Precast pile and soil nailing wall composite supporting structure

Abstract

The invention provides a precast pile and soil nailing wall composite supporting structure which comprises a side slope, a plurality of supporting piles and a top beam, the supporting piles are distributed along the edge of the side slope, the supporting piles are arranged in the side slope, and the upper ends of the supporting piles are connected with the top beam; a concrete spraying panel and a plurality of soil nail anchor rods are further arranged on the side slope, a plurality of reinforcing meshes are arranged in the concrete spraying panel, the soil nail anchor rods penetrate through the concrete spraying panel and the reinforcing meshes, one ends of the soil nail anchor rods obliquely downwards extend into a soil body of the side slope, and the other ends of the soil nail anchor rods are fixed to the side, away from the soil body, of the concrete spraying panel. By the adoption of the supporting structure, the horizontal soil arches are formed between the adjacent supporting piles, the vertical soil arches are formed between the upper and lower adjacent soil nail anchor rods, local deformation of soil bodies in the horizontal soil arches is avoided through the anchoring effect of the soil nail anchor rods and the concrete spraying panels, and the stability of the soil bodies on the edge of the slope is improved; and the effective supporting depth of the foundation pit is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of foundation pit slope support, and particularly relates to a composite support structure of precast piles and soil nailing walls. Background Art

[0002] In the field of construction, soil nailing walls or retaining piles are widely used to support the slopes of foundation pits to protect the stability of the foundation pits and the safety of underground structure construction operations.

[0003] A soil nailing wall is a support structure for soil excavation and slope stability. The soil nailing wall forms a composite body by inserting materials such as steel bars and steel pipes (called soil nailing anchors) into the soil and combining with a shotcrete surface layer, thereby improving the stability of the overall structure. The soil nailing wall is mainly used in soil layers where the groundwater level is lower than the excavation layer or after dewatering. Because it belongs to a passive support structure, it generally causes relatively large deformations on the side walls of the foundation pit. It is usually applicable to foundation pits with relatively good soil properties and a design depth not exceeding 8m. When the design depth of the foundation pit is relatively deep, it is not suitable to be used independently as a support structure.

[0004] Retaining piles form a soil retaining structure by setting a series of vertical or inclined piles on the slope of the foundation pit, blocking the lateral pressure of the soil and preventing the slope from collapsing. Retaining piles are usually combined with structures such as anchor rods, internal supports or capping beams to form a pile-anchor support system to further enhance the support effect. Retaining piles can be applied to foundation pit projects with a depth of 7 - 15 meters. However, generally, the local deformation of the soil of the foundation pit support structure is not easy to control. When the depth of the foundation pit is relatively large, the retaining piles need to be set closely, and the pile spacing does not exceed 3 times the diameter or side length of the pile body. The cost of retaining piles is high, and sometimes it causes unnecessary engineering waste invisibly.

[0005] In addition, whether it is a soil nailing wall or a retaining pile, a large amount of steel bars are usually required, which not only increases the project cost but also is not conducive to energy conservation and environmental protection. Summary of the Invention

[0006] The technical problem to be solved by the present invention is: how to increase the effective support depth of the foundation pit and reduce the project cost.

[0007] The technical solution of the present invention to solve the above technical problems is as follows: The present invention provides a composite support structure of precast piles and soil nailing walls, including a slope, retaining piles, and a capping beam. A plurality of retaining piles are provided and distributed along the edge of the slope. The retaining piles are arranged in the slope, and the upper ends of the retaining piles are connected to the capping beam; a shotcrete panel and a plurality of soil nailing anchors are also provided on the slope. A plurality of reinforcing mesh sheets are arranged in the shotcrete panel. The soil nailing anchors penetrate through the shotcrete panel and the reinforcing mesh sheets. One end of the soil nailing anchor extends obliquely downward into the soil of the slope, and the other end of the soil nailing anchor is fixed on the side of the shotcrete panel away from the soil body.

[0008] The beneficial effects of the present invention are as follows: By adopting the present invention, through multiple support piles and multiple soil nail anchors, a horizontal soil arch is formed between adjacent support piles, and a vertical soil arch is formed between adjacent upper and lower soil nail anchors, improving the stability of the soil mass at the deep part of the slope; through the anchoring effect of the soil nail anchors and the shotcrete panel, local deformation of the soil mass inside the horizontal soil arch is avoided, and the stability of the soil mass at the edge of the slope is improved; thus, effective support for the foundation pit is achieved; due to the interaction between the support piles and the soil nail anchors, both the overall and local deformations of the slope are controlled, thereby increasing the effective support depth of the foundation pit, and the support depth can reach 15 meters; at the same time, the requirement for closely arranging the support piles is reduced, unnecessary engineering waste is avoided, and the project cost is greatly reduced.

[0009] Based on the above technical solutions, the present invention can be further improved as follows.

[0010] Further, the soil nail anchors include near-pile soil nail anchors and between-pile soil nail anchors. Near-pile soil nail anchors are provided on both sides of the support pile, and multiple groups of between-pile soil nail anchors are provided between two groups of near-pile soil nail anchors on the opposite sides of every two adjacent support piles; each group of near-pile soil nail anchors includes multiple near-pile soil nail anchors distributed vertically along the slope; each group of between-pile soil nail anchors includes multiple between-pile soil nail anchors distributed vertically along the slope.

[0011] Through the arrangement of the near-pile soil nail anchors and the between-pile soil nail anchors, the certainty of the force of the soil arch between two adjacent support piles is enhanced, and at the same time, the soil anchoring effect at the edge of the slope is improved, facilitating the stabilization of the soil mass, and controlling both the overall and local deformations of the slope, thereby improving the reliability of the foundation pit support.

[0012] Further, the between-pile soil nail anchors are evenly distributed in the horizontal direction and the horizontal spacing is not greater than k / 6; the distances between the two groups of near-pile soil nail anchors and the between-pile soil nail anchors are the same and are both not greater than 2k / 6; where k is the distance between two adjacent support piles.

[0013] The reinforcement effect of the soil nail anchors on the horizontal soil arch between every two adjacent support piles is improved; at the same time, the between-pile soil nail anchors apply an anchoring force to the middle part of the horizontal soil arch, and the near-pile soil nail anchors apply an anchoring force to both sides of the horizontal soil arch, ensuring the force symmetry of the horizontal soil arch and improving the reliability of the foundation pit support.

[0014] Further, in each group of near-pile soil nail anchors and each group of between-pile soil nail anchors, the distances between the top near-pile soil nail anchor and the top between-pile soil nail anchor and the top of the support pile are both h1, h1 is not less than 2m, and the vertical spacing of the remaining near-pile soil nail anchors and the vertical spacing of the between-pile soil nail anchors are both hi, and hi is calculated by the following formula: hi = (4c·t1·t2·sinθ) / [q1·cos 2θ(1 - tanθtanφ)]; where c is the cohesion coefficient of the soil behind the pile, φ is the friction angle of the soil behind the pile, q1 is the self-weight pressure of the soil above the soil nail anchor, t1 and t2 are the lengths of the two sides of the reinforcement mesh penetrated by the soil nail anchor, and θ is the angle between the theoretical slip surface of the soil on the foundation pit side wall and the horizontal plane.

[0015] It ensures the formation of a vertical soil arching effect between adjacent soil nail anchors above and below, reduces the local deformation of the slope, and improves the reliability of the support.

[0016] Furthermore, the size of the reinforcement mesh at the position of the concrete shotcrete panel facing the retaining pile is not less than φ8@150×150×800mm. Two adjacent soil nail anchors of the same height on both sides of the same retaining pile penetrate the same reinforcement mesh, and the distance between the edge of the reinforcement mesh and the adjacent soil nail anchor is not less than a / 3; where a is the distance between two adjacent soil nail anchors of the same height on both sides of the same retaining pile. The size of the remaining reinforcement mesh is not less than φ6@150×150×300mm.

[0017] Through the reinforcement mesh at the position of the concrete shotcrete panel facing the retaining pile, the adjacent soil nail anchors on both sides of the retaining pile are connected as a whole, increasing the effective acting area of the retaining pile and improving the horizontal soil arching effect of the retaining pile; in addition, the reinforcement mesh improves the local strength of the concrete shotcrete panel and the support effect.

[0018] Furthermore, an anchor plate is also provided on the side of the concrete shotcrete panel away from the soil, and the other end of the soil nail anchor is fixed to the anchor plate by a nut.

[0019] Fixing the soil nail anchor through the anchor plate increases the force-bearing area of the concrete shotcrete panel against the tension of the soil nail anchor, avoids local excessive deformation and rupture of the concrete shotcrete panel, and improves the reliability of the support.

[0020] Furthermore, the end of the soil nail anchor extending into the soil of the slope inclines downward by 0° - 15° relative to the normal line on the side of the concrete shotcrete panel facing the soil.

[0021] It improves the anchoring effect of the soil nail anchor on the soil.

[0022] Furthermore, the soil nail anchor, the anchor plate, and the reinforcement mesh are all made of basalt fiber.

[0023] Using BFRP composite materials to replace a large amount of steel usage is convenient for construction, saves a large amount of construction costs, and is convenient for popularization and use.

[0024] Furthermore, the concrete shotcrete panel is formed by shotcreting basalt fiber concrete. In the basalt fiber concrete, the dosage of basalt fiber is not less than 0.7% of the cement dosage; the thickness of the concrete shotcrete panel is not less than 3% of the horizontal spacing of the soil nail anchors.

[0025] The strength of the concrete shotcrete panel is increased, and the support stability is improved.

[0026] Furthermore, the aggregate of the retaining pile and the aggregate of the capping beam are basalt fiber bars; both the retaining pile and the capping beam are cast with basalt fiber concrete; in the basalt fiber concrete of the retaining pile, the dosage of basalt fiber is not less than 0.5% of the cement dosage; in the basalt fiber concrete of the capping beam, the dosage of basalt fiber is not less than 1% of the cement dosage.

[0027] The stirrups and longitudinal bars of the retaining pile and the capping beam are replaced with basalt fiber bars, saving a large amount of steel usage, being convenient for construction, saving a large amount of construction costs, and being convenient for popularization and use; through the casting of basalt fiber concrete, the strength of the retaining pile and the capping beam is improved, and the support reliability is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic structural diagram of the vertical arrangement of the retaining pile of the present invention.

[0029] Figure 2 It is a schematic structural diagram of the inclined arrangement of the retaining pile of the present invention.

[0030] Figure 3 It is Figure 2 Detail drawing of part A of

[0031] Figure 4 It is a schematic structural diagram of the present invention in the overlooking direction along the slope.

[0032] Figure 5 It is a schematic structural diagram of the reinforcement mesh sheet at the position facing the retaining pile.

[0033] In the drawings, the technical features represented by the reference numerals are as follows: 1 - retaining pile; 2 - capping beam; 3 - concrete shotcrete panel; 4 - soil nail anchor; 41 - adjacent pile soil nail anchor; 42 - inter - pile soil nail anchor; 5 - reinforcement mesh sheet; 6 - anchoring backing plate; 7 - nut; 8 - theoretical slip surface. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The principles and features of the present invention will be described below. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0035] Refer to Figures 1-5 .

[0036] The present invention provides a composite retaining structure of precast piles and soil nailing walls, including a slope, retaining piles 1, and a capping beam 2. A plurality of the retaining piles 1 are provided and distributed along the edge of the slope. The retaining piles 1 are arranged within the slope, and the upper ends of the retaining piles 1 are connected to the capping beam 2. A concrete shotcrete panel 3 and a plurality of soil nailing bolts 4 are further provided on the slope. A plurality of reinforcing mesh sheets 5 are arranged within the concrete shotcrete panel 3. The soil nailing bolts 4 penetrate through the concrete shotcrete panel 3 and the reinforcing mesh sheets 5. One end of the soil nailing bolt 4 obliquely extends downward into the soil body of the slope, and the other end of the soil nailing bolt 4 is fixed on the side of the concrete shotcrete panel 3 away from the soil body.

[0037] During construction: First, the retaining piles 1 are arranged in a sparse row along the side wall of the foundation pit (i.e., the slope). The spacing of the retaining piles 1 is arranged according to the horizontal soil arch effect generated by the retaining piles 1 on the soil body. Specifically, the spacing of the retaining piles 1 can be set to 6 to 8 times the diameter or side length of the retaining piles 1, and this distance corresponds to a horizontal soil arch. The longitudinal reinforcement of the pile body can be uniformly symmetrically arranged or asymmetrically arranged on the inner and outer sides of the foundation pit along the pile circumference. The longitudinal reinforcement of the pile body can be partially prestressed. The stirrups of the pile body are spiral stirrups made of basalt fiber (BFRP) bars. The pile body concrete can be ordinary concrete or BFRP concrete. When BFRP concrete is used, the BFRP parameter is not less than 0.5% of the cement content. The length of the retaining pile 1 is not less than 1.3 times the designed excavation depth of the foundation pit, and the capping beam 2 can be flush with the top of the slope. The pile sinking and pile planting processes can be carried out by using the hammering and hole-leading processes or the pile planting process. When the pile planting process is used to form the pile, the periphery of the precast pile should be filled with BFRP-reinforced cement soil. The retaining pile 1 body can be vertically arranged or arranged at an inclination of 15 to 25° along the slope.

[0038] The capping beam 2 at the top of the constructed retaining pile 1 can be cast in place with BFRP concrete in the original groove. The concrete of the capping beam 2 body can be ordinary concrete or BFRP concrete. When BFRP concrete is used, the BFRP parameter is not less than 1.0% of the cement content. The width B1 of the capping beam 2 is the diameter or side length (long side) B of the retaining pile 1 + 100 mm (50 mm wider on each side), and the height of the capping beam 2 is not less than 1.2 times the diameter or side length of the retaining pile 1.

[0039] When constructing the soil nail anchor rods 4 and the shotcrete panel 3, the soil nail anchor rods 4 or the shotcrete panel 3 can be constructed first. When constructing the soil nail anchor rods 4 first, the soil nail anchor rods 4 are first implanted into the slope, and the rebar holes of the soil nail anchor rods 4 are filled with cement slurry; the strengthening mesh 5 is arranged on the corrected and leveled slope; one end of the soil nail anchor rod 4 exposed on the slope is wrapped and protected, and then the shotcrete panel 3 is sprayed, and finally one end of the soil nail anchor rod 4 exposed on the slope is fixed on the shotcrete panel 3. When the coating is relatively loose and the self-stability is poor or the soil is not suitable for long-term exposure (such as special soils such as expansive soil and red clay), it is advisable to construct the shotcrete panel 3 first, that is: first arrange the strengthening mesh 5 on the corrected and leveled slope, spray to form the shotcrete panel 3, then drill holes on the shotcrete panel 3 to construct the soil nail anchor rods 4, and fill the rebar holes of the soil nail anchor rods 4 with cement slurry, and finally fix one end of the soil nail anchor rod 4 exposed on the slope on the shotcrete panel 3.

[0040] By adopting the present invention, through multiple retaining piles 1 and multiple soil nail anchor rods 4, a horizontal soil arch is formed between adjacent retaining piles 1, and a vertical soil arch is formed between adjacent upper and lower soil nail anchor rods 4, improving the stability of the soil mass in the deep part of the slope; through the anchoring action of the soil nail anchor rods 4 and the shotcrete panel 3, local deformation of the soil mass inside the horizontal soil arch is avoided, and the stability of the soil mass at the edge of the slope is improved; thereby realizing effective support for the foundation pit; due to the interaction between the retaining piles 1 and the soil nail anchor rods 4, the overall and local deformations of the slope are simultaneously controlled, thereby increasing the effective support depth of the foundation pit, and the support depth can reach 15 meters; at the same time, the requirement for the close arrangement of the retaining piles 1 is reduced, the unnecessary engineering waste is avoided, and the project cost is greatly reduced.

[0041] Furthermore, the soil nail anchor rods 4 include adjacent-pile soil nail anchor rods 41 and between-pile soil nail anchor rods 42. The adjacent-pile soil nail anchor rods 41 are arranged on both sides of the retaining pile 1, and multiple groups of between-pile soil nail anchor rods 42 are arranged between two groups of adjacent-pile soil nail anchor rods 41 on the opposite sides of each adjacent two retaining piles 1; each group of adjacent-pile soil nail anchor rods 41 includes multiple adjacent-pile soil nail anchor rods 41 distributed vertically along the slope; each group of between-pile soil nail anchor rods 42 includes multiple between-pile soil nail anchor rods 42 distributed vertically along the slope.

[0042] Through the arrangement of the adjacent-pile soil nail anchor rods 41 and the between-pile soil nail anchor rods 42, the certainty of the soil arch force between adjacent two retaining piles 1 is enhanced, and at the same time, the soil anchoring effect at the edge of the slope is improved, facilitating the stabilization of the soil mass, and simultaneously controlling the overall and local deformations of the slope, and improving the reliability of the foundation pit support.

[0043] Furthermore, the between-pile soil nail anchor rods 42 are distributed at equal intervals in the horizontal direction and the horizontal spacing is not greater than k / 6; the distances between the two groups of adjacent-pile soil nail anchor rods 41 and the between-pile soil nail anchor rods 42 are the same and are both not greater than 2k / 6; wherein, k is the distance between adjacent two retaining piles 1.

[0044] Preferably, the horizontal spacing between every two adjacent groups of soil nail anchors 42 between piles is k / 6, and the distance between the soil nail anchor 41 adjacent to the pile and the soil nail anchor 42 between piles is 2k / 6.

[0045] The reinforcement effect of the soil nail anchor 4 on the horizontal soil arch between every two adjacent retaining piles 1 is improved; meanwhile, the soil nail anchor 42 between piles applies an anchoring force to the middle of the horizontal soil arch, and the soil nail anchor 41 adjacent to the pile applies an anchoring force to both sides of the horizontal soil arch, ensuring the force symmetry of the horizontal soil arch and improving the reliability of the foundation pit support.

[0046] Further, in each group of soil nail anchors 41 adjacent to the pile and each group of soil nail anchors 42 between piles, the distances from the soil nail anchors 41 and 42 adjacent to the pile at the top to the top of the retaining pile 1 are both h1, and h1 is not less than 2 m. The vertical spacing of the remaining soil nail anchors 41 adjacent to the pile and the vertical spacing of the soil nail anchors 42 between piles are both hi, and hi is calculated by the following formula: hi = (4c·t1·t2·sinθ) / [q1·cos 2 θ(1 - tanθtanφ)]; in the formula, c is the cohesion coefficient of the soil behind the pile, φ is the friction angle of the soil behind the pile, q1 is the self-weight pressure of the soil above the soil nail anchor 4, t1 and t2 are the side lengths of the two sides of the reinforcement mesh 5 penetrated by the soil nail anchor 4, and θ is the angle between the theoretical slip surface 8 of the soil on the side wall of the foundation pit and the horizontal plane.

[0047] Note: c is the cohesion coefficient of the soil behind the pile, φ is the friction angle of the soil behind the pile, and the thickness-weighted average value can be taken according to experimental determination; q1 is the self-weight pressure of the soil above the soil nail anchor 4, q1 = γH, γ is the unit weight of the soil, and H is the thickness of the soil above the soil nail anchor 4; t1 and t2 are the side lengths of the two sides of the reinforcement mesh 5 penetrated by the soil nail anchor 4, and the reinforcement mesh 5 can be determined according to needs; θ is the angle between the theoretical slip surface 8 of the soil on the side wall of the foundation pit and the horizontal plane, and θ = 45° + φ / 2.

[0048] It ensures the formation of a vertical soil arch effect between the upper and lower adjacent soil nail anchors 4, reduces the local deformation of the slope, and improves the support reliability.

[0049] Further, the size of the reinforcement mesh 5 at the position of the concrete shotcrete panel 3 facing the retaining pile 1 is not less than φ8@150×150×800 mm. The two soil nail anchors 41 adjacent to the pile and at the same height on both sides of the same retaining pile 1 penetrate the same piece of reinforcement mesh 5, and the distance between the edge of the reinforcement mesh 5 and the soil nail anchor 41 is not less than a / 3; where a is the distance between the two soil nail anchors 41 adjacent to the pile and at the same height on both sides of the same retaining pile 1; The size of the remaining reinforcement mesh 5 is not less than φ6@150×150×300 mm.

[0050] Note: φ8 is the material diameter of the reinforcement mesh 5, @150×150×800mm means that both the longitudinal and transverse dimensions of the mesh of the reinforcement mesh 5 are 150mm, and the side length of the reinforcement mesh 5 is 800mm.

[0051] Through the reinforcement mesh 5 facing the retaining pile 1, the adjacent pile soil nail anchors 41 on both sides of the retaining pile 1 are connected as a whole, increasing the effective acting area of the retaining pile 1 and enhancing the horizontal soil arch effect of the retaining pile 1; in addition, the reinforcement mesh 5 improves the local strength of the shotcrete panel 3 and enhances the support effect.

[0052] Furthermore, an anchor plate 6 is also provided on the side of the shotcrete panel 3 away from the soil body, and the other end of the soil nail anchor 4 is fixed to the anchor plate 6 through a nut 7.

[0053] Preferably, the thickness of the anchor plate 6 is not less than 10mm, and the width of the anchor plate 6 is not less than 3 times the diameter of the soil nail anchor 4. The anchor plate 6 can be made of steel plate or basalt fiber board.

[0054] By fixing the soil nail anchor 4 with the anchor plate 6, the stress area of the shotcrete panel 3 against the tension of the soil nail anchor 4 is increased, avoiding local excessive deformation and rupture of the shotcrete panel 3 and enhancing the reliability of the support.

[0055] Furthermore, one end of the soil nail anchor 4 extending into the soil body of the slope is inclined downward by 0° to 15° with respect to the normal line on the soil body side of the shotcrete panel 3.

[0056] The anchoring effect of the soil nail anchor 4 on the soil is enhanced.

[0057] Furthermore, the soil nail anchor 4, the anchor plate 6 and the reinforcement mesh 5 are all made of basalt fiber.

[0058] Using BFRP composite materials to replace a large amount of steel bar usage is convenient for construction, saves a large amount of construction costs and is easy to promote and use.

[0059] Furthermore, the shotcrete panel 3 is formed by shotcreting basalt fiber concrete. In the basalt fiber concrete, the content of basalt fiber is not less than 0.7% of the cement usage; the thickness of the shotcrete panel 3 is not less than 3% of the horizontal spacing of the soil nail anchors 4.

[0060] The strength of the shotcrete panel 3 is increased and the support stability is enhanced.

[0061] Furthermore, the aggregate of the retaining pile 1 and the aggregate of the capping beam 2 are basalt fiber bars; both the retaining pile 1 and the capping beam 2 are cast with basalt fiber concrete; in the basalt fiber concrete of the retaining pile 1, the content of basalt fiber is not less than 0.5% of the cement dosage; in the basalt fiber concrete of the capping beam 2, the content of basalt fiber is not less than 1% of the cement dosage.

[0062] The stirrups and longitudinal bars of the retaining pile 1 and the capping beam 2 are replaced with basalt fiber bars, saving a large amount of steel usage, being convenient for construction, saving a large amount of construction costs, and being easy to promote and use; through the casting of basalt fiber concrete, the strength of the retaining pile 1 and the capping beam 2 is improved, and the retaining reliability is enhanced.

[0063] In the description of the present invention, it should be understood that if there are descriptive terms indicating orientation, direction or positional relationship, such as: "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., the orientation or positional relationship indicated in this specification is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of understanding the present invention and simplifying the description, rather than indicating or implying that the part, component or whole indicated must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation to the present invention.

[0064] In addition, if there are ordinal descriptive terms, such as: "first", "second", etc., their use in this specification is for the convenience of understanding or simplifying the description. For example, in order to distinguish multiple technical features of the same type or function and having to be mentioned separately, this specification may use the way of prefixing or suffixing ordinal descriptive terms to distinguish them. Therefore, it cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0065] In the present invention, if descriptive terms for the relative structural relationship are used, such as "installed", "connected", "joined", "fixed", etc., unless otherwise clearly specified and defined, they should be understood in a broad sense. For example, "installed", "connected", "joined", etc. can be a fixed connection, a detachable connection, or integrated; can be a mechanical connection or an electrical connection; can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components; "fixed" can be a fixed integration or a detachable fixation through fasteners; can be directly fixed or fixed through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above descriptive terms in the present invention can be understood according to the specific circumstances, the context, the coherence of the context before and after, etc.

[0066] In the present invention, if descriptive terms with an affiliated or connection meaning appear, for example, the first feature is "on" or "under" the second feature, unless otherwise clearly specified and defined, they should not be understood in a restrictive sense. For example, "on" or "under" can be that the first and second features are in direct contact or the first feature and the second feature are in indirect contact through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above descriptive terms in the present invention can be understood according to the specific circumstances, the context, the coherence of the context before and after, etc.

[0067] Furthermore, the first feature being "above", "over" and "on top of" the second feature can mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher horizontal level than the second feature. The first feature being "under", "beneath" and "underneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower horizontal level than the second feature.

[0068] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments, examples, and the features of different embodiments and examples described in this specification, and these combinations or combinations should all fall within the scope summarized by the present invention.

[0069] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can, within the scope of information available in the public domain and in combination with the technical inspiration provided in this application document, make changes, modifications, substitutions, and variations to the above embodiments, which are still covered by the protection scope of this application.

Claims

1. A composite support structure of prefabricated piles and soil nail walls, characterized in that: The invention comprises a slope, a support pile (1), and a crown beam (2). The support pile (1) is provided with a plurality of support piles and distributed along the edge of the slope. The support pile (1) is arranged in the slope, and the upper end of the support pile (1) is connected to the crown beam (2). The slope is also provided with a concrete spraying panel (3) and a plurality of soil nail anchor rods (4). The concrete spraying panel (3) is provided with a plurality of reinforcing mesh sheets (5). The soil nail anchor rods (4) penetrate the concrete spraying panel (3) and the reinforcing mesh sheets (5). One end of the soil nail anchor rod (4) extends obliquely downward into the soil body of the slope, and the other end of the soil nail anchor rod (4) is fixed to a side of the concrete spraying panel (3) away from the soil body.

2. The composite support structure of precast piles and soil nail walls according to claim 1 is characterized in that: The soil nail anchor rods (4) include temporary pile soil nail anchor rods (41) and inter-pile soil nail anchor rods (42). Temporary pile soil nail anchor rods (41) are provided on both sides of the supporting piles (1), and multiple groups of inter-pile soil nail anchor rods (42) are provided between two groups of temporary pile soil nail anchor rods (41) on opposite sides of each two adjacent supporting piles (1); each group of temporary pile soil nail anchor rods (41) includes multiple temporary pile soil nail anchor rods (41) vertically distributed along the slope; each group of inter-pile soil nail anchor rods (42) includes multiple inter-pile soil nail anchor rods (42) vertically distributed along the slope.

3. The composite support structure of precast piles and soil nail walls according to claim 2 is characterized in that: The inter-pile soil nail anchor rods (42) are evenly spaced in the horizontal direction and the horizontal spacing is no greater than k / 6; the distances between the two groups of temporary pile soil nail anchor rods (41) and the inter-pile soil nail anchor rods (42) are the same and are no greater than 2k / 6; wherein k is the distance between two adjacent support piles (1).

4. The composite support structure of precast piles and soil nail walls according to claim 2 is characterized in that: In each group of temporary pile soil nail anchor rods (41) and each group of inter-pile soil nail anchor rods (42), the distances between the temporary pile soil nail anchor rods (41) and the inter-pile soil nail anchor rods (42) located at the top and the top of the supporting pile (1) are both h1, and h1 is not less than 2m; the vertical spacings of the remaining temporary pile soil nail anchor rods (41) and the vertical spacings of the inter-pile soil nail anchor rods (42) are all hi, and hi is calculated by the following formula: hi = (4c·t1·t2·sinθ) / [q1·cos 2 θ(1-tanθtanφ)]; where c is the cohesion coefficient of the soil behind the pile, φ is the friction angle of the soil behind the pile, q1 is the deadweight pressure of the soil above the soil nail anchor (4), t1 and t2 are the lengths of the two sides of the reinforcing mesh (5) through which the soil nail anchor (4) passes, and θ is the angle between the theoretical slip surface (8) of the soil on the side wall of the foundation pit and the horizontal plane.

5. The composite support structure of precast piles and soil nail walls according to claim 2 is characterized in that: The size of the reinforcing mesh (5) at the position of the concrete spraying panel (3) facing the supporting pile (1) is not less than φ8@150×150×800mm, two equal-height temporary pile soil nail anchor rods (41) on both sides of the same supporting pile (1) penetrate the same reinforcing mesh (5), and the distance between the edge of the reinforcing mesh (5) and the temporary pile soil nail anchor rod (41) is not less than a / 3; wherein a is the distance between the two equal-height temporary pile soil nail anchor rods (41) on both sides of the same supporting pile (1); The size of the remaining reinforcing mesh sheets (5) is not less than φ6@150×150×300mm.

6. The composite support structure of precast piles and soil nail walls according to claim 1 is characterized in that: An anchoring pad (6) is also provided on the side of the concrete spraying panel (3) away from the soil body, and the other end of the soil nail anchor rod (4) is fixed to the anchoring pad (6) via a nut (7).

7. The composite support structure of precast piles and soil nail walls according to claim 6 is characterized in that: The soil nail anchor rod (4), the anchor pad (6) and the reinforcing mesh (5) are all made of basalt fiber.

8. The composite support structure of precast piles and soil nail walls according to claim 1 is characterized in that: One end of the soil nail anchor rod (4) extending into the soil of the slope is tilted downward by 0° to 15° relative to the normal line of the concrete spraying panel (3) facing the soil side.

9. The composite support structure of precast piles and soil nail walls according to claim 1 is characterized in that: The concrete spraying panel (3) is formed by spraying basalt fiber concrete, in which the amount of basalt fiber added is not less than 0.7% of the amount of cement; the thickness of the concrete spraying panel (3) is not less than 3% of the horizontal spacing of the soil nail anchor rods (4).

10. The composite supporting structure of precast piles and soil nail walls according to claim 1 is characterized in that: The aggregates of the support pile (1) and the crown beam (2) are basalt fiber bars; the support pile (1) and the crown beam (2) are both cast using basalt fiber concrete; the basalt fiber content of the basalt fiber concrete of the support pile (1) is not less than 0.5% of the cement content; the basalt fiber content of the basalt fiber concrete of the crown beam (2) is not less than 1% of the cement content.

Images