DE102013205765B4 - Quality assurance system for diaphragm wall joints - Google Patents

Abstract

Test unit (100) for testing a section of a diaphragm wall joint, comprising: a base section (101) which is designed to attach the test unit (100) to a diaphragm wall production device, the test unit (100) at least one sensing arm (103) deflectable via a hinge mechanism (103). 110) as well as a detection unit for detecting a deflection of the at least one feeler arm (110) with respect to the base section (101), and the at least one feeler arm (110) being prestressed by means of a prestressing device on the test unit (100), characterized in that for deflection of the at least one probe arm in a test position, a sensor for detecting the hydrostatic pressure is provided on the test unit (100).

Description

Technical area

The present invention relates to a test unit which is used to monitor diaphragm wall joints, a diaphragm wall production device, in particular a diaphragm wall grab or a diaphragm wall cutter, with such a test unit, and a method for testing a diaphragm wall joint.

State of the art

Diaphragm walls are used in civil engineering to secure and seal construction pits, to secure slopes or other land crossings and to encapsulate contaminated soil areas.

Various methods and devices are already known for producing such diaphragm walls. For example, so-called diaphragm wall grippers are used in the production of diaphragm walls, such as those in FIG WO 94/21864 A1 or DE 39 33 866 A1 to be discribed. The already excavated slot is treated with a support fluid, in particular bentonite, and in this way it prevents it from collapsing. After reaching the final depth, reinforcement material is introduced into the slot and the slot is then filled with concrete.

In the prior art, two different methods are known for producing diaphragm walls, namely the production of a single-stitch or a multi-stitch lamella. Single-stitch lamellas are used when there are increased specifications due to static requirements. In the case of less sensitive framework conditions, multi-stitch lamellas can be produced, which significantly speeds up the process.

When producing diaphragm walls, there is always the requirement that individual diaphragm wall sections must be brought into contact with one another in such a way that both power transmission and watertightness between the diaphragm wall sections is ensured. The main focus here is on the production of suitable joint constructions.

A known method is for example in the DE 10 2005 055 254 A1 described. In particular, in a first phase a slot is made in which a starting lamella is to be made. Joint pipes, which delimit the starting lamella as such, are positioned in the slot section. In a further step, the reinforcement for the start lamella is inserted between the two joint pipes. Then the concrete for the starting lamella is poured in. After completion of this work, a certain distance from this first start lamella in an area of the slot lying at a certain distance from it, another section is excavated for another start lamella, a reinforcement cage is introduced in the same way and the slot section is filled with concrete.

Another procedure is in the EP 1 803 853 A1 described in which a lost flat joint is used to ensure water impermeability.

However, trench walls can also be made with a trench cutter. Examples are in the US 2012/000148 A1 or the DE 103 08 538 A1 disclosed. The latter document relates to a method for producing a trench wall in the ground, in which at least one cutting wheel arranged on a trench wall cutter is set in rotary motion by a drive, the trench wall cutter is lowered into the ground, soil material located below the cutting wheel being cleared away and a cutting slot being made .

The EP 1 983 111 A1 relates to a formwork element for delimiting a diaphragm wall section. The formwork element is characterized by a plurality of formwork parts which have a plate-shaped base body, in particular made of concrete, and are connected to one another at their adjacent horizontal end faces.

In general, there is the problem with all known joint elements that the closing elements / joint elements of a lamella are surrounded by concrete. If such a circulation takes place, the joint element can no longer reliably fulfill the intended function, namely both to ensure power transmission between adjacent slats and also to ensure watertightness between the slats.

To counter this problem, it is known to use a so-called joint chisel, which is guided along the joint element after the connection lamella has been excavated and which eliminates any possible circulation. However, whether possible circulations have been eliminated cannot be guaranteed with final certainty and at least not verifiable.

One way of checking a joint element is to measure it using ultrasound. However, such a measurement has some disadvantages. On the one hand, a relatively long inspection time must be allowed for in order to check the joint element. In addition, as the depth of the slot increases, the suspension properties change, which can lead to the recorded measurement signals are difficult to interpret or possibly cannot be clearly assessed.

Furthermore, the so-called cross-hole method is known, in which guide tubes are built into both the primary lamella and the secondary lamella, which a transmitter and a receiver then drive along at the same height. The test is carried out after both the primary lamella and the secondary lamella have already been manufactured. By lowering the transmitter and the receiver at the same height, the measured ultrasonic transit times should remain constant, and inclusions in the diaphragm wall joints are to be assumed wherever transit time differences occur.

However, with this method, a defect can only be detected retrospectively, since both the primary lamella and the secondary lamella have already been produced. There is only the possibility of using further auxiliary measures to form an additional sealing level.

From the field of borehole measurements, the DE 1 803 736 A1 known, which discloses a probe. The probe comprises a body and at least one contact shoe connected to the body by at least one main arm articulated to the body, the contact shoe being spread apart from the body by a leaf spring, one end of which has a clamp attached to the body, while the other end extends supported in the vicinity of the contact shoe.

Furthermore, the DE 2 045 519 A1 known, which shows an excavator grab for digging a slot. The gripper can have a sensor on each upper edge of the clamping plate, which is attached in such a way that the sensor tips just do not touch the wall of the slot above the clamping plate when the feed is correct.

The DE 43 35 479 A1 shows a method for detecting the inclination of excavations relative to the perpendicular as a function of the excavation depth using a measuring cell arranged on the excavation tool.

Subject of the invention

The object of the present invention is to provide a device and a method with which a diaphragm wall joint can be checked reliably and with little effort in order to be able to ensure a high-quality diaphragm wall.

Such a device is provided by the subject matter of claim 1 and a trench wall production device, in particular a trench wall gripper or a trench wall cutter, according to claim 7. The present invention also relates to a method according to claim 9. Further preferred embodiments can be found in the dependent claims.

The core idea of the present invention is to provide a mechanical test unit with at least one probe arm, which test unit can be guided along a trench wall joint with the probe arm touching the trench wall joint and, when it moves relative to the trench wall joint, can detect its topographical shape at least in sections via the deflection of the probe arm .

In particular, the present invention relates to a test unit for testing a section of a diaphragm wall joint, with a base section for attaching the test unit to a diaphragm wall production device, in particular a diaphragm wall grab or a trench wall cutter. The test unit has at least one feeler arm that can be deflected via a hinge mechanism and a detection unit for detecting a deflection of the at least one feeler arm relative to the base section.

The test unit according to the invention has the advantage that leaks caused by circulations or the like in a diaphragm wall cannot arise in the first place, since they are already detected before the diaphragm wall is completed. The measurement protocol recorded by the test unit can serve as proof that the diaphragm wall joints have been properly produced.

According to the invention, the at least one probe arm is further pretensioned on the test unit by means of a pretensioning device. By releasing the pretensioning device, the feeler arm can thus be moved quickly into an operating position in a simple manner.

Furthermore, a sensor for detecting the hydrostatic pressure is provided on the test unit for deflecting the at least one probe arm into a test position. With this sensor, on the one hand, the current depth of the sink can be determined and, on the other hand, changes in the hydrostatic pressure can be determined for further measures. Alternatively, it is possible for the diaphragm wall production device to include such a sensor and for the data determined by this to be made available to the test unit.

According to a further embodiment, the test unit comprises a control unit which determines when the detected hydrostatic pressure remains constant over a specific time interval. In this case, the control unit leaves the at least one probe arm deflect into a test position. If the feeler arm is held in a pretensioned state, as described above, this means that the control unit can release the pretensioning direction. The probe arm is then deflected into its operating position and can be used to test a diaphragm wall joint.

The test unit can also comprise an inclination sensor. This can be used to determine the alignment of the test unit in the trench or in relation to the trench wall to be tested. Alternatively, it is also possible that such a sensor is already provided on the diaphragm wall production device and that this information is integrated into a database of the test unit.

Furthermore, the test unit according to the invention can comprise a data carrier which records the data determined by the detection unit. As an alternative or in addition, a cable-connected connection device, for example, can be provided with which the data determined by the test unit are transmitted to the surface of the earth during its operation.

According to a further embodiment, a roller is attached to a distal end of the deflectable probe arm. This role can roll on a diaphragm wall joint and thus ensure secure contact between the probe arm and the diaphragm wall joint without getting stuck. The role is made in particular from hard plastic. This material has proven to be advantageous for the use mentioned, since it enables the probe arm to be optimally guided along the trench wall joint.

The present invention also relates to a trench wall production device, in particular a trench wall grab or a trench wall cutter, with a test unit as described above. Here it can also be provided that said control unit is attached in the area of the diaphragm wall production device.

The present invention further relates to a method having the features according to claim 9.

When guiding the test unit, the probe arm is in contact with the trench wall joint to be tested, and the deflection angle of the probe arm while the test unit is being guided along the trench wall is recorded. Conclusions about defects in the area of the diaphragm wall joint can be drawn from the recorded profile. In addition, it is recorded whether lost joint elements were damaged when using the chisel.

According to a preferred embodiment of the method according to the invention, the hydrostatic pressure is detected in the area of the test unit and, if the detected hydrostatic pressure remains constant over a certain time interval, the at least one probe arm is deflected into a test position. If the hydrostatic pressure remains constant over the specific time interval, it can be assumed that the test unit has reached the lower edge of the diaphragm wall. As a result, a measurement can begin.

Figure list

• 1 is a schematic view of a diaphragm wall grab with the inspection unit according to the invention (joint inspector).
• 2a shows the in 1 Diaphragm wall grab shown with joint inspector viewed from one side.
• 2 B shows your further embodiment of the diaphragm wall grab with joint inspector viewed from one side.
• 3rd shows an exemplary process sequence for producing a diaphragm wall and checking the diaphragm wall joints, using a lost flat steel joint.
• 4th shows an alternative production method for producing a diaphragm wall by means of a shuttering pipe and a corresponding inspection of the diaphragm wall joint.
• 5 shows a further alternative method for producing diaphragm walls using a prefabricated joint element.
• 6th is a side view of an already partially manufactured diaphragm wall.

Detailed description of the preferred embodiments

A preferred embodiment of the present invention will now be described in detail. Further modifications mentioned in this context can in each case be combined with one another in order to form new embodiments. The same applies to alternative procedural steps. In addition, it can be seen that the method described later is particularly suitable for use with the joint inspector (test unit) described below.

The present embodiment relates to a grout inspector 100 on a known diaphragm wall grab 10 can be attached. Such a diaphragm wall grab 10 comprises a support section 20th as well as two opposite the carrier section 20th deflectable excavator buckets 30th . With the Excavator buckets 30th a slot is first dug in a subsoil.

At the beam section 20th of the diaphragm wall grab 10 is the joint inspector according to the invention 100 appropriate. The grout inspector 100 comprises a base element 101 that is used to attach the joint inspector 100 on the carrier section 20th of the diaphragm wall grab 10 serves. The fastening can be done mechanically, for example by means of screws, or magnetically.

The joint inspector also includes 100 a base plate 102 that have a hinge mechanism 103 having. About this joint mechanism 103 are several probe arms 110 compared to the base element 101 or the base plate 102 deflectable. The probe arms can be used individually or in combination with the base element 101 or the base plate 102 be pivoted.

In addition, is at the joint inspector 100 in the area of the base element 101 an electronics unit 102 attached, which has, among other things, a control unit.

The grout inspector 100 comprises a biasing device with which the feeler arms 110 opposite the base plate 102 be kept in a pretensioned condition. This pre-tensioned condition is checked before the joint inspector is used 100 set and, as described later, can be solved by suitable means. The pretensioning device is not explicitly shown in the figures, since it is in the base element 101 is recorded.

In a further modification it is also possible to use the joint inspector 100 to operate without a pretensioning device, and to pivot the probe arms into their operating position, for example by means of a motor.

In addition, is the grout inspector 100 provided with a sensor that can detect the hydrostatic pressure, and this data to the electronics unit 102 , and in particular the control unit, transmits. Said pretensioning device or another mechanism for putting the probe arms into operation 110 is with the electronics unit 102 , in particular the control unit, coupled.

The one on the diaphragm wall grab 10 mounted joint inspector 100 is pretensioned in the embodiment described here before its use by means of the pretensioning device mentioned, so that the feeler arms 110 on a side portion of the carrier portion 20th abut or are guided essentially parallel to this. The diaphragm wall grab is then operated in the usual manner in order to produce a trench in a subsurface.

Recorded by the joint inspector 100 provided sensor no further hydrostatic pressure increase over a certain period of time, this is evaluated in the control unit with the fact that the diaphragm wall grab 10 with the joint inspector 100 has reached the final depth of the slot. In this case, the control unit can unlock the pretensioning device, whereby the feeler arms 110 opposite the side wall of the carrier section 20th of the diaphragm wall grab 10 are issued and come into contact with a diaphragm wall joint of an already produced diaphragm wall section.

About the hinge mechanism 103 can the probe arms 110 between the outermost point of deflection and the side wall of the beam section 20th or one at the joint inspector 100 provided stop are deflected. This deflection movement can be recorded and the recorded information, as explained below, used to check the diaphragm wall joint.

The diaphragm wall grab is used for this 10 with the joint inspector 100 move from the final depth of the slot in the direction of the earth's surface, using the feeler arms 110 are in contact with the diaphragm wall that has already been produced, and in particular the diaphragm wall joint. While the diaphragm wall grab is being raised, the feeler arms are deflected 110 a profile of the existing diaphragm wall joint and possible over-profiles through circulating concrete added. In addition, it can be recorded whether lost, ie installed or left, joint elements have been damaged.

The data relating to the deflection of the probe arms 110 are recorded in combination with the respective depth in a data carrier, the part of the electronic unit 102 is. After the diaphragm wall grab has reached the surface again, the data from the joint inspector 100 that are stored in the data carrier are transmitted via a radio device and thus displayed directly on a computer, for example. Alternatively or additionally, the determined data can also be stored for documentation purposes.

In addition to this data transfer after the diaphragm wall grab has been extended, it is also possible for the joint inspector 100 recorded deflection data of the probe arms 110 immediately while the diaphragm wall grab is running up 10 to the earth's surface, and thus to check a diaphragm wall joint in almost real time while it is being scanned by the joint inspector.

In 3rd a process sequence for producing a diaphragm wall and checking a diaphragm wall joint is shown. The diaphragm wall 200 comes with multiple slots 200a-200c established a first primary slot 201 in the slot 200a concreted and another primary slot to be concreted in the slot 200c with reinforcement elements 204 prepared. There are three slots 200a-200c through a lost steel flat joint 202 , 203 separated from each other (step 1 ). Then also the second primary slot 205 produced by backfilling with concrete (step 2 ). The first primary slot 201 and the second primary slot 205 are at a distance from each other. Then in the steps 3rd and 4th the diaphragm wall joints in the area of the lost flat steel joints 202 , 203 with the joint inspector 100 checked.

In 4th an alternative process sequence for producing a diaphragm wall and checking a diaphragm wall joint is shown. The diaphragm wall 300 comes with multiple slots 300a-300c established a first primary slot 301 in the slot 300a concreted and another primary slot to be concreted in the slot 300c with reinforcement elements 304 prepared. The diaphragm wall joints are thereby 302 , 303 through a shuttering pipe 310 produces, which after the respective step for producing the primary slots 301 , 305 is removed. The primary slot 301 and the second primary slot 305 are at a distance from each other. Then in the steps 3rd and 4th the diaphragm wall joints of the primary slots 301 . 305 with the joint inspector 100 checked.

In 5 a process sequence for producing a diaphragm wall and checking a diaphragm wall joint is shown. The diaphragm wall 400 comes with multiple slots 400a-400c established a first primary slot 401 in the slot 400a concreted and another primary slot to be concreted in the slot 400c with reinforcement elements 404 prepared. The three sections 400a-400c are each caused by a lost CWS screed 402 , 403 separated from each other (step 1 ). Then also the second primary slot 405 produced by backfilling with concrete (step 2 ). The primary slot 401 and the second primary slot 405 are at a distance from each other. Then in the steps 3rd and 4th the diaphragm wall joints in the area of the lost CWS planks 402 , 403 with the joint inspector 100 checked.

6th shows a side view of an already partially manufactured diaphragm wall. As in the step 3rd indicated in the figures is the joint inspector 100 guided from the lower edge of the diaphragm wall in the direction of the surface of the earth along a diaphragm wall joint, and thereby a deflection of the probe arms 110 captured to determine a surface profile.

Claims (12)

Test unit (100) for testing a section of a diaphragm wall joint, comprising: a base section (101) which is designed to attach the test unit (100) to a diaphragm wall production device, the test unit (100) at least one sensing arm (103) deflectable via a hinge mechanism (103). 110) and a detection unit for detecting a deflection of the at least one probe arm (110) with respect to the base section (101), and wherein the at least one probe arm (110) is pretensioned by means of a pretensioning device on the test unit (100), characterized in that for For deflecting the at least one probe arm into a test position, a sensor for detecting the hydrostatic pressure is provided on the test unit (100). Test unit (100) according to Claim 1 , characterized in that a control unit determines when the detected hydrostatic pressure remains constant over a certain time interval, and in this case the control unit allows the at least one probe arm to be deflected into a test position. Test unit (100) according to one of the preceding claims, characterized in that the test unit (100) comprises an inclination sensor. Test unit (100) according to one of the preceding claims, characterized in that the test unit (100) comprises a data carrier which records the data determined by the detection unit. Test unit (100) according to one of the preceding claims, characterized in that a roller is attached to a distal end of the deflectable probe arm (110). Test unit (100) according to Claim 5 , characterized in that the role is made of hard plastic. Diaphragm wall production device with a test unit according to one of the preceding claims. Diaphragm wall production facility according to Claim 7 , wherein the diaphragm wall production device is a diaphragm wall grab or diaphragm wall cutter. Method for checking a section of a trench wall joint with a checking unit (100), the at least one probe arm (110) which can be deflected via a joint mechanism (103) and a sensor for detecting the hydrostatic pressure, with the following steps: detecting the hydrostatic pressure in the area of the test unit (100) and releasing a prestressing device provided for biasing the probe arm (110) for deflecting the probe arm (110), guiding the test unit (100) along a Trench wall and detection of a deflection of the at least one probe arm (110). Procedure according to Claim 9 , in which the test unit is attached to a diaphragm wall production device, with the step of: producing a trench by means of a diaphragm wall production device and producing a diaphragm wall. Method according to one of the Claims 9 - 10 if the detected hydrostatic pressure remains constant over a certain time interval, the at least one probe arm (110) is deflected into a test position. Method according to one of the Claims 9 - 11 , in which the detected deflection of the at least one probe arm (110) is logged while the test unit (100) is being guided along the trench wall, in particular in a data carrier provided in the test unit that records the data determined by the detection unit or the logged data Data are transmitted to the earth's surface in particular by means of a cable.

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