Triangular frame support row pile foundation pit supporting structure and construction method thereof

Abstract

The application discloses a triangular frame support row-pile foundation pit supporting structure and a construction method thereof, and the supporting structure comprises a row-pile system and an inclined support system. The row-pile system comprises pile bodies and a crown beam, and the crown beam is connected to the top of the pile bodies. The inclined support system comprises inclined columns, waist beams, foot beams and a net-spraying concrete surface layer. When the soil and stone of each excavation layer is excavated from top to bottom, the inclined columns are arranged in a V shape and are sequentially and side by side arranged to form a triangular frame. The top of the inclined column is connected to the pile body. The waist beam is located at the bottom of each excavation layer and is connected to the bottom of the inclined column. The foot beam is located in the last excavation layer and is connected to the bottom end of the inclined column and is embedded in the rock. The net-spraying concrete surface layer is filled in the triangular frame. Without using anchor rods and internal support structures, the application can support the deep foundation pit slope, does not operate beyond the red line of the construction range, does not excessively occupy the space in the foundation pit and affects the construction in the foundation pit, guarantees the stability of the foundation pit slope, prevents the collapse of the foundation pit and is simple and convenient to construct.

Description

Technical Field

[0001] The invention relates to a triangular lattice-supported pile foundation pit support structure and a construction method thereof, belonging to the technical field of building construction foundation pit support. Background Art

[0002] During the construction of earthwork projects, large-scale excavation of foundation pits is a common method of earthwork excavation. Usually, due to loose soil or deep excavation depth, the foundation pit slopes must be supported to prevent the foundation pit from collapsing to ensure construction safety. During construction, the applicant found that the pile anchor support commonly used in foundation pit support projects usually has an anchor length of 10 to 20 meters. The regulations require that the length of the anchor anchored in the soil layer must not exceed the red line of the construction area. Therefore, in many cases, pile anchor support is not applicable; the support within the foundation pit does not require the use of anchor rods, but it occupies too much space in the foundation pit, seriously hindering the construction of the structure within the foundation pit and affecting the construction progress; the cantilever pile support that does not require internal support or anchor rods cannot withstand the lateral soil load of deeper foundation pits due to its structural force form limitations, and is only suitable for supporting shallower foundation pits. Summary of the Invention

[0003] Based on the above, the present invention provides a triangular frame support pile foundation pit support structure and a construction method thereof. During the construction process of the foundation pit support project, the deeper foundation pit slope is supported without using anchor rod fixation and internal support structure. The operation will not exceed the construction red line, and too much space in the foundation pit will not be occupied. At the same time, the stability of the foundation pit slope is guaranteed to overcome the shortcomings of the existing technology.

[0004] The technical solution of the present invention is: a triangular frame support pile foundation pit support structure, comprising:

[0005] A pile system includes a pile body and a cap beam, wherein the cap beam is connected to the top of the pile body;

[0006] The inclined support system includes inclined columns, waist beams, foot beams and a mesh sprayed concrete surface layer. When the earth and stone are excavated in layers from top to bottom, the inclined columns are arranged side by side in a V-shape and tilted in sequence to form a triangular frame. The tops of the inclined columns are connected to the piles. The waist beams are located at the bottom of each excavation layer and connected to the bottoms of the inclined columns. The foot beams are located in the last excavation layer and connected to the bottoms of the inclined columns and placed in embedded rocks. The mesh sprayed concrete surface layer fills the triangular frame.

[0007] In one example, the crown beam is located at the upper end of the pile body. After the pile body is cast, the pile head is broken and the steel bars are chiseled out, and then anchored and cast with the crown beam steel bars.

[0008] In one example, the piles are arranged in sequence along the upper opening of the foundation pit slope according to the layout positioning.

[0009] In one example, the lower part of the pile body penetrates into the bearing layer to ensure that the pile body is stressed.

[0010] In one example, the lower reserved steel bars of the crown beam are anchored into the upper ends of the inclined column steel bars.

[0011] In one example, a cushion layer is provided at the bottom of the waist beam, and the lower reserved steel bars of the waist beam are anchored into the upper ends of the inclined column steel bars.

[0012] In one example, the foot beam is located in the last excavation layer and is anchored and cast with the steel bars at the bottom end of the inclined column in the embedded rock.

[0013] In one example, a steel mesh is provided in the mesh sprayed concrete surface layer.

[0014] In one example, a cut-off ditch is provided at the upper slope of the foundation pit, and a drainage ditch is provided at the lower slope foot of the foundation pit.

[0015] The present invention also provides a construction method of the triangular lattice support pile foundation pit support structure, comprising:

[0016] Step 1, pile construction: first, the foundation pit part to be excavated is laid out and positioned, and the support pile position is determined at the upper edge of the foundation pit slope. Then, drilling is carried out, and the pre-made steel cage is installed in the drilled hole. The grouting pipe is placed and concrete is poured. When the cast-in-place pile concrete reaches a certain strength, the pile head is manually broken until the longitudinal steel bar of the pile head is exposed to meet the specification requirements. The above steps are repeated. Pile bodies are set in this way in all the foundation pit parts that need to be supported to form a continuous underground pile wall.

[0017] Step 2: Crown beam construction: After the pile row construction is completed, the pile heads are broken to expose the longitudinal reinforcement. At this time, a continuous crown beam is set at the pile head. The crown beam adopts a cast-in-place reinforced concrete structure. During the crown beam reinforcement binding stage, the exposed longitudinal reinforcement of the pile head and the crown beam reinforcement must be anchored, and then the crown beam concrete is cast in the formwork to connect the pile row into an integral structure. At the same time, the crown beam needs to reserve reinforcement on the inner side close to the foundation pit for subsequent anchoring connection with the inclined column reinforcement.

[0018] Step 3, soil excavation: first confirm the excavation slope angle, then carry out the first layer excavation;

[0019] Step 4, inclined column frame support: After the excavation of the first soil layer is completed, a cushion layer is first set at the slope foot of the first excavation layer of the foundation pit. Then, the waist beam position is positioned and laid out on the cushion layer, and the first layer of waist beam reinforcement is tied. It should be noted that the waist beam reinforcement is the same as the crown beam reinforcement. Anchor reinforcement must be reserved at the lower end of the inner side close to the foundation pit for anchoring and connecting the inclined columns of the next excavation layer. At this time, an inclined column frame for support is also set up at the same time. The inclined columns are set close to the slope surface and arranged in a V shape in sequence. The lower end of the inclined column is anchored to the first layer of waist beam reinforcement, and the upper end reinforcement is anchored to the reserved reinforcement at the lower end of the crown beam. Then, the inclined column frame and waist beam are integrally supported and cast. At this time, the crown beam, inclined column and first layer waist beam form a triangular frame arranged in sequence, forming a support system for the first layer of foundation pit excavation and slope.

[0020] Step 5, foot beam construction: The second layer of soil excavation and support method is the same as above, until the slope excavation reaches the last layer; at this time, the excavation has reached the bottom of the foundation pit. At this time, a foundation trench with a depth less than the height of the foot beam needs to be mechanically excavated on the bearing layer at the bottom of the foundation pit to embed the rock. This is used to fix the foot beam and provide support for the foot beam and inclined column frame. Then, the foot beam concrete cushion layer is set, and the foot beam reinforcement is tied to the last layer of foundation pit slope inclined column reinforcement. No reserved anchor reinforcement is required at the lower end of the foot beam, and then concrete is poured;

[0021] Step 6, construction of mesh spraying surface layer: mesh spraying is carried out on the area within the triangular frame. First, the steel bars need to be straightened before use and tied in sequence to form a steel mesh with the required strength. When spraying concrete, a base layer of concrete must first be sprayed on the soil as a cushion layer for the steel mesh to prevent the steel bars from directly contacting the soil and causing rusting. After that, pads are set and the steel mesh is placed. Then a second layer of concrete spraying is carried out on the steel mesh until the required thickness is reached.

[0022] Beneficial effects of the present invention: Compared with the prior art, the present invention has the following advantages: 1. Compared with the traditional anchor-type pile support, there is no need to use anchor rods, which avoids the problem that the length of the anchor rods easily exceeds the red line of the construction range, and is applicable to a wider range of construction scenarios. 2. Compared with the traditional internal support type pile support, there is no need to set support beams in the foundation pit, which reduces the occupation of the construction site in the foundation pit and has little impact on the construction in the foundation pit, which can effectively improve the construction progress and speed up the construction period. 3. Compared with traditional cantilever support or soil nail wall support, the structure has stronger integrity, better load resistance and support capacity for the foundation pit, and can be applied to deeper foundation pits where cantilever support is not applicable. 4. The construction process of this structure is simple, the construction materials are common, and the construction is simple and convenient.

[0023] In summary, after adopting the present invention, during the construction process of foundation pit pile support engineering, the deeper foundation pit slope can be supported without using anchor rod fixation and internal support structure. The operation will not exceed the construction red line, and too much space in the foundation pit will not be occupied. At the same time, the stability of the foundation pit slope is guaranteed, and the foundation pit collapse is prevented. The construction is simple and convenient, the construction progress is accelerated, and the safety of the foundation pit construction is guaranteed. It is suitable for deeper foundation pit excavation scenarios where the excavation is carried out to the bearing layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a cross-sectional diagram of a triangular frame-supported pile foundation pit support structure;

[0025] Figure 2 A schematic diagram of a triangular frame-supported pile foundation pit support structure from one perspective;

[0026] Figure 3 A schematic diagram of the load-bearing structure of a single pile in a triangular frame-supported pile foundation pit support structure;

[0027] Figure 4 This is a force diagram of a triangular frame supported pile foundation pit support structure;

[0028] Figure 5 This is a schematic diagram of the foundation pit support structure of a triangular frame support pile during the first layer of earthwork excavation.

[0029] Figure 6 This is a schematic diagram of the foundation pit support structure of a triangular frame support pile during the second layer excavation of earthwork in layers;

[0030] Figure 7 This is a schematic diagram of the foundation pit support structure of a triangular frame support pile when the third layer of earthwork is excavated in layers;

[0031] Figure 8 A schematic diagram of a triangular frame support pile foundation pit support structure used as a whole in a foundation pit;

[0032] Description of reference numerals:

[0033] 1 pile body, 2 crown beam, 3 waist beam, 31 first layer waist beam, 32 second layer waist beam, 4 foot beam, 5 inclined column, 6 mesh sprayed concrete surface layer, 7 drainage ditch, 8 intercepting ditch, 9 soil and rock layer, 91 non-bearing layer, 92 bearing layer, 10 cushion layer. DETAILED DESCRIPTION

[0034] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0035] See Figures 1 to 8 The present embodiment provides a triangular frame supported pile pit support structure, including a pile system and an inclined support system.

[0036] The pile system includes a pile body 1 and a crown beam 2. The crown beam 2 is located on the upper part of the pile body 1. After the pile body 1 is poured, the pile head is broken and the exposed pile longitudinal reinforcement is anchored with the crown beam 2 reinforcement before pouring the crown beam 2 concrete.

[0037] The inclined support system includes inclined columns 5, a cushion layer 10, a waist beam 3, a foot beam 4 and a mesh sprayed concrete surface layer 6. When the inclined columns 5 are excavated in layers, each excavation layer is V-shaped and arranged side by side to form a triangular frame. As an inclined support structure, the waist beam 3 is located at the bottom of each excavation layer and is integrally cast with the steel bars of the inclined columns 5. The cushion layer 10 is located at the bottom of the waist beam 3. The foot beam 4 is located in the last excavation layer and is connected to the bottom end of the inclined column 5 and placed in the embedded rock. The mesh sprayed concrete surface layer 6 is composed of steel mesh and concrete. The steel mesh is anchored into the steel bars of the surrounding inclined columns 5 to fill the triangular gaps between the inclined columns 5.

[0038] Please refer again Figures 1 to 8 The construction method of the above-mentioned triangular frame support pile foundation pit support structure is as follows:

[0039] S1. Pile construction: First, the part of the foundation pit that needs to be excavated is marked out and the position of the supporting piles is determined at the upper edge of the foundation pit slope. The intercepting ditch 8, mud pool and sedimentation pool are excavated and built outside the supporting piles; then the drilling operation is carried out. The drilling plan can be formulated according to the actual situation of the soil and rock layer 9 on site. The sequential method or the skipping pile method can be used. If the soil on site is rock and soil with good stability or weathered rock, the sequential method can be used. This method can reduce mechanical movement and improve construction efficiency. If the soil on site is backfill soil or loose red clay, the skipping pile method should be used to prevent the foundation pit from collapsing. Next, prepare the drilling machine. Ensure the drill rod is perpendicular to the ground to prevent the hole from deviating. While the drilling machine is drilling, the mud or gravel stirred up by the drilling should be promptly transported to the mud pit. When the hole reaches the required design depth, that is, through the non-bearing stratum 91 and into the bearing stratum 92, clean water is used to wash the hole. A grouting machine is used to inject clean water from the bottom of the hole to completely overflow the mud in the hole. Once the overflow is completely clear water, the mud in the hole has been completely cleaned. At this point, the pre-fabricated steel cage is manually or mechanically installed into the drilled hole. It is important to ensure that the steel cage is upright and falls to the bottom of the hole, and that it does not touch the pile wall. Then install the grouting pipe. The grouting pipe should be dropped to the bottom of the hole to avoid concrete segregation caused by excessive pouring height. The pipe should be pulled upward in sections during grouting. After the pouring of the bored pile is completed and the concrete of the bored pile reaches a certain strength, the pile head can be manually broken until the longitudinal reinforcement of the pile head is exposed to meet the specification requirements. This part of the reinforcement is the reinforcement anchored to the crown beam 2 reinforcement. Repeat the above steps and set bored piles (i.e. pile body 1) in this way in the parts of the foundation pit that need to be supported to form a continuous underground pile wall.

[0040] S2, Crown Beam 2 Construction: After the pile rows are completed, the pile heads are broken to expose the longitudinal reinforcement. A continuous crown beam 2 is then installed at the pile heads. Crown beam 2 is constructed of cast-in-place reinforced concrete. During the crown beam 2 reinforcement stage, the exposed longitudinal reinforcement at the pile heads is anchored to the crown beam 2 reinforcement. Formwork is then supported and concrete is poured for crown beam 2, connecting the pile rows into a single, integrated structure. Reinforcement is also reserved on the inner side of crown beam 2, near the foundation pit, for subsequent anchoring to the inclined column 5 reinforcement.

[0041] S3, Soil Excavation: See again Figures 5 to 7 The soil of deeper foundation pits is usually excavated in layers (taking the figure as an example, three layers of excavation are used). First, the excavation slope angle is confirmed, and then the first layer of excavation is carried out. Mechanical excavation is used for foundation pit excavation. Since pile rows have been set up in the foundation pit slope at this time, the pile rows play a role similar to cantilever pile rows, and have a certain resistance to the external soil load. In addition, the excavation depth of each layer excavation must not exceed the depth, so it will not cause foundation pit collapse at this time.

[0042] S4, inclined column 5 frame support: After the first soil layer is excavated, a plain concrete cushion layer 10 is first set at the foot of the slope of the first excavation layer of the foundation pit as the cushion layer 10 of the first layer of waist beam 31. Then, the position of the waist beam 3 is positioned and laid out on the cushion layer 10, and the steel bars of the first layer of waist beam 31 are tied. It should be noted that the steel bars of the waist beam 3 are the same as those of the crown beam 2. Anchor steel bars need to be reserved at the lower end of the inner side near the foundation pit for anchoring and connecting the inclined columns 5 of the next excavation layer; at this time, the inclined column 5 frame for support is also set; at this time, refer to Figure 5 The inclined columns 5 are set close to the slope surface and arranged in a V-shape. The lower ends of the inclined columns 5 are connected to the steel bars of the first-layer waist beam 31 by anchoring, and the upper steel bars are connected to the reserved steel bars at the lower end of the crown beam 2 by anchoring. Then, the inclined column 5 frame and the waist beam 3 are integrally supported and cast; at this time, the crown beam 2, the inclined columns 5 and the first-layer waist beam 31 form a triangular frame arranged in sequence, forming a support system for the first-layer foundation pit excavation and slope reduction.

[0043] S5, construction of foot beam 4: the excavation and support method of the second soil layer is the same as above, until the slope is excavated to the last layer (in this embodiment, the waist beam 3 is composed of the first waist beam 31 and the second waist beam 32); at this time, the excavation has reached the bottom of the foundation pit. At this time, it is necessary to mechanically excavate a foundation trench with a depth less than the height of the foot beam 4 on the bearing layer 92 at the bottom of the foundation pit to embed the rock, which is used to fix the foot beam 4 and provide support for the foot beam 4 and the inclined column 5 frame. Then, the concrete cushion layer 10 of the foot beam 4 is set, and the steel bars of the foot beam 4 are tied to the steel bars of the inclined column 5 on the slope of the last layer of the foundation pit. There is no need to set reserved anchor steel bars at the lower end of the foot beam 4. Then, concrete is poured, and a drainage ditch 7 is excavated and built at the bottom of the foundation pit on the inner edge of the foot beam 4.

[0044] S6, construction of mesh sprayed concrete surface layer 6: At this time, the crown beam 2, waist beam 3, foot beam 4 and inclined column 5 form a number of triangular frames arranged in sequence, and the soil layer in the frame is exposed; the area inside the triangular frame needs to be meshed and sprayed with concrete. First, the steel bars need to be straightened before use and tied in sequence to form a steel mesh with the required strength; when spraying concrete, a base layer of concrete must first be sprayed on the soil as a steel mesh cushion layer 10 to prevent the steel bars from directly contacting the soil and causing rusting of the steel bars. After that, pads are set and steel mesh sheets are placed. Then, a second layer of concrete spraying is performed on the steel mesh until the required thickness is reached. At the intersection of the mesh spray barrel surface layer and the beams (crown beam 2, waist beam 3, foot beam 4) and inclined column 5, a reinforced layer of sprayed concrete must be made to ensure the connectivity and integrity of the structure.

[0045] At this point the overall support structure is complete. Figure 3 and Figure 4; The lower pile bodies 1 of the pile rows are all deep into the bearing layer 92, and the two inclined columns 5 and the foot beams 4 form a triangle. The inclined columns 5, the piles and the ground also form a triangle, so the structure also has good stability at this time; the soil outside the pile row gives the pile row an inward load, and the pile row is close to the inner side of the foundation pit at the bottom of the inclined columns 5. There is an unexcavated triangular soil and rock area, and the soil in this area also gives the pile row an outward load, which can offset part of the external load; at the same time, since the foot beams 4 at the bottom of the inclined columns 5 are fixed in the rock embedded in the bearing layer 92, the inclined columns 5 are reinforced concrete structures, and concrete is a good compressive material, which gives the pile body 1 an oblique upward support force in reverse, which can effectively resist external soil loads; most of the soil load outside the foundation pit is borne by the pile row, and a small part of the soil load outside the foundation pit and the soil load at the bottom of the inclined columns 5 are borne by the inclined columns 5 and the mesh sprayed concrete surface layer 6. In this case, the pile row, inclined columns 5, beams (crown beam 2, waist beam 3, foot beam 4), mesh sprayed concrete surface layer 6, triangular soil and rock area at the bottom of the inclined columns 5, and bearing layer 92 can also be considered as a whole, forming a triangular retaining wall structure with a certain deadweight and anchored into the bearing layer 92, providing effective support to prevent foundation pit collapse. Compared with existing technologies, the present invention has the following advantages: 1. Compared with traditional anchor-type pile row support, it does not require anchor rods, avoiding the problem of anchor rod lengths easily exceeding the construction range redline, and is applicable to a wider range of construction scenarios. 2. Compared with traditional internally supported pile row support, it does not require support beams within the foundation pit, reducing the construction site occupation within the foundation pit and having a minimal impact on the construction within the foundation pit, effectively improving construction progress and accelerating the construction period. 3. Compared with traditional cantilever support or soil nail wall support, this structure has stronger integrity, better load resistance and foundation pit support capabilities, and is suitable for deeper foundation pits where cantilever support is not suitable. 4. The structure has simple construction technology, common construction materials, and is easy and convenient to construct.

[0046] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A construction method for a triangular lattice supported pile foundation pit support structure, characterized in that: The supporting structure includes: A pile row system comprises a pile body (1) and a crown beam (2), wherein the crown beam (2) is connected to the top of the pile body (1); An inclined support system comprises inclined columns (5), waist beams (3), foot beams (4) and a mesh sprayed concrete surface layer (6), wherein the inclined columns (5) are arranged in a V-shape and tilted side by side in each excavation layer to form a triangular frame when excavating earth and stone from top to bottom, the top of the inclined columns (5) is connected to the pile body (1), the waist beams (3) are located at the bottom of each excavation layer and connected to the bottom of the inclined columns (5), the foot beams (4) are located in the last excavation layer and connected to the bottom of the inclined columns (5) and placed in the embedded rock, and the mesh sprayed concrete surface layer (6) fills the triangular frame; The construction method of the triangular lattice support pile foundation pit support structure includes: Step 1, pile construction: first, the foundation pit portion to be excavated is positioned and the support pile position is determined at the upper edge of the foundation pit slope, and then drilling is performed, and the pre-made steel cage is installed in the drilled hole, and the grouting pipe is placed and concrete is poured. When the cast-in-place pile concrete reaches a certain strength, the pile head of the pile body (1) is manually broken until the longitudinal steel bar of the pile head is exposed to meet the specification requirements, and the above steps are repeated. The pile body (1) is set in this way in all the foundation pit portions that need to be supported to form a continuous underground pile wall; Step 2, crown beam construction: After the pile row construction is completed, the pile heads are broken to expose the longitudinal reinforcement. At this time, a continuous crown beam (2) is set at the pile head. The crown beam (2) adopts a cast-in-place reinforced concrete structure. During the stage of tying the crown beam (2) reinforcement, the exposed longitudinal reinforcement of the pile head and the crown beam (2) reinforcement are anchored and then the crown beam (2) concrete is cast in the formwork to connect the pile row into an integral structure. At the same time, the crown beam (2) needs to reserve reinforcement on the inner side close to the foundation pit for subsequent anchoring connection with the inclined column (5) reinforcement. Step 3, soil excavation: first confirm the excavation slope angle, then carry out the first layer excavation; Step 4, inclined column frame support: After the excavation of the first soil layer is completed, a cushion layer (10) is first set at the foot of the slope of the first excavation layer of the foundation pit, and then the position of the waist beam (3) is positioned and laid out on the cushion layer (10), and the first layer of waist beam (31) steel bars are tied. It should be noted that the waist beam (3) steel bars are the same as the crown beam (2) steel bars, and anchor steel bars need to be reserved at the lower end of the inner side near the foundation pit for anchoring and connecting the inclined columns (5) of the next excavation layer; at this time, a support is also set at the same time. The inclined columns (5) are arranged close to the slope surface and arranged in a V-shaped manner. The lower end of the inclined column (5) is connected to the steel bar of the first layer of waist beam (31) by anchoring, and the upper end steel bar is connected to the reserved steel bar at the lower end of the crown beam (2). Then, the inclined column (5) frame and the waist beam (3) are integrally supported and cast. At this time, the crown beam (2), the inclined column (5) and the first layer of waist beam (31) form a triangular frame arranged in sequence, forming a support system for the first layer of foundation pit excavation and slope reduction; Step 5, foot beam construction: the second layer of soil excavation and support method is the same as above, until the slope excavation reaches the last layer; at this time, the excavation has reached the bottom of the foundation pit, and it is necessary to mechanically excavate a foundation groove with a depth less than the height of the foot beam (4) on the bearing layer (92) at the bottom of the foundation pit to embed the rock for fixing the foot beam (4) and providing support for the foot beam (4) and the inclined column (5) frame. Then, the foot beam (4) concrete cushion layer (10) is set, and the foot beam (4) steel bars are tied to the last layer of foundation pit slope inclined column (5) steel bars. No more reserved anchor steel bars are required at the lower end of the foot beam (4), and then concrete is poured; Step 6, mesh spraying and concrete surface construction: mesh spraying and concrete spraying are carried out on the area within the triangular frame. First, the steel bars need to be straightened before use and then tied in sequence to form a steel mesh with the required strength. When spraying concrete, a base layer of concrete spraying is first carried out on the soil as a steel mesh cushion layer (10) to prevent the steel bars from directly contacting the soil and causing rusting of the steel bars. After that, pads are set and steel mesh sheets are placed. Then, a second layer of concrete spraying is carried out on the steel mesh until the required thickness is reached.

2. The construction method of the triangular lattice support pile foundation pit support structure according to claim 1 is characterized in that: The crown beam (2) is located at the upper end of the pile body (1), and after the pile body (1) is cast, the pile head is broken and the steel bars are chiseled out, and then the crown beam (2) is anchored and cast.

3. The construction method of the triangular lattice support pile foundation pit support structure according to claim 1 is characterized in that: The pile bodies (1) are arranged in sequence along the upper opening of the foundation pit slope according to the layout positioning.

4. The construction method of the triangular lattice support pile foundation pit support structure according to claim 1 is characterized in that: The lower part of the pile body (1) penetrates into the bearing layer (92), ensuring that the pile body (1) is stressed.

5. The construction method of the triangular lattice support pile foundation pit support structure according to claim 1 is characterized in that: The lower reserved steel bars of the crown beam (2) are anchored into the upper ends of the steel bars of the inclined columns (5).

6. The construction method of the triangular lattice support pile foundation pit support structure according to claim 1 is characterized in that: A cushion layer (10) is provided at the bottom of the waist beam (3), and the lower portion of the waist beam (3) has reserved steel bars anchored into the upper ends of the steel bars of the inclined columns (5).

7. The construction method of the triangular lattice support pile foundation pit support structure according to claim 1 is characterized in that: The foot beam (4) is located in the last excavation layer and is anchored and cast with the steel bars at the bottom end of the inclined column (5) in the embedded rock.

8. The construction method of the triangular lattice support pile foundation pit support structure according to claim 1 is characterized in that: A steel mesh is provided in the mesh sprayed concrete surface layer (6).

9. The construction method of the triangular lattice support pile foundation pit support structure according to claim 1, characterized in that: The upper slope of the foundation pit is provided with a cut-off ditch (8), and the lower slope of the foundation pit is provided with a drainage ditch (7).

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