High-precision layered controlled pouring method for large-section immersed tube concrete

Abstract

A high-precision layered controlled pouring method for large-section immersed tube concrete, wherein the bottom plate pouring and the top plate pouring are both inclined layer-by-layer pouring, and the wall pouring is horizontal layer-by-layer pouring: when the bottom plate pouring and the top plate pouring are performed, the pump truck and / or the ground pump are controlled by the pouring speed to pour the concrete layer by layer, and the thickness of the concrete layer is controlled. In the embodiment of the present invention, the top plate and the bottom plate of the immersed tube are both inclinedly poured, and the pump truck and / or the ground pump are controlled by the pouring speed v to pour the concrete layer by layer, and the thickness of the concrete layer is controlled by the thickness H, so as to ensure that when the next concrete layer is just poured and covers the previous concrete layer, the previous concrete layer has not yet been initially solidified, thereby avoiding too large a time difference between the concrete layers, preventing the occurrence of cold joints between the concrete layers, and ensuring the strength requirements of the large-section immersed tube.

Description

Technical Field

[0001] The invention belongs to the technical field of immersed tube tunnel construction, and in particular relates to a high-precision layered controlled pouring method of large-section immersed tube concrete. Background Art

[0002] The immersed tube tunnel is assembled from multiple sections of immersed tubes, which need to be prefabricated in a dry dock. In order to meet higher traffic flow, the immersed tube tunnel needs to have a larger internal space, so that the prefabricated immersed tube has a larger cross-section.

[0003] When pouring concrete for prefabricated immersed tubes, layered pouring is generally adopted. Layered pouring is divided into two methods: horizontal layering and inclined layering:

[0004] When the horizontal layering method is adopted, the volume of concrete required to be poured for each layer is large, which requires a large volume of concrete production per unit time. However, the number of mixing stations is limited, and the concrete poured in large sections needs to be iced, which will further prolong the concrete mixing time, making it difficult to meet the concrete volume demand per unit time.

[0005] When the inclined layering method is adopted, although the volume of concrete required for pouring each layer can be reduced to a certain extent, and the pressure on the mixing station can be reduced, in order to ensure the early strength of the chamfered concrete when pouring the bottom plate, the feeding point is located at the four chamfers. The large cross-section makes the longitudinal width of each layer of concrete larger. The concrete needs to flow and spread after feeding. Affected by the slump and expansion of the concrete, if the thickness of each layer of concrete is set larger, the time to complete the pouring of one layer of concrete is still longer, resulting in a large time difference in the paving between the two adjacent layers of concrete. When pouring the next layer of concrete, the upper layer of concrete is prone to initial setting, which makes it easy for cold joints to appear between the two layers of concrete, making it impossible for the large-section immersed tube to meet the strength requirements. Summary of the invention

[0006] In view of the shortcomings existing in the related technology, the present invention provides a high-precision layered controlled pouring method for large-section immersed tube concrete, so as to solve the problem that when the current inclined layered pouring method is applied to the pouring of large-section immersed tubes, the time difference between adjacent layers is large, which leads to the easy occurrence of cold joints that cannot meet the strength requirements.

[0007] The present invention provides a high-precision layered controlled pouring method for large-section immersed tube concrete, comprising full-section layered pouring of the immersed tube segment space formed between the inner formwork and the outer formwork, wherein the full-section layered pouring includes bottom plate pouring, wall pouring after the bottom plate pouring is completed, and top plate pouring after the wall pouring is completed:

[0008] The bottom plate casting and the top plate casting are both cast obliquely layer by layer, and the wall casting is cast horizontally layer by layer:

[0009] When pouring the bottom slab and top slab, the pouring speed is Control the pump truck and / or ground pump to pour concrete in layers and control the thickness of the concrete layers , and The following constraints must be met:

[0010]

[0011] Where t is the initial setting time of concrete, is the distance between the concrete feeding point and the adjacent wall outer wall, s is the slump of concrete, u is the expansion of concrete, is the height of the concrete paving point, is the horizontal width of the concrete paving, is the longitudinal length of the concrete paving, is the maximum pouring speed, and n is the number of concrete paving layers.

[0012] In some of the embodiments, for the concrete layer in the base plate with the top end reaching the elevation of the base plate, the concrete stacking volume is The calculation formula is replaced by:

[0013]

[0014] For the concrete layer in the top slab that reaches the top or the elevation on the top slab, the concrete stacking volume The calculation formula is replaced by;

[0015]

[0016] Wherein, M is the cross-sectional area of ​​the triangular region at the end of the top plate.

[0017] In some of the embodiments, concrete is spread to the four lower chamfers through four string tubes that penetrate into the immersed tube steel cage from top to bottom, and as the concrete layers are gradually stacked from bottom to top, the string tubes gradually move upward. After the lower chamfers are poured, the wall is poured through the string tubes, and the pouring between the two lower chamfers corresponding to the driveway is started simultaneously.

[0018] In some of the embodiments, the wall casting includes the casting of the middle partition wall and the casting of the side walls. The casting of the middle partition wall starts before the casting of the side walls so that the top surface of the middle partition wall concrete is 0.8 to 1.0 m higher than the top surface of the side wall concrete.

[0019] In some embodiments, the layer thickness of the upper part of the middle partition wall at the upper chamfer is less than the layer thickness of the lower part of the middle partition wall, and the number of concrete layers of the middle partition wall is greater than the number of concrete layers of the side wall, so that the casting of the side wall can be completed before the casting of the middle partition wall;

[0020] When the pouring of the middle partition wall is completed, the concrete layer of the top plate extends to the top of the middle partition wall, and the sum of the pouring time between the concrete layer at the top of the middle partition wall and the concrete layer of the adjacent top plate meets the requirement of 0.9 to 1.1t.

[0021] In some of the embodiments, when the base plate is poured, the pouring of concrete layers on both sides is performed alternately, so that the concrete layers are staggered under the carriageway.

[0022] In some of the embodiments, each concrete layer is first spread from the first end to the second end in the longitudinal direction, and when it is spread to 3 to 5 meters away from the second end, it is then spread from the second end to the first end.

[0023] In some of the embodiments, the immersed tube reinforcement cage is located in the concrete pouring space between the inner formwork and the outer formwork, and the inner formwork and the outer formwork are both provided with a plurality of vibration holes from top to bottom, and the vibration holes on the inner formwork are staggered with the vibration holes on the outer formwork;

[0024] When pouring the wall, the concrete layers are vibrated alternately from bottom to top through the vibration holes on the inner formwork and the vibration holes on the outer formwork, and the vibrating rod is inserted obliquely into the corresponding concrete layer and extends downward to the adjacent next concrete layer with a thickness of 5 to 10 cm.

[0025] In some embodiments, one side of the inner template is divided into an inner upper chamfer section, an inner wall section, an inner lower chamfer section and an inner bottom plate section from top to bottom, and the inner wall section, the inner lower chamfer section and the inner bottom plate section are all provided with vibration holes, and the number of vibration holes in the inner bottom plate section is greater than that in the inner lower chamfer section;

[0026] The outer formwork is divided into an outer upper chamfer section and an outer wall section from top to bottom, and both the outer upper chamfer section and the outer wall section are provided with vibration holes;

[0027] When pouring the upper chamfer and the lower chamfer, the vibrating rod is obliquely inserted into the vibration holes of the inner lower chamfer section and the outer upper chamfer section, and after the first vibration is completed, the second vibration is performed, and the length of the vibrating rod used in the second vibration is greater than that used in the first vibration.

[0028] Based on the above technical scheme, the top plate and the bottom plate of the immersed tube in the embodiment of the present invention are both cast obliquely, and the pouring speed v is used to control the pump truck and / or the ground pump to pour the concrete layer by layer, and the thickness H is used to control the thickness of the concrete layer. The pouring speed and the thickness of the concrete layer are set based on the maximum pouring speed that can be provided by the supply capacity of the mixing station, the required range of the concrete layer thickness, and the sum of the pouring time of two adjacent concrete layers is between 90% and 120% of the initial setting time of the concrete, thereby ensuring that when the next concrete layer to be poured just covers the previous concrete layer, the previous concrete layer has not yet been initially solidified, thereby avoiding excessive time difference in paving between concrete layers, preventing cold joints between concrete layers, and ensuring the strength requirements of large-section immersed tubes. This solves the problem that when the current inclined layered casting method is applied to the casting of large-section immersed tubes, the large time difference in paving of adjacent layers makes it easy to form cold joints that cannot meet the strength requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0030] Figure 1 It is a flowchart of the high-precision layered controlled pouring method of large-section immersed tube concrete of the present invention;

[0031] Figure 2 It is a schematic diagram of concrete layering demarcation of half width of a immersed tube in the high-precision layered controlled pouring method of large-section immersed tube concrete of the present invention;

[0032] Figure 3 Schematic diagram of the bottom plate pouring in the high-precision layered controlled pouring method of large-section immersed tube concrete of the present invention Figure 1 ;

[0033] Figure 4 Schematic diagram of the bottom plate pouring in the high-precision layered controlled pouring method of large-section immersed tube concrete of the present invention Figure 2 ;

[0034] Figure 5 It is a schematic diagram of the layout of the vibration holes in the high-precision layered controlled pouring method of large-section immersed tube concrete of the present invention.

[0035] In the figure:

[0036] 1. Bottom plate; 2. Wall; 21. Side wall; 22. Middle partition wall; 3. Top plate; 4. Driving lane; 5. Lower chamfer; 6. Upper chamfer; 7. Inner formwork; 71. Inner upper chamfer section; 72. Inner wall section; 73. Inner lower chamfer section; 74. Inner bottom plate section; 8. Outer formwork; 81. Outer upper chamfer section; 82. Outer wall section; 9. Vibration hole. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0038] In the description of the present invention, it should be understood that the terms "center", "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0039] The terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Thus, a feature defined as "first", "second", and "third" may explicitly or implicitly include one or more of the features.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] like Figure 1 As shown, in an illustrative embodiment of the method for high-precision layered controlled pouring of large-section immersed tube concrete of the present invention, the method for high-precision layered controlled pouring of large-section immersed tube concrete is as follows: the immersed tube segment space formed between the inner formwork and the outer formwork is subjected to full-section layered pouring, wherein the full-section layered pouring includes bottom plate pouring, and after the bottom plate pouring is completed, the wall is poured, and after the wall pouring is completed, the top plate is poured.

[0042] The bottom plate casting and the top plate casting are both cast obliquely layer by layer, and the wall casting is cast horizontally layer by layer. When casting the bottom plate and the top plate, the casting speed is Control the pump truck and / or ground pump to pour concrete in layers and control the thickness of the concrete layers , and The following constraints must be met:

[0043]

[0044] Where t is the initial setting time of concrete, is the distance between the concrete feeding point and the adjacent wall outer wall, s is the slump of concrete, u is the expansion of concrete, is the height of the concrete paving point, is the horizontal width of the concrete paving, is the longitudinal length of the concrete paving, is the maximum pouring speed, and n is the number of concrete layers. The number of concrete layers n of the bottom slab and top slab can be different.

[0045] The section of the immersed tube is divided into three parts: bottom plate 1, wall 2 and top plate 3. The order of concrete layering in each part is set from bottom to top. The wall of the immersed tube includes two side walls 21 located on both sides and two middle partition walls 22 located in the middle.

[0046] According to the design strength grade of concrete, the mix ratio of each component in the concrete is selected, and the concrete's slump s, expansion u, initial setting time t and other property parameters are determined accordingly.

[0047] The pouring speed is affected by the supply capacity of the mixing station, which has a maximum value, namely .

[0048] The immersed tube is generally prefabricated in sections and divided into multiple pipe sections. The longitudinal length L of the concrete paving is set according to the longitudinal length of the pipe section.

[0049] The thickness of the concrete layer is generally set at 30cm to 50cm. After the size of the immersed tube section is determined according to the design requirements, the concrete layers are delineated for the bottom plate, wall and top plate according to the set concrete layer thickness. For the concrete layers in the top plate and bottom plate, the concrete layers are set at an angle, and the thickness of the concrete layers remains consistent in the horizontal direction. For the concrete layers in the wall, since they are poured horizontally, the thickness of the concrete layers is not only consistent in the horizontal direction, but also the horizontal width x of the concrete paving is equal to the horizontal width of the wall.

[0050] For the bottom plate and top plate of the immersed tube section, the concrete layers are delineated in an oblique pouring manner, even if the concrete layers in the bottom plate and top plate are inclined; for the wall part of the immersed tube section, the concrete layers are delineated in a horizontal pouring manner, even if the concrete layers in the wall are horizontally set.

[0051] When pouring the base plate, pour it layer by layer from bottom to top. The first concrete layer is poured at a pouring speed of ; followed by The second concrete layer is poured at a pouring speed of According to the above method, the subsequent concrete layers of the base plate are poured in sequence, and during the pouring process, the pouring speed and thickness of each concrete layer are controlled.

[0052] The top slab is cast in the same way as the bottom slab.

[0053] When pouring the bottom slab and top slab, the pouring speed is Control the pump truck and / or ground pump to pour concrete in layers and control the thickness of the concrete layers According to the thickness of each concrete layer, the volume of the concrete pile after paving the i-th layer of concrete can be obtained. The volume of the corresponding concrete layer is calculated based on the difference in the stacking volume. The volume is further divided by the pouring speed of the corresponding concrete layer to obtain the pouring time of the concrete layer. The sum of the pouring times of adjacent concrete layers needs to be between 90% and 120% of the initial setting time of the concrete.

[0054] In the above-mentioned schematic embodiment, in the high-precision layered controlled pouring method of large-section immersed tube concrete, the top and bottom plates of the immersed tube are both poured obliquely, and the pouring speed v is used to control the pump truck and / or ground pump to pour the oblique concrete layers, and the thickness H is used to control the thickness of the concrete layers. The pouring speed and the thickness of the concrete layers are set based on the maximum pouring speed that can be provided by the supply capacity of the mixing station, the required range of the concrete layer thickness, and the sum of the pouring time of two adjacent concrete layers is between 90% and 120% of the initial setting time of the concrete, thereby ensuring that when the next concrete layer to be poured just covers the previous concrete layer, the previous concrete layer has not yet been initially solidified, thereby avoiding excessive time difference in paving between concrete layers, preventing cold joints between concrete layers, and ensuring the strength requirements of large-section immersed tubes; it solves the problem that when the current inclined layered pouring method is applied to the pouring of large-section immersed tubes, the large time difference in paving of adjacent layers makes it easy to form cold joints that cannot meet the strength requirements.

[0055] In some embodiments, when pouring the base plate, the four lower chamfers of the base plate are first poured layer by layer, and then the space between the two lower chamfers corresponding to the roadway is poured layer by layer.

[0056] When pouring the wall, after the lower chamfer of the base plate is poured, the wall is poured layer by layer based on it.

[0057] When pouring the top slab, pour it layer by layer from both sides to the middle.

[0058] Embodiment 1:

[0059] like Figure 2 As shown, the number of paving layers n of the bottom plate portion is 8, the four lower chamfers all have the 1st to 5th concrete layers of the bottom plate portion, and the 6th to 8th concrete layers of the bottom plate portion are located under the two lanes.

[0060] When pouring the 1st to 5th concrete layers at a lower chamfer from bottom to top, the material discharge point is located below the corresponding side wall and moves vertically upward with each layer of pouring. When pouring the 6th to 8th concrete layers under a lane from bottom to top, the material discharge point moves horizontally with each layer of pouring.

[0061] The bottom plate can be divided into four parts horizontally, each of which includes the 1st to 5th concrete layers of a lower chamfer and the 6th to 8th concrete layers of the lower half of the roadway. Since the four lower chamfers are poured in layers from bottom to top at the same time, and the lower half of the roadway is poured in layers from both sides to the middle at the same time, the pouring of the four parts of the bottom plate is carried out synchronously, so when the pouring quality verification of the bottom plate part is carried out, the pouring quality verification of one part of the bottom plate only needs to be carried out.

[0062] The pouring speed of the base plate ~ and thickness ~ , calculate the concrete stacking volume of this part of the concrete layer of the bottom plate ~ .at this time, The distance between the first concrete layer unloading point and the outer wall of the side wall. is the distance between the discharge point of the second concrete layer and the outer wall of the side wall, arrive And so on. ~ are the same, ~ gradually increase in size; The longitudinal length of the first concrete layer paving of this section, The longitudinal length of the second concrete layer paving of this section, arrive And so on; is the lateral width of the first concrete layer of the section, is the lateral width of the second concrete layer of this section, arrive And so on; is the thickness of the first concrete layer in the section, is the sum of the thickness of the first and second concrete layers of this part, is the sum of the thickness of the first, second and third concrete layers of this part, arrive And so on.

[0063] According to the slump s and expansion u of concrete, it can be Obtain the inclination α of the concrete layering by oblique pouring, so when a, h, u and s are known, x can be obtained. More specifically, It is divided into two parts through the unloading point, one part is , and the other part through the known and the concrete inclination α, and the sum of the two parts gives , arrive Obtained in the manner described above.

[0064] like Figure 3 As shown, calculation When To calculate the surface area of ​​the first concrete layer's discharge point close to the side wall's outer wall;

[0065] In the formula To calculate the surface area of ​​the first concrete layer's discharge point away from the outer wall of the side wall;

[0066] Add the two and multiply by the vertical length , that is, the concrete stacking volume of a layer of concrete is obtained .

[0067] calculate , in the formula To calculate the surface area of ​​the second concrete layer discharge point close to the outer wall of the side wall;

[0068] In the formula To calculate the surface area of ​​the second concrete layer's discharge point away from the side wall's outer wall;

[0069] Add the two and multiply by the vertical length , that is, the concrete stacking volume of the second layer of concrete is obtained .

[0070] According to the above method, calculate ~ .

[0071] pass ~ , you can get the volume of the 1st to 8th concrete layers ~ . Square volume ~ Divide by the corresponding concrete pouring speed ~ , you can get the pouring time of the 1st to 8th concrete layers.

[0072] The sum of the pouring time of two adjacent concrete layers is controlled to be between 90% and 120% of the initial setting time t, so as to set After the value of ~ and thickness ~ The constraints and settings are obtained so that each concrete layer of the base plate can be poured according to the corresponding pouring speed and thickness, which can ensure that the sum of the initial setting time of the corresponding two adjacent layers is between 90% and 120% of the initial setting time t.

[0073] If according to the current The value of the required control of the thickness of each concrete layer is too small, resulting in the sum of the thickness of the concrete layers being less than the total thickness of the base plate. The numerical value of .

[0074] like Figure 2 As shown, the number n of paving layers of the top plate portion is 10, specifically the 1st to 10th concrete layers of the top plate portion.

[0075] When the 1st to 10th concrete layers of the top plate are poured in sequence, the material discharge point moves laterally with the pouring of each layer.

[0076] Since the top plate is poured layer by layer from both sides to the middle, the concrete layers on both sides of the top plate are symmetrical, and the top plate can be divided into two parts horizontally. Each part contains the 1st to 10th concrete layers on one side. The pouring of the two parts of the top plate is carried out simultaneously. Therefore, when the pouring of the top plate is controlled, the required pouring speed and thickness can be obtained through one part of the top plate.

[0077] The pouring speed of the top plate ~ and thickness ~ , calculate the concrete stacking volume of this part of the top slab concrete layer ~ .at this time, The distance between the first concrete layer unloading point and the outer wall of the side wall. is the distance between the discharge point of the second concrete layer and the outer wall of the side wall, arrive And so on. arrive gradually increase in size; The longitudinal length of the first concrete layer paving of this section, The longitudinal length of the second concrete layer paving of this section, arrive And so on; is the lateral width of the first concrete layer of the section, is the lateral width of the second concrete layer of this section, arrive And so on; is the thickness of the first concrete layer in the section, is the sum of the thickness of the first and second concrete layers of this part, is the sum of the thickness of the first, second and third concrete layers of this part, arrive And so on.

[0078] Since we know a, h, u and s, we can get x, and thus get the value of this part of the top plate. arrive , and then the top plate of this part is obtained according to the formula ~ .pass ~ , obtain the volume of the 1st to 10th concrete layers ~ . Square volume ~ Divide by the corresponding concrete pouring speed ~ , you can get the pouring speed of the 1st to 8th concrete layers ~ The pouring time of the 1st to 10th concrete layers can be obtained.

[0079] The sum of the pouring time of two adjacent concrete layers is controlled to be between 90% and 120% of the initial setting time t, so as to set After the value of ~ and thickness ~ By obtaining the constraints and settings of the concrete, each concrete layer of the top plate can be poured according to the corresponding pouring speed and thickness, so that the sum of the initial setting time of the corresponding two adjacent layers is between 90% and 120% of the initial setting time t.

[0080] When pouring in layers, the bottom plate is poured first. When pouring the bottom plate, the four lower chamfers are poured synchronously first. For each lower chamfer, pour layer by layer from bottom to top. When the top surface of the concrete layer is flush with the top of the lower chamfer, the concrete pouring of the four lower chamfers is completed. Due to the large cross-sectional span of the bottom plate, oblique pouring is adopted to form a V-shaped uncast space under the driveway. Then the uncast space under the driveway is poured layer by layer from bottom to top until the top surface of the concrete layer is flush with the bottom surface of the driveway.

[0081] The walls are cast from bottom to top layer by layer on the concrete foundation already cast at the four lower chamfers. As the cross-sectional span of the walls is small, horizontal casting is still adopted.

[0082] The top slab is poured in an oblique manner, pouring layer by layer from both sides to the middle until the concrete completely covers the immersed tube reinforcement cage.

[0083] In some embodiments, for the concrete layer in the bottom plate whose top reaches the elevation of the bottom plate, the concrete stacking volume is The calculation formula is replaced by:

[0084]

[0085] For the concrete layer in the top slab that reaches the top or the elevation on the top slab, the concrete stacking volume The calculation formula is replaced by:

[0086]

[0087] Wherein, M is the cross-sectional area of ​​the triangular region at the end of the top plate.

[0088] The elevation on the bottom plate is the height of the top surface of the bottom plate. Figure 2 As shown, the number of paving layers n of the bottom plate portion is 8, the four lower chamfers all have the 1st to 5th concrete layers of the bottom plate portion, and the bottoms of the two lanes all have the 6th to 8th concrete layers of the bottom plate portion. More specifically, Figure 4 As shown in the figure, when pouring the 6th to 8th concrete layers, the discharge point has gradually moved away from the outer wall of the side wall, the bottom plate on the side of the discharge point close to the side wall has been completely filled with concrete, and the concrete on the other side of the discharge point is inclined. arrive are the same.

[0089] Therefore, for the bottom plate ~ , the calculation formula is still:

[0090] ;

[0091] In the calculation of the base plate When , the calculation formula is:

[0092]

[0093] in the formula To calculate the surface area of ​​the sixth concrete layer discharge point close to the outer wall of the side wall, the surface area of ​​this part is a rectangle.

[0094] In the formula To calculate the surface area of ​​the sixth concrete layer's discharge point away from the side wall's outer wall.

[0095] Add the two and multiply by the vertical length , that is, the concrete stacking volume of six layers of concrete is obtained .

[0096] According to the above method, we can further calculate and .

[0097] According to the above method, subsequent concrete layer volume calculations and pouring speed calculations are carried out in sequence to ensure that the layered pouring of the base plate at the current pouring speed can meet the pouring time of two adjacent concrete layers and between 90% and 120% of the initial setting time of the concrete.

[0098] The elevation on the top plate is the height of the top surface of the top plate. Figure 2 As shown in the figure, the number of paving layers n of the top plate is 10. When pouring the 5th to 10th concrete layers, the material discharge point has gradually moved away from the outer wall of the side wall, and the bottom plate on the side of the material discharge point close to the side wall has been completely filled with concrete, while the concrete on the other side of the material discharge point is inclined. arrive are the same.

[0099] Therefore, for the top plate ~ , the calculation formula is still:

[0100] ;

[0101] In calculating the top plate When , the calculation formula is:

[0102] ;

[0103] in the formula To calculate the surface area of ​​the side of the side wall outer wall near the feeding point of the fifth concrete layer, since the immersed tube has an upper chamfer 6, the top of the side wall outer wall (the end face of the top plate) is an inclined surface, and the part of the top plate located outside its top end is a triangle, such as Figure 2As shown, the area of ​​this part is M. The extra area after multiplying the length by the height is the same as M, so M is subtracted.

[0104] In the formula To calculate the surface area of ​​the sixth concrete layer's discharge point away from the side wall's outer wall;

[0105] Add the two and multiply by the vertical length , that is, the concrete stacking volume of five layers of concrete is obtained .

[0106] According to the above method, we can further calculate arrive .

[0107] According to the above method, subsequent concrete layer volume calculations and pouring speed calculations are carried out in sequence to ensure that the top plate is poured in layers at the current pouring speed to meet the pouring time of two adjacent concrete layers and between 90% and 120% of the initial setting time of the concrete.

[0108] The volume of concrete pile that reaches the upper elevation is calculated in the above manner, and the calculation result is more accurate, avoiding the problem of too small calculation result of the concrete pile volume, thereby ensuring the accuracy of the concrete layer volume calculation, and then obtaining the accurate pouring speed, ensuring that the sum of the pouring time of adjacent concrete layers is between 90% and 120% of the initial setting time of the concrete, avoiding too large time difference in paving between concrete layers, thereby preventing cold joints between concrete layers and ensuring the strength requirements of large-section immersed tubes.

[0109] In some embodiments, when calculating the pouring speed, the concrete stacking volume, concrete layer volume and pouring speed are calculated in sequence for the concrete layers whose bottom ends are located below the bottom plate elevation or the top plate elevation. That is, the concrete layers whose bottom ends are higher than the bottom plate elevation and the top plate elevation are not involved in the calculation of the pouring speed. Based on the supply capacity of the mixing station, the layers can be poured at a pouring speed not lower than the adopted pouring speed.

[0110] For the bottom slab, when the concrete layers of the lower chamfers on both sides converge under the roadway, the subsequent concrete pouring is stacked in layers on top, and the cross-section on the side where the material discharge point is far from the outer wall of the side wall is not a triangle. If the original formula is used for cross-section calculation, the calculation result will be inaccurate. For the top slab, when the concrete layers on both sides converge in the center of the top slab, the subsequent concrete pouring is stacked in layers on top, and the cross-section on the side where the material discharge point is far from the outer wall of the side wall is not a triangle. If the original formula is used for cross-section calculation, the calculation result will be inaccurate.

[0111] Therefore, this part of the concrete layer does not participate in the calculation of the pouring speed, such as Figure 2As shown, the 5th to 8th concrete layers of the bottom plate and the 9th and 10th concrete layers of the top plate are not involved in the calculation of the pouring speed.

[0112] In addition, since the subsequently poured concrete was layered and could not touch the bottom, the lateral width of this part of the concrete layer was greatly reduced, the amount of concrete earthwork was greatly reduced, and the corresponding pouring time was also greatly reduced. By pouring this part of the concrete layer at the pouring speed of the previous concrete layer, it can be ensured that the sum of the pouring time of adjacent concrete layers in this part is between 90% and 120% of the initial setting time of the concrete, avoiding cold joints caused by excessive time difference in paving, ensuring the strength requirements of the immersed tube, reducing the workload of data calculation, and improving work efficiency.

[0113] In some embodiments, concrete is spread to four lower chamfers through four string tubes that penetrate into the immersed tube steel cage from top to bottom, and as the concrete layers are gradually stacked from bottom to top, the string tubes gradually move upward. After the lower chamfers are poured, the wall pouring is started through the string tubes, and the pouring between the two lower chamfers corresponding to the driveway is started simultaneously.

[0114] The string tube is gradually raised to cast the lower chamfer layer by layer, and then the wall (side wall and middle partition wall) above the lower chamfer is cast layer by layer, so that the bottom plate casting and wall casting are quickly connected. The string tube does not need to move horizontally to change the horizontal position of the material discharge point, making the operation more convenient. While entering the wall casting, the lower part of the carriageway is cast, even if the rear end of the bottom plate casting is carried out simultaneously with the side wall casting, the operation efficiency is improved.

[0115] In addition, each string tube is assembled from multiple sections. As the string tube rises with the concrete surface, it is removed section by section from the top to ensure that the height of the concrete free fall along the string tube is less than 2m.

[0116] In some embodiments, the wall casting includes the casting of the middle partition wall and the casting of the side walls. The casting of the middle partition wall starts before the casting of the side walls, so that the top surface of the middle partition wall concrete is 0.8 to 1.0 m higher than the top surface of the side wall concrete, that is, the cast part of the middle partition wall is 0.8 to 1.0 m higher than the cast part of the side wall.

[0117] The middle partition wall is cast higher than the side walls, so that the center of gravity of the poured concrete is closer to the center, improving stability and avoiding displacement or deformation of one side of the formwork due to excessive pressure on the center of gravity, thereby ensuring the accuracy of the prefabricated immersed tube shape.

[0118] In some embodiments, the layer thickness of the upper portion of the middle partition wall at the upper chamfer is smaller than the layer thickness of the lower portion of the middle partition wall, and the number of concrete layers of the middle partition wall is greater than the number of concrete layers of the side wall.

[0119] The middle partition wall is poured layer by layer from top to bottom. When pouring to the top, the thickness of the concrete layer decreases, and the pouring time of each layer is also reduced. The sum of the pouring time of two adjacent concrete layers in the middle partition wall is significantly less than 0.9~1.1t. Therefore, after completing the pouring of one concrete layer, you can wait for a period of time before pouring the next concrete layer, and the total time still meets the requirement of 0.9~1.1t.

[0120] At the same time, the side wall is poured layer by layer from top to bottom. Since the number of concrete layers is less than that of the middle partition wall, the pouring of the next concrete layer is started after the pouring of one concrete layer is completed, without any time interval in between, so that the sum of the pouring time of two adjacent concrete layers not only meets the requirement of less than 0.9-1.1t, but also enables the pouring of the side wall to be completed before the pouring of the middle partition wall. Since the top plate is poured from both sides to the middle, the side wall that has been poured serves as the bottom surface of the top plate, so the top plate pouring starts when the top plate pouring is completed but the pouring of the middle partition wall is not completed.

[0121] When the pouring of the middle partition wall is completed, the top slab has completed the pouring of multiple concrete layers. The concrete layers of the top slab have extended to the top of the middle partition wall and connected with it, and the sum of the pouring time between the concrete layer at the top of the middle partition wall and the concrete layer of the adjacent top slab meets the requirement of 0.9~1.1t, that is, the two adjacent concrete layers at the top of the middle partition wall and the bottom of the top slab meet the pouring quality requirements, thereby avoiding the cold joint caused by the large difference in pouring time between the bottom slab and the middle partition wall, and ensuring the strength requirements of large-section immersed tubes.

[0122] In some embodiments, when pouring the base plate, the pouring of concrete layers on both sides is performed alternately, so that the concrete layers are staggered under the roadway.

[0123] More specifically, for the bottom plate on one side of the immersed tube, this part of the bottom plate is first poured layer by layer at the two lower chamfers on both sides, and the concrete pouring on both sides is carried out alternately in layers. The subsequent pouring of concrete layers under the subsequent carriageway is also carried out in an alternating manner, so that the parts where the concrete on both sides are connected are staggered from bottom to top under the carriageway.

[0124] By staggering the start time of pouring at the two lower chamfers on one side of the immersed tube, the concrete can be poured alternately in layers on both sides to form an interlaced structure, and the sum of the pouring times of adjacent concrete layers at each lower chamfer can be ensured to meet the requirement of 0.9 to 1.1 t.

[0125] The bottom plate on the other side of the immersed tube is also cast alternately in the above manner to form an interlaced structure under the corresponding lane.

[0126] The concrete layers are staggered under the carriageway so that the concrete layers on both sides can support each other vertically, making the concrete structure of this part denser, improving the strength of the bottom plate structure under the carriageway, carrying a larger traffic flow, and improving the traffic capacity of the immersed tube tunnel.

[0127] In some embodiments, each concrete layer is first paved from the first end to the second end in the longitudinal direction, and when it is paved to 3 to 5 meters away from the second end, it is then paved from the second end to the first end.

[0128] When the poured concrete is pushed to 3 to 5 meters away from one end, the direction of the concrete distribution is changed to avoid the accumulation of floating slurry in the end embedded parts or the area with dense steel bars, so as to ensure the compactness of the concrete pouring and the quality of the pouring operation. Since the concrete is pushed to 3 to 5 meters away from one end, the longitudinal length L of the concrete paving is the longitudinal length of the pipe section minus 3 to 5 meters when the pouring quality is verified. The reduction of the longitudinal length reduces the earthwork volume of each concrete layer, so that the concrete layers can have a greater thickness when the concrete layers are divided, the number of concrete layers is reduced, the number of layered pouring operations is reduced, the work intensity is reduced, and the work efficiency is improved.

[0129] In some embodiments, Figure 5 As shown, the immersed tube reinforcement cage is located in the concrete pouring space between the inner formwork 7 and the outer formwork 8. Both the inner formwork and the outer formwork are provided with a plurality of vibration holes 9 from top to bottom, and the vibration holes on the inner formwork 7 are staggered with the vibration holes on the outer formwork.

[0130] When pouring the wall, the concrete layers are vibrated alternately from bottom to top through the vibration holes on the inner formwork and the vibration holes on the outer formwork, and the vibrating rod is inserted obliquely into the corresponding concrete layer and extends downward to the adjacent next concrete layer with a thickness of 5 to 10 cm.

[0131] Since the inner and outer vibration holes are arranged alternately from top to bottom, a vibrating rod is inserted through each vibration hole to vibrate the concrete. When the total number of vibration holes is smaller, it can be ensured that the vibration can cover all positions of the vertical space, thereby ensuring the quality of the wall concrete vibration and avoiding bubbles in the concrete. In addition, the reduction in the number of vibration holes reduces the impact of the openings on the strength of the formwork, improves the stability of the formwork, and thereby ensures the accuracy of the shape of the prefabricated immersed tube.

[0132] The vibrating rod is inserted at an angle so that it can act on the concrete more in height and width, maximizing the vibration range and ensuring that all bubbles float up and float out. The vibrating rod is inserted into the next concrete layer, so that it can vibrate the corresponding concrete layer while re-vibrating the adjacent concrete layer below, so that each concrete layer can be vibrated twice, improving the vibration effect.

[0133] In some embodiments, one side of the inner formwork 7 is divided into an inner upper chamfer section 71, an inner wall section 72, an inner lower chamfer section 73 and an inner bottom plate section 74 from top to bottom, and the inner wall section, the inner lower chamfer section and the inner bottom plate section are all provided with vibration holes, and the number of vibration holes in the inner bottom plate section is greater than that in the inner lower chamfer section.

[0134] The outer template 8 is divided into an outer upper chamfer section 81 and an outer wall surface section 82 from top to bottom, and both the outer upper chamfer section and the outer wall surface section are provided with vibration holes.

[0135] After the lower chamfer of the bottom plate is cast, the inner lower chamfer section at the bottom end of the inner formwork can be attached to the solidified concrete at the lower chamfer, so that the four lower chamfers of the bottom plate respectively support the corresponding inner lower chamfer sections of the inner formwork, thereby improving the stability of the formwork system and the accuracy of immersed tube prefabrication.

[0136] When pouring the upper chamfer and the lower chamfer, the vibrating rod is obliquely inserted into the vibration holes of the inner lower chamfer section and the outer upper chamfer section, and after the first vibration is completed, the second vibration is performed, and the length of the vibrating rod used in the second vibration is greater than that used in the first vibration.

[0137] Since the inner lower chamfer section of the inner formwork is self-injured and covers the concrete poured at the lower chamfer, the concrete at the lower chamfer can be vibrated through the vibration holes set on the inner lower chamfer section, so that the bubbles in the concrete are discharged through the vibration holes, avoiding bubbles remaining in the concrete. In addition, since the spaces at the upper chamfer and the lower chamfer are both inclined, it is difficult to discharge the bubbles. Re-vibration with a longer vibrating rod can ensure the discharge of bubbles and the vibration effect at the chamfer.

[0138] Finally, it should be noted that: the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0139] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A high-precision layered controlled pouring method for large-section immersed tube concrete, comprising: performing full-section layered pouring on the immersed tube segment space formed between the inner formwork and the outer formwork, wherein the full-section layered pouring includes pouring the bottom plate, pouring the wall after the bottom plate is poured, and pouring the top plate after the wall is poured; It is characterized in that The bottom plate casting and the top plate casting are both cast obliquely layer by layer, and the wall casting is cast horizontally layer by layer: When pouring the bottom slab and top slab, the pouring speed is Control the pump truck and / or ground pump to pour concrete in layers and control the thickness of the concrete layers , and The following constraints must be met: in, is the concrete stacking volume, t is the initial setting time of concrete, is the distance between the concrete feeding point and the adjacent wall outer wall, s is the slump of concrete, u is the expansion of concrete, is the height of the concrete paving point, is the horizontal width of the concrete paving, is the longitudinal length of the concrete paving, is the maximum pouring speed, and n is the number of concrete paving layers.

2. According to claim 1, the high-precision layered controlled pouring method for large-section immersed tube concrete is characterized in that: When pouring the base plate, first pour the four lower chamfers of the base plate layer by layer, and then pour the space between the two lower chamfers corresponding to the carriageway layer by layer; When pouring the wall, after the lower chamfer of the bottom plate is poured, the wall is poured layer by layer based on it; When pouring the top slab, pour it layer by layer from both sides to the middle.

3. According to claim 1, the high-precision layered controlled pouring method for large-section immersed tube concrete is characterized in that: For the concrete layer in the base plate whose top reaches the elevation of the base plate, the concrete stacking volume The calculation formula is replaced by; For the concrete layer in the top slab that reaches the top or the elevation on the top slab, the concrete stacking volume The calculation formula is replaced by: Wherein, M is the cross-sectional area of ​​the triangular region at the end of the top plate.

4. According to claim 1, the high-precision layered controlled pouring method for large-section immersed tube concrete is characterized in that: The concrete is spread to the four lower chamfers through four string tubes that penetrate into the immersed tube steel cage from top to bottom, and as the concrete layers are gradually stacked from bottom to top, the string tubes gradually move upward. After the lower chamfers are poured, the wall pouring is started through the string tubes, and the pouring between the two lower chamfers corresponding to the driveway is started simultaneously.

5. According to claim 1, the high-precision layered controlled pouring method for large-section immersed tube concrete is characterized in that: The wall casting includes the casting of the middle partition wall and the casting of the side walls. The casting of the middle partition wall starts before the casting of the side walls so that the top surface of the middle partition wall concrete is 0.8 to 1.0 m higher than the top surface of the side wall concrete.

6. The high-precision layered controlled pouring method for large-section immersed tube concrete according to claim 5 is characterized in that: The layer thickness at the upper chamfer of the middle partition wall is smaller than the layer thickness at the lower part of the middle partition wall, and the number of concrete layers of the middle partition wall is greater than the number of concrete layers of the side wall, so that the casting of the side wall can be completed before the casting of the middle partition wall; When the middle partition wall is poured, the concrete layer of the top plate extends to the top of the middle partition wall, so that the sum of the pouring time between the concrete layer at the top of the middle partition wall and the concrete layer of the adjacent top plate meets the requirement of 0.9 to 1.1t.

7. The high-precision layered controlled pouring method for large-section immersed tube concrete according to claim 1 is characterized in that: When pouring the base slab, the pouring of concrete layers on both sides is carried out alternately so that the concrete layers are staggered under the carriageway.

8. The high-precision layered controlled pouring method for large-section immersed tube concrete according to claim 1 is characterized in that: Each concrete layer is first spread from the first end to the second end in the longitudinal direction, and when it is spread to 3 to 5 meters away from the second end, it is then spread from the second end to the first end.

9. The high-precision layered controlled pouring method for large-section immersed tube concrete according to claim 1 is characterized in that: The immersed tube reinforcement cage is located in the concrete pouring space between the inner formwork and the outer formwork, and the inner formwork and the outer formwork are both provided with a plurality of vibration holes from top to bottom, and the vibration holes on the inner formwork and the vibration holes on the outer formwork are arranged alternately; When pouring the wall, the concrete layers are vibrated alternately from bottom to top through the vibration holes on the inner formwork and the vibration holes on the outer formwork, and the vibrating rod is inserted obliquely into the corresponding concrete layer and extends downward to the adjacent next concrete layer with a thickness of 5 to 10 cm.

10. The high-precision layered controlled pouring method for large-section immersed tube concrete according to claim 9, characterized in that: One side of the inner template is divided into an inner upper chamfer section, an inner wall section, an inner lower chamfer section and an inner bottom plate section from top to bottom. The inner wall section, the inner lower chamfer section and the inner bottom plate section are all provided with vibration holes, and the number of vibration holes in the inner bottom plate section is greater than that in the inner lower chamfer section. The outer template is divided into an outer upper chamfer section and an outer wall section from top to bottom, and both the outer upper chamfer section and the outer wall section are provided with vibration holes; When pouring the upper chamfer and the lower chamfer, the vibrating rod is obliquely inserted into the vibration holes of the inner lower chamfer section and the outer upper chamfer section, and after the first vibration is completed, the second vibration is performed, and the length of the vibrating rod used in the second vibration is greater than that used in the first vibration.

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