Fertilizer-groove-free foundation pit support and basement exterior wall comprehensive construction method

Abstract

The invention discloses a non-fertilizer-groove foundation pit support and basement outer wall comprehensive construction method. The method comprises the following steps of geological exploration analysis, support pile construction, earth and stone excavation, waist beam and prestressed lattice support construction, internal-adhesion-prevention pre-paving anti-adhesion waterproof construction, single-side formwork erecting and segmented and layered pouring construction. The method is adopted for construction under the construction condition close to a railway business line, the influence on the railway can be reduced, and the effects of rapid construction, construction period shortening and the like are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of deep foundation pit construction adjacent to a railway operating line, and in particular to a fertilizer-free foundation pit support and a comprehensive construction method for a basement exterior wall. Background Art

[0002] As the total scale and mileage of railways continue to increase, the problem that comes with it is that there are more and more construction projects close to the operating lines of railways. How to reduce the impact on railways is an issue that every construction project near the operating lines of railways, especially deep foundation pit projects, needs to consider and solve urgently.

[0003] By eliminating the fertilizer trough and reducing the foundation pit support, the impact on the railway operating line can be reduced to a certain extent. However, the problem caused by construction without a fertilizer trough is that there is no operating space for exterior wall waterproofing and exterior wall formwork construction.

[0004] In the prior art, in order to cope with the narrow operating space of the exterior wall waterproofing, the external waterproofing and inner pasting technology is adopted. However, although the conventional external waterproofing and inner pasting technology has a low requirement for the operating space, it usually still requires the installation of a fertilizer tank, and it is difficult to completely eliminate the fertilizer tank. In addition, the conventional external waterproofing and inner pasting usually also requires the installation of a leveling layer, a protective layer and a cushion layer of the bottom plate, etc. The operation is relatively complicated and there is a waste of materials.

[0005] When the operating space of the exterior wall is relatively narrow, the single-side formwork construction technology is also used. However, it is not easy to take into account the common single-side formwork construction technology and the exterior wall waterproofing effect, and there is a hidden danger of side leakage. For example, the conventional practice of single-side formwork of some exterior walls is to use tension bolts welded on the support piles. The tension bolts pass through and damage the waterproof membrane, which is prone to leakage. Summary of the invention

[0006] The purpose of the present invention is to provide a comprehensive construction method for foundation pit support without fertilizer trough and basement exterior wall under the condition of construction near the railway operating line, based on the above technical problems, so as to reduce the impact on the railway and have the effects of fast construction and shortened construction period. The purpose of the present invention is achieved through the following technical solutions: A fertilizer-free foundation pit support and basement exterior wall comprehensive construction method comprises the following steps: Step 1: Geological survey and analysis: Check whether the construction area contains strongly weathered sandstone or moderately weathered sandstone geological layers, and check whether the compressive strength of the weathered sandstone geological layers meets the construction standards for support piles. If the compressive strength meets the standards, proceed to step 2; Step 2: Support pile construction: locate and lay out the support piles, use a rotary drilling machine to drill holes at the support piles, tie up the steel cages simultaneously, and pour concrete after the steel cages are hoisted; Step 3: Earthwork excavation: Use an excavator to excavate the earthwork until the weathered sandstone is reached, and then re-measure the elevation and structure edge line; Step 4: Construction of waist beam and prestressed lattice support: During the earth excavation process, waist beam and lattice support are constructed. Excavate to the waist beam bottom elevation, tie waist beam steel bars and pour concrete, embed steel plates and add load-bearing ear plates at the waist beam position; excavate to the support position, tie concrete support steel bars and pour concrete; the lattice support is steel, and the upper and lower ends of the lattice support are respectively installed at the load-bearing ear plate and the support of the waist beam. After the lattice support is installed, prestress is applied; Step 5: External waterproofing and internal pasting, pre-paving and reverse-adhesive waterproofing construction: Construction is carried out from the outside to the inside, which is to spray the inner surface of the support pile with a mesh of 10mm, construct a 20mm thick cement mortar leveling layer to make the surface of the support pile vertical, construct a 6mm thick waterproof mortar layer, and pre-pave a 1.5mm thick polymer self-adhesive film waterproof membrane; Step 6: Single-side formwork and segmented and layered pouring construction: The construction of the lowest level of the basement is as follows: 1) Before pouring the floor slab, embedded parts and anti-slope formwork for the bottom floor slab shall be set; 2) The floor slab and the counterslope are cast together; 3) External wall reinforcement binding; 4) Installation of the lower wall formwork, primary and secondary ribs and diagonal braces: single-sided formwork, secondary ribs and primary ribs are made of square wood and double-sided steel back ribs respectively, and one side of the main rib is connected with a gripper through a screw; the upper part of the diagonal brace is connected to the gripper, and the lower part is supported on the embedded parts that have been set. The verticality of the single-sided formwork is adjusted by adjusting the length of the diagonal brace; 5) Casting of the lower wall section, and use of the floor slab formwork frame as a safe operating platform to achieve single-side formwork vibration operation; 6) Formwork removal: remove the lower wall formwork, primary and secondary ribs and diagonal braces; 7) Installation of the upper wall formwork, primary and secondary ribs and diagonal braces: single-sided formwork, secondary ribs and primary ribs are made of square wood and double-sided steel back ribs respectively, and one side of the main rib is connected with a gripper through a screw; the upper part of the diagonal brace is connected to the gripper, and the lower part is supported on the embedded parts that have been set. The verticality of the single-sided formwork is adjusted by adjusting the length of the diagonal brace; 8) Before pouring the upper floor slab, embedded parts are set up, and the upper floor slab anti-slope formwork is supported; 9) The upper wall, the floor slab and the counterslope of the upper layer are cast together, and the floor slab formwork frame is used as a safe operating platform to achieve single-side formwork vibration operation; 10) Formwork removal: remove the upper wall formwork, primary and secondary ribs and diagonal braces; Repeat steps 3) to 10) of the lowest basement construction for the upper basement construction. If there is another basement, continue to repeat steps 3) to 10) until the top basement. When pouring the upper wall of the top basement, the upper wall and the top plate are poured together, and there is no need to construct a counter-slope.

[0007] Wherein: in step 1, the compressive strength of the weathered sandstone geological layer reaches the support pile construction standard: the standard value of the saturated uniaxial compressive strength is greater than 15MPa.

[0008] For further optimization, a crusher is used to crush the stone in step three. When excavating deep foundation pits near railways, no slope can be allowed and vertical excavation is required. For rocks with a volume exceeding the threshold, a cutting machine is required to remove the rocks evenly.

[0009] Furthermore, the specific operation of step five for constructing a 20mm thick cement mortar leveling layer to make the surface of the supporting pile vertical is: construct the cement mortar in two layers, the first layer is 10mm thick, and the second layer is 10mm thick. Use a wooden trowel to rub the surface as you apply it, and water it every other day for maintenance.

[0010] Furthermore, in step five, a 6 mm thick waterproof mortar layer is constructed, and the mass ratio of cement, mortar and waterproof powder in the waterproof mortar is 1:2.5:0.05.

[0011] Furthermore, the embedded parts in step six in item 1) and item 8) include 4 L-shaped steel bars and 1 hook bolt, the hook bolt is fixed on the hanging formwork with nuts before concrete pouring for connecting wooden beams, the L-shaped steel bars are tied to the steel bars on the main bars of the raft (floor) slab, and the L-shaped steel bars are used to tighten the bottom of the diagonal brace; the 4 L-shaped steel bars include one C16 embedded steel bar and 3 C20 embedded steel bars, the diagonal brace of the anti-ridge formwork system is tightened on the C16 embedded steel bar with wooden beams, and the lower end of the diagonal brace of the wall formwork is tightened with the C20 embedded steel bar.

[0012] Furthermore, in step 4) and step 7) of step six, first fix the secondary ribs to the template by nails, and then set screws to pass through the template and the main ribs to connect the template, secondary ribs and main ribs as a whole; the main ribs are connected to the gripping seat by screws and fastened by bolts, so that the template, secondary ribs, main ribs and gripping seat can be connected as a whole.

[0013] Furthermore, in steps 4) and 7) of step six, the diagonal brace is composed of a steel pipe with an internal thread and a threaded rod connected to the bottom of the steel pipe, the bottom of the threaded rod is connected to the U-shaped steel plate, and the two walls of the U-shaped steel plate are provided with a corresponding pair of through holes, the embedded steel bars are supported against the inner wall of the U-shaped steel plate, the steel pipe is rotated to adjust the length of the diagonal brace to control the verticality of the template, and is tightened by adjusting the screw rod to cross the pair of through holes of the U-shaped steel plate.

[0014] Furthermore, in step 9) of step eight, the floor formwork frame is used as a safe operating platform to implement the specific operation of the single-sided formwork vibration operation: the spacing of the slab formwork frame is 1000×1000, the sweeping rod is 200, the first step distance is 1600, and the core filling rods are set up and the steel fence is laid above the first step distance of 1800 from the ground. The construction workers can stand on the steel fence to vibrate the single-sided formwork exterior wall.

[0015] Beneficial effects of the present invention: In view of the strongly weathered sandstone and moderately weathered sandstone geology, the present invention proposes a fertilizer-free trough foundation pit support and a comprehensive construction method for basement exterior walls under the construction conditions close to the railway operating line. The fertilizer-free trough foundation pit support is adopted to effectively reduce the perimeter of the foundation pit support, save the number of supporting piles, and the foundation pit edge is farther away from the railway, reducing the impact on the railway, and has the effects of fast construction and shortened construction period.

[0016] The waterproof construction of the basement exterior wall of the present invention adopts the facade pre-paving reverse bonding process, does not require a bottom plate leveling layer and a protective layer, and can form effective bonding.

[0017] The basement exterior wall structure construction of the present invention adopts single-side formwork and segmented pouring construction, which does not damage the waterproofing of the exterior wall and can ensure a better forming effect.

[0018] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the construction of waist beams and lattice supports; Figure 2 This is a schematic diagram of waterproofing construction; Figure 3 This is a schematic diagram of embedded parts; Figure 4 This is a schematic diagram of template fixing; Figure 5 This is a schematic diagram of the construction of the lower section of the -2F layer in the embodiment; Figure 6 This is a schematic diagram of the construction of the upper section of the -2F layer in the embodiment; Figure 7 This is a schematic diagram of the construction of the lower section of the -1F layer in the embodiment; Figure 8 This is a schematic diagram of the construction of the upper section of the -1F layer in the embodiment; Fig. 9 This is a schematic diagram of the lower end structure of the diagonal brace.

[0020] 1. Waist beam; 2. Lattice support; 3. Support; 4. Support pile; 5. Hook bolt; 6. C16 embedded steel bar; 7. C20 embedded steel bar; 8. Water-stop steel plate; 9. Anti-slope formwork; 10. Wooden beam; 11. Secondary rib; 12. Main rib; 13. Formwork; 14. Screw; 15. Grab seat; 16. Diagonal brace; 161. Steel pipe; 162. Threaded rod; 163. U-shaped plate; 17. Pad; 18. Steel fence. DETAILED DESCRIPTION

[0021] Example 1 A fertilizer-free foundation pit support and basement exterior wall comprehensive construction method comprises the following steps: Step 1: Geological survey and analysis: Check whether the construction area contains strongly weathered sandstone or moderately weathered sandstone geological layers, and check whether the compressive strength of the weathered sandstone geological layers meets the support pile construction standards. If the compressive strength meets the standards, proceed to step 2.

[0022] The project in this embodiment can be divided into four engineering geological layers, a layer of miscellaneous fill, a layer of clay, a layer of strongly weathered sandstone and a layer of moderately weathered sandstone. The standard value of the saturated uniaxial compressive strength of moderately weathered sandstone is 29.11 MPa, which is a very hard rock. In view of the high foundation strength, the fertilizer-free trough construction method with support piles close to the outer wall of the basement is adopted to reduce the scope of foundation pit support and reduce the impact on the railway.

[0023] Step 2: Support pile construction: locate and lay out the support pile positions, use a rotary drilling rig to drill holes in the support pile positions, simultaneously tie up the steel cage, and then pour concrete after hoisting the steel cage.

[0024] Step 3, earthwork excavation: Use an excavator to excavate earthwork until you reach the harder medium-weathered sandstone, re-measure the elevation and structure edge line, and use a crusher to crush the stone. The foundation pit contains large medium-weathered rocks. When excavating deep foundation pits near railways, you cannot slope and need to excavate vertically. During the vertical excavation process, if you encounter large medium-weathered rocks (large volume means exceeding the threshold, and the threshold is generally the average volume), if you crush the entire rock, it may cause large unevenness, and the foundation pit may collapse, affecting the railway operation line. Therefore, if you encounter individual large rocks on the bottom layer and side wall edges, you need to use a cutting machine to level and remove the rocks. Step 4: Construction of waist beam and prestressed lattice support: During the earth excavation process, waist beam 1 and lattice support 2 are constructed: excavate to the bottom elevation of waist beam 1, tie waist beam steel bars and pour concrete, embed steel plates and add load-bearing ear plates at waist beam 1; excavate to the position of support 3, tie concrete support steel bars and pour concrete; the lattice support 2 is Q345 steel, and the two ends of the lattice support 2 are respectively installed at the support 3 and the load-bearing ear plates of waist beam 1. After the lattice support is installed, prestress is applied; the waist beam and lattice support construction is as follows Figure 1 shown.

[0025] Step 5: External waterproofing and internal pasting pre-paving and reverse adhesive waterproofing construction: Construction is carried out from the outside to the inside, in turn, the inner surface of the support pile is sprayed with a mesh of 10mm, a 20mm thick cement mortar leveling layer is constructed to make the surface of the support pile vertical, a 6mm thick waterproof mortar layer is constructed, and a 1.5mm thick polymer self-adhesive film waterproofing membrane is pre-paved (commercially available materials such as EVAHDPE polymer self-adhesive film waterproofing membrane); the waterproofing construction diagram is as follows Figure 2 shown.

[0026] During the layered formwork pouring of the side wall, the construction joints are waterproofed with 3mm water-stop steel plates 8. Double-row buckle-type steel pipe external scaffolding → mesh spraying → external wall surface base treatment (20mm M15 mortar leveling) → 6mm waterproof mortar → acceptance → detail treatment (additional layer) → 1.5mm thick polymer self-adhesive membrane waterproofing membrane construction → acceptance → scaffolding removal → next process.

[0027] Layered mortar construction, the first layer is 10mm thick cement mortar (cement to mortar mass ratio 1:3); the second layer is 10mm thick cement mortar (cement to mortar mass ratio 1:3), rub it with a wooden trowel as you apply it, and water it every other day for maintenance. The interval between each mortar layer should be controlled and should not be too fast to prevent cracking, which will affect the workability and bonding strength of the mortar and cause hollowing and cracking. The wall surface after plastering should be kept flat with the original wall surface. If the flatness deviation is large, waterproof mortar should be used for secondary smoothing. Waterproof mortar 1:2.5 cement mortar mixed with 5% of cement waterproof powder 6mm.

[0028] Special parts treatment: Waterproof layer stubble: leave a stepped stubble, with a stubble of 50mm between layers; Waterproof layer joint: first clean the stubble, then evenly apply cement slurry on the stubble. Overlap each layer, with clear layers, and press after smearing; Waterproof layer at the corners: must be rounded. The diameter of the outer corner is 1 cm, and the diameter of the inner corner is 5 cm.

[0029] Waterproof mortar maintenance: Water spraying maintenance of waterproof mortar is the last key process to ensure the quality of waterproof plastering projects. If this work is not done in time and seriously, the water in the cement slurry will evaporate, resulting in shrinkage cracks. After 8 to 12 hours of applying each layer of mortar on the exterior wall, use a sprayer to spray a small amount of water for maintenance. In summer, this work can be done in advance. After 24 hours, you can water it heavily for maintenance and keep it in a moist state. The maintenance period is generally more than 7 days.

[0030] Construction of polymer pre-laid anti-adhesive membrane: Draw control lines → cut rolls → lay large surfaces (from low to high, with the sand surface facing the construction workers) → partially fix the rolls → glue the overlapping edges of the rolls → organize acceptance → tie steel bars on the bottom plate → pour concrete for the side walls.

[0031] (1) Elastic control line Before laying the roll material over a large area, first use a steel tape measure to determine the laying position and overlap size of the roll material, then use a line marker to mark the position, and then use special tools to cut to size based on the marked position.

[0032] (2) Large surface waterproofing membrane: Lay the roll material flat on the base layer according to the popped-up reference line position, tear off the isolation paper at the roll material joints, and lay the adjacent roll materials. While pasting, use a rubber roller (or other tools such as a scraper) to roll forward and outward (drive) to expel the air, so that the roll material joints are firmly pasted. Construction should be carried out in order from low to high. Before construction, first lay the roll material on the longitudinal edge of the position to be laid, align and overlap the edge line of the unrolled roll material with the popped-up control line or the inner edge line of the overlapped edge of the previous roll material, then unfold the roll material and roll it forward so that the roll material is laid on the waterproof mortar layer, with the sand surface facing the construction personnel. While rolling the roll material, adjust the position of the roll material so that the roll material rolls forward in a straight line, ensuring that the overlap with the overlapped edge of the previous roll material is 80mm. The short side joints of the rolls are determined according to the overlap method (80mm for overlap construction and 160mm sand-free self-adhesive rolls for butt joint construction). The short side joints of two adjacent rolls should be staggered by a distance of not less than 500mm. When constructing large surfaces at the corners, the rolls need to be cut after unfolding to fully release the internal stress of the rolls, and then wrap the corners, with double-sided tape for fixing. The overlapped parts of the rolls can be sealed by gluing or butt jointing.

[0033] (3) Local fixation of coiled material During the construction process, in order to prevent the roll material from moving, wrinkling, or encountering construction on facades, slopes, etc., the overlapped edges of the roll material are fixed every 500mm within 10~20mm from the outer edge with high polymer double-sided tape.

[0034] (4) Coil overlap treatment At the T-shaped overlap of the roll material (the overlapped junction of the long and short sides), a small triangle should be cut out of the middle roll material to strengthen the adhesion between the roll materials and prevent the local roll materials from having too many layers and being too thick, which will cause water seepage channels inside.

[0035] Overlap of the long side of the roll: The long side of the roll can be overlapped directly by gluing the overlapped side of the roll. The isolation film on the overlapped side can be torn off only after the large surface of the roll is laid. While tearing off the isolation film, use a roller to roll the waterproof roll in the same direction to make the two rolls overlap fully and densely, and ensure that the overlapped side size is not less than 80mm, as shown in the following figure: Overlapping the short sides of roll materials: There are two ways to overlap the short sides of roll materials, one is overlapping with special double-sided tape and the other is butt-jointing with self-adhesive roll materials underneath. Regardless of the overlapping method, it is necessary to ensure that the contact width between each roll material and the adhesive layer is not less than 80mm. After the overlap is completed, it must be compacted with a pressure roller.

[0036] After the waterproofing project is accepted, the subsequent construction process will be carried out, and the steel bars will be tied directly on the top of the membrane and the concrete raft will be poured.

[0037] Step 6: Single-side formwork and segmented and layered pouring construction: In this embodiment, the basement is divided into two floors -F2 layer construction is as follows: 1) Before pouring the floor (bottom, raft) slab, embedded parts are set up, and the anti-slope formwork of the bottom floor slab is supported; Before pouring the raft (floor) slab, embed L-shaped steel bars at four locations (3 C20 embedded steel bars, 1 C16 embedded steel bar) and 1 hook bolt. The hook bolt 5 is fixed to the hanging formwork with a nut before pouring the concrete. One end of the diagonal brace of the hanging formwork is fixed to the wooden beam with an iron nail, and the other end is tightened with the embedded steel bars. The diagonal brace of the anti-slope formwork system uses wooden beams 10 to tighten on the C16 embedded steel bars 6. The C16 embedded steel bars are tied to the iron bars 300 on the main bars of the raft slab; C20 embedded steel bars 7 are used to fix the embedded parts of the diagonal brace, a total of 3 locations, and the C20 embedded steel bars are tied to the iron bars 150 on the main bars of the raft slab. The positions of each embedded part are as follows: Figure 3 shown.

[0038] 2) The floor slab and the counterslope are cast together.

[0039] 3) Binding of reinforcement bars on the exterior walls of buildings.

[0040] 4) -2F layer lower wall formwork, primary and secondary ribs and diagonal bracing installation: the formwork connection and fixation are as follows: Figure 4The secondary ribs 11 and the main ribs 12 of the single-sided formwork are reinforced with square wood and double steel back ribs respectively. The secondary ribs 11 are first fixed to the wall formwork 13 by iron nails, and then screws 14 are set to pass through the wall formwork 13 and the main ribs 12 to connect the formwork, the secondary ribs and the main ribs as a whole; pads 17 are set on both sides of the inner and outer sides of the screw 14 passing through the wall formwork 13, and pads 17 are set at the screw 14 passing through the main rib 12.

[0041] The main rib 12 is connected to the gripping seat 15 through a screw rod and fastened with bolts to connect the formwork 13, the secondary rib 11, the main rib 12 and the gripping seat 15 as a whole; the upper part of the diagonal brace 16 is connected to the gripping seat 15, and the lower part is supported on the embedded part C20 embedded steel bar 7 that has been set. The diagonal brace 16 forms an effective connection with the gripping seat 15 and the embedded part C20 embedded steel bar 7. The verticality of the single-side formwork panel, i.e. the wall formwork 13, can be adjusted by adjusting the length of the diagonal brace 16. Figure 5 shown.

[0042] The structure of the lower part of the diagonal brace is as follows Fig. 9 As shown, the diagonal brace 16 is composed of a steel pipe 161 with an internal thread and a threaded rod 162 connected to the bottom of the steel pipe. The bottom of the threaded rod 162 is connected to a U-shaped steel plate 163, and the two walls of the U-shaped steel plate 163 are provided with a corresponding pair of through holes. The embedded steel bars are supported by the inner wall of the U-shaped steel plate. The steel pipe 161 is rotated to adjust the length of the diagonal brace 16 to control the verticality of the template, and is tightened by adjusting the screw rod to cross the pair of through holes of the U-shaped steel plate.

[0043] 5) -2F layer lower wall casting, and use the floor slab formwork as a safe operating platform to achieve single-sided formwork vibration operation; the slab formwork body erection spacing is 1000×1000, the sweeping rod is 200, the first step is 1600, and above the first step 1800 from the ground, the core filling rod is erected and the steel fence is laid 18. The construction workers can stand on the steel fence to vibrate the single-sided formwork exterior wall. Casting situation see Figure 5 .

[0044] 6) Dismantling formwork: remove the lower section of the wall formwork, primary and secondary ribs and diagonal braces.

[0045] 7) -2F upper wall formwork, primary and secondary ribs and diagonal brace installation: the formwork fixing method and diagonal brace tightening adjustment method are the same as step 4).

[0046] 8) Before pouring the -1F floor slab, set up embedded parts and the -1F floor slab anti-slope formwork; the embedded parts setting method is the same as step 1).

[0047] 9) The upper wall of the -2F layer and the -1F layer floor and anti-slope are cast together, and the floor slab formwork frame is used as a safe operation platform to achieve single-side formwork vibration operation; the casting situation is shown in Figure 6 .

[0048] 10) Dismantling formwork: Remove the lower section of the wall formwork, primary and secondary ribs and diagonal braces.

[0049] The construction of -F1 basement repeats the steps 3) to 10) of -F2, but -F1 is the top floor of the basement, so when pouring the upper wall, the upper wall and the top plate are poured together, and there is no need to construct a counter-slope. Figure 7 , 8 .

[0050] The above-mentioned embodiments are only partial embodiments of the present invention and cannot cover the whole of the present invention. Based on the above-mentioned embodiments and drawings, technical personnel in this field can obtain more implementation methods without paying creative work. Therefore, these implementation methods obtained without paying creative work should be included in the protection scope of the present invention.

Claims

1. A comprehensive construction method for foundation pit support and basement exterior wall without fertilizer trough, characterized by: The following steps are involved: Step 1: Geological survey and analysis: Check whether the construction area contains strongly weathered sandstone or moderately weathered sandstone geological layers, and check whether the compressive strength of the weathered sandstone geological layers meets the support pile construction standards. If the compressive strength meets the standards, proceed to step 2; Step 2: Support pile construction: Locate and lay out the support pile positions, use a rotary drilling rig to drill holes in the support pile positions, tie the steel cage simultaneously, and then pour concrete after hoisting the steel cage. Step 3: Excavation: Use an excavator to excavate the earth and dig to the weathered sandstone, and re-measure the elevation and structure edge; Step 4: Construction of waist beam and prestressed lattice support: During the earthwork excavation process, the waist beam and lattice support are constructed. Excavation is carried out to the waist beam bottom elevation, waist beam reinforcement is tied and concrete is poured, steel plates are pre-embedded at the waist beam position and load-bearing ear plates are added; excavation is carried out to the support position, concrete support reinforcement is tied and concrete is poured; the lattice support is steel, and the upper and lower ends of the lattice support are respectively installed at the load-bearing ear plates and supports of the waist beam. After the lattice support is installed, prestressing is applied; Step 5: External waterproofing and internal pre-paving with reverse adhesive waterproofing: Construction is carried out from the outside to the inside, in order to spray 10mm of mesh on the inner surface of the support pile, construct a 20mm thick cement mortar leveling layer to make the surface of the support pile vertical, construct a 6mm thick waterproof mortar layer, and pre-pave a 1.5mm thick polymer self-adhesive film waterproof membrane; Step 6: Single-side formwork and segmented and layered pouring construction: The construction of the lowest level of the basement is as follows: 1) Before pouring the floor slab, embedded parts and anti-slope formwork for the bottom floor slab should be installed; 2) The floor slab and the counterslope are cast together; 3) External wall reinforcement binding; 4) Installation of the lower wall formwork, primary and secondary ribs, and diagonal braces: For single-sided formwork, use square timber and double-sided steel backing for the secondary and primary ribs, respectively. One side of the primary rib is connected to a gripper via screws. The upper portion of the diagonal brace is connected to the gripper, while the lower portion rests on the pre-installed embedded parts. The verticality of the single-sided formwork can be adjusted by adjusting the length of the diagonal brace. 5) Concrete the lower wall section and use the floor slab formwork as a safe operating platform to achieve single-sided formwork and vibration operations; 6) Formwork removal: remove the lower wall formwork, primary and secondary ribs and diagonal braces; 7) Installation of the upper wall formwork, primary and secondary ribs, and diagonal braces: For single-sided formwork, use square timber and double-sided steel backing for the secondary and primary ribs, respectively. One side of the primary rib is connected to a gripper via screws. The upper portion of the diagonal brace is connected to the gripper, while the lower portion rests on the pre-installed embedded parts. The verticality of the single-sided formwork can be adjusted by adjusting the length of the diagonal brace. 8) Before pouring the upper floor slab, set up embedded parts and support the upper floor slab with anti-slope formwork; 9) The upper wall, the floor slab and the counterslope of the upper layer are cast together, and the floor slab formwork frame is used as a safe operating platform to achieve single-sided formwork and vibration operations; 10) Formwork removal: remove the upper wall formwork, primary and secondary ribs and diagonal braces; Repeat steps 3) to 10) of the lowest basement construction for the upper basement. If there is another basement, continue to repeat steps 3) to 10) until the top basement. When pouring the upper wall of the top basement, the upper wall and top plate are poured together, and there is no need to construct a counter-slope.

2. The comprehensive construction method for fertilizer trough foundation pit support and basement exterior wall according to claim 1 is characterized by: In step 1, the compressive strength of the weathered sandstone geological layer reaches the support pile construction standard: the saturated uniaxial compressive strength standard value is greater than 15 MPa.

3. The comprehensive construction method for fertilizer trough foundation pit support and basement exterior wall according to claim 1 is characterized by: In step three, a crusher is used to crush the stone. When excavating a deep foundation pit near a railway, no slope can be set and vertical excavation must be carried out. For rocks that exceed the threshold in volume, a cutting machine is required to remove the rocks evenly.

4. The comprehensive construction method for fertilizer trough foundation pit support and basement exterior wall according to claim 1 is characterized by: Step five: Construct a 20mm thick cement mortar leveling layer to make the surface of the support pile vertical. The specific operation is: construct the cement mortar in two layers, the first layer is 10mm thick, and the second layer is 10mm thick. Use a wooden trowel to rub the surface as you apply it, and water it every other day for maintenance.

5. The comprehensive construction method for fertilizer trough foundation pit support and basement exterior wall according to claim 1 is characterized by: In step five, a 6 mm thick waterproof mortar layer is constructed, in which the mass ratio of cement, mortar and waterproof powder is 1:2.5:0.

05.

6. The comprehensive construction method for fertilizer trough foundation pit support and basement exterior wall according to claim 1 is characterized by: The embedded parts in step 6, items 1) and 8), include four L-shaped steel bars and one hook bolt. The hook bolt is fixed to the hanging formwork with nuts before concrete pouring for connecting to the wooden beams. The L-shaped steel bars are tied to the steel bars on the main reinforcement of the raft slab, and the L-shaped steel bars are used to tighten the bottom of the diagonal brace. The four L-shaped steel bars include one C16 embedded steel bar and three C20 embedded steel bars. The diagonal brace of the anti-slope formwork system is tightened to the C16 embedded steel bar with wooden beams, and the lower end of the diagonal brace of the wall formwork is tightened to the C20 embedded steel bar.

7. The comprehensive construction method for fertilizer trough foundation pit support and basement exterior wall according to claim 1 is characterized by: In steps 4) and 7) of step 6, first fix the secondary ribs to the formwork with nails, then set screws through the formwork and main ribs to connect the formwork, secondary ribs and main ribs into a whole; the main ribs are connected to the gripping base with screws and tightened with bolts to connect the formwork, secondary ribs, main ribs and gripping base into a whole.

8. The comprehensive construction method for fertilizer trough foundation pit support and basement exterior wall according to claim 1 is characterized by: In steps 4) and 7) of step six, the diagonal brace consists of a steel pipe with an internal thread and a threaded rod connected to the bottom of the steel pipe. The bottom of the threaded rod is connected to the U-shaped steel plate, and a corresponding pair of through holes are set on the two walls of the U-shaped steel plate. The embedded steel bars are supported by the inner wall of the U-shaped steel plate. The steel pipe is rotated to adjust the length of the diagonal brace to control the verticality of the template, and it is tightened by adjusting the screw rod across the pair of through holes in the U-shaped steel plate.

9. The comprehensive construction method for fertilizer trough foundation pit support and basement exterior wall according to claim 1 is characterized by: In step 9 of step eight, the floor formwork frame is used as a safe operating platform to implement the specific operations of the single-sided formwork vibration operation: the slab formwork frame is erected at a spacing of 1000×1000, the sweeping rod is 200, the first step distance is 1600, and above the first step distance of 1800 from the ground, the core filling rods are erected and the steel fence is laid. The construction workers can stand on the steel fence to vibrate the single-sided formwork exterior wall.

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