A phased diversion construction method for river-crossing structures

Abstract

The invention discloses a phased diversion construction method for a river-crossing structure, which belongs to the construction of a river-crossing structure. The phased diversion construction method for a river-crossing structure includes step one: constructing a steel temporary bridge and carrying a pile driving device; step two: setting up locking steel pipe piles and constructing a first-stage cofferdam; step three: constructing a box culvert structure section in the first-stage cofferdam; step four: constructing a cofferdam conversion structure; step five: dismantling the first-stage cofferdam and constructing a second-stage cofferdam; step six: constructing a box culvert structure section in the second-stage cofferdam; step seven: after completing the construction of all the box culvert structure sections in the second-stage cofferdam, dismantling the second-stage cofferdam. The phased cofferdam method is adopted, firstly setting the first-stage cofferdam, and constructing the box culvert structure section in the first-stage cofferdam, after the construction of the box culvert structure section in the first-stage cofferdam is completed, constructing the cofferdam conversion structure, dismantling the first-stage cofferdam, and constructing the second-stage cofferdam at the same time, the cofferdam conversion structure forms a closed water-stop conversion system, which not only realizes the rapid conversion of the flood discharge channel and improves the construction efficiency, but also ensures the normal flow of the river.

Description

Technical Field

[0001] The invention relates to the construction of a river-penetrating structure, and in particular to a phased diversion construction method of a river-penetrating structure. Background Art

[0002] In recent years, there are more and more bridges across rivers and lakes, and large municipal water supply culverts crossing waters. When underwater components need to be constructed by dry construction, cofferdams must be used as water retaining facilities. In the construction of water conservancy projects, temporary enclosure components are also needed to build permanent water conservancy facilities. Large earth-rock cofferdams or concrete core wall earth-rock cofferdams are usually used in water conservancy projects. Their function is to prevent water and soil from entering the construction location of the building, so as to drain water in the cofferdam, excavate foundation pits, and build structures.

[0003] Generally speaking, in the construction of major water structures, the height of the cofferdam must be higher than the highest water level that may occur during the construction period. Except as part of the formal building, the cofferdam generally needs to be dismantled after use. However, cutting off the river will change the hydrological conditions of the river, which will have a significant negative impact on both the river ecosystem and the water supply. Therefore, in order to meet the needs of flood discharge, a construction method that can avoid cutting off the river channel is urgently needed to reduce the impact on the water ecosystem and water supply while completing the construction of the river-crossing structure. Summary of the invention

[0004] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a phased diversion construction method for a river-penetrating structure, which can use phased cofferdam diversion to avoid cutting off the river channel, reduce the impact on the water ecosystem, improve the construction efficiency of the river-penetrating structure, and ensure the safety of the project.

[0005] A phased diversion construction method for a river-crossing structure according to an embodiment of the present invention comprises: step one: constructing a steel temporary bridge on one side of the planned land, and carrying a pile driving device on the steel temporary bridge; step two: driving locking steel pipe piles by the pile driving device on the steel temporary bridge, and constructing two first transverse water stop walls and a longitudinal water stop wall, so that the two first transverse water stop walls, the longitudinal water stop wall and the river bank are enclosed to form a first-stage cofferdam; step three: sequentially constructing a plurality of box culvert structure sections in the first-stage cofferdam along the extension direction of the first-stage cofferdam; step four: constructing a cofferdam conversion structure on the conversion box culvert structure section at one end of the first-stage cofferdam away from the river bank, so that the transition box culvert structure section A water-stop conversion system is formed between the first-stage cofferdam and the box culvert structure. Step 5: After completing the construction of all the box culvert structure sections in the first-stage cofferdam, seal the empty boxes of the transition box culvert structure section, backfill the first foundation pit, dismantle the first-stage cofferdam, and use the piling equipment on the steel temporary bridge to drive locking steel pipe piles to construct two second transverse water-stop walls, so that the two second transverse water-stop walls, the cofferdam conversion structure and the river bank are combined to form the second-stage cofferdam. Step 6: In the second-stage cofferdam, construct multiple remaining box culvert structure sections in sequence along the extension direction of the second-stage cofferdam. Step 7: After completing the construction of all the box culvert structure sections in the second-stage cofferdam, dismantle the second-stage cofferdam.

[0006] A phased diversion construction method for a river-penetrating structure according to an embodiment of the present invention has at least the following beneficial effects: a phased cofferdam method is adopted, a first-stage cofferdam is first set, a box culvert structure section is constructed in the first-stage cofferdam, and after the construction of the box culvert structure section in the first-stage cofferdam is completed, a cofferdam conversion structure is constructed, the first-stage cofferdam is dismantled, and a second-stage cofferdam is built at the same time. The cofferdam conversion structure forms a closed water-stopping conversion system, which not only realizes the rapid conversion of flood discharge channels during the construction period of two adjacent segments and improves construction efficiency, but also avoids river interception, ensures normal flood discharge and water flow of the river, and thus reduces the impact of the river-penetrating structure construction on the water ecosystem, water resource supply and surrounding economic activities.

[0007] According to some embodiments of the present invention, in step two, a butter mixture ointment made of asphalt, butter, talcum powder and sawdust in a weight ratio of 4:6:10:1 is applied inside the locking mouth of the locking steel pipe pile to prevent water leakage between two adjacent locking steel pipe piles.

[0008] According to some embodiments of the present invention, in step 2, a first transverse waterstop wall, a longitudinal waterstop wall on the water-facing side, and a first transverse waterstop wall on the water-retaining side are constructed in sequence.

[0009] According to some embodiments of the present invention, in step two, after completing the construction of the first transverse waterstop wall and the longitudinal waterstop wall, the water level in the first-stage cofferdam is lowered to the first design water level, and the first purlin is installed in the upper extension direction of the first transverse waterstop wall. After completing the construction of the first purlin, the water level in the first-stage cofferdam is lowered to the second design water level, and the second purlin is installed in the upper extension direction of the first transverse waterstop wall so that the second purlin is located below the first purlin. After completing the installation of the second purlin, the first foundation pit is excavated to the first design elevation, and finally the bottom sealing concrete is poured at the bottom of the first foundation pit.

[0010] According to some embodiments of the present invention, in step four, the cofferdam conversion structure includes: a conversion mechanism, which is arranged between two first transverse waterstop walls and is sleeved on the transition box culvert structure section; a reinforcement mechanism, which is connected to the first transverse waterstop wall and is connected to the conversion mechanism, and is used to enhance the structural stability of the conversion mechanism.

[0011] According to some embodiments of the present invention, the conversion mechanism includes: two conversion walls, the two conversion walls are arranged in parallel, the conversion wall is arranged between two first transverse water stop walls, and the conversion wall and the transition box culvert structure section are cast as a whole; a plurality of connecting walls, one end of the connecting wall is spanned between the conversion wall and the transition box culvert structure section, and the other end is connected to the first transverse water stop wall, and the connecting wall is used to block the gap between the first transverse water stop wall and the conversion wall.

[0012] According to some embodiments of the present invention, the reinforcement mechanism includes: a plurality of top-to-top assemblies, which are evenly distributed between two conversion walls in a vertical direction, and are used to enhance the overall stiffness of the conversion wall; a plurality of diagonal brace assemblies, which are horizontally arranged and connected to the conversion wall, and are evenly distributed between two first transverse water-stop walls in a vertical direction.

[0013] According to some embodiments of the present invention, in step 2, concrete is poured between the side wall of the transition box culvert structure section and the first transverse water stop wall to increase the pouring range of the bottom seal concrete.

[0014] According to some embodiments of the present invention, in step five, backfilling is performed between both sides of all box culvert structure segments and the first transverse water stop wall using earth filled in ton bags.

[0015] According to some embodiments of the present invention, a water-stop membrane is fixedly provided on the water-facing end of the first-stage cofferdam and the second-stage cofferdam.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention is further described below in conjunction with the accompanying drawings and embodiments:

[0018] Figure 1 It is a schematic flow chart of a phased diversion construction method of a river-crossing structure according to an embodiment of the present invention;

[0019] Figure 2 yes Figure 1 Structural schematic diagram of the middle cofferdam transfer structure;

[0020] Figure 3 yes Figure 2 Structural diagram of the middle locking steel pipe pile;

[0021] Figure 4 yes Figure 1 Sectional view of the middle transition box culvert structure section;

[0022] Figure 5 yes Figure 1 Top view of the middle cofferdam transfer structure.

[0023] Reference numerals:

[0024] First stage cofferdam 100, first transverse water stop wall 110, longitudinal water stop wall 120, locking steel pipe pile 130, first enclosure purlin 140, first transverse brace 141, second enclosure purlin 150, second transverse brace 151, bottom seal concrete 160;

[0025] Box culvert structure section 200, transition box culvert structure section 210, empty box 211;

[0026] Cofferdam conversion structure 300, conversion mechanism 310, conversion wall 311, connecting wall 312, reinforcement mechanism 320, top assembly 321, first horizontal beam 3211, connecting beam 3212, diagonal bracing assembly 322, second horizontal beam 3221, third horizontal beam 3222, diagonal bracing beam 3223. DETAILED DESCRIPTION

[0027] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0028] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are 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, and do not indicate or imply 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.

[0029] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0030] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0031] refer to Figures 1 to 5 A phased diversion construction method for a river-crossing structure according to an embodiment of the present invention is described.

[0032] like Figures 1 to 5 As shown, a phased diversion construction method of a river-crossing structure according to an embodiment of the present invention includes:

[0033] Step 1: Construct a temporary steel bridge on one side of the planned land, and install piling equipment on the temporary steel bridge;

[0034] Step 2: Use the pile driving equipment on the steel temporary bridge to drive the locking steel pipe piles 130, and construct the two first transverse water stop walls 110 and the longitudinal water stop wall 120, so that the two first transverse water stop walls 110 and the longitudinal water stop wall 120 are enclosed with the river bank to form the first stage cofferdam 100;

[0035] Step 3: sequentially constructing a plurality of box culvert structure segments 200 in the first stage cofferdam 100 along the extension direction of the first stage cofferdam 100;

[0036] Step 4: construct a cofferdam conversion structure 300 on the transition box culvert structure section 210200 at one end of the first-stage cofferdam 100 away from the river bank, so as to form a water-stop conversion system between the transition box culvert structure section 210 and the first-stage cofferdam 100;

[0037] Step 5: After completing the construction of all the box culvert structure sections 200 in the first-stage cofferdam 100, seal the empty box 211 of the transition box culvert structure section 210, backfill the first foundation pit, dismantle the first-stage cofferdam 100, and drive the locking steel pipe piles 130 through the pile driving equipment on the steel temporary bridge, and construct two second transverse water stop walls, so that the two second transverse water stop walls, the cofferdam conversion structure 300 and the river bank are enclosed to form the second-stage cofferdam;

[0038] Step 6: sequentially construct multiple box culvert structure segments 200 in the second stage cofferdam along the extension direction of the second stage cofferdam;

[0039] Step 7: After completing the construction of all box culvert structure sections 200 in the second-stage cofferdam, dismantle the second-stage cofferdam.

[0040] Therefore, if Figure 2 As shown, a phased cofferdam method is adopted, firstly, a first-stage cofferdam 100 is set up, and a box culvert structure section 200 is constructed in the first-stage cofferdam 100. After the construction of the box culvert structure section 200 in the first-stage cofferdam 100 is completed, a cofferdam conversion structure 300 is constructed, the first-stage cofferdam 100 is dismantled, and a second-stage cofferdam is built at the same time. The cofferdam conversion structure 300 forms a closed water-stop conversion system, which not only realizes the rapid conversion of the flood discharge channel during the construction period of two adjacent sections and improves the construction efficiency, but also avoids intercepting the river and ensures the normal flow of the river, thereby reducing the impact of the construction of river-crossing structures on the water ecosystem, water resources supply and surrounding economic activities.

[0041] It should be noted that the inverted siphon culvert is mainly composed of an inlet section, a horizontal section and an outlet section. The inlet section is composed of an inlet ditch, a sedimentation tank, an inlet, etc. The horizontal section is the main body of the inverted siphon, which is composed of a foundation, a box culvert structure section, a joint, etc. The outlet section is composed of an outlet well, an outlet ditch, etc.

[0042] The following is a specific embodiment to illustrate the construction method of a river-crossing structure diversion in stages:

[0043] It should be noted that the river-crossing structure is constructed from the north bank to the south bank of the river, and the river flows from west to east. Figures 2 to 5 As shown, the left is north, the right is south, the front is west, and the back is east, that is, the front is the upstream of the river, and the back is the downstream of the river. Therefore, in this specific embodiment, the river-crossing structure is constructed from left to right, and the river flows from front to back.

[0044] Step 1: Construct a temporary steel bridge and install piling equipment. A temporary steel bridge is constructed on one side of the planned land. The temporary steel bridge is 128m long and 8m wide. It is located on the west side of the upstream locking steel pipe pile 130 cofferdam. The foundation of the temporary steel bridge uses a 28m long Φ559 steel pipe. Specifically, the steel pipe is buried about 25.8m deep. The pile top beam uses a double-jointed 450×150×11.5 I-beam, the transverse distribution beam uses a 220×110×7.5 I-beam, and the bridge deck uses a 280×84×9.5 channel steel.

[0045] Furthermore, a 75-ton crawler crane was positioned on the steel temporary bridge, and a vibrating hammer was hung on the crawler crane, and the two were combined as the main equipment for piling.

[0046] Step 2: Set up locking steel pipe piles 130 and construct the first stage cofferdam 100. At a distance of 1m from the steel temporary bridge, a crawler crane with a vibrating hammer is used to drive the locking steel pipe piles 130. In this specific embodiment, the two first transverse water stop walls 110 are respectively the first transverse water stop wall 110 facing the upstream water and the first transverse water stop wall 110 facing the downstream water. Specifically, the locking steel pipe piles 130 are constructed from the north bank of the river toward the center of the river, and are driven in sequence in the direction of the first transverse water stop wall 110 facing the upstream water, the longitudinal water stop wall 120 in the river, and the first transverse water stop wall 110 facing the downstream water to form the first stage cofferdam 100 across half of the river.

[0047] like Figure 3 As shown, after the construction of the first-stage cofferdam 100 is completed, the water level in the first-stage cofferdam 100 is lowered to 0m, and then the first purlin 140 arranged along the extension direction is installed on each first transverse water stop wall 110, and the first purlin 140 on each first transverse water stop wall 110 is located in the first-stage cofferdam 100, and a first cross brace 141 extending along the front-back direction is arranged between the two first purlins 140, wherein a plurality of first cross braces 141 are arranged, and the plurality of first cross braces 141 are evenly distributed along the extension direction of the first transverse water stop wall 110, and the plurality of first cross braces 141 and the two first purlins 140 are combined to form the first layer of the support structure of the first-stage cofferdam 100. Specifically, the first purlin 140 is 458H-shaped steel, and the first cross brace 141 is a 630-diameter steel pipe pile.

[0048] Specifically, after the steel pipe piles are transported to the site, it is necessary to clean up the debris between the cable mouths and observe whether the lock mouths are deformed. For steel pipe piles with deformed lock mouths, they should be adjusted before use, and then a butter mixture ointment made of asphalt, butter, talcum powder, and sawdust with a weight ratio of 4:6:10:1 is applied to the lock mouth of the steel pipe pile to prevent water leakage between two adjacent locking steel pipe piles 130.

[0049] Specifically, when the locking steel pipe piles 130 are driven in, if the verticality of the locking steel pipe piles 130 is good, the locking steel pipe piles 130 are driven to the required depth at one time. When the verticality is poor, the driving is performed in two times, that is, all the locking steel pipe piles 130 are driven in to about half the depth first, and then driven in for the second time until the required depth is reached.

[0050] Specifically, since steel pipe pile leakage generally occurs at the locking position, a locking leakage test is required with a short steel pipe pile of the same type before construction to check the tightness of the steel pipe pile locking position to avoid leakage of the locking steel pipe pile 130 after construction due to being too loose or too tight.

[0051] Specifically, if there is a small leakage in the first-stage cofferdam 100 after pumping, a bag of dry fine sand or sawdust, fly ash and other fillers are quickly slipped down on the steel pipe pile at the leaking place by using the principle of suction generated by the water pressure difference drop at the leaking place. Under the action of suction, the fillers will be sucked into the leaking place of the joint, blocking the leaking channel to reduce the amount of leakage. If the leakage is more serious after pumping, the pumping side of the locking steel pipe pile 130 is plugged with materials such as slats, cotton wool, and hemp wool.

[0052] After the construction of the first purlin 140 is completed, the water level in the first stage cofferdam 100 is lowered to -6m, and then the second purlin 150 arranged along the extension direction is installed on each first transverse water stop wall 110, and the second purlin 150 is located below the first purlin 140. Similarly, the two second purlins 150 are both located in the first stage cofferdam 100, and a second cross brace 151 extending along the front-to-back direction is arranged between the two second purlins 150, wherein a plurality of second cross braces 151 are arranged, and the plurality of second cross braces 151 are evenly distributed along the extension direction of the first transverse water stop wall 110, and the plurality of second cross braces 151 and the two second purlins 150 are combined to form the second layer support structure of the first stage cofferdam 100. Specifically, the second purlin 150 is a double-jointed 400H steel, and the second cross brace 151 is a 630 steel pipe.

[0053] Furthermore, a first diagonal brace is provided between two adjacent first transverse braces 141, and a second diagonal brace is also provided between two adjacent second transverse braces 151. A stable triangle is formed between the first diagonal brace and the two adjacent first transverse braces 141, and a stable triangle is formed between the second diagonal brace and the two adjacent second transverse braces 151, thereby increasing the structural stability of the first purlin 140 and the second purlin 150 and enhancing the overall structural rigidity of the first-stage cofferdam 100.

[0054] After the installation of the second perimeter purlin 150 is completed, the first foundation pit is excavated to -12.2 m, the excavation of the first foundation pit is completed, and finally, the bottom sealing concrete 160 is poured at the bottom of the first foundation pit.

[0055] It should be noted that before pouring the bottom concrete 160, the first and second support layers of the first-stage cofferdam 100 are in the most unfavorable state, and it is necessary to further analyze the stress conditions of each component in the locking steel pipe pile 130 support system, that is, the first and second support layers.

[0056] Step 3: construct the box culvert structure section 200 in the first stage cofferdam 100. Construct multiple box culvert structure sections 200 in sequence from north to south until the construction of all the box culvert structure sections 200 in the first stage cofferdam 100 is completed. It should be noted that the box culvert structure section 200 in the first stage cofferdam 100 far from the river bank is the transition box culvert structure section 210.

[0057] Step 4: construct the cofferdam conversion structure 300. It should be noted that the cofferdam conversion structure 300 includes a conversion mechanism 310 and a reinforcement mechanism 320. The conversion mechanism 310 is arranged between the two first transverse water stop walls 110, and the conversion mechanism 310 is sleeved on the transition box culvert structure section 210; the reinforcement mechanism 320 is connected to the first transverse water stop wall 110, and the reinforcement mechanism 320 is connected to the conversion mechanism 310, and the reinforcement mechanism 320 is used to enhance the structural stability of the conversion mechanism 310.

[0058] Specifically, the conversion mechanism 310 includes two conversion walls 311 and a plurality of connecting walls 312. The two conversion walls 311 are arranged in parallel. The conversion wall 311 is arranged between the two first transverse water stop walls 110. The conversion wall 311 is integrally cast with the transition box culvert structure section 210. One end of the connecting wall 312 is arranged between the conversion wall 311 and the transition box culvert structure section 210, and the other end is connected to the first transverse water stop wall 110. The connecting wall 312 is used to block the gap between the first transverse water stop wall 110 and the conversion wall 311.

[0059] The reinforcement mechanism 320 includes a plurality of top-joint assemblies 321 and a plurality of diagonal brace assemblies 322. The plurality of top-joint assemblies 321 are evenly distributed between the two transfer walls 311 in the vertical direction. The top-joint assemblies 321 are used to enhance the overall rigidity of the transfer wall 311. Specifically, the top-joint assemblies 321 include a plurality of top-joint members, which are arranged between the two transfer walls 311 in the vertical direction, wherein each top-joint member includes two first horizontal beams 3211 arranged along the extension direction of the transfer wall 311, and a plurality of connecting beams 3212 evenly distributed between the two first horizontal beams 3211.

[0060] Specifically, the diagonal brace assembly 322 is horizontally arranged, the diagonal brace assembly 322 is connected to the conversion wall 311, and multiple diagonal brace assemblies 322 are evenly distributed between the two first transverse water stop walls 110 in the vertical direction. The diagonal brace assembly 322 includes multiple diagonal brace members, and the multiple diagonal brace members are arranged between the two first transverse water stop walls 110 in the vertical direction, and the multiple diagonal brace members are all connected to the corresponding conversion wall 311. Each diagonal brace member includes two second horizontal beams 3221 arranged along the extension direction of the first transverse water stop wall 110, a third horizontal beam 3222 arranged along the extension direction of the transfer wall 311, and a plurality of diagonal brace beams 3223 connected between the second horizontal beams 3221 and the third horizontal beams 3222. The two ends of the third horizontal beam 3222 are respectively vertically connected to the two second horizontal beams 3221. One end of the diagonal brace beam 3223 is arranged on the third horizontal beam 3222, and the other end is selectively arranged on one of the second horizontal beams 3221. Then, the diagonal brace beams 3223, the second horizontal beams 3221 and the third horizontal beams 3222 enclose a stable right triangle. In this specific embodiment, two diagonal brace beams 3223 are arranged in parallel on each second horizontal beam 3221. The diagonal brace beams 3223, the second horizontal beams 3221 and the third horizontal beams 3222 enclose a stable right isosceles triangle. Further, the diagonal brace members are symmetrically arranged about the central axis of the extension direction of the box culvert structure section 200.

[0061] like Figure 2 and Figure 5As shown, in the southernmost section of the cofferdam 100 in the first stage, two parallel tooth walls of 800mm×500mm are poured on the outside when pouring the culvert body concrete. Both tooth walls are perpendicular to the first transverse water stop wall 110, and a transfer wall 311 is embedded in the middle. The transfer wall 311 is a 12m long Larsen IV steel sheet pile, and the distance between the two transfer walls 311 is 2m. Since there is usually a gap between the first transverse water stop wall 110 and the box culvert structure section 200, connecting walls 312 for connecting the first transverse water stop wall 110 are also provided at both ends of the transfer wall 311. One end of the connecting wall 312 close to the transfer wall 311 is straddled on the side wall of the transfer wall 311 and the transition box culvert structure section 210, and the other end is fixedly connected to the first transverse water stop wall 110. Specifically, the connecting wall 312 is a 18m long Larsen IV steel sheet pile, and the steel sheet pile and the steel pipe pile are connected by full welding of steel plates. After the conversion between the conversion wall 311 and the first transverse water stop wall 110 is completed, concrete is poured in the gap between the first transverse water stop wall 110, the two connecting walls 312 and the transition box culvert structure section 210 for secondary plugging. Thus, a closed cofferdam water stop conversion system is formed between the first transverse water stop wall 110, the conversion wall 311, the connecting wall 312 and the box culvert structure section 200. Furthermore, a reinforcing beam is arranged at the top of the conversion wall 311 and the connecting wall 312, and the reinforcing beam is arranged along the extension direction of the conversion wall 311 and is located at the upper end of the second horizontal beam 3221, thereby enhancing the overall rigidity between the conversion wall 311 and the first transverse water stop wall 110, and jointly bearing the water pressure.

[0062] Step 5: Remove the first-stage cofferdam 100 and construct the second-stage cofferdam. Use brick walls to block the middle empty box 211 of the transition box culvert structure section 210. At the same time, use ton bags to backfill the gaps between the two sides of the continuous box culvert structure section 200 and the steel pipe piles. Specifically, fill the gaps between the first transverse water stop wall 110 and all the box culvert structure sections 200 until they are flush with the top of the box culvert structure section 200. Then remove the second layer of support, that is, the second purlin 150 and the horizontal braces and diagonal braces set on the second purlin 150. Use the top of the box culvert structure section 200 as a construction platform, and the construction workers stand on the top of the box culvert structure section 200 to cut, and cooperate with the crawler crane to lift, so as to prevent safety accidents such as structural fall caused by cutting and breaking. After the second layer of support is removed, the first stage cofferdam 100 is backfilled with earth in layers by compaction, and the top of the box culvert structure section 200 is backfilled to -4.7m, so that the soil pressure inside and outside the first transverse water stop wall 110 is balanced.

[0063] After the backfilling of the first-stage cofferdam 100 is completed, the residues in the first-stage cofferdam 100 are cleared, and water is injected into the first-stage cofferdam 100 to reach a certain water level before pulling out the piles, so that the water levels inside and outside the first-stage cofferdam 100 are the same, and then a vibrating hammer is used to pull out the piles, clean them one by one, and transport them away in time to ensure the cleanliness of the site.

[0064] It should be noted that when the locking steel pipe piles 130 of the first-stage cofferdam 100 are removed, the second-stage cofferdam can be reused.

[0065] The locking steel pipe piles 130 in the second stage cofferdam are driven by a crawler crane with a vibrating hammer. In this specific embodiment, the two second transverse water stop walls are respectively the second transverse water stop wall facing the upstream water and the second transverse water stop wall facing the downstream water. Specifically, the locking steel pipe piles 130 are constructed from the north bank of the river toward the center of the river, and the second transverse water stop wall facing the upstream water and the second transverse water stop wall facing the downstream water are driven at the same time to form a second stage cofferdam across half of the river with the cofferdam conversion structure 300.

[0066] After the construction of the second-stage cofferdam is completed, the water level in the second-stage cofferdam is lowered to 0m, and then the third purlin arranged along the extension direction is installed on each second transverse water stop wall, and the third purlin on each second transverse water stop wall is located in the second-stage cofferdam, and a third cross brace extending along the front-back direction is arranged between the two second purlins 150, wherein a plurality of third cross braces are arranged, and the plurality of third cross braces are evenly distributed along the extension direction of the second transverse water stop wall, and the plurality of third cross braces and the two second purlins 150 are combined to form the first layer of the supporting structure of the second-stage cofferdam. Specifically, the second purlin 150 is 458H steel, and the second cross brace 151 is Ф630 steel pipe pile.

[0067] After the construction of the third purlin is completed, the water level in the second stage cofferdam is lowered to -6m, and then the fourth purlin set in the extension direction is installed in the upper direction of each second transverse water stop wall, and the fourth purlin is located below the second purlin 150. Similarly, the two fourth purlins are located in the second stage cofferdam, and the fourth cross brace extending in the front-to-back direction is set between the two fourth purlins, wherein there are multiple fourth cross braces, and the multiple fourth cross braces are evenly distributed along the extension direction of the second transverse water stop wall. The multiple fourth cross braces and the two fourth purlins are combined to form the second layer of support structure of the second stage cofferdam. Specifically, the fourth purlin is a double-jointed 400H steel, and the fourth cross brace is a Ф630 steel pipe.

[0068] Furthermore, a third diagonal brace is arranged between two adjacent third transverse braces, a fourth diagonal brace is also arranged between two adjacent fourth transverse braces, a stable triangle is formed between the third diagonal brace and the two adjacent third transverse braces, and a stable triangle is formed between the fourth diagonal brace and the two adjacent fourth transverse braces, thereby increasing the structural stability of the third purlin and the fourth purlin and enhancing the overall structural stiffness of the second stage cofferdam.

[0069] After the installation of the fourth perimeter purlin is completed, the second foundation pit is excavated to -12.2m, the excavation of the second foundation pit is completed, and finally the bottom sealing concrete 160 is poured at the bottom of the second foundation pit.

[0070] Furthermore, a water-stopping geomembrane is fixedly hung on the water-facing end of the second-stage cofferdam.

[0071] Step 6: Construct box culvert structure sections 200 in the second stage cofferdam. Construct multiple box culvert structure sections 200 in sequence from south to north until the construction of all box culvert structure sections 200 in the second stage cofferdam is completed.

[0072] Step 7: After completing the construction of all box culvert structure sections 200 in the second-stage cofferdam, dismantle the second-stage cofferdam.

[0073] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present invention.

Claims

1. A method for phased diversion construction of a river-crossing structure, characterized in that: include: Step 1: construct a temporary steel bridge on one side of the planned land, and install piling equipment on the temporary steel bridge; Step 2: using the pile driving equipment on the temporary steel bridge to drive the locking steel pipe piles (130), and constructing two first transverse water stop walls (110) and a longitudinal water stop wall (120), so that the two first transverse water stop walls (110), the longitudinal water stop wall (120) and the river bank are enclosed to form a first-stage cofferdam (100); Step 3: sequentially constructing a plurality of box culvert structure sections (200) in the first-stage cofferdam (100) along the extension direction of the first-stage cofferdam (100); Step 4: constructing a cofferdam conversion structure (300) on the transition box culvert structure section (210) at one end of the first-stage cofferdam (100) away from the river bank, so as to form a water-stop conversion system between the transition box culvert structure section (210) and the first-stage cofferdam (100); Step 5: After completing the construction of all the box culvert structure sections (200) in the first-stage cofferdam (100), the empty box (211) of the transition box culvert structure section (210) is sealed, the first foundation pit is backfilled, the first-stage cofferdam (100) is dismantled, and the locking steel pipe piles (130) are driven by the pile driving equipment on the steel temporary bridge, and the two second transverse water stop walls are constructed, so that the two second transverse water stop walls, the cofferdam conversion structure (300) and the river bank are enclosed to form the second-stage cofferdam; Step 6: sequentially constructing a plurality of remaining box culvert structure segments (200) in the second stage cofferdam along the extension direction of the second stage cofferdam; Step 7: After completing the construction of all the box culvert structure sections (200) in the second-stage cofferdam, the second-stage cofferdam is dismantled.

2. A method for diverting a river through a structure in stages according to claim 1, characterized in that: In step 2, a butter mixture ointment made of asphalt, butter, talcum powder and sawdust in a weight ratio of 4:6:10:1 is applied inside the locking mouth of the locking steel pipe pile (130) to prevent water leakage between two adjacent locking steel pipe piles (130).

3. The method for phased diversion construction of a river-crossing structure according to claim 1 is characterized in that: In step 2, the first transverse water stop wall (110) and the longitudinal water stop wall (120) on the water-facing side and the first transverse water stop wall (110) on the water-receiving side are constructed in sequence.

4. The method for phased diversion construction of a river-crossing structure according to claim 1 is characterized in that: In step 2, after the construction of the first transverse water stop wall (110) and the longitudinal water stop wall (120) is completed, the water level in the first stage cofferdam (100) is lowered to the first design water level, and the first purlin (140) is installed on the first transverse water stop wall (110) along the extension direction. After the construction of the first purlin (140) is completed, the water level in the first stage cofferdam (100) is lowered to the second design water level, and the second purlin (150) is installed on the first transverse water stop wall (110) along the extension direction so that the second purlin (150) is located below the first purlin (140). After the installation of the second purlin (150) is completed, the first foundation pit is excavated to the first design elevation, and finally, the bottom sealing concrete (160) is poured at the bottom of the first foundation pit.

5. The method for diverting a river through a structure in stages according to claim 1, characterized in that: In step 4, the cofferdam conversion structure (300) includes: A conversion mechanism (310), wherein the conversion mechanism (310) is arranged between the two first transverse water stop walls (110), and the conversion mechanism (310) is sleeved on the transition box culvert structure section (210); A reinforcing mechanism (320), wherein the reinforcing mechanism (320) is connected to the first transverse water stop wall (110), the reinforcing mechanism (320) is connected to the conversion mechanism (310), and the reinforcing mechanism (320) is used to enhance the structural stability of the conversion mechanism (310).

6. A method for diverting a river through a structure in stages according to claim 5, characterized in that: The conversion mechanism (310) comprises: Two transfer walls (311), the two transfer walls (311) are arranged in parallel, the transfer wall (311) is arranged between the two first transverse water stop walls (110), and the transfer wall (311) and the transition box culvert structure section (210) are integrally cast; A plurality of connecting walls (312), one end of each connecting wall (312) is arranged between the conversion wall (311) and the transition box culvert structure section (210), and the other end is connected to the first transverse water stop wall (110), and the connecting wall (312) is used to block the gap between the first transverse water stop wall (110) and the conversion wall (311).

7. A method for diverting a river through a structure in stages according to claim 6, characterized in that: The reinforcing mechanism (320) comprises: A plurality of top-to-top assemblies (321), wherein the plurality of top-to-top assemblies (321) are evenly distributed between the two transfer walls (311) in a vertical direction, and the top-to-top assemblies (321) are used to enhance the overall rigidity of the transfer wall (311); A plurality of diagonal brace assemblies (322), wherein the diagonal brace assemblies (322) are arranged horizontally, the diagonal brace assemblies (322) are connected to the conversion wall (311), and the plurality of diagonal brace assemblies (322) are evenly distributed between the two first transverse water stop walls (110) along the vertical direction.

8. The method for diverting a river through a structure in stages according to claim 4, characterized in that: In step 2, concrete is poured between the side wall of the transition box culvert structure section (210) and the first transverse water stop wall (110) to increase the pouring range of the bottom seal concrete (160).

9. The method for diverting a river through a structure in stages according to claim 1, characterized in that: In step five, backfilling is performed between both sides of all box culvert structure sections (200) and the first transverse water stop wall (110) using ton bags of earth.

10. The method for diverting a river through a structure in stages according to claim 1, characterized in that: Water stop membranes are fixedly arranged at the water-facing ends of the first-stage cofferdam (100) and the second-stage cofferdam.

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