Construction method for assembling precast anchorage caisson sinking well by cable crane

Abstract

The application provides a construction method for assembling a prefabricated anchor sinking well by using a cable crane, which comprises the following steps: firstly, constructing the approach bridge piers and cap beams of a suspension bridge; then, using the two approach bridge piers on the two sides of the design position of the anchor of the suspension bridge as cable crane towers, using the cap beams on the bridge piers as the cross beams of the towers to install the cable turning saddles, using the pier caps outside the bridge piers as the anchor systems of the cable cranes, erecting the cable crane system which crosses the anchor of the suspension bridge, assembling the anchor sinking well prefabricated blocks by using the cable crane, and expanding the horizontal coverage range of the cable crane by using the ground traction equipment to cooperate with the cable crane through the swinging and moving method, so as to complete the construction of the prefabricated anchor sinking well. The application does not need to separately set up cable crane towers and anchors, so that the cable crane method is applied to the construction of the fabricated anchor sinking well at a low cost, and is conducive to promoting the popularization of the prefabricated assembly technology in the construction of the anchor sinking well.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of bridge construction, and relates to an anchorage construction of a suspension bridge, in particular to a construction method for assembling a prefabricated anchorage caisson by using a cable crane. BACKGROUND

[0002] Figure 1 A common suspension bridge structure schematic diagram is shown in the figure, a suspension bridge crosses a river, and a main tower 10 and an anchorage 20 are respectively arranged on both sides of the river, the main cables 30 of the suspension bridge are anchored to the anchorage 20 on both sides through the top of the two main towers 10, the main span girder 40 of the suspension bridge is connected to the main cables 30 through the suspenders 50, the side spans and the approach bridge girder are simple supported beams or cast-in-situ beams, and the anchorage 20 is located between the two approach bridge piers 1.

[0003] The suspension bridge usually adopts a gravity type anchorage, and the gravity type anchorage is usually constructed by using a caisson method. The traditional anchorage caisson is usually constructed by using a cast-in-situ method, which has the problems of many construction personnel and machines, large occupied area, difficult control of cracks caused by hydration heat of mass concrete, slow construction progress affecting the construction period, and the like.

[0004] At present, the prefabricated construction technology is widely used in bridge engineering, for example, the bridge girder, bent cap, pier and cable tower have generally begun to use prefabricated structures, but the anchorage caisson construction technology is rarely used, especially in large caisson construction. The main restricting factors are that the weight of a single mass concrete prefabricated block of a large caisson is large, generally more than 100 tons, the lifting capacity of ordinary lifting equipment cannot meet the requirements, and the construction area of a large caisson is large, the length of the existing large anchorage caisson is more than 100 meters, and the width is more than 70 meters, the construction range of ordinary lifting equipment cannot meet the requirements. The main large-tonnage lifting equipment at present mainly includes large-tonnage crawler cranes, tower cranes and gantry cranes. If a large-tonnage crawler crane is used, the lifting radius is limited and cannot cover the construction area of a large caisson. If a large-tonnage tower crane or a large-span gantry crane is used, special design and manufacture are required, which not only has high cost, but also has safety hazards due to the softening of the surrounding soil during caisson construction, which greatly affects the stability of the tower crane foundation and the gantry crane track foundation.

[0005] Cable crane is a special hoisting equipment, which is supported by two cable towers, and the two ends of the bearing cable are anchored with anchorages. A trolley is arranged on the bearing cable, and a lifting system is arranged on the trolley. The trolley is pulled on the bearing cable through a traction system. The cable crane has the advantages of strong lifting capacity, large span range and high safety. If it is used for the hoisting construction of the prefabricated sinking well, it can meet the construction requirements from the technical point of view, but there are big problems from the economic point of view, because the construction cost of the cable crane is very high, mainly the construction cost of the cable tower and the anchoring system is high, and as a temporary structure, it also needs to be removed after the construction is completed, and the material waste is large. Therefore, at present, the cable crane method is generally only used in the hoisting construction of the main beam and arch rib of the large-span cable-stayed bridge, suspension bridge and arch bridge, and it is used only when it has a cost advantage compared with the support method, sliding method, rotation method and other construction methods or other construction methods are restricted by environmental factors and cannot be implemented. If it is used for the construction of the anchor of the suspension bridge, the use cost must be greatly reduced to be feasible. SUMMARY

[0006] The purpose of the present application is to solve the above problems, and to provide a construction method for assembling a prefabricated anchor sinking well by using a cable crane at a low cost, so as to promote the application of prefabricated assembly technology in large anchor sinking wells.

[0007] Through the analysis of the structure of the suspension bridge, the existing construction process and the structure of the cable crane system, it is found that when the cast-in-place method is used to construct the anchor of the suspension bridge, the site construction personnel and vehicles are many, and the site occupies a large area. Therefore, the bridge piers on both sides of the anchor are usually constructed after the anchor is constructed. The bridge piers on both sides of the anchor of the suspension bridge are similar to two cable tower towers. If the bridge piers are constructed first, the bridge piers can be used as the tower to set up the cable crane system across the anchor of the suspension bridge, so that the anchor of the suspension bridge can be constructed by using the cable crane system. If the prefabricated assembly technology is used to construct the anchor, the amount of construction and the site occupation are small, and the disturbance to the soil around the anchor is also small. Therefore, the bridge piers can be constructed first, and then the anchor can be constructed.

[0008] Based on the above idea, the present application provides a construction method for assembling a prefabricated anchor sinking well by using a cable crane at a low cost, which is characterized by comprising the following steps:

[0009] Step 1, constructing a cable crane system for the construction of the anchor of the suspension bridge:

[0010] First, the construction of the approach bridge piers and bent caps of the suspension bridge is completed, then the two approach bridge piers on both sides of the design position of the anchor of the suspension bridge are used as cable crane towers, the bent caps on the piers are used as the cross beams of the towers to install the cable crane saddles, the bent caps on the outer sides of the towers are used as the anchoring systems of the cable crane to install the anchor seats and the steering wheels, the load bearing cables, the hoisting cables and the traction cables are strung between the two towers, the two ends of the load bearing cables are connected with the anchor seats on the two bent caps respectively, the cable crane trolley is installed on the load bearing cables, the hoisting cables and the traction cables are connected with the hoisting winch set and the traction winch respectively after passing through the steering wheels on the two bent caps, the saddle transverse moving device is arranged on the bent cap of the pier where the saddle is installed, and the installation of the cable crane system is completed.

[0011] The guide walls of the anchor caisson are constructed, and the prefabricated block segments of the anchor caisson are processed.

[0012] Step two, the first segment of the anchor caisson is installed.

[0013] The first segment of the anchor caisson is a steel box structure, which is processed in blocks in a factory, transported to the hoisting area of the cable crane, and hoisted to the installation position by the cable crane. During the hoisting process of the cable crane, the saddle transverse moving device is used to push the saddle to move transversely on the bent cap to expand the transverse coverage of the cable crane. The block segments of the anchor caisson that are beyond the transverse coverage of the cable crane are connected in the air with the block segments hoisted by the cable crane on the ground outside the anchor caisson, and the block segments are pulled outward by the heavy-duty tractor while the height of the block segments is lowered by the cable crane, so that the block segments are pulled to the installation position by swinging.

[0014] The first segment of the anchor caisson is welded into a whole, and the concrete of the first segment of the anchor caisson is poured.

[0015] Step three, the second and third segments of the anchor caisson are assembled by the cable crane in the manner of step two, and the steel bars between the block segments and the wet joint concrete between the block segments are connected.

[0016] Step four, the soil in the compartments of the anchor caisson is excavated, and the excavated soil is hoisted by the cable crane to the slag car outside the anchor caisson; the anchor caisson segments are sunk by excavating the soil in the compartments of the anchor caisson.

[0017] Step five, the subsequent segments of the anchor caisson are hoisted and sunk in sequence in the manner of steps three and four.

[0018] Step six, the silt in the anchor caisson is removed, the bottom sealing concrete is poured, the core is filled in the anchor caisson, the well cover is poured, and the construction of the anchor caisson is completed.

[0019] The present application is suitable for the fabricated anchorage sinking well construction on the land of a suspension bridge. The present application uses the approach bridge pier on both sides of the anchorage as the cable crane tower system and anchoring system, and does not need to separately set up the cable tower and anchorage, so that the cable crane method is applied to the fabricated anchorage sinking well construction with lower cost, and is conducive to promoting the popularization and generalization of the prefabricated assembly technology in the anchorage sinking well construction. The bridge pier used as the cable crane tower is a permanent structure, is not affected by the softening of the surrounding soil caused by the anchorage sinking well construction, is more stable than the cable tower, anchorage and other temporary structures of the conventional cable crane, the construction safety is guaranteed, and the removal process and material waste of the temporary structure after the construction is completed are avoided. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a schematic diagram of a suspension bridge structure using gravity type anchorage;

[0021] Figure 2 is a schematic diagram of the side view structure of the cable crane system built by the approach bridge pier of the suspension bridge according to the present application;

[0022] Figure 3 is a schematic diagram of the plane structure of the cable crane system according to the present application;

[0023] Figure 4 is a schematic diagram of the state of the first segment of the sinking well hoisted by the cable crane;

[0024] Figure 5 is a schematic diagram of the state of the prefabricated block installed by the swing method beyond the horizontal coverage range of the cable crane;

[0025] Figure 6 is a schematic diagram of the state of the prefabricated sinking well segment assembled to a certain height on the ground;

[0026] Figure 7 is a schematic diagram of the state of the sinking of the prefabricated sinking well;

[0027] Figure 8 is a schematic diagram of the state of the prefabricated sinking well after the construction is completed. DETAILED DESCRIPTION

[0028] The specific construction method of the present application is as follows:

[0029] Step one, build the cable crane system for the anchorage construction of the suspension bridge:

[0030] As Figure 2 , Figure 3As shown, first, the approach bridge piers 1 and the cap beams 2 on the piers of the suspension bridge are constructed, then the two approach bridge piers 1 on both sides of the anchor design position of the suspension bridge are used as cable crane towers, the cap beams 2 on the piers are used as beam of the cable crane tower to install the cable crane saddle, the bearing platform 3 of the pier outside the cable crane tower is used to install the anchor seat and the steering wheel, the load-bearing cable 4 and the hoisting cable and the traction cable are arranged between the two cable towers, the two ends of the load-bearing cable 4 are connected with the anchor seats on the bearing platforms 3, the cable crane trolley 5 is installed on the load-bearing cable 4, the hoisting cable and the traction cable are connected with the cable crane trolley, the hoisting cable and the traction cable pass through the steering wheels on the bearing platforms and are connected with the hoisting winch set and the traction winch 6, the saddle transverse moving device is arranged on the pier cap beam where the cable crane saddle is installed, and the cable crane system installation is completed;

[0031] The anchor well guide wall 7 of the suspension bridge is constructed, and the anchor well prefabricated block section is processed;

[0032] Step two, install the first section of the anchor well;

[0033] As shown in Figure 4 , Figure 5 , the first section of the anchor well 8 is a steel box structure, which is processed in blocks in the factory, transported to the cable crane hoisting area, and hoisted to the installation position in blocks by the cable crane. During the hoisting process of the cable crane, the saddle transverse moving device is used to push the saddle to move transversely on the cap beam to expand the transverse coverage of the cable crane. Since the transverse width of the anchor is greater than the length of the cap beam, the anchor well block section that exceeds the transverse coverage of the cable crane can be connected with the anchor well block section hoisted by the cable crane in the air on the ground outside the anchor well by using a heavy-duty towing vehicle 9 or a large-tonnage chain hoist. The towing vehicle 9 pulls the block section outward, while the cable crane lowers the height of the anchor well block section 81, and the anchor well block section 81 is pulled to the installation position by swinging;

[0034] The steel boxes of the first section of the anchor well 8 are welded into a whole, and the concrete of the first section of the steel box is poured;

[0035] Step three, as shown in Figure 6 , the second and third prefabricated block sections of the anchor well 8 are assembled by the cable crane in the manner of step two, and the steel bars between the block sections are connected and the wet joint concrete between the block sections is poured;

[0036] Step four, as shown in Figure 7 , the soil in the compartments of the anchor well 8 is excavated, and the excavated soil is hoisted to the slag car outside the anchor well by the cable crane. The anchor well section is sunk by excavating in the compartments of the anchor well;

[0037] Step five: the subsequent sections of the anchor well are hoisted and sunk in sequence in the manner of steps three and four;

[0038] Step six: as shown in Figure 8The anchor sinking well is constructed by removing the silt in the anchor sinking well, pouring the bottom sealing concrete, filling the core in the sinking well and pouring the well cover.

Claims

1. A construction method for assembling precast anchor caissons using cable hoisting, characterized in that, Includes the following steps: Step 1: Constructing the cable-stayed suspension system for the anchorage construction of the suspension bridge: First, the approach bridge piers and cap beams of the suspension bridge are constructed. Then, the two approach bridge piers on both sides of the designed anchorage position of the suspension bridge are used as cable-stayed towers. The cap beams on the piers are used as the crossbeams of the towers to install the cable saddles. The pier foundations on the outside of the towers are used as the cable-stayed anchorage system to install the anchorage seats and steering wheels. Cable-stayed load-bearing cables, lifting cables, and traction cables are erected between the two towers. The two ends of the load-bearing cables are connected to the anchorage seats on the two foundations respectively. Cable-stayed cranes are installed on the load-bearing cables. The lifting cables and traction cables are connected to the cable-stayed cranes respectively. After the lifting cables and traction cables pass around the steering wheels on the two foundations, they are connected to the lifting winch unit and the traction winch respectively. A cable saddle lateral movement device is set on the cap beam of the pier where the cable saddles are installed, thus completing the installation of the cable-stayed system. Construction of guide walls for anchorage caissons of suspension bridges; fabrication of precast blocks for anchorage caissons; Step 2, Install the first section of the anchor caisson: The first section of the caisson is a steel box structure, which is processed in sections at the factory and transported to the cable crane lifting area. The sections are then lifted one by one by the cable crane to the installation position. During the cable crane lifting process, the cable saddle is moved laterally on the cap beam by the cable saddle lateral movement device to expand the lateral coverage range of the cable crane. For caisson sections that exceed the lateral coverage range of the cable crane, a heavy-duty tractor is used on the ground outside the caisson to connect the caisson section lifted by the cable crane in the air. The tractor pulls the section outward, while the cable crane lowers the height of the caisson section and pulls the caisson section to the installation position by swinging. The first section of the steel box is welded into a whole, and the concrete of the first section of the steel box is poured. Step 3: Following the method in Step 2, use cable cranes to assemble the second and third precast sections of the anchor caisson, while connecting the reinforcing bars between the sections and pouring the wet joint concrete between the sections. Step 4: Excavate the soil inside the caisson compartment and use a cable crane to lift the excavated soil onto a muck truck outside the anchor caisson; the caisson segment sinks by excavating the soil inside the caisson compartment. Step 5: Following the methods described in Steps 3 and 4 above, hoist and lower the subsequent sections of the caisson in sequence; Step Six: Remove the mud and sand from the anchor caisson, pour the bottom sealing concrete, fill the core inside the caisson, pour the well cover, and complete the anchor caisson construction.

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