Method for connecting steel blade foot of open caisson or cofferdam with precast concrete segment

Abstract

The application discloses a method for connecting a steel blade foot of a caisson or cofferdam with a prefabricated concrete segment, which comprises the following steps: installing a temporary supporting cushion and a steel blade foot, and setting a temporary support; installing a positioning pin shaft and a prefabricated concrete segment on the top of the steel blade foot, and installing an elastic sealing ring; installing a counterweight on the top of the prefabricated concrete segment, pouring self-compacting concrete into the steel blade foot; removing the counterweight, injecting waterproof mortar into the prefabricated concrete segment; removing the temporary supporting cushion, sinking the steel blade foot and the prefabricated concrete segment, and installing the remaining prefabricated concrete segments in the sinking process. The method has the advantages that the prefabricated concrete segment and the steel blade foot are accurately positioned through the positioning pin shaft and the bolt hole, the concrete in the steel blade foot has no dead angle through the setting of the overflow port, the bonding effect of the self-compacting concrete and the thread is fully utilized, and the nut installation problem in the narrow space of the blade foot is solved.

Description

Technical Field

[0001] This invention relates to the field of construction tools technology, specifically to a method for connecting the steel cutting edge of a caisson or cofferdam to precast concrete segments. Background Technology

[0002] The connection between precast concrete segments and steel cutting edges typically employs pre-tightening bolts and shear keys. To enhance the rigidity of the cutting edge, self-compacting concrete is generally poured inside. The pouring of pre-tightening bolts and self-compacting concrete involves overlapping processes. If the self-compacting concrete is poured first, the positioning of the pre-tightening nuts requires extremely high precision; if the precast concrete segments and pre-tightening bolts are installed first, dead zones may exist in the pouring of the self-compacting concrete inside the cutting edge. Therefore, a method is needed that can simultaneously ensure accurate positioning of the pre-tightening nuts and eliminate concrete dead zones within the steel cutting edge after connecting the precast concrete segments and steel cutting edges as a single unit. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of the prior art by providing a method for connecting the steel cutting edge of a caisson or cofferdam to precast concrete segments. This method uses positioning pins and bolt holes to accurately position the precast concrete segments to the steel cutting edge, and the inclusion of an overflow port ensures that there are no dead zones in the concrete within the steel cutting edge.

[0004] The objective of this invention is achieved through the following technical solutions:

[0005] A method for connecting the steel cutting edge of a caisson or cofferdam to precast concrete segments, wherein the connection method is as follows:

[0006] Step 1: Install temporary supports, install steel cutting feet on the temporary supports, and set temporary supports on both sides of the steel cutting feet;

[0007] Step 2: Remove the temporary support and install the positioning pin on the top of the steel blade foot;

[0008] Step 3: Install a precast concrete segment on the top of the steel cutting foot using the positioning pin, and install an elastic sealing ring between the steel cutting foot and the precast concrete segment;

[0009] Step 4: Install counterweights on top of the precast concrete segments, pour self-compacting concrete into the steel cutting edge, and wait for the concrete to cure.

[0010] Step 5: Remove the counterweight and inject waterproof mortar into the precast concrete segment;

[0011] Step 6: Remove the temporary supports, allow the steel cutting edge and precast concrete segments to sink, and install the remaining precast concrete segments during the sinking process.

[0012] Optionally, the top of the steel cutting foot has an overflow port and a bolt hole, and the top of the steel cutting foot is provided with a positioning pin between the overflow port and the bolt hole. The side wall of the steel cutting foot is provided with a grouting hole near the top, and the top of the grouting hole is higher than the top of the steel cutting foot.

[0013] Optionally, in step 3, the precast concrete segment is mounted on the top of the steel blade foot through the bolt hole and the positioning pin.

[0014] Optionally, in step 4, self-compacting concrete is injected into the steel cutting foot through the injection hole.

[0015] Optionally, the overflow port is connected to the outside air and is located close to the precast concrete segment.

[0016] Optionally, the precast concrete segment includes a precast segment body and a pre-tightening bolt disposed within the precast segment body, the lower end of the pre-tightening bolt extending out of the bottom of the precast segment body.

[0017] Optionally, in step 5, after removing the counterweight, a pre-tightening force is applied to the pre-tightening bolt, and then waterproof mortar is injected into the precast concrete segment.

[0018] Optionally, the preform body has a groove on top, and the upper end of the pre-tightening bolt extends beyond the bottom surface of the groove and is lower than the top surface of the preform body.

[0019] Optionally, the two sides of the precast concrete segment are provided with longitudinally embedded continuous steel plates, the bottom of the embedded continuous steel plates are flush with the bottom surface of the precast concrete segment, and the embedded continuous steel plates are provided with a pouring hole through the transverse direction near the bottom.

[0020] Optionally, in step 5, waterproof mortar is injected into the precast concrete segment through the pouring hole.

[0021] The advantages of this invention are: it provides a method for connecting the steel cutting edge of a caisson or cofferdam to a precast concrete segment, which enables precise positioning of the precast concrete segment and the steel cutting edge through positioning pins and bolt holes, and ensures that there are no dead corners in the concrete inside the steel cutting edge through the setting of the overflow port, while making full use of the bonding effect between the self-compacting concrete and the thread, and eliminating the problem of nut installation in the narrow space inside the cutting edge. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the steel cutting edge of the present invention;

[0023] Figure 2 This is a schematic diagram of the connection structure between the steel cutting edge and the precast concrete segment of the present invention.

[0024] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0025] Figure 4 This is a schematic diagram of the connection structure of the steel cutting foot, precast concrete segment, and counterweight block of the present invention.

[0026] Figure 5 This is a schematic diagram of the connection structure of the steel cutting foot, precast concrete segment, and counterweight block of the present invention.

[0027] Figure 6 for Figure 5 A schematic diagram of the connection structure after removing the counterweight;

[0028] Figure 7 This is a schematic diagram of the structure of the steel cutting edge of the present invention, after which two precast concrete segments are assembled. Detailed Implementation

[0029] The markings in the diagram are as follows: 1. Steel cutting edge, 2. Overflow port, 3. Positioning pin, 4. Bolt hole, 5. Grouting hole, 6. Temporary support, 7. Precast concrete segment, 8. Pre-tightening bolt, 9. Groove, 10. Elastic sealing ring, 11. Embedded continuous steel plate, 12. Pouring hole, 13. Counterweight, 14. Shear key, 15. Stiffening plate, 71. Precast segment body, 100. Concrete, 200. Grouting surface, 300. Temporary support, 400. Remaining precast concrete segment.

[0030] Example: Please refer to Figure 2 and Figure 3 The diagram illustrates a method for connecting the steel cutting edge of a caisson or cofferdam to precast concrete segments. The method includes a hollow steel cutting edge 1 into which concrete can be poured. The top of the steel cutting edge 1 has an overflow port 2 for ventilation and a bolt hole 4. A positioning pin 3 is located at the top of the steel cutting edge 1, between the overflow port 2 and the bolt hole 4. A precast concrete segment 7 is positioned and installed at the top of the steel cutting edge 1 via the overflow port 2 and the bolt hole 4. A grouting hole 5 is located on the side wall of the steel cutting edge 1 near the top, communicating with the interior of the steel cutting edge 1, and the top of the grouting hole 5 is higher than the top of the steel cutting edge 1.

[0031] like Figure 3 As shown, in this embodiment, the precast concrete segment 7 includes a precast segment body 71 and a pre-tightening bolt 8 disposed within it. The lower end of the pre-tightening bolt 8 extends beyond the bottom of the precast segment body 71. The precast segment body 71 has a groove 9 on its top, and the upper end of the pre-tightening bolt 8 extends beyond the bottom surface of the groove 9 and is lower than the top surface of the precast segment body 71. The lower end of the pre-tightening bolt 8 has a deep thread.

[0032] like Figure 3 and Figure 4 As shown, in this embodiment, an elastic sealing ring 10 is provided near the edge of the bottom of the precast concrete segment 7 to contact and seal with the top of the steel blade foot 1. Longitudinal embedded steel plates 11 are provided on both sides of the precast concrete segment 7, with the bottom of the embedded steel plates 11 flush with the bottom surface of the precast concrete segment 7. A pouring hole 12 is provided transversely through the embedded steel plates 11 near the bottom.

[0033] In this embodiment, the overflow port 2 is connected to the outside air and is located close to the precast concrete segment 7. It also includes a counterweight block 13 that can be pressed down on the top of the precast concrete segment 7.

[0034] This embodiment also includes a method for connecting the steel cutting edge of a caisson or cofferdam to precast concrete segments, wherein the connection method is as follows:

[0035] Step 1: Install temporary support 6, install steel cutting foot 1 on temporary support 6, and set temporary supports 300 on both sides of steel cutting foot 1;

[0036] Step 2: Remove the temporary support 300 and install the positioning pin 3 on the top of the steel blade foot 1;

[0037] Step 3: Install the precast concrete segment 7 on the top of the steel blade foot 1 through the bolt hole 4 and the positioning pin 3, and install the counterweight 13 on the top of the precast concrete segment 7;

[0038] Step 4: Pour self-compacting concrete 100 into the steel blade foot 1 through the grouting hole 5, and wait for the concrete 100 to cure.

[0039] Step 5: Remove the counterweight 13, apply pre-tightening force to the pre-tightening bolt 8, and inject waterproof mortar into the pouring hole 12;

[0040] Step 6: Remove temporary support 6, allow the steel blade foot precast concrete segment to sink, and install the remaining precast concrete segment 400.

[0041] The following description will further illustrate the characteristics and functions of the present invention.

[0042] like Figure 3 and Figure 5 As shown, when using the steel blade foot precast concrete segment casting and molding kit of this embodiment, the following operations are performed:

[0043] like Figure 1As shown, initially, a temporary support 6 is set at the bottom of the steel blade foot 1 to make the overall center of gravity more fixed and stable. Then, a lifting device can be used to lift the precast concrete segment 7, and the pre-tightening bolt 8 of the precast concrete segment 7 is passed through the bolt hole 4. The positioning hole at the bottom of the precast concrete segment 7 is aligned with the positioning pin 3, and the precast concrete segment 7 is gradually lowered and fixed to the top of the steel blade foot 1.

[0044] like Figure 6 and Figure 7 As shown, concrete 100 is then gradually poured directly into the steel cutting edge 1 until the concrete reaches the casting surface 200. The highest level of the casting surface 200 should be slightly higher than the top surface of the steel cutting edge 1. At the same time, a lifting device can be used to suspend the counterweight 13 and press it onto the top of the precast concrete segment 7, while waiting for the concrete to dry. When the concrete is almost dry, the counterweight 13 is removed and the pre-tightening bolts 8 are further tightened. Then, waterproof mortar is injected through the pouring hole 12, and then a period of time is allowed.

[0045] Finally, after the precast concrete segment 7 with the steel cutting edge has completely solidified, the temporary support 6 is removed, and the precast concrete segment with the steel cutting edge can sink. The steel cutting edge precast concrete segment 7 can continue to sink by adding the remaining precast concrete segments with the same structure above it.

[0046] It is worth noting that the grouting holes begin on the side of the steel cutting edge, and vent holes (overflow outlets) are opened on the top surface. The grouting surface extends beyond the top surface of the cutting edge to ensure the compaction of the concrete inside. Furthermore, the pre-tightening bolts are embedded in the self-compacting concrete for a certain length, and the lower end of the pre-tightening bolts has deep threads, improving the adhesion between the pre-tightening bolts and the concrete. Finally, a counterweight is placed on top of the precast concrete segment to ensure that the waterproof elastic sealing ring is in working condition before the pre-tightening bolts are tightened. The counterweight is equivalent to the pre-tightening force of the pre-tightening bolts, and the counterweight is removed after the pre-tightening bolts are tightened. After the self-compacting concrete inside the steel cutting edge reaches its design strength, the pre-tightening bolts are tightened, which enhances the connection between the precast concrete segment and the steel cutting edge. The diameter of the bolt holes at the top of the steel cutting edge is larger than the diameter of the pre-tightening bolts by a certain size, which solves the problem of high installation accuracy of the pre-tightening bolts.

[0047] In summary, this invention provides a method for connecting the steel cutting edge of a caisson or cofferdam to precast concrete segments. The method uses positioning pins and bolt holes to accurately position the precast concrete segments to the steel cutting edge. Furthermore, the inclusion of an overflow port ensures that there are no dead corners in the concrete within the steel cutting edge. It also fully utilizes the bonding effect between the self-compacting concrete and the threads, and eliminates the problem of installing nuts in the narrow space within the cutting edge.

[0048] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for connecting the steel cutting edge of a caisson or cofferdam to precast concrete segments, characterized in that, The connection method is as follows: Step 1: Install temporary supports, install steel cutting feet on the temporary supports, and set temporary supports on both sides of the steel cutting feet; Step 2: Remove the temporary support and install the positioning pin on the top of the steel blade foot; Step 3: Install a precast concrete segment on the top of the steel cutting foot using the positioning pin, and install an elastic sealing ring between the steel cutting foot and the precast concrete segment; Step 4: Install counterweights on top of the precast concrete segments, pour self-compacting concrete into the steel cutting edge, and wait for the concrete to cure. Step 5: Remove the counterweight and inject waterproof mortar into the precast concrete segment; Step 6: Remove the temporary supports, allow the steel cutting edge and precast concrete segments to sink, and install the remaining precast concrete segments during the sinking process. The precast concrete segment includes a precast segment body and a pre-tightening bolt disposed within the precast segment body, with the lower end of the pre-tightening bolt extending out of the bottom of the precast segment body; In step 5, after removing the counterweight, a pre-tightening force is applied to the pre-tightening bolts, and then waterproof mortar is injected into the precast concrete segment. The counterweight has a preload force equivalent to that of the preload bolt.

2. The method for connecting the steel cutting edge of a caisson or cofferdam to precast concrete segments according to claim 1, characterized in that, The top of the steel cutting foot has an overflow port and a bolt hole. The positioning pin is provided at the top of the steel cutting foot between the overflow port and the bolt hole. The side wall of the steel cutting foot has a grouting hole near the top position. The top of the grouting hole is higher than the top of the steel cutting foot.

3. The method for connecting the steel cutting edge of a caisson or cofferdam to precast concrete segments according to claim 2, characterized in that, In step 3, the precast concrete segment is installed on the top of the steel blade foot through the bolt hole and the positioning pin.

4. The method for connecting the steel cutting edge of a caisson or cofferdam to precast concrete segments according to claim 2, characterized in that, In step 4, self-compacting concrete is injected into the steel cutting foot through the injection hole.

5. The method for connecting the steel cutting edge of a caisson or cofferdam to precast concrete segments according to claim 2, characterized in that, The overflow port is connected to the outside air and is located close to the precast concrete segment.

6. The method for connecting the steel cutting edge of a caisson or cofferdam to precast concrete segments according to claim 1, characterized in that, The preform body has a groove on top, and the upper end of the pre-tightening bolt extends beyond the bottom surface of the groove and is lower than the top surface of the preform body.

7. The method for connecting the steel cutting edge of a caisson or cofferdam to precast concrete segments according to claim 1, characterized in that, The two sides of the precast concrete pipe segment are provided with longitudinally embedded continuous steel plates. The bottom of the embedded continuous steel plates is flush with the bottom surface of the precast concrete pipe segment, and the embedded continuous steel plates are provided with a pouring hole through the transverse direction near the bottom.

8. The method for connecting the steel cutting edge of a caisson or cofferdam to precast concrete segments according to claim 7, characterized in that, In step 5, waterproof mortar is injected into the precast concrete segment through the pouring hole.

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