A Larssen steel sheet pile retaining structure and its construction method

Abstract

The present application relates to the technical field of construction engineering, and particularly relates to a retaining structure of Larssen steel sheet piles and a construction method thereof. The retaining structure includes a first retaining module, which includes Larssen steel sheets and pile impact hangers. The bottom surface of the pile impact hanger is provided with a clamping groove, and the upper part of the Larssen steel sheet is inserted into the clamping groove. The top surface of the pile impact hanger is provided with a bearing platform, and there is a through groove on the bearing platform. Vertical sliding grooves are respectively provided on both side surfaces of the pile impact hanger, and limiting guide grooves are provided on the inner side surfaces of the vertical sliding grooves. The second and third retaining modules are respectively connected to both sides of the first retaining module through a limiting sliding rod, and both ends of the limiting sliding rod are respectively located in the vertical sliding grooves and the limiting guide grooves of the pile impact hangers of the second and third retaining modules. The present application adopts a superimposed construction plan of a guide beam and a pilot hole, effectively controlling the quality and accuracy of the axis position of the Larssen steel sheet pile sinking and the verticality of the pile. The penetration of the pile is good, the sheet pile has no deformation, and the quality of the sheet pile retaining is significantly improved.

Description

Technical Field

[0001] This application relates to the technical field of construction engineering, and in particular, to a retaining structure of Larsen steel sheet piles and its construction method. Background Art

[0002] Larsen steel sheet piles, also known as U-shaped steel sheet piles, use the "U-shaped protrusions" on both sides of each sheet pile to interlock adjacent sheet piles. The interlocking structure can form a high-strength watertight structure, making Larsen steel sheet piles widely used in temporary support during foundation pit excavation. It is not only simple and fast in construction, low in cost, but also reusable. However, during the driving process of Larsen steel sheet piles, when encountering hard clay soil, it is difficult to drive the Larsen steel sheet piles. It is difficult to control the quality such as the axis position of the steel sheet pile driving and the verticality of the pile, the accuracy control is poor, and the sheet pile is prone to bending deformation, which affects reuse and increases the project cost. Summary of the Invention

[0003] In order to ensure the verticality of Larsen steel sheet pile driving and improve the retaining quality of Larsen steel sheet piles, this application provides a retaining structure of Larsen steel sheet piles and its construction method, which adopts the following technical solutions:

[0004] A retaining structure of Larsen steel sheet piles includes a first retaining module. The first retaining module includes a Larsen steel sheet and a pile driving hanging part. The bottom surface of the pile driving hanging part is provided with a clamping groove, and the upper part of the Larsen steel sheet is inserted into the clamping groove. The top surface of the pile driving hanging part is provided with a bearing platform, and there is a through groove on the bearing platform. Vertical sliding grooves are respectively provided on both side surfaces of the pile driving hanging part, and limiting guide grooves are provided on the inner side surfaces of the vertical sliding grooves. On both sides of the first retaining module, there are second retaining modules and third retaining modules with the same structure respectively. Limiting sliding rods are connected between the first retaining module, the second retaining module and the third retaining module. The middle part of the limiting sliding rod is recessed into the through groove of the pile driving hanging part of the first retaining module. The two ends of the limiting sliding rod are respectively located in the vertical sliding grooves of the pile driving hanging parts of the second retaining module and the third retaining module, and the lug ears provided at the ends of the limiting sliding rod are fitted into the limiting guide grooves.

[0005] By adopting the above technical solutions, during the driving of the pile driver, the bearing platform provides a larger contact surface for the Larsen steel sheet and the pile hammer, reducing the situation that the Larsen steel sheet is driven obliquely due to the misalignment of the center of the Larsen steel sheet and the pile hammer during driving, which helps to maintain the verticality of the Larsen steel sheet and the driving efficiency; at the same time, the limiting sliding rod clamped between the second retaining module and the third retaining module is used to press and limit the first retaining module. During construction, since the limiting sliding rod is recessed into the bearing platform, it is not impacted by the pile hammer, but slides down as the Larsen steel sheet sinks, playing a guiding role for the Larsen steel sheet and further preventing the Larsen steel sheet from tipping and deflecting.

[0006] Optionally, a pull rope is respectively threaded through the limiting slide bars between the first support module and the second support module, and between the first support module and the third support module. A counterweight is suspended at the end of the pull rope.

[0007] By adopting the above technical solution, the counterweight arranged on the limiting slide bar can effectively reduce the center of gravity of the overall support structure, increase the pressing effect of the limiting slide bar on the first support module, and improve the stability of the structure.

[0008] Optionally, a scale plate or an inclination alarm device is arranged at the position on the limiting slide bar where the pull rope abuts.

[0009] By adopting the above technical solution, when the limiting slide bar, i.e., the sheet pile, inclines, the pull rope on the limiting slide bar deflects under the pulling of the counterweight. At this time, the deflection situation of the pull rope can be directly seen on the scale plate, so as to judge the inclination degree of the sheet pile, which is convenient for construction workers to judge and discover the inclination problem of the sheet pile and correct it in time.

[0010] Optionally, the inclination alarm device includes a device body connected to the limiting slide bar. A sector-shaped groove is arranged in the middle of the device body. The pull rope passes through the sector-shaped groove. A first pressure sensor and a second pressure sensor are respectively arranged on both sides in the sector-shaped groove. The first pressure sensor and the second pressure sensor are connected to a control chip. The control chip is connected to a battery and an alarm. When the pull rope swings and presses on the first pressure sensor or the second pressure sensor, the control chip obtains and judges that the pressure value of the first pressure sensor or the pressure value of the second pressure sensor is greater than the set threshold, and the control chip controls the alarm to give an alarm.

[0011] By adopting the above technical solution, when the sheet pile inclines, the pull rope in the sector-shaped groove swings under the action of the counterweight. After swinging, the pull rope presses on one side of the first pressure sensor or the second pressure sensor, increasing the pressure value collected by the first pressure sensor or the second pressure sensor. When the control chip receives that the collected pressure value is too large, it triggers the alarm to give an alarm, reminding the staff to take corrective measures in time, overcoming the problems of inaccurate visual judgment and untimely discovery of the inclination of the sheet pile, and improving the construction quality and efficiency.

[0012] Optionally, scale lines are arranged on the pile impact hanging parts on the side of the vertical chute.

[0013] By adopting the above technical solution, during construction, the driving depth of the sheet pile can be accurately judged by checking the position of the limiting slide bar parallel to the top surface of the sheet pile on the scale lines, without repeated measurement, which provides convenience for construction.

[0014] Optionally, a bolt fastening assembly is arranged between the pile impact hanging part of the first support module and the sheet pile.

[0015] By adopting the above technical solution, the bolt fastening assembly locks and fixes the pile impact hanging piece and the Larssen steel sheet. On the one hand, it prevents the jumping of the pile impact hanging piece during pile hammer impact, improving the structural stability. On the other hand, after the pile impact hanging piece and the Larssen steel sheet become an integral whole, during pile pulling, the lifting rope can be fixed on the pile impact hanging piece, such as on the bolt fastening assembly, improving the convenience of pile pulling.

[0016] Optionally, a pile impact hanging piece is respectively provided at the upper and lower parts of the Larssen steel sheets of the second support module and the third support module.

[0017] By adopting the above technical solution, the pile impact hanging piece serves as the base of the Larssen steel sheet, which can prevent the second support module and the third support module from tipping over, further improving the stability of the Larssen steel sheet.

[0018] Optionally, the limiting slide bar is composed of two spliced T-shaped steel parts. The T-shaped steel part includes a middle steel plate, and two angle steels serving as lugs are locked at the end of the middle steel plate; a connecting piece is locked between the two T-shaped steel parts, the connecting piece is recessed in the through groove, and the connecting piece is provided with a positioning block for being fitted into the limiting guide groove.

[0019] By adopting the above technical solution, the limiting slide bar composed of two spliced T-shaped steel parts has a simple structure. The assembled structure is convenient for transportation, the refined body type has low consumable material cost, and the cooperation between the positioning block and the limiting guide groove further limits the positional relationship between the limiting slide bar and the first support module, preventing the limiting slide bar on the first support module from sliding and the Larssen steel sheet from tilting, improving the structural stability.

[0020] Optionally, U-shaped locking mouths are provided on both sides of the Larssen steel sheet of the first support module. Multiple Larssen steel sheets are connected end to end through the U-shaped locking mouths to form the main body of the Larssen steel sheet pile. An H-shaped steel beam is provided on the inner side of the main body of the Larssen steel sheet pile. A T-shaped steel part is connected between the H-shaped steel beam and the pile impact hanging piece of the main body of the Larssen steel sheet pile. One end of the T-shaped steel part with a lug is clamped at the bottom of the vertical sliding groove, and the other end of the T-shaped steel part is locked with one side of the H-shaped steel beam through an angle steel. A cross bracing steel pipe is connected to the other side of the H-shaped steel beam, and the cross bracing steel pipe is used for connecting the H-shaped steel beams on two opposite sides in the main body of the closed Larssen steel sheet pile.

[0021] By adopting the above technical solution, during the driving of the Larssen steel sheet pile, the pile impact hanging piece and the limiting slide bar serve as the guiding components. After disassembly and recombination, they can also be used as the support components to reinforce the main body of the closed Larssen steel sheet pile. The components are flexible in use, have high utilization rate, reduce the raw material inventory and transportation pressure, and have high practicality.

[0022] A construction method for the Larssen steel sheet pile support structure as described above includes the following steps:

[0023] Step 1: Lay out the construction coordinate lines according to the construction drawings. Use a rotary drilling rig to drill grouting pilot holes along the construction coordinate lines. At regular intervals, set up a denser section with a smaller spacing between the pilot holes.

[0024] Step 2: Select qualified Larsen steel sheets. Insert the clamping groove of a pile impact hanging part into the upper part of the Larsen steel sheet to form a first support module. Erect the second support module and the third support module with the same structure on both sides of the first support module respectively. Then place a limiting sliding rod vertically downward into the through groove and vertical sliding groove of the pile impact hanging part. The first support module, the second support module, and the third support module are connected to form a tripod support structure, making the first support module stand stably.

[0025] Step 3: Use the screen driving method for construction. Connect another Larsen steel sheet to one end of the Larsen steel sheet of the first support module. After several Larsen steel sheets are connected in a row, they form a screen shape.

[0026] Step 4: Use a pile driver to drive the Larsen steel sheet. When driving, the pile hammer impacts on the bearing platform of the pile impact hanging part of the first support module. Both ends of the limiting sliding rod slide downward as the Larsen steel sheet of the first support module sinks. During driving, the bearing platform is always kept horizontal under the guiding pressure of the limiting sliding rod, making the Larsen steel sheet be vertically driven into the foundation.

[0027] By adopting the above technical solutions, the spacing density of the pilot holes is set in sections. This can not only avoid excessive density of the pilot holes and loosening of the pile foundation, but also facilitate the driving of the U-shaped lock of the Larsen steel sheet, improving the penetration degree of the sheet pile and the construction effect of the pilot holes. At the same time, using the Larsen steel sheet as a pile driving guide beam not only saves the additional costs of purchasing, storing, and transporting the guide beam, but also compared with the traditional guide beam that needs to be locked to the ground to prevent the guide beam from being displaced by the extrusion of the Larsen steel sheet during pile driving. In the tripod support structure composed of three Larsen steel sheets and the limiting sliding rod, the two side Larsen steel sheets do not need to be locked to the ground separately, making the construction more convenient and the stability also meeting the construction requirements.

[0028] In summary, the present application includes at least one of the following beneficial technical effects:

[0029] 1. The present application makes use of the Larsen steel sheet as a guide beam by using local materials, which not only saves the additional costs of purchasing, storing, and transporting the guide beam, but also the Larsen steel sheet used as the guide beam does not need to be locked to the ground, making the construction more convenient. At the same time, the pile impact hanging part provides a bearing platform with a larger contact surface between the Larsen steel sheet and the pile hammer, reducing the situation that the Larsen steel sheet is driven obliquely due to the misalignment of the centers of the Larsen steel sheet and the pile hammer during driving, helping to maintain the perpendicularity of the Larsen steel sheet and the driving efficiency. When constructing with the structure of the present application, the quality and precision such as the axis position of the Larsen steel sheet pile sinking and the perpendicularity of the pile are more convenient to control, improving the penetration degree of the pile, reducing the bending deformation of the sheet pile, and improving the quality of the sheet pile support.

[0030] This application adopts the construction plan of using a rotary drilling rig to lead holes and a crawler pile driver for driving, which ensures the smooth implementation of the steel sheet pile construction in the rock stratum section. The spacing density of the lead holes is set in sections, which can not only avoid excessive lead hole density and loosening of the pile foundation, but also facilitate the driving of the U-shaped lock of the Larsen steel sheet pile, improve the penetration degree of the sheet pile and the construction effect of the lead hole, and increase the benefits. Description of the Drawings

[0031] Figure 1 is a schematic diagram of the pile driving construction structure of this application.

[0032] Figure 2 is a schematic diagram of the structure of the first support module of this application.

[0033] Figure 3 is a schematic diagram of the structure of the inclination alarm device of this application.

[0034] Figure 4 is a schematic diagram of the inner pile support structure of this application.

[0035] Figure 5 is a construction flow chart of this application.

[0036] Description of the reference numerals: 1. Second support module; 2. Larsen steel sheet; 21. U-shaped lock; 3. Pile impact hanging part; 31. Clamping groove; 32. Bearing platform; 33. Through groove; 34. Vertical sliding groove; 35. Limit guide groove; 36. Scale line; 4. First support module; 5. Third support module; 6. Limit sliding rod; 61. Lug; 62. Pulling rope; 63. Counterweight block; 7. Inclination alarm device; 71. Device body; 72. Sector groove; 73. First pressure sensor; 74. Second pressure sensor; 75. Control chip; 76. Battery; 77. Alarm; 8. Bolt fastening assembly; 9. T-shaped steel part; 91. Middle steel plate; 92. Angle steel; 93. Connecting piece; 94. Positioning stop block; 10. H-shaped steel beam; 11. Cross bracing steel pipe. Detailed Description of the Embodiment

[0037] The following is a further detailed description of this application in combination with the attached Figures 1-5 drawings.

[0038] Refer to Figures 1-2, an embodiment of the present application discloses a retaining structure of a Larssen steel sheet pile, including a first retaining module 4. The first retaining module 4 includes a Larssen steel sheet 2 and a pile driving hanging member 3. A clamping groove 31 is provided on the bottom surface of the pile driving hanging member 3. The clamping groove 31 is a rectangular groove, and its inner top surface is a plane matching the thickness of the Larssen steel sheet 2. Since the Larssen steel sheet 2 has a certain thickness and hardness, after the pile driving hanging member 3 is inserted into the upper part of the Larssen steel sheet 2 through the clamping groove 31, the pile driving hanging member 3 has good stability and is not easy to skew and fall. At the same time, in this embodiment, the pile driving hanging member 3 and the Larssen steel sheet 2 are fixed by a bolt fastening assembly 8 passing through. Specifically, a number of corresponding through holes are provided on the side surface of the pile driving hanging member 3 and the Larssen steel sheet 2, and then the bolts are passed through the through holes and locked by nuts, so that the integrity of the pile driving hanging member 3 and the Larssen steel sheet 2 is improved, the structural strength is increased, and it is also beneficial to the subsequent pile pulling operation using the pile driving hanging member 3. A bearing platform 32 is provided on the top surface of the pile driving hanging member 3, a through groove 33 is provided on the bearing platform 32, vertical sliding grooves 34 are respectively provided on both side surfaces of the pile driving hanging member 3, and scale lines 36 are provided on the pile driving hanging member 3 on the side surface of the vertical sliding groove 34. A limiting guide groove 35 is provided on the inner side surface of the vertical sliding groove 34; second retaining modules 1 and third retaining modules 5 with the same structure are respectively provided on both sides of the first retaining module 4. A limiting slide bar 6 is connected between the first retaining module 4, the second retaining module 1 and the third retaining module 5. The middle part of the limiting slide bar 6 is recessed into the through groove 33 of the pile driving hanging member 3 of the first retaining module 4. Both ends of the limiting slide bar 6 are respectively located in the vertical sliding grooves 34 of the pile driving hanging members 3 of the second retaining module 1 and the third retaining module 5. The lug 61 provided at the end of the limiting slide bar 6 is fitted into the limiting guide groove 35. A pull rope 62 is respectively passed through the limiting slide bar 6 between the first retaining module 4 and the second retaining module 1 and between the first retaining module 4 and the third retaining module 5. A counterweight 63 is connected and suspended at the end of the pull rope 62. A scale disk or an inclination alarm device 7 is provided at the position where the pull rope 62 abuts against the limiting slide bar 6.

[0039] Referring to Figure 3 , in this embodiment, an inclination alarm device 7 is adopted. The inclination alarm device 7 includes a device body 71 connected to the limiting slide bar 6. A sector groove 72 is provided in the middle of the device body 71. The pull rope 62 passes through the sector groove 72. First pressure sensors 73 and second pressure sensors 74 are respectively provided on both sides in the sector groove 72. The first pressure sensor 73 and the second pressure sensor 74 are connected to a control chip 75. The control chip 75 is connected to a battery 76 and an alarm 77. When the pull rope 62 swings and presses on the first pressure sensor 73 or the second pressure sensor 74, the control chip 75 obtains and judges that the pressure value of the first pressure sensor 73 or the pressure value of the second pressure sensor 74 is greater than the set threshold, and the control chip 75 controls the alarm 77 to give an alarm.

[0040] In addition, in this embodiment, a pile driving hanger 3 is respectively provided at the upper and lower parts of the Larsen steel plate 2 of the No. 2 support module 1 and the No. 3 support module 5. The pile driving hanger 3 at the bottom mainly serves as a support base for the No. 2 support module 1 and the No. 3 support module 5, preventing the Larsen steel plate 2 of the No. 2 support module 1 and the No. 3 support module 5 from sliding with the ground or the Larsen steel plate 2 from tilting, thereby improving the stability of the guide beam structure composed of the No. 2 support module 1 and the No. 3 support module 5.

[0041] Reference Figure 2 The limit slide bar 6 is composed of two T-shaped steel parts 9, which include a middle steel plate 91. The ends of the middle steel plate 91 are locked with two angle steels 92 as lugs 61. U-shaped locks 21 are provided on both sides of the Larsen steel plate 2 of the No. 1 support module 4. Multiple Larsen steel plates 2 are connected end to end through the U-shaped locks 21 to form the Larsen steel plate 2 pile body. A connector 93 is locked between the two T-shaped steel parts 9. The connector 93 is recessed in the through groove 33. The connector 93 is provided with a positioning block 94 for fitting into the limit guide groove 35. In this embodiment, the connector 93 is composed of two side steel plates. The two ends of the two side steel plates are respectively bolted to the middle steel plates 91 of the two T-shaped steel parts 9. The side surfaces of the side steel plates are provided with positioning blocks 94 for fitting into the limit guide groove 35.

[0042] Reference Figure 4 In addition to being used as a pile striking medium during pile driving to improve the quality of pile sinking, the pile striking hanger 3 can also be used as a support component in the main body of the Larsen steel plate 2 pile after pile sinking is completed. Specifically, after pile sinking is completed, an H-shaped steel beam 10 is set on the inner side of the main body of the Larsen steel plate 2 pile, and a T-shaped steel member 9 is connected between the H-shaped steel beam 10 and the pile striking hanger 3 of the main body of the Larsen steel plate 2 pile. The T-shaped steel member 9 is a part of the limit slide bar 6 removed and disassembled after pile sinking is completed, or directly selected from the original part that has not been spliced with the limit slide bar 6. One end of the T-shaped steel member 9 is provided with a lug 61, which is clamped at the bottom of the vertical slide groove 34, and the other end of the T-shaped steel member 9 is locked with one side of the H-shaped steel beam 10 through an angle steel 92. The other side of the H-shaped steel beam 10 is connected to a cross brace steel pipe 11, and the cross brace steel pipe 11 is used to connect the H-shaped steel beams 10 on two opposite sides of the closed Larsen steel plate 2 pile main body.

[0043] Reference Figure 5 A construction method of the above-mentioned Larsen steel sheet pile support structure comprises the following steps:

[0044] Step 1: According to the construction drawings, the construction coordinate lines are laid out, and a rotary drilling machine is used to perform grouting and drilling along the construction coordinate lines. At each interval, a dense section with a smaller spacing between the drilling holes is set. The dense section is used to drive in the U-shaped lock 21 of the Larsen steel plate 2.

[0045] Step 2: Select qualified Larssen steel sheet 2. Insert the clamping groove 31 of a pile impact hanger 3 into the upper part of the Larssen steel sheet 2 to form a first support module 4, and lock the pile impact hanger 3 and the Larssen steel sheet 2 with bolts. Make the second support module 1 and the third support module 5 with the same structure in the same way. Stand the second support module 1 and the third support module 5 with the same structure on both sides of the first support module 4 respectively. Then place a limiting slide bar 6 composed of two T-shaped steel parts 9 with counterweight blocks 63 and tilt alarm devices 7 locked together from top to bottom into the through groove 33 and vertical chute 34 of the pile impact hanger 3. Fit the lug 61 of the T-shaped steel part 9 into the limiting guide groove 35 of the pile impact hanger 3 of the second support module 1 and the third support module 5, and fit the central positioning block 94 of the T-shaped steel part 9 into the limiting guide groove 35 of the pile impact hanger 3 of the first support module 4, so that the first support module 4, the second support module 1 and the third support module 5 are connected to form a tripod support structure, and make the first support module 4 stand stably.

[0046] Step 3: Use the screen driving method for construction. Connect another Larssen steel sheet 2 at one end of the Larssen steel sheet 2 of the first support module 4. After several Larssen steel sheets 2 are connected in a row, they form a screen shape. The screen driving method is not easy to cause the sheet piles to buckle, twist, tilt and the wall surface to be uneven. The driving accuracy is high and it is easy to achieve closed closure. The construction sequences of the screen driving method include forward sequence, reverse sequence, reciprocating sequence, middle division sequence, neutralization sequence and composite sequence. The driving sequence has a direct impact on the verticality, displacement, expansion and contraction in the axial direction, the unevenness of the sheet pile wall and the driving efficiency of the sheet piles. Therefore, the driving sequence is one of the keys to the sheet pile construction technology. The selection principle is: when the sheet piles already driven at both ends of the screen wall are reversely inclined, the forward sequence should be used for driving; on the contrary, use the reverse sequence for driving; when the sheet piles at both ends of the screen wall remain vertical, the reciprocating sequence can be used for driving; when the length of the sheet pile wall is very long, the composite sequence can be used for driving.

[0047] Step 4: Use a pile driver to drive the Larssen steel sheets 2 in turn. When driving, the pile hammer impacts on the bearing platform 32 of the pile impact hanger 3 of the first support module 4. Both ends of the limiting slide bar 6 slide downward as the Larssen steel sheet 2 of the first support module 4 sinks. During driving, the bearing platform 32 is always kept horizontal under the guiding pressure of the limiting slide bar 6, so that the Larssen steel sheet 2 is vertically driven into the foundation. In order to ensure the closing effect of the main body of the Larssen steel sheet 2 pile, corner sheet piles should be used at the four corners of the main body of the Larssen steel sheet 2 pile. If there are no such sheet piles, auxiliary measures such as using old tires or rags to seal the joints can be used.

[0048] Step 5, after the driving of the main body of the Larssen steel sheet pile 2 is completed, in order to strengthen the stability between the closed Larssen steel sheet piles 2, an H-shaped steel beam 10 is arranged on the inner side of the main body of the Larssen steel sheet pile 2, and the T-shaped steel part 9 of the disassembled limit slide bar 6 is used to lock and fix the H-shaped steel beam 10. One end of the lug 61 of the T-shaped steel part 9 is clamped at the bottom of the vertical chute 34, and the other end of the T-shaped steel part 9 is locked and connected to one side of the H-shaped steel beam 10 through an angle steel 92. Then, a cross-bracing steel pipe 11 is locked and connected between the H-shaped steel beams 10 on two opposite sides to form a complete support structure.

[0049] Meanwhile, before construction, material inspection and appearance inspection shall be carried out on the Larssen steel sheet pile 2. Each sheet pile shall be inspected one by one. The unqualified sheet piles shall be corrected. Ordinary sheet piles with severely rusted and deformed connecting lock joints shall be removed. Grease shall be applied to the lock joints of the sheet piles to facilitate driving and extraction. Appearance inspection includes surface defects, length, width, thickness, height, end rectangular ratio, straightness, and lock joint shape, etc. When hoisting and loading / unloading the sheet piles, two-point lifting shall be preferably adopted. The pile driver shall adopt Hitachi 450 crawler hydraulic vibratory hammer for pile driving and extraction equipment. Before pile driving, the accurate center line of the support piles shall be carefully set out.

[0050] After the main structure construction is completed and the foundation pit is backfilled, the sheet piles shall be pulled out for repeated use. Before pulling out the sheet piles, excessive soil carried by pile pulling shall be avoided, so as not to cause ground settlement and displacement, which may endanger the constructed underground structure and affect the safety of adjacent original buildings, structures or underground pipelines. After the steel sheet piles are pulled out, the foundation pores shall be promptly filled and compacted with cement slurry or medium-coarse sand.

[0051] In this embodiment, Hitachi 450 vibratory extraction equipment is used for pile extraction in the project: by using the forced vibration generated by the hydraulic vibration equipment to disturb the soil mass and destroy the cohesion of the soil around the sheet piles to overcome the pile extraction resistance, and relying on the action of the vibration extraction force to pull out the piles. Attention shall be paid to the pile extraction starting point and sequence during pile extraction: for the closed sheet pile wall, the pile extraction starting point shall be more than 5 piles away from the corner piles. Determine the pile extraction starting point according to the situation during pile driving. If necessary, the method of skip extraction can also be used. The pile extraction sequence is preferably opposite to that during pile driving. Vibration and extraction: During pile extraction, the lock joints of the sheet piles can be vibrated alive by the hydraulic vibration equipment first to reduce the adhesion of the soil, and then extract while vibrating. The vibration extraction equipment shall gradually apply load along with the vibration, and the vibration extraction force is generally slightly less than the compression limit of the shock absorber. For sheet piles with greater extraction resistance, the method of intermittent vibration shall be adopted, with each vibration lasting for 15 minutes.

[0052] The above are all the preferred embodiments of this application, and the protection scope of this application is not limited accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application shall be covered within the protection scope of this application.

Claims

1. A Larssen steel sheet pile support structure, characterized in that: It includes a first support module (4). The first support module (4) includes a Larssen steel sheet (2) and a pile driving pendant (3). The bottom surface of the pile driving pendant (3) is provided with a clamping groove (31), and the upper part of the Larssen steel sheet (2) is inserted into the clamping groove (31). The top surface of the pile driving pendant (3) is provided with a bearing platform (32), and a through groove (33) is formed on the bearing platform (32). Vertical sliding grooves (34) are respectively arranged on both side surfaces of the pile driving pendant (3), and limiting guide grooves (35) are arranged on the inner side surfaces of the vertical sliding grooves (34). Second support modules (1) and third support modules (5) with the same structure are respectively arranged on both sides of the first support module (4). A limiting slide bar (6) is connected between the first support module (4), the second support module (1) and the third support module (5). The middle part of the limiting slide bar (6) is recessed into the through groove (33) of the pile driving pendant (3) of the first support module (4). Both ends of the limiting slide bar (6) are respectively located in the vertical sliding grooves (34) of the pile driving pendants (3) of the second support module (1) and the third support module (5). The lug (61) provided at the end of the limiting slide bar (6) is fitted into the limiting guide groove (35). The limiting slide bar (6) is composed of two spliced T-shaped steel parts (9). The T-shaped steel part (9) includes a middle steel plate (91), and two angle steels (92) serving as lugs (61) are locked at the end of the middle steel plate (91). A connecting piece (93) is locked between the two T-shaped steel parts (9). The connecting piece (93) is recessed into the through groove (33), and the connecting piece (93) is provided with a positioning block (94) for fitting into the limiting guide groove (35).

2. The retaining structure of Larssen steel sheet piles according to claim 1, characterized in that: A pulling rope (62) is respectively threaded through the limiting slide bar (6) between the first support module (4) and the second support module (1) and between the first support module (4) and the third support module (5). A counterweight (63) is connected and suspended at the end of the pulling rope (62).

3. The L-shaped steel sheet pile retaining structure according to claim 1, characterized in that: A scale or an inclination alarm device (7) is arranged at the position where the pulling rope (62) abuts against the limiting slide bar (6).

4. The Larssen steel sheet pile retaining structure according to claim 3, wherein: The inclination alarm device (7) includes a device body (71) connected to the limiting slide bar (6). A sector groove (72) is arranged in the middle of the device body (71). The pulling rope (62) passes through the sector groove (72). A first pressure sensor (73) and a second pressure sensor (74) are respectively arranged on both sides in the sector groove (72). The first pressure sensor (73) and the second pressure sensor (74) are connected to a control chip (75). The control chip (75) is connected to a battery (76) and an alarm (77). When the pulling rope (62) swings and presses on the first pressure sensor (73) or the second pressure sensor (74), the control chip (75) obtains and judges that the pressure value of the first pressure sensor (73) or the pressure value of the second pressure sensor (74) is greater than the set threshold value, and the control chip (75) controls the alarm (77) to give an alarm.

5. The retaining structure of Larssen steel sheet piles according to claim 1, characterized in that: Scale lines (36) are arranged on the pile driving pendant (3) on the side of the vertical sliding groove (34).

6. The retaining structure of Larssen steel sheet piles according to claim 1, wherein: A bolt fastening assembly (8) is threaded through between the pile driving pendant (3) and the Larssen steel sheet (2) of the first support module (4).

7. The sheet pile retaining structure according to claim 1, characterized in that: A pile driving hanger (3) is respectively provided on the upper and lower parts of the Larsen steel plates (2) of the No. 2 support module (1) and the No. 3 support module (5).

8. The L-shaped steel sheet pile support structure according to claim 1, characterized in that: The Larsen steel plate (2) of the first support module (4) is provided with U-shaped locking openings (21) on both sides. A plurality of Larsen steel plates (2) are connected end to end through the U-shaped locking openings (21) to form a Larsen steel plate (2) pile body. An H-shaped steel beam (10) is provided on the inner side of the Larsen steel plate (2) pile body. A T-shaped steel member (9) is connected between the H-shaped steel beam (10) and the pile striking hanger (3) of the Larsen steel plate (2) pile body. One end of the T-shaped steel member (9) is provided with a lug (61) and is clamped at the bottom of the vertical slide groove (34). The other end of the T-shaped steel member (9) is locked with one side of the H-shaped steel beam (10) through an angle steel (92). The other side of the H-shaped steel beam (10) is connected with a cross bracing steel pipe (11). The cross bracing steel pipe (11) is used to connect the H-shaped steel beams (10) on two opposite sides of the closed Larsen steel plate (2) pile body.

9. A construction method of the retaining structure of Larssen steel sheet piles as described in claim 1, characterized in that: The following steps are involved: Step 1: According to the construction drawings, the construction coordinate lines are laid out, and a rotary drilling machine is used to perform grouting and drilling along the construction coordinate lines. At intervals, a dense section with a smaller spacing between the drilling holes is set, and the dense section is used to drive in the U-shaped lock (21) of the Larsen steel plate (2); Step 2, select a Larsen steel plate (2) of qualified quality, plug the clamping groove (31) of a pile striking hanger (3) into the upper part of the Larsen steel plate (2) to form a No. 1 support module (4), erect a No. 2 support module (1) and a No. 3 support module (5) of the same structure on both sides of the No. 1 support module (4), and then place a limit slide bar (6) from top to bottom in the through groove (33) and the vertical slide groove (34) of the pile striking hanger (3), and connect the No. 1 support module (4), the No. 2 support module (1) and the No. 3 support module (5) to form a tripod support structure, so that the No. 1 support module (4) is stably erected; Step 3: using a screen-type driving method to connect one end of the Larsen steel plate (2) of the No. 1 support module (4) to another Larsen steel plate (2), and a plurality of Larsen steel plates (2) are connected in a row to form a screen shape; Step 4, using a pile driver to drive the Larsen steel plate (2), during which the pile hammer strikes the load-bearing platform (32) of the pile driving hanger (3) of the No. 1 support module (4), and the two ends of the limit slide bar (6) slide downward as the Larsen steel plate (2) of the No. 1 support module (4) sinks. During the driving, the load-bearing platform (32) is always kept horizontal by the pressure guided by the limit slide bar (6), so that the Larsen steel plate (2) is kept vertically driven into the foundation.

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