents into the ground can facilitate in the soil can be plugged in. For use in Soil, the adapter can be designed like a spit and attached to the ring electrodes using a joint clamp become.

After the planned tunnel route has been fully explored the tunnel can be driven using the pilot hole 12 take place, as shown in Fig. 4. Here the tunnel boring device 22 is based on the Pilot bore 12, so that no expensive position monitoring must be carried out. The pilot hole can be at Use track jacking for apron drainage. Also can use communication lines during tunnel construction the pilot hole, which may also be carried out an intrusion well can be expanded.

Fig. 5 shows a vertical section through the soil in Area of a planned tunnel route. One parallel to planned tunnel route 120 running bore 112c is located at a greater distance from the planned tunnel route below the planned tunnel excavation. These are preferably full exploratory bore 112c, which is executed in a course-controlled manner Information about the underlying geological strata give. So it can be seen, for example, whether affected area below the planned tunnel driveway swellable horizons, e.g. Clays, or anhydrites, that are may be able to build up a source pressure. This can be of particular interest in areas where too Deformations still occur today that may only be too a later point in time when the tunnel route is endangered being able to lead. Rock samples can also be taken from the Remove the hole below the planned tunnel approach and also insert a measuring string 110c to a geoelectric Perform tomography. Here, as in FIG. 5 is indicated, any layers between that in the Exploration drilling along the planned tunnel route introduced measuring strand 110b, the measuring strand 110a or the Electrodes on the surface of the earth and the measuring string 110c in the Drill exploration hole 112c. Finally, it offers this also gives the possibility of voltage sensors 140 to monitor the deformed mountains and possibly an undersole from this hole Initiate relaxation. Finally there is the possibility of this Use borehole for under-drainage.

If it is of particular importance that a high Density of information especially in the area of the planned Tunnel route is won, then approximately two horizontal drilling in the area of the planned Tunnel route are driven, each in a measuring line is introduced. In the same way, of course also four or more measuring strings in parallel mutually extending holes are introduced, the Measurements carried out between two measuring strands become. In the example shown in Figure 5, two could Measuring strands in the designated 120, with interrupted Lines shown areas must be introduced. If each different electrodes of the one measuring string as Current electrodes are switched and two electrodes of the other measuring string than potential electrodes are switched, so there can be a large number between the two measuring lines of cuts and a very precise, tomographic image in the desired area of the planned Win tunnel driving.

For example, there are four along a planned tunnel route horizontal bores running parallel to each other introduced, so these precise layer representations are made between two measuring strands and thus a total of six different cuts in the area of the planned Route management can be won (four sides and two Diagonals between the four parallel ones Test bores).

Are in the area of the planned route Areas with special geological properties, so can these are recognized on the one hand and theirs on the other Dimensions can be determined with high accuracy. Because of the fact that the electrodes in the respective measuring strands both with a current as well as one These measurements can be connected to the power line perform with high precision and especially along carry out the planned route without any after Measurement to have to move the measuring string.

Planned tunnel routes or other structures are located often very far below the surface or Water surface, so that measurements from the earth, or Water surface from only with a lower resolution can be carried out. By measuring between two in approximately parallel measuring strands, in two Horizontal holes have also been drilled in great depth of exploration with very high information density achieve. Because the structure of the underground is not known beforehand is through the targeted exploration along the planned routing a very high resolution of the in geological information available in this area win.

While in the above in particular the application of Measuring strands in the bores running parallel to each other of course, everyone can be described other measurement methods and exploration techniques mentioned above in the respective holes or between the holes deploy.

Claims (21)

1. Method for the reconnaissance of planned tunnel routes which run essentially horizontally, including the following steps:

   preliminary reconnaissance of the geology along the planned tunnel route for the preparation of a pilot borehole;

   making a continuous pilot borehole with a drill head which can be guided during drilling along the planned tunnel route;

   taking samples from the pilot borehole; and

   geophysical reconnaissance of the pilot borehole.
2. Method according to claim 1, characterised in that the pilot borehole is made essentially along the centre line of the planned tunnel route.
3. Method according to claim 1, characterised in that, when making the pilot borehole, drilling progress parameters are recorded and then used for borehole reconnaissance.
4. Method according to claim 3, characterised in that one or more of the following drilling progress parameters are used for borehole reconnaissance: drilling contact pressure, speed of advance, abrasion of the drill head.
5. Method according to any of the above claims, characterised in that, during sample taking, samples are taken from the flushing backflow of the pilot borehole.
6. Method according to any of the above claims, characterised in that, during sample taking, starting from the essentially horizontal pilot borehole, lateral sample boreholes are made.
7. Method according to any of the above claims, characterised in that preliminary reconnaissance is effected by geophysical depth sounding from the surface.
8. Method according to any of the above claims, characterised in that the borehole is used for the temporary installation of voltage measuring devices.
9. Method according to any of the above claims, characterised in that hydrogeological tests, for example pH or conductivity measurements, are carried out in the borehole, and in that in the process continuous or batch water samples are taken.
10. Method according to any of the above claims, characterised in that the borehole is examined with a video camera.
11. Method according to any of the above claims, characterised in that the borehole is completed with a filter string as a drainage system or horizontal well.
12. Method according to any of the above claims, characterised in that the borehole is used for vibration measurements during advance.
13. Method according to any of the above claims, characterised in that lateral blind bores are made from the borehole.
14. Method according to any of the above claims, characterised in that, during reconnaissance of the borehole, geophysical probes are pulled through the borehole.
15. Method for driving a tunnel, including the following the following steps:

    reconnaissance of the planned tunnel route by a method according to any of the above claims 1 to 13;

    driving the tunnel route while orienting the advance by the pilot borehole.
16. Method according to claim 15, characterised in that the pilot borehole is simultaneously used for drainage of the area ahead.
17. Method according to claim 15 or 16, characterised in that the pilot borehole is used for communication lines during tunnel construction.
18. Method according to one or more of claims 15 to 17, characterised in that the pilot borehole is widened into a penetrating borehole.
19. Method according to one or more of claims 15 to 18, characterised in that the pilot borehole is used for return airways and hence for face dust extraction or for intake airways.
20. Method according to one or more of claims 15 to 19, characterised in that the pilot borehole is used as a rescue supply borehole after falling-in events for the face region.
21. Method according to one or more of the above claims, characterised in that the pilot borehole is used for guiding rods for expansion boreholes, e.g. by the raise drilling method.

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