Double-row steel sheet pile soil core combined cofferdam structure and construction method

Abstract

The invention discloses a double-row steel sheet pile and soil core combined cofferdam structure and a construction method. The double-row steel sheet pile and soil core combined cofferdam structure comprises double-row pile connecting units, steel sheet piles, brackets, steel enclosing purlins, dredger fill and drainage plates. Each double-row pile connecting unit is formed by welding an upper connecting plate between two connecting steel sheet piles; the double-row pile connecting units are inserted into a soil body, and a steel sheet pile is inserted between every two double-row pile connecting units; corbels are welded to the outer sides of the steel sheet piles, steel enclosing purlins are arranged on the corbels, and the steel enclosing purlins, the steel sheet piles and the corbels are connected in a welded mode; dredger fill is filled between the two rows of steel sheet piles and is compacted by a hammer-attached soil squeezer; a drainage plate is inserted into the dredger fill; earth excavation is conducted on the side, close to water, of the double-row pile cofferdam to form a foundation pit; when shallow excavation is conducted on the foundation pit, no sand filling pipe bag is arranged; when the foundation pit is deeply excavated, a slope section is reserved; sand filling pipe bags are arranged on the outer side of the slope section and stacked on the outer side of the slope section in a staggered mode. The hammer-attached soil squeezing device comprises an attached hammer, a pressing plate, water permeable holes, geotechnical cloth and a brush.

Description

Technical Field

[0001] The invention relates to the technical field of cofferdams, and in particular to a double-row steel sheet pile soil core combined cofferdam structure and a construction method. Background Art

[0002] With the rapid development of the country's society and economy, the construction of transportation infrastructure such as bridges, ports, water conservancy and water transport projects has become increasingly important. These projects often inevitably need to be constructed in complex water environments such as rivers, lakes, and oceans. The construction environment is complex, but the construction of bridge piers or port foundations requires a relatively stable environment. In order to create such a construction environment, double-row steel sheet pile cofferdams have become the preferred solution for construction under complex geological conditions due to their advantages such as light and thin weirs, small footprint, and high space utilization.

[0003] When the construction scope is large, an extra-long cofferdam is required for support. At this time, due to the long construction time and changes in the construction environment and hydrological conditions around the cofferdam, higher requirements are placed on the strength, water-blocking properties and environmental adaptability of the cofferdam itself. However, the current double-row steel sheet pile cofferdam structure lacks a solution for this type of situation.

[0004] Therefore, in order to adapt to the changing environment and long support time, there is an urgent need for a double-sheet pile cofferdam and its construction technology that is simple to construct, efficient, has good environmental adaptability and high strength. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] The technical problem to be solved by the present invention is to provide a double-row steel sheet pile soil core combined cofferdam structure and a construction method. A double-row pile connection unit structure is adopted. During the construction of an ultra-long cofferdam, on the one hand, it can be used as a positioning pile to be inserted into the soil layer, which can effectively improve the construction accuracy of the double-sheet pile cofferdam; on the other hand, the connection unit strengthens the connection between the steel sheet piles on both sides through connecting plates and connecting steel sheet piles, thereby improving the integrity of the double-row pile cofferdam and making it have higher strength to adapt to changes in the surrounding environment.

[0007] (II) Technical solution

[0008] The solution adopted by the present invention to solve the above technical problems is a double-row steel sheet pile soil core combined cofferdam structure, including a double-row pile cofferdam, the double-row pile cofferdam includes a double-row pile connection unit, steel sheet piles, corbels, steel purlins, blown fill, and a drainage board; the double-row pile connection unit is made by welding a connection plate between two connected steel sheet piles; and the double-row pile connection unit is inserted into the soil, and a steel sheet pile is inserted between every two double-row pile connection units; a corbel is welded on the outer side of the steel sheet pile, and a steel purlin is arranged on the corbel, and the steel purlin, the steel sheet pile and the corbel are all welded and connected; the blown fill is filled between two rows of steel sheet piles, and the blown fill is compacted by a hammer-attached soil squeezer to accelerate deposition; a drainage board is inserted in the blown fill;

[0009] The double-row pile cofferdam is excavated on the water side to form a foundation pit;

[0010] When the foundation pit is shallowly excavated, no sand-filled pipe bags are provided;

[0011] When the foundation pit is deeply excavated, a slope section is reserved; a plurality of sand-filled tube bags are arranged outside the slope section, and the plurality of sand-filled tube bags are staggered and stacked outside the slope section;

[0012] The hammer-attached soil squeezer includes an attached hammer, a pressing plate, water-permeable holes, geotextile, and a brush; the attached hammer is connected to the pressing plate; a plurality of water-permeable holes are arranged on the pressing plate; a geotextile is fixedly arranged on the bottom of the pressing plate; and brushes are fixedly arranged at both ends of the pressing plate in the length direction.

[0013] In some embodiments, the pile body width of the connecting steel sheet piles is longer than that of the steel sheet piles, and the steel sheet piles and the connecting steel sheet piles are connected by locking bites; the connecting steel sheet piles are connected to the connecting plates by welding; the connecting plates are arranged through the entire length and have the same length as the connecting steel sheet piles; or the connecting plates are arranged at intervals.

[0014] In some embodiments, the pile body of the steel sheet pile located on the water side is longer than that of the steel sheet pile located on the foundation pit side; the top surface of the steel sheet pile located on the water side is higher than the top surface of the steel sheet pile located on the foundation pit side; the bottom surface of the steel sheet pile located on the water side is lower than the bottom surface of the steel sheet pile located on the foundation pit side; the installation position of the corbel is higher than the river surface.

[0015] In some embodiments, when the excavation depth of the foundation pit is less than 5m, it is shallow excavation; when the excavation depth of the foundation pit is greater than or equal to 5m, it is deep excavation.

[0016] The solution adopted by the present invention to solve the above technical problems is a construction method of a double-row steel sheet pile soil core combined cofferdam structure, comprising the following steps:

[0017] Step (1): After the welded double-row pile connection unit is driven into the designated construction area by a vibrating hammer, a plurality of steel sheet piles are driven one by one between the two double-row pile connection units. The number of steel sheet piles between each two double-row pile connection units is designed according to the needs of the project; and the embedding depth of the steel sheet piles on the foundation pit side and the steel sheet piles on the water side should be designed according to the Technical Code for Construction Foundation Pit Support;

[0018] Step (2): welding a corbel on the outer side of the steel sheet pile, erecting a steel cofferdam, and welding the contact parts among the steel cofferdam, the corbel and the steel sheet pile;

[0019] Step (3): using a blown fill method to fill sand and soil into the cofferdam in layers. After each layer is filled, it is squeezed and compacted by a hammer-attached soil squeezer until the designed elevation is reached;

[0020] Step (4): inserting a drainage board into the blown fill soil inside the weir body;

[0021] Step (5): After the cofferdam construction is completed, the foundation pit is excavated; when the excavation depth is less than 5m, no sand-filled pipe bags are arranged; when the excavation depth is greater than or equal to 5m, a slope section needs to be reserved, and sand-filled pipe bags are arranged outside the slope section to prevent the double-row pile cofferdam from collapsing inwards;

[0022] Step (6): When arranging the sand-filled tube bags, first lay the sand-filled tube bags to the designated construction area, and then use the blowing and filling method to pressurize sand and soil into the sand-filled tube bags to complete the in-situ filling of the sand-filled tube bags.

[0023] In some embodiments, if there is a section where the excavation depth changes during the excavation of the foundation pit, the length of the steel sheet piles and the connecting steel sheet piles should be adjusted according to the change in the excavation depth of the foundation pit; according to the connection stiffness requirements of the double-row steel sheet pile-soil core combined cofferdam, the connecting plate can be arranged throughout the length with the same length as the connecting steel sheet piles, or it can be arranged at intervals.

[0024] In some embodiments, the sand used for filling in step (3) and step (6) may come from river sand around the construction site. The filling sand is sucked into the pipeline by means of suction or rake suction, and then filled into the cofferdam through the pipeline, or pressure-filled into sand-filled pipe bags.

[0025] In some embodiments, in step (4), after the drainage board is installed, the moisture in the soil will be discharged upward along the drainage board under the action of the surrounding soil pressure.

[0026] In some embodiments, in step (5), when the hammer-attached soil squeezer squeezes the soil, the brushes on both sides contact the steel sheet piles, which can prevent the hammer-attached soil squeezer from causing damage to the steel sheet piles.

[0027] In some embodiments, in step (6), the stacking height of the sand-filled tube bags should be calculated according to the Technical Code for Construction Foundation Pit Support (JGJ120-2012), and the overall stability coefficient of the foundation pit, the embedded stability safety factor, the wall bottom anti-uplift safety factor, and the pit bottom anti-uplift safety factor should meet the requirements of the code.

[0028] (III) Beneficial effects

[0029] Compared with the prior art, the present invention designs a double-row steel sheet pile soil core combined cofferdam structure and construction method.

[0030] (1) The present invention adopts a double-row pile connection unit structure. During the construction of the super-long cofferdam, the double-sheet pile connection unit can be used as a positioning pile to be driven into the soil layer, which can effectively improve the construction accuracy of the double-sheet pile cofferdam. On the other hand, the connection unit strengthens the connection between the steel sheet piles on both sides through the connection plate and the connecting steel sheet piles, thereby improving the integrity of the double-row pile cofferdam and making it have higher strength to adapt to changes in the surrounding environment.

[0031] (2) In the present invention, the retaining soil layer in the cofferdam and the filling soil in the sand-filled tube bag are both made by blowing filling technology, and the sand used for on-site filling can be directly made into mortar and then poured in, which can improve the construction efficiency; the double-row steel plate soil core combined cofferdam based on blowing filling technology provided by the present invention not only meets the supporting function of the cofferdam itself, but also has safe and reliable construction, convenient and fast, cost-saving, environmental protection, and has engineering application prospects;

[0032] (3) The present invention proposes a hammer-attached soil squeezer to squeeze the soil in the cofferdam in layers. This process compacts the blown-in soil in the cofferdam and squeezes the water in the gaps to the surface of the soil layer, thereby increasing the strength of the blown-in soil in the cofferdam, facilitating the drainage treatment in the cofferdam later, and improving the ability of the cofferdam to isolate the river water outside so that it does not affect the construction inside.

[0033] (4) The present invention proposes to insert a drain board into the soil of the cofferdam. The function of the drain board is to discharge the water in the deep soil layer, which can further realize the drainage and consolidation of the soil in the cofferdam and improve the overall strength of the cofferdam. At the same time, in the face of long-term support time, the insertion of the drain board can effectively prevent the water outside the cofferdam from penetrating into the construction area;

[0034] (5) The present invention adopts sand-filled tube bags as temporary retaining structures for deep excavation cofferdams. The sand-filled tube bags themselves have the advantages of low cost, convenient construction and easy dismantling. Using them as temporary retaining structures for cofferdams can further save construction costs and construction period. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 It is the cross-section diagram of the double-row steel sheet pile soil core composite cofferdam structure during shallow excavation;

[0037] Figure 2 It is the cross-section diagram of the double-row steel sheet pile soil core composite cofferdam structure during deep excavation;

[0038] Figure 3 It is a structural schematic diagram of a double-row steel sheet pile soil core combined cofferdam structure during deep excavation;

[0039] Figure 4 It is a structural schematic diagram of a double-row pile connection unit;

[0040] Figure 5 It is a structural schematic diagram of a double-row pile connection unit when the connection plate is arranged throughout the length;

[0041] Figure 6 It is a structural schematic diagram of a double-row pile connection unit when the connection plates are arranged at intervals;

[0042] Figure 7 It is a structural schematic diagram of a hammer-attached soil squeezer;

[0043] Figure 8 for Figure 7 Sectional view at AA;

[0044] Fig. 9 It is a schematic diagram of the insertion sequence of the double-row pile connection unit and the steel sheet pile;

[0045] Figure 10(a) is a schematic diagram of the construction site before the cofferdam is built;

[0046] Figure 10(b) is a schematic diagram of a vibratory hammer driving a steel sheet pile into the soil layer to the designed elevation;

[0047] Figure 10(c) is a schematic diagram of erecting a steel cofferdam;

[0048] Figure 10(d) is a schematic diagram of filling the cofferdam with sand by using the blown fill technique;

[0049] FIG10( e ) is a schematic diagram of accelerating the compaction of hydraulic fill by a hammer-attached soil squeezer;

[0050] FIG10( f ) is a schematic diagram of inserting a drainage board into the dredger fill;

[0051] Figure 10(g) is a schematic diagram of the arrangement of the cofferdam and the foundation pit when the foundation pit is shallowly excavated;

[0052] Figure 10(h) is a schematic diagram of the excavation depth and arrangement of sand-filled pipe bags during deep excavation of the foundation pit.

[0053] The names of the components corresponding to the various reference numerals in the figure are: 1. Double-row pile cofferdam; 1-1. Double-row pile connection unit; 1-1-1. Connecting steel sheet piles; 1-1-2. Connecting plate; 1-2. Steel sheet piles; 1-3. Corbel; 1-4. Steel purlin; 1-5. Dredged fill; 1-6. Drainage board; 2. River; 3. Riverbed; 4. Foundation pit; 5. Slope section; 6. Sand-filled pipe bag; 7. Hammer with soil squeezer; 7-1. Attached hammer; 7-2. Press plate; 7-3. Water-permeable hole; 7-4. Geotextile; 7-5. Brush. DETAILED DESCRIPTION

[0054] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0055] 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 mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected 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.

[0056] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0057] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0058] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0059] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the examples can be practiced without these specific details.

[0060] The technical solutions provided by various embodiments of the present application are described below in conjunction with the accompanying drawings.

[0061] like Figure 1-Figure 4 As shown, this embodiment provides a double-row steel sheet pile soil core combined cofferdam structure, including a double-row pile cofferdam 1, the double-row pile cofferdam 1 includes a double-row pile connection unit 1-1, a steel sheet pile 1-2, a corbel 1-3, a steel purlin 1-4, blown fill 1-5, and a drainage board 1-6; the double-row pile connection unit 1-1 is made by welding a connection plate 1-1-2 between two connected steel sheet piles 1-1-1; the double-row pile connection unit 1-1 is inserted into the soil, and every two of the double-row pile connection units 1-1 are connected to the soil. Steel sheet piles 1-2 are inserted between the row pile connection units 1-1; a corbel 1-3 is welded to the outer side of the steel sheet pile 1-2, a steel purlin 1-4 is arranged on the corbel 1-3, and the steel purlin 1-4, the steel sheet pile 1-2 and the corbel 1-3 are all welded and connected; the dredger fill 1-5 is filled between two rows of steel sheet piles 1-2, and the dredger fill 1-5 is compacted by a hammer-attached soil squeezer 7 to accelerate deposition; a drainage board 1-6 is inserted in the dredger fill 1-5;

[0062] The double-row pile cofferdam 1 is excavated on the side facing the water to form a foundation pit 4; when the foundation pit 4 is shallowly excavated, no sand-filled pipe bags 6 are provided; when the foundation pit 4 is deeply excavated, a slope section 5 is reserved; a plurality of sand-filled pipe bags 6 are arranged outside the slope section 5, and the plurality of sand-filled pipe bags 6 are staggered and stacked outside the slope section 5. Specifically, when the excavation depth of the foundation pit 4 is less than 5m, it is shallow excavation; when the excavation depth of the foundation pit 4 is greater than or equal to 5m, it is deep excavation.

[0063] like Figure 7-Figure 8 As shown, the hammer-attached soil squeezer 7 includes an attached hammer 7-1, a pressure plate 7-2, water-permeable holes 7-3, a geotextile 7-4, and a brush 7-5; the attached hammer 7-1 is connected to the pressure plate 7-2; a plurality of water-permeable holes 7-3 are arranged on the pressure plate 7-2; a geotextile 7-4 is fixedly provided at the bottom of the pressure plate 7-2; brushes 7-5 are fixedly provided at both ends of the pressure plate 7-2 in the length direction.

[0064] like Figure 3-Figure 6 As shown, specifically, the pile body width of the connecting steel sheet pile 1-1-1 is longer than that of the steel sheet pile 1-2, and the steel sheet piles 1-2 and the connecting steel sheet piles 1-1-1 are connected by locking bite; the connecting steel sheet piles 1-1-1 are connected to the connecting plates 1-1-2 by welding; the connecting plates 1-1-2 are arranged throughout the length, and the length is consistent with that of the connecting steel sheet piles 1-1-1; or the connecting plates 1-1-2 are arranged at intervals.

[0065] Specifically, the pile body of the steel sheet pile 1-2 located on the water side is longer than the steel sheet pile 1-2 located on the foundation pit 4 side; the top surface of the steel sheet pile 1-2 located on the water side is higher than the top surface of the steel sheet pile 1-2 located on the foundation pit 4 side; the bottom surface of the steel sheet pile 1-2 located on the water side is lower than the bottom surface of the steel sheet pile 1-2 located on the foundation pit 4 side; the installation position of the corbel 1-3 is higher than the river surface of the river 2.

[0066] like Figure 10(a)-Figure 10(h) As shown, this embodiment provides a construction method for a double-row steel sheet pile soil core combined cofferdam structure, comprising the following steps:

[0067] Step (1): As shown in FIG10( b), after the welded double-row pile connection unit 1-1 is driven into the designated construction area by a vibrating hammer, a plurality of steel sheet piles 1-2 are driven one by one between the two double-row pile connection units 1-1, and the driving direction is as follows: Fig. 9 As shown; the number of steel sheet piles 1-2 between every two double-row pile connection units 1-1 is designed according to the engineering needs; and the embedding depth of the steel sheet piles 1-2 located on the foundation pit 4 side and the steel sheet piles 1-2 located on the water side should be designed according to the "Technical Code for Support of Construction Foundation Pit 4";

[0068] Step (2): As shown in FIG. 10( c ), a corbel 1 - 3 is welded on the outer side of the steel sheet pile 1 - 2 , and a steel cofferdam is erected, and the contact parts among the steel cofferdam, the corbel 1 - 3 and the steel sheet pile 1 - 2 are welded;

[0069] Step (3): As shown in FIG. 10( d ) and FIG. 10( e ), sand is filled into the cofferdam in layers by blowing and filling. After each layer is filled, it is squeezed and compacted by a hammer-attached soil squeezer 7 until the designed elevation is reached. The sand for blowing and filling can come from river sand around the construction site. The filling sand is sucked into a pipeline by means of suction or rake suction, and then filled into the cofferdam through the pipeline. When the hammer-attached soil squeezer 7 squeezes the soil, the brushes 7-5 on both sides contact the steel sheet piles 1-2, which can prevent the hammer-attached soil squeezer 7 from bumping and damaging the steel sheet piles 1-2.

[0070] Step (4): As shown in FIG. 10( f ), a drain board 1-6 is inserted into the fill soil 1-5 inside the dam body; after the drain board 1-6 is inserted, the moisture in the soil will be discharged upward along the drain board 1-6 under the action of the surrounding soil pressure;

[0071] Step (5): As shown in FIG. 10( g) and FIG. 10( h), after the cofferdam construction is completed, the foundation pit 4 is excavated; when the excavation depth is less than 5 m, the sand-filled pipe bag 6 is not arranged; when the excavation depth is greater than or equal to 5 m, a slope section 5 needs to be reserved, and a sand-filled pipe bag 6 is arranged outside the slope section 5 to prevent the double-row pile cofferdam 1 from collapsing inwards;

[0072] Step (6): When arranging the sand-filled tube bags 6, the sand-filled tube bags 6 are first laid to the designated construction area, and then sand is pressed into the sand-filled tube bags 6 by blowing and filling to complete the in-situ filling of the sand-filled tube bags 6; wherein, the sand for blowing and filling can come from the river sand around the construction site, and the filling sand is sucked into the pipeline by means of suction or rake suction, and then pressed into the sand-filled tube bags 6; the stacking height of the sand-filled tube bags 6 shall be calculated in accordance with the Technical Code for Support of Construction Foundation Pit 4 (JGJ120-2012), and the overall stability coefficient, embedded stability safety coefficient, wall bottom anti-uplift safety coefficient, and pit bottom anti-uplift safety coefficient of the foundation pit 4 shall meet the requirements of the code.

[0073] Specifically, if there is a section where the excavation depth changes during the excavation of the foundation pit 4, the lengths of the steel sheet piles 1-2 and the connecting steel sheet piles 1-1-1 should be adjusted according to the change in the excavation depth of the foundation pit 4; according to the connection stiffness requirements of the double-row steel sheet piles 1-2 soil-core combined cofferdam, the connecting plate 1-1-2 can be arranged throughout the length with the same length as the connecting steel sheet piles 1-1-1, or it can be arranged at intervals.

[0074] The same and similar parts between the various embodiments in this specification can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0075] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. Double-row steel sheet pile soil core combined cofferdam structure, characterized by: The invention comprises a double-row pile cofferdam (1), wherein the double-row pile cofferdam (1) comprises a double-row pile connection unit (1-1), a steel sheet pile (1-2), a corbel (1-3), a steel purlin (1-4), blown fill (1-5), and a drainage board (1-6); the double-row pile connection unit (1-1) is made by welding a connection plate (1-1-2) between two connected steel sheet piles (1-1-1); and the double-row pile connection unit (1-1) is inserted into the soil, and a connection plate (1-1-2) is inserted between every two double-row pile connection units (1-1). Steel sheet piles (1-2) are driven; a corbel (1-3) is welded on the outer side of the steel sheet pile (1-2); a steel purlin (1-4) is arranged on the corbel (1-3); the steel purlin (1-4), the steel sheet pile (1-2) and the corbel (1-3) are all welded and connected; the dredger fill (1-5) is filled between two rows of steel sheet piles (1-2); the dredger fill (1-5) is compacted by a hammer-attached soil squeezer (7) to accelerate deposition; a drainage board (1-6) is inserted in the dredger fill (1-5); The double-row pile cofferdam (1) is excavated on one side facing the water to form a foundation pit (4); When the foundation pit (4) is shallowly excavated, no sand-filled pipe bag (6) is provided; When the foundation pit (4) is deeply excavated, a slope section (5) is reserved; a plurality of sand-filled tube bags (6) are arranged outside the slope section (5), and the plurality of sand-filled tube bags (6) are staggered and stacked outside the slope section (5); The hammer-attached soil squeezer (7) comprises an attached hammer (7-1), a pressing plate (7-2), water-permeable holes (7-3), a geotextile (7-4), and a brush (7-5); the attached hammer (7-1) is connected to the pressing plate (7-2); a plurality of water-permeable holes (7-3) are arranged on the pressing plate (7-2); a geotextile (7-4) is fixedly arranged at the bottom of the pressing plate (7-2); and brushes (7-5) are fixedly arranged at both ends of the pressing plate (7-2) in the length direction thereof.

2. The double-row steel sheet pile soil core combined cofferdam structure according to claim 1 is characterized in that: The pile body width of the connecting steel sheet pile (1-1-1) is longer than that of the steel sheet pile (1-2); the steel sheet piles (1-2) and the steel sheet piles (1-2) are connected to each other and to the connecting steel sheet piles (1-1-1) by locking engagement; the connecting steel sheet piles (1-1-1) and the connecting plates (1-1-2) are connected by welding; the connecting plates (1-1-2) are arranged throughout the length and have the same length as the connecting steel sheet piles (1-1-1); or the connecting plates (1-1-2) are arranged at intervals.

3. The double-row steel sheet pile soil core combined cofferdam structure according to claim 1 is characterized in that: The pile body of the steel sheet pile (1-2) located on the water side is longer than that of the steel sheet pile (1-2) located on the foundation pit (4) side; the top surface of the steel sheet pile (1-2) located on the water side is higher than the top surface of the steel sheet pile (1-2) located on the foundation pit (4) side; the bottom surface of the steel sheet pile (1-2) located on the water side is lower than the bottom surface of the steel sheet pile (1-2) located on the foundation pit (4) side; and the installation position of the corbel (1-3) is higher than the river surface of the river (2).

4. The double-row steel sheet pile soil core combined cofferdam structure according to claim 1 is characterized in that: When the excavation depth of the foundation pit (4) is less than 5 m, it is shallow excavation; when the excavation depth of the foundation pit (4) is greater than or equal to 5 m, it is deep excavation.

5. The construction method of the double-row steel sheet pile soil core combined cofferdam structure according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step (1): After the welded double-row pile connection unit (1-1) is driven into the designated construction area by a vibrating hammer, a plurality of steel sheet piles (1-2) are driven one by one between two double-row pile connection units (1-1), and the number of steel sheet piles (1-2) between every two double-row pile connection units (1-1) is designed according to the engineering requirements; Furthermore, the embedding depth of the steel sheet piles (1-2) located on the foundation pit (4) side and the steel sheet piles (1-2) located on the water side should be designed in accordance with the Technical Specifications for Support of Construction Foundation Pit (4); Step (2): welding a corbel (1-3) on the outer side of the steel sheet pile (1-2), erecting a steel cofferdam, and welding the contact parts among the steel cofferdam, the corbel (1-3) and the steel sheet pile (1-2); Step (3): using a blow-fill method to fill the cofferdam with sand and soil in layers. After each layer is filled, it is squeezed and compacted by a hammer-attached soil squeezer (7) until the designed elevation is reached; Step (4): inserting a drainage board (1-6) into the fill soil (1-5) inside the weir body; Step (5): after the cofferdam construction is completed, the foundation pit (4) is excavated; when the excavation depth is less than 5 m, no sand-filled pipe bags (6) are arranged; when the excavation depth is greater than or equal to 5 m, a slope section (5) needs to be reserved, and sand-filled pipe bags (6) are arranged outside the slope section (5) to prevent the double-row pile cofferdam (1) from collapsing inwards; Step (6): when arranging the sand-filled tube bags (6), the sand-filled tube bags (6) are first laid to the designated construction area, and then sand is pressed into the sand-filled tube bags (6) by blowing and filling, so as to complete the in-situ filling of the sand-filled tube bags (6).

6. The construction method of the double-row steel sheet pile soil core combined cofferdam structure according to claim 5 is characterized by: If there is a section where the excavation depth changes during the excavation of the foundation pit (4), the lengths of the steel sheet piles (1-2) and the connecting steel sheet piles (1-1-1) should be adjusted according to the change in the excavation depth of the foundation pit (4); according to the connection stiffness requirements of the double-row steel sheet piles (1-2) and the earth core combined cofferdam, the connecting plate (1-1-2) can be arranged throughout the length with the same length as the connecting steel sheet piles (1-1-1), or can be arranged at intervals.

7. The construction method of the double-row steel sheet pile soil core combined cofferdam structure according to claim 5 is characterized by: The sand used for filling in step (3) and step (6) can come from river sand around the construction site. The filling sand is sucked into the pipeline by means of suction or rake suction, and then filled into the cofferdam through the pipeline, or pressure-filled into the sand-filled pipe bag (6).

8. The construction method of the double-row steel sheet pile soil core combined cofferdam structure according to claim 5 is characterized by: In the step (4), after the drainage board (1-6) is inserted, the moisture in the soil will be discharged upward along the drainage board (1-6) under the action of the surrounding soil pressure.

9. The construction method of the double-row steel sheet pile soil core combined cofferdam structure according to claim 5, characterized in that: In the step (5), when the soil-extruding hammer (7) extrudes the soil, the brushes (7-5) on both sides contact the steel sheet piles (1-2), thereby preventing the soil-extruding hammer (7) from causing damage to the steel sheet piles (1-2).

10. The construction method of the double-row steel sheet pile soil core combined cofferdam structure according to claim 5, characterized in that: In the step (6), the stacking height of the sand-filled tube bags (6) should be calculated according to the Technical Specification for Support of Building Foundation Pit (4) (JGJ120-2012), and the overall stability coefficient, embedded stability safety factor, wall bottom anti-uplift safety factor, and pit bottom anti-uplift safety factor of the foundation pit (4) should meet the requirements of the specification.

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