Construction method for trestle steel support in shield muck pit

Abstract

The invention relates to the technical field of shield muck pit construction, in particular to a construction method for a trestle steel support in a shield muck pit. The technical problems that a conventional trestle is a reinforced concrete trestle, if a muck pit is small due to the limitation of field conditions, the soil piling capacity of the muck pit is seriously influenced, the starting date of a shield tunneling machine is possibly restricted, a conventional excavator walking channel is mostly a one-time temporary project of a concrete trestle, the construction cost is high, flying dust is generated when the conventional excavator walking channel is dismantled and broken, and the construction cost is low are solved. And economy and environmental protection are not facilitated. According to the technical scheme, the construction method for the trestle steel support in the shield muck pit comprises the following steps that firstly, a trestle base is constructed; secondly, an embedded plate is constructed; thirdly, vertical legs are reinforced; fourthly, a steel plate is laid; the problems that a concrete trestle is large in occupied space, long in construction period, high in manufacturing cost and not environmentally friendly are solved.

Description

[0001] Technical field The slag invention relates to the technical field of shield slag pit construction, and in particular to a method for constructing steel supports for a trestle in a shield slag pit. Background Art

[0002] The shield slag pit is one of the supporting facilities of shield construction. It is usually used as a temporary earth stacking place for shield slag to meet the needs of shield tunnel advancement in the shield construction site. To meet the needs of continuous advancement, the slag pit needs to be cleaned and transported out in time. To facilitate the transportation of slag, a trestle needs to be built on the slag pit to facilitate the excavator to stand and discharge slag. Considering the limitation of the starting site, the shield slag pit will not be able to meet the normal continuous advancement of the shield machine if a general concrete trestle is used. The conventional trestles are reinforced concrete trestles. If the slag pit is small due to site conditions, it will seriously affect the earth stacking capacity of the slag pit. The reinforced concrete trestles have a long construction period, which may restrict the starting date of the shield machine. The conventional excavator walking channel is mostly a one-time temporary project of a concrete trestle, which has a high cost and will generate dust when dismantled, which is not conducive to economy and environmental protection. Summary of the invention

[0003] In order to overcome the problem that conventional trestles are reinforced concrete trestles, if the slag pit is small due to site conditions, it will seriously affect the soil stacking capacity of the slag pit and may restrict the start date of the shield machine. In addition, conventional excavator walking passages are mostly one-time temporary projects of concrete trestles, which are expensive and will generate dust during dismantling, which is not conducive to economy and environmental protection.

[0004] The technical solution of the present invention is: a method for constructing steel supports for trestle bridges in a shield slag pit, the steps of which are as follows;

[0005] Step 1: Construction of the trestle base

[0006] In order to facilitate the safe movement of the excavator, the top plate of the trestle must be a plane with a uniform elevation. When making the outrigger embedded plate, we measured the elevation of the on-site outrigger position and calculated the height of the trestle base at that position;

[0007] Step 2: Embedded plate construction

[0008] After the base has been cured for 7 days, the A609 steel support is welded at the embedded plate of the base using the two-protection welding process as the trestle legs;

[0009] Step 3: Leg reinforcement construction

[0010] After the leg welding is completed, the leg needs to be reinforced by X-welding with 100 channel steel;

[0011] Step 4: Laying the steel plate

[0012] After the runway is erected, the panels are laid between the two runways;

[0013] Step 5: Welding the guardrail

[0014] Since personnel need to be regularly arranged to clean up the debris on the trestle, two guardrails are welded on the top of the trestle using 10# channel steel to ensure personnel safety;

[0015] Step 6: Flaw detection

[0016] After the completion of the trestle, the welding points need to be polished and then subjected to ultrasonic non-destructive testing by the testing unit. The trestle can be put into use only after all the tests are qualified.

[0017] As a preferred option, the bottom plate of the slag pit is the roof of the station. After the waterproofing construction of the roof in the slag pit is completed, a 200mm thick waterproof protective layer is poured on the waterproof layer. Because the top plate of the open-cut section is designed to have a slope of 28.5‰ to 6‰, the elevation of each trestle base must be different due to its different position, and the spacing between the bases is determined by the actual measured length of the top runway.

[0018] As a preferred option, the base is made of C14, 150*150 double-layer steel bar welded embedded plate, and then cast with C30 concrete in one step to ensure the stability of the base without lateral slippage. We use tie beams of the same specifications to connect all bases.

[0019] As a preference, the welding should be dense and free of welding defects such as broken welds, cold welds, bubbles, slag inclusions, etc.

[0020] As a preference, 100 channel steel is used for tie beam connection reinforcement every 1.5 meters at the top, and the runway on the top of the trestle (600*900 steel purlin) is arranged in sequence according to the spacing between columns.

[0021] As a preference, after the runways are arranged in sequence, the runways are welded to the legs using double-protection welding, and the welding standard is the same as that of the legs and embedded plates.

[0022] As a preferred method, after the middle runway is erected, a panel (2200*6000*2 steel plates) is laid between the two runways. After the panel is laid, the panel and the runway purlin are welded using double-protection welding.

[0023] As a preferred method, the welding spacing of the middle column is 3m. In order not to affect the rotation of the excavator when discharging slag, the height of the trestle guardrail is controlled at 0.5m.

[0024] As a preferred choice, the welding grinder has a power of 4.8kW, a spindle speed of 0-4100r / min, a grinding head inclination angle of 90°, a grinding head stroke of 90mm, a total machine weight of 120kg, etc. The feed amount of the grinding wheel is adjusted by a feed handwheel, and the weld is grinded by rotating the contour handwheel before flaw detection.

[0025] As a preference, be familiar with the inspected trestle, select appropriate instruments as well as straight and oblique probes, calibrate the instruments and probes, adjust the parameters, and select impedance matching from 150Ω to 400Ω; a wide range of frequency band selection, 2\~8MHz; adjustable gain range, 0.0\~110.0dB; detection range is 2.0\~5000mm (steel longitudinal wave); a wide range of sound velocity, 0-9999M / S, adjust instrument parameters according to the detection target, inspect the base material and welded joints, pay attention to the scanning speed and moving interval of the probe, analyze the location, size and shape of the defects based on the received ultrasonic signals, and rate them according to relevant standards. The trestle can be put into use only after all the tests are qualified.

[0026] Beneficial effects of the present invention:

[0027] The present invention adopts a trestle steel support construction method, which not only meets the strength, rigidity and stability required by the trestle walking excavator, but also greatly reduces the volume of the slag pit occupied by the trestle. The trestle is composed of a base, embedded plates, legs, runways, panels, tie beams, guardrails, etc. Through the adoption of the above measures, it is successfully achieved that the trestle basically does not occupy the volume of the slag pit when the slag pit is small, and the maximum slag stacking capacity of the slag pit is achieved. At the same time, when the project schedule is tight, the trestle construction period can be greatly shortened, so that the shield machine can be started as soon as possible. In the case of shield slag pit construction engineering, especially small slag pits with insufficient space, faster construction efficiency is achieved under the premise of ensuring safety and quality, providing experience accumulation for similar engineering construction, using steel structure trestles instead of traditional reinforced concrete trestles, and improving construction efficiency, floor space, slag environmental protection and other aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the steel support structure of the trestle in the shield pit of the present invention DETAILED DESCRIPTION

[0029] Example 1

[0030] This specific implementation method is a method for constructing steel supports for trestle bridges in a shield slag pit, and the steps are as follows:

[0031] Step 1: Construction of the trestle base

[0032] In order to facilitate the safe movement of the excavator, the top plate of the trestle must be a plane with a uniform elevation. When making the embedded plate for the outriggers, we measured the elevation of the on-site outrigger position and calculated the height of the trestle base at that position. The bottom plate of the slag pit is the top plate of the station. After the waterproof construction of the top plate in the slag pool is completed, a 200mm thick waterproof protective layer is poured on the waterproof layer. Because the top plate of the open-cut section has a slope of 28.5‰ to 6‰ according to the design, the elevation of each trestle base must be different due to its different position. The spacing between the bases is determined by the measured length of the top runway. The base adopts C14, 150*150 double-layer steel bar welded embedded plate, and then C30 concrete is poured in one step to form it. In order to ensure the stability of the base without lateral slippage, we use tie beams of the same specifications to connect all bases;

[0033] Step 2: Embedded plate construction

[0034] After the base has been cured for 7 days, the A609 steel support is welded at the embedded plate of the base using the two-protection welding process as the trestle legs. The welding must be dense and free of welding defects such as broken welds, false welds, bubbles, slag inclusions, etc.

[0035] Step 3: Leg reinforcement construction

[0036] After the leg welding is completed, the leg needs to be reinforced by X welding with 100 channel steel. The top is reinforced by connecting the tie beam with 100 channel steel every 1.5 meters. The runway on the top of the trestle (600*900 steel purlin) is arranged in sequence according to the column spacing. After the runway is arranged in sequence, the runway and the leg are welded by two-protection welding. The welding standard is the same as the welding of the leg and the embedded plate.

[0037] Step 4: Laying the steel plate

[0038] After the runway is erected, the panel is laid in the middle of the two runways. After the runway is erected, the panel (2200*6000*2 steel plate) is laid in the middle of the two runways. After the panel is laid, the panel and the runway purlin are welded by two-way welding.

[0039] Step 5: Welding the guardrail

[0040] Since personnel need to be regularly arranged to clean up the slag on the trestle, two guardrails are welded on the top of the trestle with 10# channel steel to ensure personnel safety. The welding distance between the columns is 3m. In order not to affect the rotation of the excavator when discharging slag, the height of the trestle guardrail is controlled at 0.5m;

[0041] Step 6: Flaw detection

[0042] After the completion of the trestle, the welding points need to be polished and then the ultrasonic non-destructive testing of the trestle welding points is carried out by the testing unit. The welding grinder has a power of 4.8kW, a spindle speed of 0-4100r / min, a grinding head tilt angle of 90°, a grinding head stroke of 90mm, a total weight of 120kg, etc. The feed amount of the grinding wheel is adjusted by a feed handwheel, and the welding points are polished by rotating the profiling handwheel. Before the flaw detection, the inspected trestle is familiar, and the appropriate instrument, straight probe and oblique probe are selected, and the instrument and probe are calibrated, the parameters are adjusted, and the impedance matching is performed. The instrument can be equipped with optional 150Ω~400Ω; the frequency band selection range is wide, 2\~8MHz; the gain range is adjustable, 0.0\~110.0dB; the detection range is 2.0\~5000mm (steel longitudinal wave); the sound velocity range is wide, 0-9999M / S. Adjust the instrument parameters according to the detection target, inspect the parent material and welding joints, pay attention to the scanning speed and moving interval of the probe, analyze the location, size and shape of the defects according to the received ultrasonic signal, and rate them according to relevant standards. The trestle can be put into use only after all the tests are qualified.

[0043] Example 2

[0044] This specific implementation method is a method for constructing steel supports for trestle bridges in a shield slag pit, and the steps are as follows:

[0045] Step 1: Construction of the trestle base

[0046] In order to facilitate the safe movement of the excavator, the top plate of the trestle must be a plane with a uniform elevation. When making the embedded plate for the outriggers, we measured the elevation of the on-site outrigger position and calculated the height of the trestle base at that position. The bottom plate of the slag pit is the top plate of the station. After the waterproof construction of the top plate in the slag pool is completed, a 200mm thick waterproof protective layer is poured on the waterproof layer. Because the top plate of the open-cut section has a slope of 28.5‰ to 6‰ according to the design, the elevation of each trestle base must be different due to its different position. The spacing between the bases is determined by the measured length of the top runway. The base adopts C14, 150*150 double-layer steel bar welded embedded plate, and then C30 concrete is poured in one step to form it. In order to ensure the stability of the base without lateral slippage, we use tie beams of the same specifications to connect all bases;

[0047] Step 2: Embedded plate construction

[0048] After the base has been cured for 7 days, the A609 steel support is welded at the embedded plate of the base using the two-protection welding process as the trestle legs. The welding must be dense and free of welding defects such as broken welds, false welds, bubbles, slag inclusions, etc.

[0049] Step 3: Leg reinforcement construction

[0050] After the leg welding is completed, the leg needs to be reinforced by X welding with 100 channel steel. The top is reinforced by connecting the tie beam with 100 channel steel every 1.5 meters. The runway on the top of the trestle (600*900 steel purlin) is arranged in sequence according to the column spacing. After the runway is arranged in sequence, the runway and the leg are welded by two-protection welding. The welding standard is the same as the welding of the leg and the embedded plate.

[0051] Step 4: Laying the steel plate

[0052] After the runway is erected, the panel is laid in the middle of the two runways. After the runway is erected, the panel (2200*6000*2 steel plate) is laid in the middle of the two runways. After the panel is laid, the panel and the runway purlin are welded by two-way welding.

[0053] Step 5: Welding the guardrail

[0054] Since personnel need to be regularly arranged to clean up the slag on the trestle, two guardrails are welded on the top of the trestle with 10# channel steel to ensure personnel safety. The welding distance between the columns is 3m. In order not to affect the rotation of the excavator when discharging slag, the height of the trestle guardrail is controlled at 0.5m;

[0055] Step 6: Flaw detection

[0056] After the completion of the trestle, the welding points need to be polished and then the ultrasonic non-destructive testing of the trestle welding points is carried out by the testing unit. The welding grinder has a power of 4.8kW, a spindle speed of 0-3100r / min, a grinding head inclination angle of 90°, a grinding head stroke of 90mm, a total weight of 120kg, etc. The feed amount of the grinding wheel is adjusted by a feed handwheel. The welding points are polished by rotating the imitation handwheel. Before the flaw detection, familiarize yourself with the inspected trestle, select the appropriate instrument, straight probe and oblique probe, calibrate the instrument and probe, adjust the parameters, and match the impedance. Optional 100Ω~150Ω; wide frequency band selection range, 0.5\~4MHz; adjustable gain range, 0.0\~800.0dB; detection range is 2.0\~5000mm (steel longitudinal wave); wide sound velocity range is 0-9999M / S. Adjust instrument parameters according to detection target, inspect parent material and welded joints, pay attention to the scanning speed and moving interval of the probe, analyze the location, size and shape of defects according to the received ultrasonic signal, and rate according to relevant standards. The trestle can be put into use only after all tests are qualified.

Claims

1. A method for constructing steel supports for trestle bridges in a shield slag pit, characterized in that: The steps are as follows; Step 1: Construction of the trestle base In order to facilitate the safe movement of the excavator, the top plate of the trestle must be a plane with a uniform elevation. When making the outrigger embedded plate, we measured the elevation of the on-site outrigger position and calculated the height of the trestle base at that position; Step 2: Embedded plate construction After the base has been cured for 7 days, the A609 steel support is welded at the embedded plate of the base using the two-protection welding process as the trestle legs; Step 3: Leg reinforcement construction After the leg welding is completed, the leg needs to be reinforced by X-welding with 100 channel steel; Step 4: Laying the steel plate After the runway is erected, the panels are laid between the two runways; Step 5: Welding the guardrail Since personnel need to be regularly arranged to clean up the debris on the trestle, two guardrails are welded on the top of the trestle using 10# channel steel to ensure personnel safety; Step 6: Flaw detection After the completion of the trestle, the welding points need to be polished and then subjected to ultrasonic non-destructive testing by the testing unit. The trestle can be put into use only after all the tests are qualified.

2. A shield tunneling slag pit trestle steel support construction method according to claim 1, characterized in that: In step one, the bottom plate of the slag pit is the roof of the station. After the waterproof construction of the roof in the slag pool is completed, a 200mm thick waterproof protective layer is poured on the waterproof layer. Because the top plate of the open-cut section has a slope of 28.5‰ to 6‰ according to the design, the elevation of each trestle base must be different due to its different position, and the spacing between the bases is determined by the actual measured length of the top runway.

3. A shield tunneling slag pit trestle steel support construction method according to claim 2, characterized in that: The base is made of C14, 150*150 double-layer steel bar welded embedded plate, and then cast with C30 concrete in one step. In order to ensure the stability of the base and prevent lateral slippage, we use tie beams of the same specifications to connect all bases.

4. The method for constructing steel supports for trestle bridges in a shield slag pit according to claim 1, characterized in that: During welding in step 2, it is necessary to ensure that the welding is dense and there are no welding defects such as broken welds, cold welds, bubbles, slag inclusions, etc.

5. The method for constructing steel supports for trestle bridges in a shield slag pit according to claim 1, characterized in that: In step three, 100 channel steel is used to connect and reinforce the tie beams every 1.5 meters at the top, and the runway on the top of the trestle (600*900 steel purlins) is arranged in sequence according to the spacing between the columns.

6. A shield tunneling slag pit trestle steel support construction method according to claim 5, characterized in that: After the runways are arranged in sequence, the runways and legs are welded using double-protection welding. The welding standards are the same as those for the legs and embedded plates.

7. The method for constructing steel supports for trestle bridges in a shield slag pit according to claim 1, characterized in that: In step 4, after the runway is erected, a panel (2200*6000*2 steel plate) is laid between the two runways. After the panel is laid, the panel and the runway purlin are welded using double-protection welding.

8. The method for constructing steel supports for trestle bridges in a shield slag pit according to claim 1, characterized in that: The welding distance between the columns in step 5 is 3m. In order not to affect the rotation of the excavator when discharging slag, the height of the trestle guardrail is controlled at 0.5m.

9. The method for constructing steel support for a trestle in a shield slag pit according to claim 1, characterized in that: In step six, the welding grinder has a power of 4.8kW, a spindle speed of 0-4100r / min, a grinding head inclination angle of 90°, a grinding head stroke of 90mm, a total machine weight of 120kg, etc. The feed amount of the grinding wheel is adjusted by a feed handwheel, and the weld is grinded by rotating the contour handwheel before flaw detection.

10. The method for constructing steel supports for trestle bridges in a slag pit of a slag shield according to claim 1, characterized in that: Be familiar with the inspected trestle, select appropriate instruments as well as straight and oblique probes, calibrate the instruments and probes, adjust the parameters, and select 150Ω~400Ω for impedance matching; a wide range of frequency band selection, 2\~8MHz; adjustable gain range, 0.0\~110.0dB; detection range is 2.0\~5000mm (steel longitudinal wave); a wide range of sound velocity, 0-9999M / S, adjust instrument parameters according to the detection target, inspect the parent material and welded joints, pay attention to the scanning speed and moving interval of the probe, analyze the location, size and shape of the defects according to the received ultrasonic signal, and evaluate the slag to be tested according to relevant standards. The trestle can be put into use only after all the tests are qualified.

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