A cast-in-place construction method for prefabricated immersed tube connection seams under ship shaking state

Abstract

The present invention provides a cast-in-place construction method for the connection seam of a prefabricated immersed tube under the shaking state of a ship, which is applicable to the field of prefabricated immersed tube construction. The present invention includes connection load value selection, connection design, construction preparation, installation of steel grid, cast-in-place construction of the connection seam, and disassembly and turnover of the steel grid. The immersed tubes at both ends of the connection seam are fixed to form a whole by the steel grid, so that the two sections of the immersed tube move synchronously. The deformation of the steel grid is further used as a reference index to make the steel grid have sufficient rigidity to ensure that no cracks will appear during the pouring and curing of concrete at the connection seam during the slight shaking of the ship, thereby ensuring the safety and durability of the immersed tube tunnel; at the same time, the steel grid is divided into four parts, upper, lower, left and right, according to different positions of the immersed tube, and a detachable connection form is adopted for the adjacent parts, so that the steel grid can be used in a turnover manner, which greatly saves construction costs.

Description

Technical Field

[0001] The invention relates to the field of prefabricated immersed tube construction, and in particular to a cast-in-place construction method for a prefabricated immersed tube connection seam in a ship shaking state. Background Art

[0002] During the construction of immersed tube tunnels, two sections of immersed tubes are connected underwater by hydraulic pressing. GINA waterstop and OMEGA waterstop are used at the connection joints to form the first and second waterproofing respectively. Due to the high cost of these two waterstops, when the length of the immersed tube is long enough, fewer connection joints are required for a tunnel. At this time, the underwater connection method is acceptable. However, in the construction process of some immersed tube tunnels, due to the site selection of prefabricated immersed tube processing plants and the size restrictions of the port immersed tube loading site, the length of the prefabricated immersed tubes is relatively short. If the hydraulic pressing method is continued, the waterstop connection joints will be increased by one to two times. It is obviously not suitable to use this method for underwater connection.

[0003] As the weight of the immersed tube is too large, it needs to be transported to the ship through a special trolley track, which is not suitable for transportation and hoisting and splicing on land. Therefore, a method of prefabricating the immersed tube joints on the ship is proposed to minimize the use of GINA waterstop and OMEGA waterstop. However, even in a port with no wind, the ship will have a slight shake. When pouring the prefabricated immersed tube joints, the shaking of the ship will cause cracks in the concrete during the solidification process, seriously affecting the safety and durability of the immersed tube tunnel. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that cracks will occur during the cast-in-place construction of the connection seams of prefabricated immersed tubes when the ship is in a rocking state. A cast-in-place construction method for the connection seams of prefabricated immersed tubes when the ship is in a rocking state is proposed, which ensures the safety and durability of the immersed tube tunnel and can be widely used in the field of prefabricated immersed tube construction.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] S1, connection load value;

[0007] The connection load value is obtained by obtaining the basic data of the immersed tubes at both ends of the connection seam, which includes the length L, width B, height H, mass M of the immersed tube and the vertical moment of inertia J of the whole after splicing. z , Ship length direction moment of inertia J x , Ship width direction moment of inertia J y, and use accelerometers and gyroscopes to measure the inertial acceleration of the immersed tube under different sea conditions and different incident wave angles. The inertial acceleration of the immersed tube corresponds to six degrees of freedom, namely, heaving inertial acceleration, longitudinal swaying inertial acceleration, swaying inertial acceleration, bowing inertial acceleration, roll inertial acceleration and pitching inertial acceleration. The cast-in-place construction of the connection joint is carried out under the condition that the sea condition level is lower than level n. The extreme values ​​of each degree of freedom of the inertial acceleration of the immersed tube corresponding to the sea condition level n are a1, a2, a3, α1, α2, and α3, respectively. The connection load is conservatively considered. The connection load includes heaving motion generating shear force in the vertical direction as Ma1, longitudinal swaying motion generating tension in the length direction of the ship as Ma2, swaying motion generating shear force in the width direction of the ship as Ma3, and bowing motion generating bending moment around the vertical direction as J z α1, the bending moment generated by the rolling motion around the length of the ship is J x α2, the bending moment generated by the pitching motion around the width of the ship is J y α3;

[0008] S2, connection design;

[0009] The connection design includes arranging a steel grid around the outer circle of the connection seam, the width of the connection seam is b, the steel grid extends l1 in the length direction of both immersed tubes, the length direction of the immersed tube is consistent with the length direction of the ship, then the length of the steel grid in the length direction of the immersed tube is 2l1+b, the steel grid is divided into four parts above, below, left and right of the immersed tube, the vertical shear force Ma1 in the connection load is mainly borne by the steel grid in the upper and lower parts of the immersed tube, the shear force Ma3 in the ship width direction is mainly borne by the steel grid in the left and right parts of the immersed tube, the tensile force Ma2 in the ship length direction is borne by the steel grid as a whole, and the vertical bending moment J z α1 is mainly borne by the steel grids on the left and right sides of the immersed tube, and the bending moment J around the width of the ship y α3 is mainly borne by the steel grids at the upper and lower parts of the immersed tube, and the bending moment J around the length of the ship x α2 is borne by the steel grid as a whole. The steel grid is subjected to force verification according to the connection load, and the spacing between steel grids, the arrangement of steel grid components and the cross-sectional area of ​​the components are adjusted until the steel grid meets the following conditions:

[0010] δ≤[δ] (1)

[0011] Wherein, δ is the mid-span deformation of the steel grid, [δ] is the allowable deformation value;

[0012] It also includes the design of the connection nodes between the steel grid and the immersed tube. The connection nodes must ensure that the steel grid and the immersed tube are rigidly connected. The design bearing capacity of the connection nodes is obtained according to the design process of the steel grid;

[0013] S3. Construction preparation;

[0014] The construction preparation includes, during the prefabrication stage of the immersed tube, pre-embedding steel plates at the designed connection nodes, reserving water-stop steel plates at the interface of new and old concrete pouring, and then selecting a port with low wind and gentle water flow, the port is equipped with lifting equipment that meets the lifting requirements and a site sufficient to complete the assembly of the steel grid, the planned construction window period is T days, and the weather at the port location in the next T+7 days is evaluated based on the meteorological data of the port location. When the wave height and wind speed in the next T+7 days are less than the wave height and wind speed corresponding to the n-level sea condition, the cast-in-place construction of the prefabricated immersed tube connection seam is started;

[0015] S4, install the steel grid;

[0016] The installation of the steel grid includes partially assembling the steel grid in a prefabrication plant, transporting it to the port by land transportation, and completing the assembly of the four parts of the steel grid of the immersed tube at the port, the nodes of the assembly are rigidly connected, the reserved steel bars of the immersed tube are rust-removed and adjusted, and then the reserved steel bars are butted, and after the butt connection is completed, each part of the steel grid is hoisted to a predetermined position by using the lifting equipment and temporarily fixed to the embedded steel plate, and the tie rods between the adjacent steel grids are installed, and the connection between the tie rods and the steel grid is bolted, and after the overall installation is completed, the steel grid is rigidly connected to the embedded steel plate;

[0017] S5. Cast-in-place construction of connection joints;

[0018] The cast-in-place construction of the connection joint includes cleaning the debris in the connection joint, roughening the concrete surface on both sides of the connection joint, pouring the micro-expansion concrete with a strength one level higher than that of the immersed tube after the formwork is set up, and performing moisture-keeping maintenance after the pouring and vibration of the connection joint concrete is completed;

[0019] S6. Dismantling and turnover of steel grid;

[0020] The disassembly and turnover of the steel grid includes removing the tie rods after the concrete of the connection joint has reached the strength requirement, and hoisting the four parts of the steel grid to the port storage site for use in the next cast-in-place construction of the immersed tube connection joint.

[0021] Furthermore, in the above S1, when the immersed tube mass M data at both ends of the connection seam are different, the larger value is taken as the basic data.

[0022] Furthermore, in the above S1, the extreme values ​​of each degree of freedom of the inertial acceleration of the immersed tube when the sea state level is 3 are respectively: a1 = 0.27 m / s 2 、a2=0.04m / s2 、a3=0.18m / s 2 , α 13 =0.07rad / s 2 , α2=0.48rad / s 2 , α3=0.18rad / s 2 .

[0023] Furthermore, in the above S2, the width b of the connection seam is not less than 3m.

[0024] Furthermore, in the above S2, the deformation allowable value [δ] is taken as 0.5 mm, and a representative calculation unit is used to verify the steel grid of each part.

[0025] Furthermore, in the above S3, the construction window period T days is not less than 14 days.

[0026] Furthermore, the height of the bottom surface of the immersed tube from the upper surface of the ship deck is not less than h+0.5m, where h is the height of the steel grid at the lower part of the immersed tube.

[0027] The beneficial effects of the present invention are as follows: a cast-in-place construction method for prefabricated immersed tube connection seams under a ship shaking state is provided. Generally, when the ship shakes, there will be a phase difference in the movement of the two sections of the immersed tube, that is, the two sections of the immersed tube are offset. The immersed tubes at both ends of the connection seam are fixed to form a whole through a steel grid, so that the two sections of the immersed tube move synchronously. Further, the deformation of the steel grid is used as a reference indicator to ensure that the steel grid has sufficient rigidity to ensure that during the slight shaking of the ship, no cracks will appear during the pouring and maintenance of concrete at the connection seam, thereby ensuring the safety and durability of the immersed tube tunnel. At the same time, the steel grid is divided into four parts, namely, up, down, left and right, according to different positions of the immersed tube, and a detachable connection form is adopted for adjacent parts, so that the steel grid can be used in a turnover manner, thereby saving construction costs to a great extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a flow chart of the cast-in-place construction method of the prefabricated immersed tube connection seam under the ship shaking state of the present invention;

[0029] Figure 2 It is a schematic diagram of the steel grid around the connection seam of the prefabricated immersed tube of the present invention;

[0030] Reference numerals in the figure: 1- immersed tube, 2- steel grid frame of upper part of immersed tube, 3- steel grid frame of left part of immersed tube, 4- steel grid frame of right part of immersed tube, 5- steel grid frame of lower part of immersed tube. DETAILED DESCRIPTION

[0031] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments given here are only used to illustrate and explain the present invention and cannot be used to limit the present invention. It should be noted that many specific details are set forth in the following description to facilitate a full understanding of the present invention, but the present invention may also have other embodiments and variations thereof, and therefore, the protection scope of the present invention is not limited by the specific embodiments disclosed below.

[0032] Example 1 is based on the main tunnel of a project along the Yangtze River Expressway in Shenzhen. The length of the immersed tube section is 5664m. The immersed tube tunnel has eight lanes on both sides. The length of the standard section of the immersed tube section is 65m, the width is 43.4m, the height is 11.4m, and the total weight is about 29250t. The width of the joint is 3m. The cast-in-place construction method of the prefabricated immersed tube joint under the rocking state of the ship is as follows:

[0033] S1, connection load value;

[0034] The length, width, height and mass of the immersed tubes at both ends of the connection seam are basically the same. The basic data of the immersed tubes at both ends of the connection seam are obtained, including the length L = 65m, width B = 43.4m, height H = 11.4m, mass M = 29250t and the vertical moment of inertia J of the whole after splicing. z =4.77×10 10 kg·m 2 , Ship length direction moment of inertia J x =4.91×10 9 kg·m 2 , Ship width direction moment of inertia J y =4.34×10 10 kg·m 2 The inertial acceleration of the immersed tube under different sea conditions and different incident wave angles was measured by using accelerometers and gyroscopes. The inertial acceleration of the immersed tube corresponds to six degrees of freedom, namely, the heave inertial acceleration a1, the longitudinal inertial acceleration a2, the sway inertial acceleration a3, the bow inertial acceleration α1, the roll inertial acceleration α2 and the pitch inertial acceleration α3. The extreme values ​​of the inertial acceleration of the immersed tube under different sea conditions are shown in Table 1. The cast-in-place construction of the connection joint was carried out under the condition that the sea condition level was lower than level 3. The extreme values ​​of the inertial acceleration of each degree of freedom of the immersed tube corresponding to the sea condition level 3 were a1=0.27m / s 2 、a2=0.04m / s 2 、a3=0.18m / s 2 , α 13 =0.07rad / s 2 , α2=0.48ra d / s 2 , α3=0.18rad / s 2, conservatively consider the connection loads, the vertical shear force generated by the heaving motion is Ma1, the tension generated by the longitudinal motion in the length direction of the ship is Ma2, the shear force generated by the transverse motion in the width direction of the ship is Ma3, and the bending moment generated by the bow motion around the vertical direction is J z α1, the bending moment generated by the rolling motion around the length of the ship is J x α2, the bending moment generated by the pitching motion around the width of the ship is J y α3;

[0035] Table 1 Extreme values ​​of inertial acceleration of immersed tubes in different sea conditions

[0036]

[0037]

[0038] S2, connection design;

[0039] A steel grid is arranged around the outer circle of the connection seam, the width of the connection seam is b=3m, the steel grid extends l1=6m in the length direction of the two immersed tubes, the length direction of the immersed tube is consistent with the length direction of the ship, the length of the steel grid in the length direction of the immersed tube is 15m, and the steel grid is divided into four parts on the upper, lower, left and right sides of the immersed tube. The vertical shear force Ma1=7897.5kN in the connection load is mainly borne by the steel grid in the upper and lower parts of the immersed tube, the shear force Ma3=1170kN in the width direction of the ship is mainly borne by the steel grid in the left and right parts of the immersed tube, the tensile force Ma2=5265kN in the length direction of the ship is borne by the steel grid as a whole, and the bending moment J around the vertical direction is 200m. z α1=5.82×10 4 kN·m is mainly borne by the steel grids on the left and right sides of the immersed tube, and the bending moment J y α3=13.63×10 4 kN·m is mainly borne by the steel grids at the upper and lower parts of the immersed tube, and the bending moment J x α2=4.11×10 4 kN·m is borne by the steel grid as a whole, and the steel grid is subjected to force verification according to the connection load, and the spacing of the steel grids, the arrangement of the steel grid components and the cross-sectional area of ​​the components are adjusted until the steel grid meets the following conditions:

[0040] δ≤[δ](1)

[0041] Wherein, δ is the mid-span deformation of the steel grid, [δ] is the allowable deformation value, which is 0.5 mm in this embodiment;

[0042] The height of the steel grid is 2m, and the height of the bottom of the immersed tube from the upper surface of the ship deck is 2.5m. This embodiment selects a representative calculation unit, and the upper and lower steel grids total 34. A single calculation unit bears a vertical shear force of 232.28kN and a bending moment of 4008.82kN·m around the width of the ship. Considering that the load is caused by the asynchronous movement of the immersed tubes at both ends of the connection seam, it is assumed that the immersed tube at one end is stationary and the immersed tube at the other end is moving. Therefore, one end of the calculation unit is fixed to the stationary immersed tube, and the other end is a free end that bears the combined action of shear force and bending moment. The cross-sectional area of ​​the calculation unit is A=88357mm 2 , the section moment of inertia is I = 80100000000mm 4 , the elastic modulus of steel is E = 206000Mpa, and the calculated vertical mid-span deformation is 0.32mm, which satisfies formula (1);

[0043] The steel grid and the immersed tube are rigidly connected, and the design bearing capacity of the connection node between the steel grid and the immersed tube is obtained according to the design process of the steel grid;

[0044] S3. Construction preparation;

[0045] During the prefabrication of immersed tubes, steel plates are embedded at the designed connection nodes, and water-stop steel plates are reserved at the interface between the new and old concrete castings. Then, a port with low wind and gentle water flow is selected. The port is equipped with lifting equipment that meets the lifting requirements and a site sufficient to complete the assembly of the steel grid. The planned construction window period is 14 days. The weather at the port location in the next 21 days is evaluated based on the meteorological data of the port location. When the wave height and wind speed in the next 21 days are less than the wave height and wind speed corresponding to the level 3 sea condition, the cast-in-place construction of the prefabricated immersed tube connection joints is started;

[0046] S4, install the steel grid;

[0047] The steel grid is partially assembled in the prefabrication plant and transported to the port by land. The four parts of the steel grid of the immersed tube are assembled at the port. The nodes of the assembly are rigidly connected. The reserved steel bars of the immersed tube are rust-proofed and adjusted, and then the reserved steel bars are butt-jointed. After the butt-jointing is completed, each part of the steel grid is hoisted to the predetermined position using lifting equipment and temporarily fixed with the embedded steel plate. The tie rods between adjacent steel grids are installed. The connection between the tie rods and the steel grid is bolted. After the overall installation is completed, the steel grid is rigidly connected with the embedded steel plate.

[0048] S5. Cast-in-place construction of connection joints;

[0049] Clean the debris in the joints, roughen the concrete surfaces on both sides of the joints, and after the formwork is set up, use micro-expansion concrete that is one level higher than the immersed tube for pouring. After the concrete pouring and vibration of the joints are completed, carry out moisture maintenance;

[0050] S6. Dismantling and turnover of steel grid;

[0051] After the concrete of the connection joints has reached the strength requirements, the tie rods are removed and the four sections of the steel grid are hoisted to the port storage site to be used in the next cast-in-place construction of the immersed tube connection joints.

[0052] In the second embodiment, the immersed tube at one end of the connecting seam is a variable cross-section section, so the length, width, height and mass of the immersed tubes at both ends of the connecting seam are inconsistent, one section is 29250t, and the other section is 26780t. When taking the basic data, the mass M is taken as the larger value 29250t.

[0053] In summary, the cast-in-place construction method of the prefabricated immersed tube connection seam under the ship shaking state of the present invention has the characteristics of easy construction and saving construction costs in the field of prefabricated immersed tube construction.

[0054] It should be understood that the above-mentioned embodiments are one or more embodiments of the present invention, and there are many other embodiments and variations thereof based on the present invention; the variations and modifications made by ordinary technicians in this industry through the present invention without making pioneering innovations all fall within the scope of protection of the present invention.

Claims

1. A cast-in-place construction method for prefabricated immersed tube connection seams under a ship shaking state, characterized in that The specific steps include: S1, connection load value; The connection load value is obtained by obtaining the basic data of the immersed tubes at both ends of the connection seam, which includes the length L, width B, height H, mass M of the immersed tube and the vertical moment of inertia J of the whole after splicing. z , Ship length direction moment of inertia J x , Ship width direction moment of inertia J y , and use accelerometers and gyroscopes to measure the inertial acceleration of the immersed tube under different sea conditions and different incident wave angles. The inertial acceleration of the immersed tube corresponds to six degrees of freedom, namely, heaving inertial acceleration, longitudinal swaying inertial acceleration, swaying inertial acceleration, bowing inertial acceleration, roll inertial acceleration and pitching inertial acceleration. The cast-in-place construction of the connection joint is carried out under the condition that the sea condition level is lower than level n. The extreme values ​​of each degree of freedom of the inertial acceleration of the immersed tube corresponding to the sea condition level n are a1, a2, a3, α1, α2, and α3, respectively. The connection load is conservatively considered. The connection load includes heaving motion generating shear force in the vertical direction as Ma1, longitudinal swaying motion generating tension in the length direction of the ship as Ma2, swaying motion generating shear force in the width direction of the ship as Ma3, and bowing motion generating bending moment around the vertical direction as J z α1, the bending moment generated by the rolling motion around the length of the ship is J x α2, the bending moment generated by the pitching motion around the width of the ship is J y α3; S2, connection design; The connection design includes arranging a steel grid around the outer circle of the connection seam, the width of the connection seam is b, the steel grid extends l1 in the length direction of both immersed tubes, the length direction of the immersed tube is consistent with the length direction of the ship, then the length of the steel grid in the length direction of the immersed tube is 2l1+b, the steel grid is divided into four parts above, below, left and right of the immersed tube, the vertical shear force Ma1 in the connection load is mainly borne by the steel grid in the upper and lower parts of the immersed tube, the shear force Ma3 in the ship width direction is mainly borne by the steel grid in the left and right parts of the immersed tube, the tensile force Ma2 in the ship length direction is borne by the steel grid as a whole, and the vertical bending moment J z α1 is mainly borne by the steel grids on the left and right sides of the immersed tube, and the bending moment J around the width of the ship y α3 is mainly borne by the steel grids at the upper and lower parts of the immersed tube, and the bending moment J around the length of the ship x α2 is borne by the steel grid as a whole. The steel grid is subjected to force verification according to the connection load, and the spacing between steel grids, the arrangement of steel grid components and the cross-sectional area of ​​the components are adjusted until the steel grid meets the following conditions: δ≤[δ] (1) Wherein, δ is the mid-span deformation of the steel grid, [δ] is the allowable deformation value; It also includes the design of the connection nodes between the steel grid and the immersed tube. The connection nodes must ensure that the steel grid and the immersed tube are rigidly connected. The design bearing capacity of the connection nodes is obtained according to the design process of the steel grid; S3. Construction preparation; The construction preparation includes, during the prefabrication stage of the immersed tube, pre-embedding steel plates at the designed connection nodes, reserving water-stop steel plates at the interface of new and old concrete pouring, and then selecting a port with low wind and gentle water flow, the port is equipped with lifting equipment that meets the lifting requirements and a site sufficient to complete the assembly of the steel grid, the planned construction window period is T days, and the weather at the port location in the next T+7 days is evaluated based on the meteorological data of the port location. When the wave height and wind speed in the next T+7 days are less than the wave height and wind speed corresponding to the n-level sea condition, the cast-in-place construction of the prefabricated immersed tube connection seam is started; S4, install the steel grid; The installation of the steel grid includes partially assembling the steel grid in a prefabrication plant, transporting it to the port by land transportation, and completing the assembly of the four parts of the steel grid of the immersed tube at the port, the nodes of the assembly are rigidly connected, the reserved steel bars of the immersed tube are rust-removed and adjusted, and then the reserved steel bars are butted, and after the butt connection is completed, each part of the steel grid is hoisted to a predetermined position by using the lifting equipment and temporarily fixed to the embedded steel plate, and the tie rods between adjacent steel grids are installed, and the connection between the tie rods and the steel grid is bolted, and after the overall installation is completed, the steel grid is rigidly connected to the embedded steel plate; S5. Cast-in-place construction of connection joints; The cast-in-place construction of the connection joint includes cleaning the debris in the connection joint, roughening the concrete surface on both sides of the connection joint, pouring the micro-expansion concrete with a strength one level higher than that of the immersed tube after the formwork is set up, and performing moisture-keeping maintenance after the pouring and vibration of the connection joint concrete is completed; S6. Dismantling and turnover of steel grid; The disassembly and turnover of the steel grid includes removing the tie rods after the concrete of the connection joint has reached the strength requirement, and hoisting the four parts of the steel grid to the port storage site for use in the next cast-in-place construction of the immersed tube connection joint.

2. The cast-in-place construction method for prefabricated immersed tube connection seams under the rocking state of a ship according to claim 1, characterized in that: In step S1, when the immersed tube mass M data at both ends of the connection seam are different, the larger value is taken as the basic data.

3. The cast-in-place construction method for prefabricated immersed tube connection seams under the rocking state of a ship according to claim 1, characterized in that: In step S1, the extreme values ​​of each degree of freedom of the inertial acceleration of the immersed tube are respectively a1=0.27m / s when the sea state level is 3. 2 、a2=0.04m / s 2 、a3=0.18m / s 2 , α1=0.07rad / s 2 , α2=0.48rad / s 2 , α3=0.18rad / s 2 .

4. The cast-in-place construction method for prefabricated immersed tube connection seams under the rocking state of a ship according to claim 1, characterized in that: In step S2, the connection seam width b is not less than 3m.

5. The cast-in-place construction method for prefabricated immersed tube connection seams under the rocking state of a ship according to claim 1, characterized in that: In step S2, the deformation allowable value [δ] is set to 0.5 mm, and a representative calculation unit is selected to verify the steel grid of each part.

6. The cast-in-place construction method for prefabricated immersed tube connection seams under the rocking state of a ship according to claim 1, characterized in that: In step S3, the construction window period T days is no less than 14 days.

7. The cast-in-place construction method for prefabricated immersed tube connection seams under the rocking state of a ship according to claim 1, characterized in that: The height of the bottom surface of the immersed tube from the upper surface of the ship deck is not less than h+0.5m, where h is the height of the steel grid at the lower part of the immersed tube.

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