A trench support structure and construction method for trenchless pipe jacking

Abstract

The application relates to the field of foundation pit support, and particularly discloses a non-excavation jacking pipe and pulling pipe foundation pit support structure and a construction method. The foundation pit support structure comprises Larsen steel sheet piles and two end slot piles buckled to the Larsen steel sheet piles, and the end slot piles are located on both sides of a pipe opening. A port plate and a plurality of shaped plates are detachably arranged between the two end slot piles, and the port plate and the plurality of shaped plates jointly form an earth retaining surface for stabilizing soil. A through hole is formed in the port plate for the pipeline to pass through, and a lock cover is detachably connected to the port plate for closing or opening the through hole. The application can support and reinforce the soil of the pipe opening while closing the pipe opening, can provide a stable jacking backstop surface, is applicable to the construction of the jacking pipe and the pulling pipe, and the components used in the construction can be recycled, so that the construction cost is saved.

Description

Technical Field

[0001] This application relates to the field of foundation pit support, and in particular to a foundation pit support structure and construction method using trenchless pipe jacking and pipe dragging. Background Technology

[0002] Trenchless construction technology, because it does not require road excavation and can cross highways, railways, rivers, surface buildings, underground structures, and various underground pipelines, is widely used in urban cable laying. It offers advantages such as construction safety, high speed, and no disruption to surface traffic. Pipe jacking and pipe pulling are commonly used trenchless construction methods.

[0003] When using the jacking and dragging method to construct pipelines, in order to reduce the risk of soil sliding and burying the foundation pit, a stable back seat surface needs to be provided for the jacking equipment in the well chamber. At the same time, the soil at the pipe opening needs to be sealed and reinforced. Currently, in common support structures, the pipe opening sealing structure usually cannot be standardized and recycled. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a trenchless pipe jacking and dragging pipe foundation pit support structure and construction method.

[0005] The technical solution for a trenchless pipe jacking and pipe dragging foundation pit support structure provided in this application is as follows:

[0006] A trenchless pipe jacking and pipe-pulling foundation pit support structure includes:

[0007] Larssen sheet piles are fixedly installed along the inner wall of the foundation pit, and walers are fixedly installed on the inner side of the Larssen sheet piles.

[0008] Two end-grooved piles are vertically installed on both sides of the pipe opening. Each end-grooved pile includes a channel steel and a tie fastener fixed to the back of the channel steel. The tie fastener is fastened to the Larssen steel sheet pile. The slots of the two end-grooved piles are arranged opposite each other.

[0009] A port plate and multiple shaping plates are detachably installed between two end-grooved piles. The port plate and multiple shaping plates together form a retaining surface for stabilizing the soil. The port plate is formed by two upper and lower halves joined together, and a through hole is provided on the port plate for the pipe to pass through.

[0010] A locking cover, detachably connected to the port plate, is used to close or open the through hole;

[0011] A positioning mechanism is used to fix the position of the port plate and the shaping plate, so that the through hole is coaxial with the pipe.

[0012] The port plate and the shaping plate are fixed between two end-pull piles by a positioning mechanism, so that the port plate and multiple shaping plates together form a retaining surface for stabilizing the soil and supporting and reinforcing the soil at the pipe opening. The through hole is sealed with a locking cap, and the sealing structure has a flat support surface, which can provide a stable jacking back seat surface. Before jacking or dragging pipe construction, the locking cap can be removed from the port plate. This application is applicable to both jacking and dragging pipe construction. Due to the use of a spliced ​​structure, components such as the port plate and shaping plate can be recycled, which helps to save construction costs.

[0013] Furthermore, the positioning mechanism includes a grooved cutting foot slidably disposed between the two end-pull pins and a plurality of H-shaped connecting purlins, the H-shaped connecting purlins being located above the grooved cutting foot; adjacent grooved cutting feet and H-shaped connecting purlins are used to fix the port plate and the plurality of shaping plates, and adjacent two H-shaped connecting purlins are used to fix the plurality of shaping plates; the positioning mechanism also includes a locking component for fixing the position of the grooved cutting foot.

[0014] Furthermore, the grooved cutting edge is provided with an upward-facing groove for supporting the port plate and multiple shaping plates arranged side by side; the H-shaped connecting purlin is provided with two grooves, the upper groove for supporting multiple shaping plates arranged side by side, and the lower groove is fitted into the upper part of the shaping plate or the port plate.

[0015] The groove of the channel-shaped cutting edge and the lower groove of the H-shaped connecting purlin fix the side-by-side end plates and multiple shaping plates between two end-pull piles; the grooves of two adjacent H-shaped connecting purlins face each other, fixing multiple side-by-side shaping plates between two end-pull piles; multiple H-shaped connecting purlins can be set, thus setting multiple rows of shaping plates from bottom to top; the position of the channel-shaped cutting edge is fixed by locking components, thereby fixing the end plates and multiple shaping plates, achieving stable support for the soil. The channel-shaped cutting edge, end plates, and shaping plates are all easy to disassemble and reassemble, facilitating recycling.

[0016] Furthermore, the grooved cutting edge is provided with a cutting edge portion on the side away from its own groove opening, which is used to cut the soil downwards as the foundation pit is excavated.

[0017] As the foundation pit is excavated, the grooved cutting edge, H-shaped connecting purlin, end plate, and multiple shaping plates sink due to their own gravity, and the cutting edge of the grooved cutting edge cuts downwards into the soil; when it sinks to a suitable position, the grooved cutting edge is locked, thereby fixing the position of the end plate and multiple shaping plates.

[0018] Furthermore, the end-pull grooved pile is provided with a plurality of insertion holes spaced apart along its own length direction, and the locking component includes a pin that passes through the insertion holes and through the end of the grooved cutting foot.

[0019] The position of the slotted cutting edge can be easily locked using a pin.

[0020] Furthermore, sealing elements for sealing gaps are provided between adjacent port plates and shaping plates, as well as between two adjacent shaping plates.

[0021] The sealing element serves to seal the surface, preventing both water leakage and grout leakage during the grouting process.

[0022] Furthermore, the port plate is fixedly provided with an inner steel ring in the through hole, and the lock cover includes a circular steel plate and a steel cylinder fixed to the circular steel plate. The outer diameter of the steel cylinder is adapted to the inner diameter of the inner steel ring. The circular steel plate and the inner steel ring are connected by bolts.

[0023] Install the lock cover on the port plate to form a fully enclosed structure, preventing soil from sliding or collapsing through the through holes on the port plate; before jacking or dragging pipe construction, remove the lock cover from the port plate to facilitate the pipe passing through the through holes on the port plate; using bolted connections can improve the ease of disassembly and assembly.

[0024] Furthermore, geotextile is provided on the side of the port plate closest to the soil.

[0025] Geotextiles can both block soil and prevent mortar from entering the gap between the lock cover and the end plate during grouting, thus avoiding difficulties in subsequent disassembly; the geotextiles can be punctured before jacking or dragging pipe construction.

[0026] Furthermore, the gap between the retaining surface formed by the port plate and the shaping plate and the soil is filled with a mortar layer.

[0027] The mortar layer can strengthen the sidewalls of the soil; due to the low strength of the mortar, it does not bond well with the sealing structure, is easy to clean, and facilitates pipe jacking or pipe dragging construction.

[0028] This application provides a construction method for a trenchless pipe jacking and pipe-pulling foundation pit support structure, comprising the following steps:

[0029] (1) Construction preparation and surveying and setting out;

[0030] (2) Larssen sheet pile construction;

[0031] (3) Excavation of the foundation pit and construction of the waler;

[0032] (4) Construction of sealing structure:

[0033] a. Install end slotted piles and slotted cutting feet, and install end plates and multiple shaping plates at the slot of the slotted cutting feet;

[0034] b. Install H-type groove purlins, and install multiple shaping plates in the upper groove of the H-type groove purlins;

[0035] c. Repeat step b to install multiple rows of shaping plates from bottom to top;

[0036] d. As the foundation pit is excavated, the grooved cutting edge, H-shaped connecting purlin, port plate and multiple shaping plates sink under their own weight. The position of the through hole on the port plate is monitored at any time. When the center of the through hole coincides with the center of the pipe, the position of the grooved cutting edge is fixed.

[0037] (5) Grouting construction: The gap between the retaining surface formed by the end plate and the shaping plate and the soil is filled with mortar;

[0038] (6) Top and drag pipe construction: Remove the lock cover on the end plate, make a cross on the geotextile, and install the equipment to carry out top and drag pipe construction;

[0039] (7) Backfilling of the foundation pit and removal of the support structure: As the foundation pit is backfilled, the grooved cutting edge, end plate and multiple shaping plates, multiple H-shaped groove walers and cofferdams are removed from bottom to top in sequence, and finally the end-pulled piles and Larssen steel sheet piles are pulled out.

[0040] In summary, this application includes at least one of the following beneficial technical effects:

[0041] 1. Sheet piles, end-pulled piles, grooved cutting edges, H-shaped joint purlins, end plates, and shaping plates together form a stable support structure to reinforce the soil at the pipe opening; the through hole is sealed with a locking cap, and the sealing structure support surface is flat, which can provide a stable back seat surface for jacking, adapting to the dual needs of pipe jacking and pipe pulling construction.

[0042] 2. This application adopts a splicing structure, and all components are made of reusable materials, which are easy to disassemble and recycle, thus helping to save construction costs;

[0043] 3. The construction method provided in this application is simple to operate and easy to achieve standardized and regulated construction. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application;

[0045] Figure 2 This is a schematic diagram of the sealing structure mainly used in the embodiments of this application to show the end grooved pile, grooved cutting foot, H-shaped grooved purlin, port plate and shaping plate;

[0046] Figure 3 This is a schematic diagram used to illustrate the port board and the shaping board in the embodiments of this application;

[0047] Figure 4 This is a schematic diagram used in the embodiments of this application to mainly illustrate the locking cap and the sealing membrane assembly.

[0048] Reference numerals: 1-Larsen sheet pile; 11-Walder; 2-End-grooved pile; 21-Rack; 22-Intercept; 3-End plate; 31-Through hole; 32-Inner steel ring; 33-Rectangular tube; 34-Square steel; 35-Steel mesh; 4-Shaped plate; 41-Reinforcing mesh; 42-Groove frame; 5-Mortar layer; 6-H-type grooved waler; 7-Groove cutting edge; 8-T-type clamp; 9-Lock cover; 91-Circular steel plate; 92-Steel cylinder; 93-Membrane plugging assembly; 931-Half steel plate ring; 932-Geotextile; 10-Pipe. Detailed Implementation

[0049] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0050] Example 1

[0051] This application discloses a trenchless pipe jacking and pipe-pulling foundation pit support structure. (Refer to...) Figure 1 The non-excavation top and pipe-dragging foundation pit support structure includes Larssen steel sheet piles 1 fixedly installed along the inner wall of the foundation pit, and walers 11 fixedly installed on the inner side of the Larssen steel sheet piles 1.

[0052] Reference Figure 1 and Figure 2 Two vertical end-grooving piles 2 are respectively installed on both sides of the pipe 10 opening. The end-grooving pile 2 includes a channel steel and a tie 21 fixed to the back of the channel steel. The tie 21 is fastened to the Larsen steel sheet pile 1. The slots of the two end-grooving piles 2 are set opposite to each other.

[0053] Reference Figure 2 A port plate 3 and multiple shaping plates 4 are detachably installed between the two end-grooved piles 2. The port plate 3 and the multiple shaping plates 4 together form a retaining surface for stabilizing the soil. The port plate 3 is formed by two upper and lower halves joined together, and a through hole 31 is opened on the port plate 3 for the pipe 10 to pass through. A locking cover 9 is detachably connected to the port plate 3. Figure 2 (Not shown in the image) is used to close or open the through hole 31. A positioning mechanism is provided on the end pull-slot pile 2 to fix the position of the port plate 3 and the shaping plate 4, so that the through hole 31 is coaxial with the pipe 10.

[0054] The end-grooved pile 2 closes the edge of the Larssen sheet pile 1, providing a certain degree of seepage prevention. The side of the end-grooved pile 2 connects to the waler 11, providing strong anti-overturning stability. The end plate 3 and the shaping plate 4 are fixed between the two end-grooved piles 2 by a positioning mechanism, so that the end plate 3 and multiple shaping plates 4 together form a retaining surface for stabilizing the soil and supporting and reinforcing the soil at the pipe opening.

[0055] The through hole 31 is sealed by the locking cover 9, and the sealing structure support surface is flat, which can provide a stable jacking back seat surface. Before jacking or dragging pipe construction, the locking cover 9 can be removed from the end plate 3. This application is applicable to both jacking and dragging pipe construction. Due to the use of a splicing structure, components such as the end-pull pile 2, end plate 3, and shaping plate 4 can be recycled, which helps to save construction costs.

[0056] Reference Figure 3 The shaping plate 4 includes a channel-shaped frame 42 with a width ≥ 5cm. A steel mesh 41 is welded inside the channel-shaped frame 42 and filled with micro-expansion concrete ≥ C25. The steel mesh 41 is ≥ Φ8 threaded steel. The frame of the port plate 3 includes rectangular tubes 33 on the left and right sides and channel steel with a width ≥ 5cm on the top and bottom sides. A steel mesh 41 is welded to the inner side of the frame of the port plate 3 and filled with concrete ≥ C30. Steel plate mesh 35 is installed on both sides of the steel mesh 41 within the frame. The short pitch (SWD) of the steel plate mesh 35 is ≥ 15mm.

[0057] Reference Figure 3 The port plate 3 is divided into upper and lower halves, which are connected into a whole by inserting square steel 34 into the rectangular tube 33. The width of the rectangular tube 33 is ≥8cm and the wall thickness is ≥1cm. The square steel 34 is made of three equally divided threaded sections. The outer diameter of the square steel 34 is the same as the inner diameter of the rectangular tube 33 to ensure that the square steel 34 fits tightly against the inner wall of the rectangular tube 33.

[0058] Reference Figure 3 An inner steel ring 32 is centrally located within the frame of the port plate 3. The inner steel ring 32 consists of two semi-circular steel rings, one above the other. The inner steel ring 32 is a groove-shaped steel ring with its groove facing outwards. The outer side of the inner steel ring 32 is welded to the side wall of the rectangular tube 33. The inner diameter of the inner steel ring 32 is at least 20cm larger than the outer diameter of the pipe 10. The inner steel ring 32 has 4-8 through-holes evenly distributed along its circumference, and the extension direction of the through-holes is parallel to the axis of the inner steel ring 32.

[0059] Reference Figure 3 Sealing elements for sealing gaps are provided between adjacent port plates 3 and shaping plates 4, as well as between two adjacent shaping plates 4. Specifically, the sealing element is a T-shaped clip 8 with a T-shaped foot height ≥1cm and a width ≥5cm. Grease is applied to the contact surface between the T-shaped clip 8 and the plate frame, and it is inserted into the gap between the plate frames from the soil-facing side to achieve a sealing effect, which can both waterproof and prevent grout leakage during the grouting process.

[0060] Reference Figure 2The positioning mechanism includes a grooved cutting foot 7 slidably disposed between two end-pull grooved posts 2 and a plurality of H-shaped connecting purlins 6, the H-shaped connecting purlins 6 being located above the grooved cutting foot 7. The positioning mechanism also includes a locking component for fixing the position of the grooved cutting foot 7. Specifically, the end-pull grooved post 2 has a plurality of insertion holes 22 spaced apart along its own length direction, and the locking component includes a pin that passes through the insertion holes 22 and through the end of the grooved cutting foot 7.

[0061] Furthermore, referring to Figure 2 The grooved cutting foot 7 has an upward-facing groove for supporting the end plate 3 and multiple shaping plates 4 arranged side by side. The groove depth of the grooved cutting foot 7 is ≥12mm, the groove width of the grooved cutting foot 7 is at least 1cm smaller than the groove width of the end pull groove pile 2, and the distance between the end of the grooved cutting foot 7 and the bottom wall of the groove of the end pull groove pile 2 is 1~2cm, so that the grooved cutting foot 7 can slide up and down along the groove of the end pull groove pile 2.

[0062] In this embodiment, refer to Figure 2 The groove of the grooved cutting foot 7 has two shaping plates 4, which are located on both sides of the port plate 3. The edge of the shaping plate 4 away from the port plate 3 is located in the groove of the end pull groove pile 2.

[0063] Reference Figure 2 The H-shaped purlin 6 has two slots, an upper one to support multiple side-by-side shaping plates 4, and a lower one to be fitted into the upper part of the shaping plate 4 or the end plate 3. The slot depth of the H-shaped purlin 6 is ≥12mm, and the slot width of the H-shaped purlin 6 is at least 1cm smaller than the slot width of the end pull pile 2, allowing the H-shaped purlin 6 to slide up and down along the slot of the end pull pile 2. The distance between the end of the H-shaped purlin 6 and the bottom wall of the slot of the end pull pile 2 is 1-2cm. After the position of the H-shaped purlin 6 is fixed, the gap between the end of the top-level H-shaped purlin 6 and the bottom wall of the slot of the end pull pile 2 can be filled with wooden wedges to improve the stability of the H-shaped purlin 6.

[0064] In this embodiment, refer to Figure 2 There are 3 shaping plates 4 in the groove above the H-shaped purlin 6, and the edges of the shaping plates 4 on both sides are located in the groove of the end pull pile 2.

[0065] Multiple H-shaped purlins 6 can be installed, allowing for multiple rows of shaping plates 4 to be installed from bottom to top, achieving stable support for the soil. The grooved cutting edge 7, end plate 3, and shaping plates 4 are all easy to assemble and disassemble, facilitating recycling. In actual construction, the dimensions of the H-shaped purlins 6, end plate 3, and shaping plates 4, as well as the number of shaping plates 4, can be adjusted according to construction needs to improve the applicability of this application to different construction scenarios.

[0066] Furthermore, the grooved cutting foot 7 has a cutting foot part on the side opposite to its own groove opening, which is used to cut the soil downward as the foundation pit is excavated.

[0067] As the foundation pit is excavated, the grooved cutting edge 7, H-shaped connecting purlin 6, end plate 3, and multiple shaping plates 4 sink due to their own gravity, and the cutting edge of the grooved cutting edge 7 cuts downwards into the soil. When it sinks to a suitable position, the grooved cutting edge 7 is locked onto the end-tensioning pile 2 by a pin, thereby fixing the position of the end plate 3 and multiple shaping plates 4. The fixing elevation should be high rather than low, and can be adjusted later by micro-vibration of the end-tensioning pile 2 to ensure that the center of the end plate 3 corresponds to the center of the pipeline 10.

[0068] Reference Figure 4 The lock cover 9 includes a circular steel plate 91 and a steel cylinder 92 welded to the circular steel plate 91, and the steel cylinder 92 is filled with concrete. The thickness of the circular steel plate 91 is ≥5mm, the thickness of the steel plate of the steel cylinder 92 is ≥3mm, the outer diameter of the steel cylinder 92 is adapted to the inner diameter of the inner steel ring 32, and the axial length of the steel cylinder 92 is consistent with the axial length of the inner steel ring 32.

[0069] Reference Figure 4 The edge of the circular steel plate 91 has multiple round holes, which correspond one-to-one with the positions of multiple through screw holes on the inner steel ring 32, thus facilitating the connection of the lock cover 9 and the inner steel ring 32 by bolts.

[0070] The locking cover 9 is connected to the inner steel ring 32, forming a fully enclosed structure for the port plate 3, preventing soil from sliding or collapsing through the through hole 31 on the port plate 3. Before jacking or dragging pipe construction, the locking cover 9 is removed from the port plate 3, making it easier for the pipe 10 to pass through the through hole 31 on the port plate 3; bolted connections improve the ease of disassembly and assembly.

[0071] Reference Figure 4 A membrane sealing assembly 93 is provided on the side of the port plate 3 closest to the soil. The membrane sealing assembly 93 includes two mating semi-steel rings 931 and geotextile 932. The thickness of the semi-steel rings 931 is ≥5mm, and the perimeter of the geotextile 932 is ≥15cm. It is coated with plastic and oil and has a certain degree of elasticity.

[0072] Reference Figure 4 The semi-steel plate ring 931 has multiple round holes, which correspond one-to-one with the positions of multiple through bolt holes on the inner steel ring 32. This facilitates the connection between the semi-steel plate ring 931 and the inner steel ring 32 after the bolt passes through the geotextile 932, and presses and fixes the geotextile 932 to the soil-facing surface of the end plate 3.

[0073] Geotextile 932 can both block the soil and prevent mortar from entering the gap between the lock cover 9 and the port plate 3 during grouting, thus avoiding difficulties in subsequent disassembly; the geotextile 932 can be cut before jacking or dragging pipe construction.

[0074] Furthermore, referring to Figure 1 The gap between the retaining surface, which is composed of the port plate 3 and the shaping plate 4, and the soil is filled with a layer of impermeable mortar 5 with an impermeability grade ≥ M7.5. The mortar layer 5 can strengthen the sidewall of the soil; due to the low strength of the mortar, it has weak bonding with the sealing structure, is easy to clean, and facilitates the construction of jacking or dragging pipes.

[0075] The implementation principle of a trenchless pipe jacking and pipe-pulling foundation pit support structure according to an embodiment of this application is as follows: The port plate 3 and multiple shaping plates 4 are installed between two end-pull piles 2 to form a retaining surface for soil stabilization. As the foundation pit is excavated, the grooved cutting edge 7, H-shaped connecting purlin 6, port plate 3, and multiple shaping plates 4 cut through the soil and sink under their own gravity. When the center of the port plate 3 coincides with the center of the pipe 10, the position of the grooved cutting edge 7 is fixed by a pin, achieving stable support for the soil. A locking cap 9 is used to seal the through hole 31 in the center of the port plate 3, resulting in a flat support surface that provides a stable jacking backing surface. Before pipe jacking or pipe-pulling construction, the locking cap 9 can be removed from the port plate 3.

[0076] This application is applicable to both pipe jacking and pipe pulling construction. Due to the use of a splicing structure, components such as the end-pull pile 2, end plate 3, shaping plate 4, grooved cutting foot 7, and H-shaped connecting purlin 6 can be recycled, which helps to save construction costs. The construction method is simple to operate and easy to achieve standardized and regulated construction.

[0077] Example 2

[0078] This application discloses a construction method for a trenchless pipe jacking and pipe-pulling foundation pit support structure, including the following steps:

[0079] (1) Construction preparation: Based on the required dimensions of the foundation pit, the depth of the foundation pit, the Larssen steel sheet pile 1 model, etc., reasonably select the dimensions and specifications of the end-grooved pile 2, end plate 3, shaping plate 4, H-type groove purlin 6, groove-type cutting foot 7, T-type clamp 8, locking cover 9, and membrane plugging component 93, and perform stability calculations and pile length verification of the support system, determine construction parameters, form reasonable design drawings, and complete material production;

[0080] (2) Surveying and setting out: Based on the material dimensions selected in the construction preparation stage, design the dimensions of pipelines and support structures, and survey and set out the centerline of pipeline 10, the centerline of Larssen sheet pile 1 support structure, and the pile positions of end slotted pile 2, as well as the ground elevation between the pile positions of end slotted pile 2.

[0081] (3) Construction of Larssen sheet pile 1: Based on the centerline of the Larssen sheet pile 1 support structure as measured and laid out, Larssen sheet pile 1 is driven from the four corners. The verticality of the pile and the driving speed are controlled. The position and verticality of the Larssen sheet pile 1 connected to the end slotted pile 2 are strictly controlled. At the same time, dewatering is carried out as needed according to the groundwater conditions.

[0082] (4) Excavation of the foundation pit and construction of the waler 11: After the Larsen steel sheet pile 1 is completed, the soil in the foundation pit is excavated. After excavation to the elevation of the first waler 11, the first waler 11 is constructed.

[0083] (5) Excavation and sealing structure construction of the foundation pit:

[0084] a. Install end-grooving piles 2, and correct the deviation of end-grooving piles 2 in a timely manner with reference to the edge line of waler 11; as the foundation pit is excavated, install waler 11, and then install grooved cutting foot 7, and install end plate 3 and multiple shaping plates 4 at the groove of grooved cutting foot 7.

[0085] b. Install the H-type groove purlin 6, and install multiple shaping plates 4 in the upper groove of the H-type groove purlin 6;

[0086] c. Repeat step b to install multiple rows of shaping plates 4 from bottom to top;

[0087] d. As the foundation pit is excavated, the grooved cutting foot 7, H-shaped connecting purlin 6, port plate 3 and multiple shaping plates 4 cut into the soil and sink under their own weight. The position of the through hole 31 on the port plate 3 is monitored at any time. When the center of the through hole 31 coincides with the center of the pipe 10, the grooved cutting foot 7 is fixed to the end pull pile 2 by a pin, and wooden wedges are inserted at both ends of the top H-shaped connecting purlin 6 to reinforce the H-shaped connecting purlin 6.

[0088] (6) Grouting construction: Fill the gap between the retaining surface formed by the end plate 3 and the shaping plate 4 and the soil with mortar. Install an attached vibrator on the end plate 3 or the shaping plate 4 to vibrate the mortar. Stop grouting when the bottom of the grooved cutting foot 7 turns into mortar and the top gap overflows with mortar. After the mortar solidifies, add wedges to the gap between the waler 11 and the end pull groove pile 2, and fix it by spot welding, binding and clamping.

[0089] (7) Top and drag pipe construction: Remove the locking cover 9 on the port plate 3, make a cross on the geotextile 932, and install the equipment to carry out top and drag pipe construction;

[0090] (8) Backfilling of the foundation pit and removal of the support structure: Release the fixing of the grooved cutting foot 7, temporarily fix the bottom end plate 3 and the shaping plate 4 with diagonal bracing, and then remove the grooved cutting foot 7; as the foundation pit is backfilled, gradually pull up the end-grooving pile 2, and remove the end plate 3 and multiple shaping plates 4, multiple H-shaped grooved walers 6 and walers 11 layer by layer from bottom to top, and finally pull out the end-grooving pile 2 and Larssen steel sheet pile 1.

[0091] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A trenchless pipe jacking and pipe-pulling foundation pit support structure, characterized in that: include: Larssen sheet piles are fixedly installed along the inner wall of the foundation pit, and walers are fixedly installed on the inner side of the Larssen sheet piles. Two end-grooved piles are vertically installed on both sides of the pipe opening. Each end-grooved pile includes a channel steel and a tie fastener fixed to the back of the channel steel. The tie fastener is fastened to the Larssen steel sheet pile. The slots of the two end-grooved piles are arranged opposite each other. A port plate and multiple shaping plates are detachably installed between two end-grooved piles. The port plate and multiple shaping plates together form a retaining surface for stabilizing the soil. The port plate is formed by two upper and lower halves joined together. A through hole for the pipe to pass through is opened on the port plate. Geotextile is installed on the side of the port plate near the soil. A locking cover, detachably connected to the port plate, is used to close or open the through hole; A positioning mechanism is used to fix the positions of the port plate and the shaping plate, so that the through hole is coaxial with the pipe; The positioning mechanism includes a grooved cutting foot slidably disposed between two end-grooving piles and a plurality of H-shaped connecting purlins, the H-shaped connecting purlins being located above the grooved cutting foot; adjacent grooved cutting feet and H-shaped connecting purlins are used to fix the port plate and the plurality of shaping plates, and adjacent two H-shaped connecting purlins are used to fix the plurality of shaping plates; the positioning mechanism also includes a locking component for fixing the position of the grooved cutting foot; The grooved cutting edge is provided with an upward-facing groove for supporting the port plate and multiple shaping plates arranged side by side; the H-shaped connecting purlin is provided with two grooves, the upper groove for supporting multiple shaping plates arranged side by side, and the lower groove is fitted into the upper part of the shaping plate or the port plate. The grooved cutting edge is provided on the side away from its own groove opening, and is used to cut the soil downward as the foundation pit is excavated. The end-grooved pile has multiple insertion holes spaced apart along its own length, and the locking component includes a pin that passes through the insertion holes and through the end of the grooved cutting foot.

2. The foundation pit support structure for trenchless pipe jacking and pipe pulling according to claim 1, characterized in that: A sealing element for sealing gaps is provided between adjacent port plates and shaping plates, as well as between two adjacent shaping plates.

3. The foundation pit support structure for trenchless pipe jacking and pipe pulling according to claim 1, characterized in that: The port plate has an inner steel ring fixedly installed in the through hole. The lock cover includes a circular steel plate and a steel cylinder fixed to the circular steel plate. The outer diameter of the steel cylinder is adapted to the inner diameter of the inner steel ring. The circular steel plate and the inner steel ring are connected by bolts.

4. The foundation pit support structure for trenchless pipe jacking and pipe pulling according to claim 1, characterized in that: The gap between the retaining surface formed by the port plate and the shaping plate and the soil is filled with a mortar layer.

5. A construction method for a trenchless pipe jacking and pipe-pulling foundation pit support structure as described in any one of claims 1-4, characterized in that: Includes the following steps: (1) Construction preparation and surveying and setting out; (2) Larssen sheet pile construction; (3) Excavation of the foundation pit and construction of the waler; (4) Construction of sealing structure: a. Install end slotted piles and slotted cutting feet, and install end plates and multiple shaping plates at the slot of the slotted cutting feet; b. Install H-type groove purlins, and install multiple shaping plates in the upper groove of the H-type groove purlins; c. Repeat step b, installing multiple rows of shaping plates from bottom to top; d. As the foundation pit is excavated, the grooved cutting edge, H-shaped connecting purlin, port plate and multiple shaping plates sink under their own weight. The position of the through hole on the port plate is monitored at any time. When the center of the through hole coincides with the center of the pipe, the position of the grooved cutting edge is fixed. (5) Grouting construction: The gap between the retaining surface formed by the end plate and the shaping plate and the soil is filled with mortar; (6) Top and drag pipe construction: Remove the lock cover on the end plate, make a cross-shaped cut on the geotextile, and install the equipment to carry out top and drag pipe construction; (7) Backfilling of the foundation pit and removal of the support structure: As the foundation pit is backfilled, the grooved cutting edge, end plate and multiple shaping plates, multiple H-shaped groove walers and cofferdams are removed from bottom to top in sequence, and finally the end-pulled piles and Larssen steel sheet piles are pulled out.

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