CN111364479A - Inclined support threaded pile supporting structure for foundation pit enclosure and construction method thereof - Google Patents

Abstract

The invention discloses an obliquely supporting threaded pile supporting structure for foundation pit enclosure, comprising supporting piles, a foundation bottom plate located under the soil layer and a plurality of threaded piles, the upper end of each threaded pile is connected to the supporting pile The upper ends of the threaded piles are connected to each other, each threaded pile passes through the foundation bottom plate and at least partially enters the supporting soil layer below the foundation bottom plate, and the threaded piles are gradually inclined toward each other from top to bottom. A water-stop casing is arranged at the penetration of the pile, and the water-stop casing is arranged on the outer periphery of the threaded pile and is detachably connected with the threaded pile. Also disclosed is a construction method of the obliquely bracing threaded pile supporting structure. Compared with the prior art, the present invention has the advantages that: by arranging a water-stop casing in the base plate, and the water-stop casing and the threaded pile are detachably connected, the threaded pile can be easily dismantled and recovered, the construction cost is reduced, and the construction need not be considered. The problem of seam is easy to handle in the later stage, and the quality is reliable.

Description

Oblique support threaded pile support structure for foundation pit enclosure and construction method thereof

technical field

The invention relates to the field of foundation pit enclosure, in particular to an oblique support threaded pile supporting structure for foundation pit enclosure, and a construction method of the structure.

Background technique

In the deep foundation pit project, it is often necessary to add a support system to increase the safety and stability of the foundation pit project, to ensure that the surrounding environment of the foundation pit and the engineering piles in the foundation pit will not be affected, and it is also necessary to ensure the safety of construction personnel and machinery. There are several common forms of support: flat support, diagonal support and anchor pull.

Flat bracing is currently the most widely used form of support for deep foundation pits. However, flat bracing generally has large span, long construction period, high cost, complex supporting structure system, and is extremely unfavorable for earthwork excavation and main structure construction. At the same time, this support form needs to be completely dismantled in the later stage, causing serious environmental pollution and many potential safety hazards.

Anchor pulls are common, such as jetting bolts or soil nailing walls, but this type of support is not suitable for soft soil and other poor soil or deep excavation foundation pits, with low safety factor and great hidden dangers to construction quality and safety. Moreover, due to the long anchoring length, it is often necessary to extend beyond the red line of the building by a dozen or tens of meters, and the surrounding environment of the site has considerable constraints on it.

At present, the common diagonal bracing such as reinforced concrete, steel pipe or section steel diagonal bracing is supported on the basement floor, which is more economical. This type of support is often used in excavation of the central island, construction areas after secondary enclosures, or local reinforcement. It can only play a role when the strength of the basement floor reaches more than 75%. The construction period is long and the deformation control response is slow. It is difficult to dismantle and deal with the structure in the later stage.

The Chinese patent with the application number of 201410107071.1 discloses an oblique support pile structure for foundation pit enclosure and a construction method thereof. The structure includes enclosure piles, crown beams, foundation pit floor, building structure, oblique support piles, Water stop device and soil improvement structure, in which the oblique support pile is obliquely implanted into the original soil below the foundation pit floor at a certain angle, and the original soil is hardened by high-pressure rotary spray pile or soil curing agent; the top of the oblique support pile is It is fixedly connected with the top of the retaining pile and embedded in the crown beam and is cast in place on the crown beam as a whole, and a water stop ring is set through the bottom plate of the building structure and the shear wall.

Compared with the flat support, the invention patent can facilitate earthwork excavation and shorten the construction period, and compared with the traditional throwing support, it can save the construction period; however, the device of this patent is one-time use, cannot be recycled and reused, and cannot realize material saving, which is bound to increase. The cost of foundation pit; although the soil at the bottom of the support has been improved, the H-shaped steel structure, steel lattice column structure or steel pipe structure all rely on frictional resistance to provide oblique support force, and the support effect is still difficult to ensure, especially when saturated soft materials are used. If the H-shaped steel structure, steel lattice column structure or steel pipe structure is cut off, it will cause water leakage in the basement structure in the later stage or affect the durability of the structure; the support itself cannot provide effective adjustment when the foundation pit is greatly deformed. Reinforcement measures can only be solved after additional measures or reinforcement measures are taken, which is extremely unfavorable in terms of disposal efficiency for projects with high risks such as foundation pits.

However, because the surrounding environment of the foundation pit is becoming more and more complex, for example: the surrounding buildings are close to the red line of the building, there are many types of pipelines around the foundation pit, and the material storage yard processing area is close to the foundation pit after the small site is deformed. When the deformation of the foundation pit is large, it is often impossible to provide reinforcement protection through the enclosure itself, and an external support system needs to be added to control the deformation.

In addition, "constructing materials-saving and accelerating the construction of a conservation-minded society" is a basic national policy that my country has adhered to for a long time, and reducing the cost of foundation pits on the premise of ensuring the safety of foundation pits is the pursuit of project investors. There are many wastes of materials and artificial resources in traditional foundation pit engineering. The supporting form has a large amount of engineering work, high cost and serious solid dust pollution in the later stage.

For this, further improvements are required.

SUMMARY OF THE INVENTION

The first technical problem to be solved by the present invention is to provide an oblique support threaded pile support structure for foundation pit enclosure, which can provide high support force, and can adapt to the deformation of foundation pit. It is also easy to recycle and reuse.

The second technical problem to be solved by the present invention is to provide a construction method for the above-mentioned obliquely braced threaded pile support structure.

The technical solution adopted by the present invention to solve the above-mentioned first technical problem is as follows: an oblique support threaded pile support structure for foundation pit enclosure, comprising a support pile, a foundation bottom plate located under the soil layer and a plurality of threads Pile, the upper end of each threaded pile is connected with the upper end of the supporting pile, each threaded pile passes through the foundation base plate from above the foundation base plate and at least partially enters the supporting soil layer below the foundation base plate, and the threaded pile gradually goes from top to bottom. Oppositely inclined, it is characterized in that a water-stop sleeve is arranged in the base bottom plate where the threaded pile penetrates, and the water-stop sleeve is arranged on the outer periphery of the threaded pile and is detachably connected to the threaded pile.

Preferably, in order to facilitate the unscrewing and retracting of the threaded pile, the inside of the water-stop casing is provided with an internal thread, so as to be threadedly connected to the threaded pile, and the threaded pile is easy to unscrew when the threaded pile is rotated and recovered, and the internal thread in the water-stop casing is also conducive to Increase the water stop of the base plate.

Preferably, in order to provide sufficient supporting force, the wall thickness of the water stop sleeve is ≥2.0 mm.

Preferably, in order to control the deformation of the foundation pit, the upper end of the support pile is provided with a crown beam, and the crown beam and the threaded pile are connected by an adjustable anchoring device.

Preferably, in order to facilitate the connection between the crown beam and the threaded pile, corbels connected to the threaded pile are arranged at intervals along the direction of the crown beam, and the crown beam is provided with a hole or an open groove for the end of the threaded pile to enter.

Preferably, in order to provide better oblique support force and anti-pulling bearing capacity, and at the same time facilitate dismantling, each threaded pile includes a first threaded pile section and a second threaded pile section that are connected to each other, and the first threaded pile section is located in the second threaded pile section. Above the threaded pile section, the second threaded pile section is screwed into the soil layer through the foundation bottom plate, the second threaded pile section is connected with the water stop casing, and mechanically engaged with the soil layer through the screw blade, the second threaded pile section is The width of the screw blade of the threaded pile section is greater than or equal to 120mm.

The technical solution adopted by the present invention to solve the above-mentioned second technical problem is: a construction method of the above-mentioned oblique support threaded pile supporting structure, comprising the following steps:

1) Construction of supporting piles: construct supporting piles around the foundation pit, and pour the crown beams used to connect with the threaded piles at the upper end of the supporting piles;

2) Installation of threaded piles: Connect the first threaded pile section and the second threaded pile section to form an integral threaded pile, and screw the threaded pile into the soil layer at a certain angle until it reaches a certain depth below the base plate required by the design ;

3) Detection of bearing capacity: extract a number of threaded piles to test the bearing capacity of oblique compression, and determine the supporting margin of the threaded piles at the same time;

4) Anchoring the threaded pile: Treat the anchoring position of the threaded pile, and insert the anchoring device. After the concrete strength of the crown beam reaches a certain level, the threaded pile is evenly spaced along the foundation pit through the anchoring device. Tighten the anchorage to the crown beam , so that the supporting pile and the threaded pile are formed into an integral structure with interaction force;

5) Excavation of the foundation pit: After the crown beam reaches a certain strength, the earthwork of the foundation pit is excavated;

6) Construction of the foundation floor: After the excavation of the foundation pit is completed, the construction of the foundation floor is carried out. When the foundation floor is constructed, the water stop sleeve is placed in the foundation floor and fixed;

7) Removal of threaded piles: After the construction of the base plate is completed and the support removal conditions required by the enclosure design are met, loosen the anchoring device at intervals, and then monitor the deformation of the foundation pit. If the data is stable, the threaded piles are removed and recycled. For stability, reinforcement measures are adopted for the foundation pit to ensure the safety of the foundation pit.

Preferably, in order to control the deformation of the foundation pit, in steps 5) and 6), if the deformation of the foundation pit exceeds the value required by the enclosure design and specification, the deformation of the foundation pit is controlled by further screwing and tightening the anchoring device, and thereafter If the deformation of the foundation pit is controlled, it is not necessary to take reinforcement measures. If the deformation of the foundation pit is not controlled, reinforcement measures should be taken.

Preferably, in step 7), when dismantling the threaded piles, the threaded piles are dismantled and recovered one by one, the first threaded pile section is removed from each threaded pile, and the second threaded pile section is screwed and recovered after cleaning the water stop casing.

Preferably, in order to avoid water leakage from the base plate, the inner wall of the water stop casing is provided with a screw plate matching the screw blades of the threaded pile, and the interior of the water stop casing is sealed by concrete after the threaded pile is recovered.

Compared with the prior art, the present invention has the advantages that: by arranging a water-stop casing in the base plate, and the water-stop casing and the threaded pile are detachably connected, the threaded pile can be easily dismantled and recovered, the construction cost is reduced, and the construction need not be considered. To solve the problem of joints, the later structural processing is simple and the quality is reliable; the threaded pile and the supporting pile are connected by an adjustable anchoring device, and the self-adjustment can be performed according to the deformation of the foundation pit during the earthwork excavation and foundation construction to ensure the safety of the foundation pit; There is no sequence in the construction process of the enclosure structure and the oblique support structure, which can greatly shorten the construction period; the support system does not require a large number of reinforced concrete structures; barrier-free excavation and structural construction can be realized; the oblique support system can be unloaded while being dismantled Edge monitoring effectively solves the problem of uneven stress release or instantaneous unloading caused by support removal.

Description of drawings

Fig. 1 is the schematic diagram of the support structure of the obliquely supported threaded pile according to the embodiment of the present invention;

2 is a cross-sectional view of a water-stop internal threaded casing of an obliquely supporting threaded pile support structure according to an embodiment of the present invention;

Fig. 3 is the connection node diagram of two sections of threaded piles of the obliquely supported threaded pile support structure according to the embodiment of the present invention;

Fig. 4 is the connection node diagram of the threaded pile and the crown beam of the obliquely supported threaded pile support structure according to the embodiment of the present invention;

FIG. 5 is a partial schematic diagram of a threaded pile of an obliquely supporting threaded pile supporting structure according to an embodiment of the present invention.

Detailed ways

The following describes in detail the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", " Rear, Left, Right, Vertical, Horizontal, Top, Bottom, Inner, Outer, Clockwise, Counterclockwise, Axial, The orientations or positional relationships indicated by "radial direction", "circumferential direction", etc. are based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the indicated devices or elements. must have a specific orientation, be constructed and operated in a specific orientation, and since the disclosed embodiments of the present invention may be arranged in different orientations, these directional terms are for illustration only and should not be regarded as limiting, such as "up", "Down" is not necessarily defined as a direction opposite or in line with the direction of gravity. Furthermore, features delimited with "first", "second" may expressly or implicitly include one or more of that feature.

Referring to FIG. 1 , an oblique support threaded pile supporting structure for foundation pit enclosure includes supporting piles 1 , foundation bottom plates 2 and threaded piles 3 . The supporting pile 1 extends longitudinally, and the foundation bottom plate 2 is located under the soil layer and at the bottom of the foundation pit.

1 and 3 , there are a plurality of threaded piles 3 , which are steel pipes made of metal, and each threaded pile 3 includes a first threaded pile section 31 and a second threaded pile section 32 , wherein the first threaded pile section 31 Located above the second threaded pile section 32 , the lower end of the first threaded pile section 31 and the upper end of the second threaded pile section 32 are connected to form a complete threaded pile 3 . The first threaded pile section 31 and the second threaded pile section 32 are threadedly connected by steel pipe casings, and are reinforced at the connection nodes, and can be dismantled and recovered in sections when dismantled. The upper end of each threaded pile 3 is connected to the upper end of the supporting pile 1 , and the lower end of each threaded pile 3 enters into the supporting soil layer below the base plate 2 . Each threaded pile 3 is inclined at a certain angle to the vertical direction, and enters the soil layer through the elevation of the foundation bottom plate 2 by screwing. The two threaded piles 3 are gradually inclined towards each other from top to bottom.

1 and 4, the upper end of the support pile 1 is provided with a crown beam 11, a hole or an open groove 12 is reserved on the crown beam 11, and the upper end of the first threaded pile section 31 is connected with the crown beam 11 through the anchoring device 13, The upper end portion of the first threaded pile section 31 enters the hole or open slot 12 . The anchoring device 13 is preferably an adjustable nut. Thereby, the threaded pile 3 is integrally formed with the support pile 1 . If the deformation of the foundation pit is relatively large in the later stage, the anchoring device 13 can be tightened by screwing to achieve the effect of controlling the deformation of the foundation pit. Preferably, the crown beam 11 is provided with a corbel 14 of reinforced concrete or steel structure. The corbel 14 and the threaded pile 3 are arranged at 90 degrees, which is convenient for the anchoring device 13 to be fixed and adjusted later.

Referring to Figure 5, the threaded pile 3 is an irregular pile, and the force-bearing form is greatly improved by fitting into the soil through the threads formed around the pile body. The first threaded pile section 31 can be a shallow thread or a smooth round steel pipe, but in the anchoring area with the crown beam 11 , it is provided with a shallow thick thread, and is equipped with a corresponding type of anchoring device 13 . The second threaded pile section 32 adopts a wide screw blade, and most of the oblique support force is provided by the helical linear pile end bearing formed by the mechanical engagement of the screw blade of the threaded pile 3 with the soil. It can provide great diagonal support and pull-out bearing capacity.

The soil layer at the lower end of the threaded pile 3 should be determined according to its physical and mechanical properties. If it is supported in the granular soil layer, the screwing of the screw blade of the threaded pile 3 can produce a shearing and compacting effect on the soil, which can provide high support force; In the soil layer with good shear resistance, as long as the soil is not disturbed, the threaded pile 3 is screwed in and out by means of a fixed thread path, which can provide high support force; when encountering the physical mechanics of the soil layer For those with poor performance, such as soft soil, a grouting pipe can be installed in the inner cavity of the steel pipe of the threaded pile 3, and a grouting hole 321 is opened on the steel pipe wall of the second threaded pile section 32 and at the position of the drill bit. , and spray cement slurry while stirring to reinforce the soil layer to form a hard soil support structure.

Preferably, the wall thickness of the threaded pile 3 is 5-15mm, the diameter of the steel pipe should be ≥80mm, and the thickness of the screw blade should be ≥3.5mm.

Referring to FIGS. 1 and 2 , in the foundation bottom plate 2 , a water-stop sleeve 4 is provided at the place penetrated by the second threaded pile section 32 , and the water-stop sleeve 4 is located on the outer periphery of the second threaded pile section 32 . The water stop casing 4 is preferably two semi-circular pipe fittings, which are spliced into a full circle by welding, and are arranged on the outer periphery of the threaded pile 3 . By arranging the water-stop casing 4, firstly, the effect of water-stopping is achieved in the later stage, and secondly, the threaded pile 3 can be rotated back and recycled in the later stage through the arrangement of the water-stop casing 4. The water stop sleeve 4 has an internal thread, and the second threaded pile section 32 passes through the water stop sleeve 4 and is threadedly connected. The internal thread of the water stop sleeve 4 is also beneficial to increase the water stop of the foundation bottom plate 2 . The outer circumference of the water-stop casing 4 is welded with steel bars to strengthen the connection between the water-stop casing 4 and the base plate 2, and a screw plate 41 that matches the screw blade of the threaded pile 3 is arranged inside, and the internal thread is formed on the screw plate. 41, in the later stage, the water stop casing 4 can be sealed by the micro-expansion concrete one grade higher than the foundation floor 2, thereby avoiding the problem of water leakage of the foundation floor 2.

Preferably, the wall thickness of the water stop casing 4 needs to be ≥ 2.0 mm, the pitch and width of the internal thread of the water-stop casing 4 need to correspond to the pitch and width of the second threaded pile section 32 , and the embedding angle needs to be the same as the threaded pile 3 . . Before the threaded pile 3 is fixed, the water stop sleeve 4 needs to be inserted into the foundation bottom plate 2 and take protective measures in the later stage. When the water stop sleeve 4 is connected to the base plate 2, it is necessary to use the surrounding steel bars to weld and fix it, so as to prevent the base plate 2 from being dislocated or damaged during construction, so that the threaded piles 3 cannot be screwed and recovered in the later stage.

Alternatively, the inner wall surface of the water-stop sleeve 4 can also be a smooth surface, and the threaded pile 3 passes through the water-stop sleeve 4 and can move relative to the water-stop sleeve 4 at this time. The water-stop sleeve 4 can be provided with an annular water-stop steel strip on the inner side wall surface to play the role of water-stop. As long as the water-stop casing 4 is arranged in the foundation bottom plate 2, and the water-stop casing 4 and the threaded pile 3 are connected in a non-fixed and detachable manner, the screw pile 3 can be retracted and recovered.

The construction method of the above-mentioned obliquely braced threaded pile support structure includes the following steps:

1) Construction of the supporting pile 1: construct the supporting pile 1 around the preset foundation pit, pour the reinforced concrete crown beam 11 on the upper end of the supporting pile 1, and set the reinforced concrete corbel at a certain distance along the direction of the crown beam 11 14. There are holes or open grooves 12 reserved on the crown beam 11 to form straight through holes for screwing the threaded piles 3. The position and number of the corbels 14 correspond to the holes or the open grooves 12 respectively; the spacing of the corbels 14 is equal to the threaded piles. The spacing of 3, the reinforcement bars are preferably set at 11 of the crown beams;

2) Install the threaded pile 3: Connect the first threaded pile section 31 and the second threaded pile section 32 to form an integral threaded pile 3, and use a drilling rig to screw the threaded pile 3 into the soil layer at an angle until the design is achieved. A certain depth below the required base plate 2 (a certain depth under the soil layer); in this embodiment, the soil layer is granular soil, after screwing in place, no high-pressure grouting is required to reinforce the soil layer; the drilling rig is preferably a 90-degree angle-adjustable drilling rig to provide support The length of the second threaded pile section 32, the distance of the screw blade, the width of the screw blade, etc. shall be determined by the oblique compression test in advance. During the test, an isolation casing shall be installed in the excavation area of the upper section, so as to measure reliably. support data;

3) Detection of bearing capacity: Extract a number of threaded piles 3 for oblique compressive bearing capacity detection to ensure the safety of the foundation pit; when performing compressive testing, a pressurizing device can be installed at the position of the corbel 14 to ensure that the applied force is consistent with the The threaded piles 3 are on the same force axis; the support allowance of the threaded piles 3 needs to be determined during the detection, so as to ensure that the surplus can be used for self-adjustment reinforcement when the foundation pit is greatly deformed in the later stage;

4) Anchoring the threaded pile 3: The anchoring position of the threaded pile 3 is processed, and the anchoring device 13 is inserted. After the concrete strength of the crown beam 11 reaches a certain level, such as 75%, the thread is passed through the anchoring device 13 along the foundation pit. The piles 3 are tightened and anchored evenly at intervals. At this time, the supporting piles 1 and the threaded piles 3 are formed into an integral structure with interaction force;

5) Excavation of foundation pit: After the crown beam 11 reaches a certain strength, carry out earthwork excavation according to the specifications and the special construction plan for earthwork excavation. Since the oblique support threaded pile 3 has been adopted, and the foundation pit and earthwork excavation can be carried out If a certain prestress is applied by screwing, the excavation of the foundation pit can be excavated to the design elevation at one time, and it is not necessary to do oblique support after partial excavation, and then carry out large-scale earthwork excavation;

6) Construction of the base plate 2: After the excavation of the foundation pit is completed, the construction of the base plate 2 is carried out, such as the construction of the cushion layer, the brick tire membrane, the waterproofing of the base plate, the binding of the steel bars of the base plate, and the replacement of the support belt; when constructing the foundation plate 2, the The water-stop sleeve 4 is placed in the foundation base plate 2 and is firmly welded by steel bars. When the concrete is poured into the foundation base plate 2, the water-stop sleeve 4 is directly poured into the foundation base plate 2 as a whole; measures shall be taken to ensure water-stopping during the pouring process No concrete and cement slurry are introduced into the casing 4 to ensure that the second threaded pile section 32 can be smoothly screwed and recovered in the later stage;

7) Removal of threaded piles: After the construction of the base plate 2 is completed and the support removal conditions required by the enclosure design are met, the anchoring devices 13 are loosened at intervals, and then the deformation monitoring of the foundation pit is carried out. If the data is stable, the threaded piles 3 can be carried out one by one. Demolition and recycling, if the data is unstable, other reinforcement measures shall be taken to ensure the safety of the foundation pit; when demolishing, demolition and recycling shall be carried out one by one, and the first threaded pile section 31 of each threaded pile shall be removed first, and the first threaded pile section 31 shall be removed after cleaning the water stop casing 4. The second threaded pile section 32 is screwed and recovered; after the threaded pile 3 is recovered, the pile hole is closed with high-grade micro-expanded concrete, and the maintenance work is done well;

In steps 5) and 6), if the deformation of the foundation pit is large and exceeds the value required by the enclosure design and specification, the deformation of the foundation pit can be controlled by further screwing and tightening the anchoring device 13, and then the deformation of the foundation pit is obtained. If the deformation of the foundation pit is not controlled, reinforcement measures are not required.

The oblique support threaded pile structure of the present invention has recyclability, can provide high support force, and can be reinforced and adjusted according to the deformation of the foundation pit. Waste and other situations ensure the safety, economy and environmental protection of foundation pit construction. After the oblique support is completed and the pressure support force test is completed, the foundation pit can be excavated at one time, and the mechanical excavation operation space is large. The cross section of the support pile is constructed in one piece, and the internal concave-convex thread structure of the water-stop steel plate outside the casing can effectively solve the problem of water leakage in the cross section in the later stage. When the oblique support system is dismantled, it can be monitored while unloading, which effectively solves the problem of uneven stress release or instantaneous unloading caused by the dismantling of the support.

Claims (10)

1. An obliquely supported threaded pile support structure for foundation pit enclosure, comprising a support pile (1), a foundation bottom plate (2) located below the soil layer, and a plurality of threaded piles (3), each threaded The upper end of the pile (3) is connected with the upper end of the supporting pile (1), and each threaded pile (3) passes through the foundation bottom plate (2) and at least partially enters the supporting soil layer below the foundation bottom plate (2). The piles (3) are gradually inclined toward each other from top to bottom, and it is characterized in that a water-stop casing (4) is arranged in the foundation bottom plate (2) at the place where the threaded pile (3) penetrates, and the water-stop casing (4) It is arranged on the outer periphery of the threaded pile (3) and is detachably connected to the threaded pile (3). 2. The oblique support threaded pile support structure for foundation pit enclosure according to claim 1, characterized in that: the inner side of the water stop casing (4) is provided with an internal thread, so as to be connected with the threaded pile (3). ) threaded connection. 3. The oblique support threaded pile support structure for foundation pit enclosure according to claim 2, characterized in that: the wall thickness of the water stop casing (4) is ≥2.0 mm. 4. The obliquely supported threaded pile support structure for foundation pit enclosure according to claim 1, wherein the upper end of the support pile (1) is provided with a crown beam (11), and the crown beam (11) is provided on the upper end of the support pile (1). The beam (11) and the threaded pile (3) are connected by an adjustable anchoring device (13). 5. The oblique support threaded pile support structure for foundation pit enclosure according to claim 4, characterized in that: along the direction of the crown beam (11), there are spaced threaded piles (3) connected to each other. A corbel (14), the crown beam (11) is provided with a hole or an open groove (12) for the end of the threaded pile (3) to enter. 6. The obliquely braced threaded pile support structure for foundation pit enclosure according to claim 1, wherein each threaded pile (3) comprises a first threaded pile section (31) and a first threaded pile section (31) that are connected to each other. Two threaded pile sections (32), the first threaded pile section (31) is located above the second threaded pile section (32), and the second threaded pile section (32) passes through the foundation bottom plate (2) and is screwed into the soil layer, The second threaded pile section (32) is connected to the water-stop casing (4), and mechanically engaged with the soil layer through the screw blade, and the width of the screw blade of the second threaded pile section (32) is ≥120 mm. 7. A construction method for the obliquely bracing threaded pile support structure according to any one of claims 1 to 6, comprising the steps of: 1) Construction of supporting piles (1): The supporting piles (1) are constructed around the foundation pit, and the crown beams (11) for connecting with the threaded piles (3) are poured at the upper end of the supporting piles (1); 2) Install the threaded pile (3): connect the first threaded pile section (31) and the second threaded pile section (32) to form an integral threaded pile (3), and screw the threaded pile (3) at a certain angle. into the soil layer until it reaches a certain depth below the base plate (2) required by the design; 3) Testing the bearing capacity: extract a number of threaded piles (3) for oblique compressive bearing capacity testing, and at the same time determine the supporting margin of the threaded piles (3); 4) Anchoring the threaded pile (3): The anchoring position of the threaded pile (3) is processed, and the anchoring device (13) is inserted. After the concrete strength of the crown beam (11) reaches a certain level, the anchoring is carried out along the foundation pit. The device (13) tightens and anchors the threaded piles (3) with the crown beams (11) evenly at intervals, thereby making the retaining piles (1) and the threaded piles (3) form an integral structure with an interaction force; 5) Excavation of the foundation pit: After the crown beam (11) reaches a certain strength, the foundation pit excavation is carried out; 6) Construction of the foundation floor (2): After the excavation of the foundation pit is completed, the construction of the foundation floor (2) is carried out. When the foundation floor (2) is constructed, the water stop sleeve (4) is placed in the foundation floor (2). , and fixed; 7) Removal of threaded piles (3): After the construction of the foundation bottom plate (2) is completed and the support removal conditions required by the enclosure design are met, first loosen the anchoring device (13) at intervals, and then monitor the deformation of the foundation pit. Remove the threaded pile (3) for recycling, and if the data is unstable, take reinforcement measures for the foundation pit to ensure the safety of the foundation pit. 8. the construction method of the obliquely braced threaded pile supporting structure according to claim 7, is characterized in that: in step 5) and 6), if the foundation pit deformation exceeds the numerical value of enclosure design and specification requirements, adopt The anchoring device (13) is further screwed and tightened to control the deformation of the foundation pit. After that, the deformation of the foundation pit is controlled and no reinforcement measures are required. If the deformation of the foundation pit is not controlled, reinforcement measures are required. 9. The construction method of the obliquely braced threaded pile supporting structure according to claim 7, characterized in that: in step 7), when removing the threaded pile (3), dismantling and recycling is carried out one by one, and each threaded pile (3). 3) Remove the first threaded pile section (31), clean the water stop casing (4), and then screw and recover the second threaded pile section (32). 10. The construction method of the obliquely supported threaded pile support structure according to claim 9, characterized in that: a screw plate matching the screw blade of the threaded pile (3) is provided on the inner wall of the water stop casing (4), After the threaded pile (3) is recovered, the inside of the water stop casing (4) is sealed by concrete.

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