Assembled L-shaped retaining wall structure of grouting miniature steel pipe piles

Abstract

The invention belongs to the technical field of retaining walls, discloses a grouting miniature steel pipe pile fabricated L-shaped retaining wall structure, and aims to solve the problem that a counterfort retaining wall cannot perform slope support in a soft area. The prefabricated support comprises an assembly type bottom plate, an assembly type vertical plate and a cast-in-place buttress, a boss is formed on the assembly type bottom plate, reserved holes are formed in the assembly type bottom plate, the boss and the assembly type vertical plate, reserved steel pipes are inserted into the reserved holes of the assembly type vertical plate, the lower ends of the reserved steel pipes are connected to miniature steel pipes, and the lower ends of the reserved steel pipes are connected to the miniature steel pipes. The lower pre-embedded connecting piece on the boss and the upper pre-embedded connecting piece on the assembly type vertical plate are connected and then are pre-embedded in a first pouring body poured in the later period. And the micro steel pipe is grouted to form a grouting micro steel pipe pile in the pile hole. The grouting micro steel pipe piles and the counterfort retaining wall are integrated; and the grouting micro steel pipe piles are used as the foundation of the L-shaped retaining wall, so that the bearing capacity of the foundation is improved, and the counterfort retaining wall is more widely used.

Description

Technical Field

[0001] The invention belongs to the technical field of retaining walls, and in particular relates to an assembled L-shaped retaining wall structure with grouting micro steel pipe piles. Background Art

[0002] Retaining structures are divided into two types: flexible and rigid. Since flexible retaining walls have good seismic performance, they are usually used in retaining wall designs in earthquake-prone areas and high-intensity areas. Commonly used ones include cantilever retaining walls, anti-slide piles, pile-anchor structures, reinforced earth retaining walls, buttress retaining walls, etc.

[0003] A counterfort retaining wall is a retaining wall that is connected to the heel plate by adding a buttress at a certain distance along the vertical arm of the cantilever retaining wall. It is generally a reinforced concrete structure. Its main features are simple structure, convenient construction, small wall section, light weight, better performance of material strength, and adaptability to foundations with low bearing capacity. It is suitable for areas lacking stone materials and earthquake areas. It is generally used to stabilize embankments in higher fill sections to reduce earthwork volume and floor space. The buttress retaining wall has a small cross-sectional size, and the weight of the soil on the heel plate can effectively resist overturning and sliding. The vertical plate and buttress jointly bear the bending moment and shear force generated by the soil pressure. In the prior art, there are also many technical documents about buttress retaining walls. For example, the patent with application number 2018204130807 discloses a buttress retaining wall, including a wall panel, a wall heel plate, a wall toe plate and a buttress. The wall heel plate or the wall toe plate is provided with a reserved hole, and the reserved hole is located at a position where other engineering pile foundations overlap with the wall heel plate or the wall toe plate of the buttress retaining wall, and the other engineering pile foundation is arranged in the reserved hole. The utility model avoids drilling other engineering pile foundations when they are located at the wall heel plate or the wall toe plate of the buttress retaining wall by arranging the reserved hole on the wall heel plate or the wall toe plate of the buttress retaining wall, which is convenient for construction, saves engineering workload, and avoids damage to the buttress retaining wall structure caused by drilling.

[0004] The patent with application number 2021213476628 discloses an ultra-high buttress retaining wall support structure, including a panel, a toe plate, a heel plate and a buttress plate, all of which are reinforced concrete structures, and backfill is filled behind the retaining wall structure; unloading plates are vertically graded on the back of the panel, and each level of unloading plates forms an unloading and decompression platform; the unloading plates overlap the adjacent buttress plates; multiple PVC drainage pipes are arranged on the panel from bottom to top, and a drainage layer and a back-filtration gravel layer composed of geotextile mats are arranged next to the back of the panel, forming a whole surface back-filtration drainage channel, which can quickly discharge the accumulated water behind the wall; a cushion layer is arranged at the bottom of the retaining wall structure, and a drainage ditch is arranged next to the panel at the top of the retaining wall. This scheme sets unloading plates at a certain height on the back of the panel of the conventional buttress retaining wall, and the unloading plates overlap the adjacent buttress plates to grade the backfill on the back of the wall. The backfill on the unloading plates increases the deadweight of the buttress retaining wall and improves its ability to withstand soil pressure.

[0005] Patent application number 2023206721785 discloses a pile-supported buttress retaining wall composite structure, comprising supporting piles, a base plate and a buttress retaining wall, wherein the buttress retaining wall is fixedly connected to the supporting piles through the base plate; a drainage pipe is provided in the buttress retaining wall, one end of the drainage pipe is placed inside the buttress retaining wall, and the other end extends from the buttress retaining wall perpendicular to the base plate; the supporting piles comprise a front row of piles, a middle row of piles and a rear row of piles, wherein the front row of piles, the middle row of piles and the rear row of piles are sequentially embedded in the soil layer, the pile body embedding ratio is 4 / 3, and the pile top is fixedly connected to the base plate.

[0006] As the buttress retaining wall illustrated in the example above, although it has the advantages of convenient and quick construction, it cannot support the slope in areas with weak foundation bearing capacity. The main reason is that the weak foundation bearing capacity is prone to collapse, and the deadweight of the buttress retaining wall aggravates the collapse and deformation of the stratum. Summary of the invention

[0007] In order to solve the problem that buttress retaining walls cannot support slopes in weak areas, the present invention provides a grouting micro steel pipe pile assembled L-shaped retaining wall structure, which integrates grouting micro steel pipe piles and buttress retaining walls (i.e., L-shaped retaining walls) into one; grouting micro steel pipe piles are used as the basis of the L-shaped retaining wall to improve the bearing capacity of the foundation, so that buttress retaining walls are more widely used and the problem of insufficient bearing capacity of the foundation is solved. The use of grouting micro steel pipe piles can also increase the anti-slip and anti-overturning capabilities of the buttress retaining wall, thereby improving the stability of the slope support. At the same time, the grouting operation of the grouting micro steel pipe piles can also improve the original soil properties of the slope, increase the shear strength of the slope, and thus reduce the soil pressure behind the buttress retaining wall.

[0008] In order to solve the technical problem, the technical solution adopted by the present invention is:

[0009] A grouting micro steel pipe pile assembled L-shaped retaining wall structure, characterized in that it includes an assembled base plate, an assembled vertical plate and a buttress cast in situ, wherein a boss corresponding to the assembled vertical plate is formed on the assembled base plate, the assembled base plate, the boss and the assembled vertical plate are all provided with reserved holes, and multiple rows of reserved holes are arranged on the assembled base plate, each row of reserved holes includes at least 2 reserved holes; one row of reserved holes in the multiple rows of reserved holes corresponds to the position of the assembled vertical plate so that the reserved holes on the boss can be aligned with the reserved holes on the assembled vertical plate, and the reserved holes on the boss penetrate the assembled base plate. The bottom surface of the assembled base plate, the reserved hole of the assembled vertical plate runs through the entire assembled vertical plate; a reserved steel pipe is inserted into the reserved hole of the assembled vertical plate, and the lower end of the reserved steel pipe is connected to the micro steel pipe of the micro steel pipe pile in the pile hole, and a plurality of grouting holes are opened on the reserved steel pipe; a lower embedded connecting piece is embedded in the boss, and an upper embedded connecting piece is embedded in the assembled vertical plate, and the lower embedded connecting piece and the upper embedded connecting piece are connected and embedded in the first casting body cast later; a micro steel pipe is implanted in the pile hole, and the micro steel pipe forms a grouting micro steel pipe pile in the pile hole after grouting.

[0010] In some embodiments, the size of the reserved steel pipe is smaller than the size of the reserved hole, and a protective layer is formed between the reserved steel pipe and the reserved holes of the assembled vertical plate, the boss, and the assembled bottom plate after pouring.

[0011] In some embodiments, the reserved steel pipe includes an upper reserved steel pipe and a lower reserved steel pipe, the lower reserved steel pipe is connected to the upper reserved steel pipe by welding or screws, the lower end of the lower reserved steel pipe is connected to the micro steel pipe of the micro steel pipe pile, and the upper end of the lower reserved steel pipe is higher than the upper end surface of the boss; the connection between the upper reserved steel pipe and the lower reserved steel pipe is staggered with the connection between the upper embedded connector and the lower embedded connector; the grouting holes of the reserved steel pipe are distributed on the upper reserved steel pipe. That is to say, the lower reserved steel pipe of the reserved steel pipe has no grouting holes.

[0012] In some embodiments, the remaining reserved holes on the prefabricated base plate except for the reserved holes corresponding to the prefabricated vertical plates are provided with short reserved steel pipes, the lower ends of the short reserved steel pipes are connected to the micro steel pipes of the micro steel pipe piles, and the upper ends of the short reserved steel pipes extend out of the upper end surface of the prefabricated base plate; the circumferential direction of the area where the short reserved steel pipes extend out of the prefabricated base plate is connected to a number of steel bars serving as the skeleton of the caps of the micro steel pipe piles.

[0013] In some embodiments, a sealing end cap is provided at the top of the pile hole.

[0014] In some embodiments, the lower embedded connecting member includes a lower vertical steel plate embedded in both sides of the reserved hole of the boss and a lower horizontal steel plate embedded in the assembled base plate, the lower end of the lower vertical steel plate and the lower horizontal steel plate are interconnected to form a whole, and the upper end of the lower vertical steel plate extends out of the upper end surface of the boss; the upper embedded connecting member includes an upper horizontal steel plate embedded in the assembled vertical plate and an upper vertical steel plate embedded in both sides of the reserved hole of the assembled vertical plate, the upper end of the upper vertical steel plate is interconnected with the upper horizontal steel plate, the lower end of the upper vertical steel plate extends out of the assembled vertical plate and is connected to the lower vertical steel plate and embedded in the first casting body cast later.

[0015] In some embodiments, a reinforcement plate is cast on-site on the side of the prefabricated bottom plate and the prefabricated vertical plate facing the soil, and the protective layer of the reserved steel pipe is cast and formed synchronously with the reinforcement plate, the first casting body and the buttress; connecting steel bars are connected to the positions of the upper vertical steel plate and the lower vertical steel plate corresponding to the reinforcement plates and the buttresses, and the connecting steel bars are interconnected with the frame inside the reinforcement plate and the frame of the buttress.

[0016] In some embodiments, at least a portion of the multiple reserved holes on the prefabricated vertical plate correspond to the positions of the buttresses to be cast later, and connecting steel bars are connected to the positions of the reserved steel pipes corresponding to the reinforcement plates and buttresses, and the connecting steel bars are connected to the frame inside the reinforcement plate and the frame of the buttresses.

[0017] In some embodiments, embedded steel bars are embedded in the assembled base plate and the assembled vertical plate at positions corresponding to the buttresses, and the embedded steel bars extend out of the assembled base plate or the embedded steel bars extend out of the assembled vertical plate and are interconnected with the skeleton of the buttresses; embedded steel bars are embedded in the assembled base plate and the assembled vertical plate at positions corresponding to the reinforcement plates, and the embedded steel bars extend out of the assembled base plate or the embedded steel bars extend out of the assembled vertical plate and are interconnected with the skeleton of the reinforcement plates.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The grouting micro steel pipe pile assemblable L-shaped retaining wall structure of the present invention integrates grouting micro steel pipe piles and buttress retaining wall (i.e., L-shaped retaining wall) into one; the grouting micro steel pipe piles are used as the foundation of the L-shaped retaining wall to improve the bearing capacity of the foundation, so that the buttress retaining wall is more widely used and the problem of insufficient bearing capacity of the foundation is solved. The use of grouting micro steel pipe piles can also increase the anti-slip and anti-overturning capabilities of the buttress retaining wall, thereby improving the stability of the slope support. At the same time, the grouting operation using the grouting micro steel pipe piles can also improve the original soil properties of the slope, increase the shear strength of the slope, and thus reduce the soil pressure behind the buttress retaining wall.

[0020] The main purpose of the present invention to set the reserved steel pipe in sections is to facilitate the construction of grouting micro steel pipe piles, and also to facilitate the hoisting of the assembled base plate and the assembled vertical plate. In addition, due to the structural design of the reserved steel pipe in the lower section, the micro steel pipe can improve the molding quality of the upper end of the micro steel pipe pile when grouting to form the grouting micro steel pipe pile. Because after grouting, the micro steel pipe pile has a soft texture in a part of the top area of ​​the micro steel pipe pile due to the sedimentation of the slurry, so it needs to be cut off and then grouting is carried out again, resulting in a long construction period. The present invention adopts the design of the lower reserved steel pipe. When the micro steel pipe is grouting to form the grouting micro steel pipe pile (or called micro steel pipe pile), due to the structural design of the lower reserved steel pipe, the grouting slurry liquid surface floats to the upper top of the lower reserved steel pipe. The volume of the slurry decreases during the solidification process, and the sedimentation occurs at the upper top of the lower reserved pipe. Therefore, the micro steel pipe can be formed once, and the micro steel pipe pile (i.e., grouting micro steel pipe pile) with good forming quality can be obtained without secondary grouting, and the construction efficiency of the micro steel pipe pile is improved. The removal operation of the settlement area (i.e., the area with soft texture) in the lower reserved steel pipe can be carried out simultaneously with other operations on the construction site. Therefore, the present invention can shorten the construction time of the micro steel pipe pile as a whole, thereby improving the construction efficiency.

[0021] The present invention uses a short reserved steel pipe and a steel bar connected thereto as a cap of a micro steel pipe pile. Since the short reserved steel pipe and the steel pipe of the micro steel pipe pile are connected to each other to form a whole, the connection strength between the assembled base plate and the micro steel pipe pile (grouting micro steel pipe pile) can be improved. At the same time, the short reserved steel pipe is used to improve the one-time molding quality of the micro steel pipe pile, thereby shortening the construction time of the micro steel pipe pile as a whole and improving the construction efficiency.

[0022] The first cast body of the present invention serves to connect the boss of the assembled base plate and the assembled vertical plate, and also serves as a connecting medium between the reinforcement plate and the buttress, so that the assembled base plate (including the boss), the assembled vertical plate, the buttress and the reinforcement plate form an organic whole.

[0023] At the same time, the skeleton of the reinforcement plate and the skeleton of the buttress are connected to each other by connecting steel bars, so that when the assembled vertical plate and the reinforcement plate are subjected to soil pressure, the soil pressure can be dispersed to the entire L-shaped retaining wall structure, and the assembled vertical plate will not crack or fail due to excessive local pressure. However, the buttress-type retaining wall in the prior art often has cracks and support failure due to excessive local pressure. The main reason is that when the soil pressure is transmitted to the vertical plate, it is dispersed only by the structural strength of the vertical plate itself; while in the present invention, when the soil pressure borne by the assembled vertical plate is directly transmitted by the assembled vertical plate, on the one hand, the first casting body and the reinforcement plate and the embedded steel pipe cast in one piece can disperse and transmit the effect particles, thereby transmitting the soil pressure to the buttress, the assembled bottom plate and the grouting micro steel pipe piles, thereby improving the support force on the slope soil.

[0024] Although the present invention also utilizes upper embedded connectors and lower embedded parts to realize the connection between the assembled vertical plate and the assembled bottom plate (including the boss); however, since the upper embedded connectors and the lower embedded parts are arranged along the length direction of the assembled vertical plate, and the first cast body, the reinforcement plate and the buttress are cast together, in addition to the connection between the upper embedded connectors and the lower embedded parts, the assembled vertical plate, the assembled bottom plate and the buttress also utilize the cast bodies cast on site (i.e., the first cast body, the reinforcement plate and the buttress) to form an organic whole. When transmitting the slope soil pressure, it is no longer just transmitted by the upper embedded connectors and the lower embedded parts, but transmitted through the overall structure to reduce the force at the connectors (the upper embedded connectors and the lower embedded parts), so as to prevent the problem of failure of the buttress retaining wall caused by failure of the connectors.

[0025] The grouting micro steel pipe pile assembled L-shaped retaining wall structure of the present invention utilizes the casting body (first casting body, reinforcement plate and buttress) to make the assembled base plate, assembled vertical plate and buttress form an organic whole, and can also utilize the reinforcement effect of the reserved steel pipe to improve the connection strength between the assembled vertical plate and the assembled base plate; at the same time, the lower end of the reserved steel pipe is inserted into the pile hole and interconnected with the micro steel pipe of the micro steel pipe pile, so that when the assembled vertical plate is subjected to the lateral pressure of the soil body, part of the force can be directly transmitted to the grouting micro steel pipe pile in the soil body by the reserved steel pipe, thereby achieving the purpose of improving the anti-overturning and anti-slip. When the reserved steel pipe is used to transmit the force, the force at the connection between the assembled base plate and the assembled vertical plate is also reduced, reducing the risk of damage to the connection between the assembled vertical plate and the assembled base plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of an embodiment of a grouting micro steel pipe pile assembled L-shaped retaining wall structure of the present invention;

[0027] Figure 2It is a cross-sectional structural schematic diagram of an embodiment of the present invention;

[0028] Figure 3 for Figure 2 A schematic diagram of a partial enlarged view of the center A;

[0029] Figure 4 for Figure 2 A schematic diagram of a partial enlarged view of point B in the middle;

[0030] Figure 5 for Figure 2 A schematic diagram of a partial enlarged view of position C in the middle;

[0031] Figure 6 for Figure 2 A schematic diagram of a partial enlarged view of point D in the middle;

[0032] Markings in the figure: 1. Assembled base plate, 11. Boss, 12. Reserved hole, 13. Lower embedded connector, 131. Lower vertical steel plate, 132. Lower horizontal steel plate, 14. Protective layer, 15. Reserved steel pipe, 151. Upper reserved steel pipe, 152. Lower reserved steel pipe, 2. Assembled vertical plate, 21. Upper embedded connector, 211. Upper vertical steel plate, 212. Upper horizontal steel plate, 3. Buttress, 4. First cast body, 5. Reinforcement plate, 6. Pile hole, 7. Micro steel pipe, 8. Platform cap, 9. Short reserved steel pipe, 91. Rebar, 10. Sealing end cover. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with embodiments, which are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, other embodiments obtained by ordinary technicians in the field without creative work are all within the scope of protection of the present invention.

[0034] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention; the terms "first", "second", and "third" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance; in addition, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In conjunction with the accompanying drawings, the grouting micro steel pipe pile assembled L-shaped retaining wall structure of the present invention includes an assembled base plate 1, an assembled vertical plate 2 and a buttress 3 cast in situ, wherein the assembled base plate 1 is formed with a boss 11 corresponding to the assembled vertical plate 2, and the assembled base plate 1, the boss 11 and the assembled vertical plate 2 are all provided with reserved holes 12, and the assembled base plate 1 is provided with multiple rows of reserved holes 12, and each row of reserved holes 12 includes at least 2 reserved holes; one row of reserved holes 12 in the multiple rows of reserved holes corresponds to the position of the assembled vertical plate 2 so that the reserved holes 12 on the boss 11 can be aligned with the reserved holes 12 on the assembled vertical plate 2 (that is, the assembled base plate is provided with multiple rows of reserved holes, one row of reserved holes passes through the boss 11 and is aligned with the reserved holes on the assembled vertical plate 2 The reserved holes 12 are aligned with each other), the reserved holes 12 on the boss 11 penetrate the bottom surface of the assembled base plate 1, and the reserved holes 12 of the assembled vertical plate 2 penetrate the entire assembled vertical plate 2; a reserved steel pipe 15 is inserted into the reserved hole 12 of the assembled vertical plate 2, and the lower end of the reserved steel pipe 15 is connected to the micro steel pipe 7 of the micro steel pipe pile in the pile hole 6, and a plurality of grouting holes are opened on the reserved steel pipe 15; a lower embedded connecting piece 13 is embedded in the boss 11, and an upper embedded connecting piece 21 is embedded in the assembled vertical plate 2, and the lower embedded connecting piece 13 and the upper embedded connecting piece 21 are connected and embedded in the first casting body 4 which is cast later; a micro steel pipe 7 is implanted in the pile hole 6, and the micro steel pipe 7 forms a grouting micro steel pipe pile in the pile hole 6 after grouting. That is, the first cast body 4 is used to cast the outer periphery of the upper vertical steel plate 211 of the exposed prefabricated vertical plate 2 and the lower vertical steel plate 131 of the exposed boss, and is used to connect the prefabricated vertical plate 2 and the boss 11. Before casting the first cast body, the lower end surface of the prefabricated vertical plate and the upper end surface of the boss should be roughened to improve the connection tightness between the first cast body 4 and the prefabricated vertical plate 2 and the boss 11.

[0036] The grouting micro steel pipe pile assemblable L-shaped retaining wall structure of the present invention integrates grouting micro steel pipe piles and buttress retaining wall (i.e., L-shaped retaining wall) into one; the grouting micro steel pipe piles are used as the foundation of the L-shaped retaining wall to improve the bearing capacity of the foundation, so that the buttress retaining wall is more widely used and the problem of insufficient bearing capacity of the foundation is solved. The use of grouting micro steel pipe piles can also increase the anti-slip and anti-overturning capabilities of the buttress retaining wall, thereby improving the stability of the slope support. At the same time, the grouting operation using the grouting micro steel pipe piles can also improve the original soil properties of the slope, increase the shear strength of the slope, and thus reduce the soil pressure behind the buttress retaining wall.

[0037] The lower end of the micro steel pipe 7 is implanted into the bearing layer of the soil, which can be understood by those skilled in the art and will not be described in detail. In the specific implementation process, the lower end of the micro steel pipe extends into the bearing layer for at least 0.5m.

[0038] In some embodiments, the size of the reserved steel pipe 15 is smaller than the size of the reserved hole 12, and a protective layer 14 is formed between the reserved steel pipe 15 and the reserved hole 12 of the assembled vertical plate 2, the boss 11, and the assembled bottom plate 1 after pouring. The reserved steel pipe 15 is protected from corrosion by the protective layer 14, and is connected with the assembled vertical plate, the boss, and the assembled bottom plate to form a whole.

[0039] In the specific implementation process, the size of the pile hole 6 is larger than the size of the micro steel pipe 7 of the micro steel pipe pile, the lower end of the reserved steel pipe 15 is sleeved on the periphery of the micro steel pipe 7 of the micro steel pipe pile, and the size of the reserved steel pipe 15 is also smaller than the size of the pile hole 6. The size of the reserved hole 12 is adapted to the size of the pile hole 6, so that the reserved steel pipe 15 after casting can form a cast protective layer 14 in the assembled base plate 1, the boss 11 and the assembled vertical plate 2. The reserved steel pipe is protected by the cast protective layer 14, and is connected to the assembled base plate, the boss and the assembled vertical plate.

[0040] In some embodiments, the reserved steel pipe 15 includes an upper reserved steel pipe 151 and a lower reserved steel pipe 152, the lower reserved steel pipe 152 and the upper reserved steel pipe 151 are connected to each other by welding or screws, the lower end of the lower reserved steel pipe 152 is connected to the micro steel pipe 7 of the micro steel pipe pile, and the upper end of the lower reserved steel pipe 152 is higher than the upper end surface of the boss 11; the connection between the upper reserved steel pipe 151 and the lower reserved steel pipe 152 is staggered with the connection between the upper embedded connector 21 and the lower embedded connector 13; the grouting holes of the reserved steel pipe 15 are distributed on the upper reserved steel pipe 151. That is, no grouting holes are provided on the lower reserved steel pipe 152 of the reserved steel pipe 15.

[0041] In some embodiments, the lower reserved steel pipe 152 and the micro steel pipe 7 of the micro steel pipe pile are integrated as a whole. It can also be understood that the lower reserved steel pipe 152 is an upward extension of the micro steel pipe 7 of the micro steel pipe pile.

[0042] The main purpose of the present invention to set the reserved steel pipe in sections is to facilitate the construction of grouting micro steel pipe piles, and also to facilitate the hoisting of the assembled base plate and the assembled vertical plate. In addition, due to the structural design of the reserved steel pipe in the lower section, the molding quality of the upper end of the micro steel pipe pile can be improved when the micro steel pipe is grouting to form the grouting micro steel pipe pile. Because after the grouting of the micro steel pipe pile, the sedimentation of the slurry makes a part of the top area of ​​the micro steel pipe soft, so it needs to be cut off and then grouting is carried out again, resulting in a long construction period. The present invention adopts the design of the lower reserved steel pipe. When the micro steel pipe is grouting to form the grouting micro steel pipe pile (or called micro steel pipe pile), due to the structural design of the lower reserved steel pipe, the grouting slurry liquid surface floats to the upper top of the lower reserved steel pipe. The volume of the slurry decreases during the solidification process, and the sedimentation occurs at the upper top of the lower reserved pipe. Therefore, the micro steel pipe can be formed once, and the micro steel pipe pile (i.e., grouting micro steel pipe pile) with good forming quality can be obtained without secondary grouting, and the construction efficiency of the micro steel pipe pile is improved. The removal operation of the settlement area (i.e., the area with soft texture) in the lower reserved steel pipe can be carried out simultaneously with other operations on the construction site. Therefore, the present invention can shorten the construction time of the micro steel pipe pile as a whole, thereby improving the construction efficiency.

[0043] In some embodiments, the remaining reserved holes 12 on the assembled base plate 1, except for the reserved holes 12 corresponding to the assembled vertical plate 2, are provided with short reserved steel pipes 9, the lower ends of the short reserved steel pipes 9 are connected to the micro steel pipes 7 of the micro steel pipe piles, and the upper ends of the short reserved steel pipes 9 extend out of the upper end surface of the assembled base plate 1; the circumferential direction of the area where the short reserved steel pipes 9 extend out of the assembled base plate 1 is connected to a number of steel bars 91 as the skeleton of the cap 8 of the micro steel pipe pile. That is to say, the skeleton of the cap 8 is composed of the short reserved steel pipes 9 and the steel bars 91 connected to the short reserved steel pipes 9, and then the periphery of the short reserved steel pipes 9 and the steel bars 91 is poured with concrete to form the cap 8. The present invention uses the short reserved steel pipes and the steel bars connected thereto as the caps of the micro steel pipe piles. Since the short reserved steel pipes and the steel pipes of the micro steel pipe piles are connected to each other to form a whole, the connection strength between the assembled base plate and the micro steel pipe piles (grouting micro steel pipe piles) can be improved.

[0044] During the specific implementation process, the number of the reserved holes 12 on the assembled base plate 1 is greater than the number of the reserved holes 12 on the assembled vertical plate 2, and the reserved steel pipes 15 (the lower reserved steel pipes 151 in the reserved steel pipes 15) are arranged in the reserved holes 13 on the assembled base plate 1 corresponding to the assembled vertical plate 2, and the remaining reserved holes 12 on the assembled base plate 1 (excluding the reserved holes corresponding to the reserved holes of the assembled vertical plate) are configured with short reserved steel pipes 9.

[0045] Among them, the remaining reserved holes on the assembled bottom plate, except for the reserved dragons of the assembled vertical plates, have the same function as the reserved steel pipes in the lower section by setting short reserved steel pipes, which serves the purpose of improving the one-time molding quality of the micro steel pipe piles, thereby shortening the construction time of the micro steel pipe piles as a whole and improving the construction efficiency. When the micro steel pipe piles are cast, the settlement area (i.e., the area with softer texture) in the short reserved steel pipe can be operated simultaneously when the assembled vertical plates are hoisted. Since the time for removing the softer sections and the time for the secondary casting of the micro steel pipe piles are eliminated, the construction efficiency of the grouting micro steel pipe piles can be improved as a whole, thereby shortening the construction period of the entire L-shaped retaining wall structure.

[0046] In the specific implementation process, a sealing end cap is provided at the top of the pile hole to prevent the injected slurry from overflowing from the area between the lower reserved steel pipe and the short reserved steel pipe and the pile hole when the micro steel pipe pile is grouting. A hole is provided in the middle of the sealing end cap for the lower reserved steel pipe and the short reserved steel pipe to pass through, so that the lower reserved steel pipe and the short reserved steel pipe can extend out of the ground.

[0047] In some embodiments, the lower embedded connecting member 13 includes a lower vertical steel plate 131 embedded in both sides of the reserved hole 12 of the boss 11 and a lower horizontal steel plate 132 embedded in the assembled base plate 1, the lower end of the lower vertical steel plate 131 and the lower horizontal steel plate 132 are interconnected to form a whole, and the upper end of the lower vertical steel plate 131 extends out of the upper end surface of the boss 11; the upper embedded connecting member 21 includes an upper horizontal steel plate 212 embedded in the assembled vertical plate 2 and an upper vertical steel plate 211 embedded in both sides of the reserved hole 12 of the assembled vertical plate 2, the upper end of the upper vertical steel plate 211 is interconnected with the upper horizontal steel plate 212, the lower end of the upper vertical steel plate 211 extends out of the assembled vertical plate 2 and is connected to the lower vertical steel plate 131 and embedded in the first casting body 15 cast later. During the process of hoisting the assembled vertical plate 2 , the assembled bottom plate 1 and the assembled vertical plate 2 are first firmly connected by connecting the upper vertical steel plate 211 and the lower vertical steel plate 131 , and then the first casting body 4 is cast.

[0048] In the specific implementation process, in order to ensure the normal implantation of the reserved steel pipe, the upper horizontal steel plate and the lower horizontal steel plate are provided with through holes corresponding to the positions of the reserved steel pipe. Among them, the upper vertical steel plate of the upper embedded connector and the lower vertical steel plate on the boss are fastened to each other by screws and nuts.

[0049] In the specific implementation process, the upper vertical steel plate 211 is symmetrically embedded in the assembled vertical plate on both sides of the reserved hole of the assembled vertical plate, and the lower vertical steel plate 131 is symmetrically embedded in the boss on both sides of the reserved hole of the boss. That is to say, the upper vertical steel plate and the lower vertical steel plate each include two pieces, and the two vertical plates are arranged parallel to each other, thereby improving the connection stability between the assembled vertical plate and the boss on the assembled bottom plate, that is, only by connecting the upper vertical steel plate and the lower vertical steel plate, the connection between the assembled bottom plate and the assembled vertical plate can be ensured to be stable.

[0050] Among them, during the prefabrication process of the prefabricated vertical panels and the prefabricated bottom panels, the steel bar skeleton (or embedded steel bar) corresponding to the areas around the reserved holes and the vertical panels and horizontal steel plates is encrypted, thereby improving the strength of the prefabricated vertical panels and the prefabricated bottom panels and preventing cracks from occurring around the reserved holes, horizontal steel plates, and vertical steel plates due to excessive force.

[0051] In some embodiments, the side of the fabricated bottom plate 1 and the fabricated vertical plate 2 facing the soil is cast with a reinforcement plate 5 on site, and the protective layer 14 of the reserved steel pipe 15 is cast and formed synchronously with the reinforcement plate 5, the first cast body 4 and the buttress 3; the upper vertical steel plate 211 and the lower vertical steel plate 131 are connected with connecting steel bars at positions corresponding to the reinforcement plate 5 and the buttress 3, and the connecting steel bars are connected to the skeleton in the reinforcement plate 5 and the skeleton of the buttress 3. Among them, the first cast body 4 plays the role of connecting the boss 11 of the fabricated bottom plate 1 with the fabricated vertical plate 2, and at the same time serves as a connecting medium between the reinforcement plate 5 and the buttress 3, so that the fabricated bottom plate 1 (including the boss 11), the fabricated vertical plate 2, the buttress 3 and the reinforcement plate 5 are organically formed into a whole.

[0052] At the same time, the skeleton of the reinforcement plate and the skeleton of the buttress are connected to each other by connecting steel bars, so that when the assembled vertical plate and the reinforcement plate are subjected to soil pressure, the soil pressure can be dispersed to the entire L-shaped retaining wall structure, and the assembled vertical plate will not crack or fail due to excessive local pressure. However, the buttress-type retaining wall in the prior art often has cracks and support failure due to excessive local pressure. The main reason is that when the soil pressure is transmitted to the vertical plate, it is dispersed only by the structural strength of the vertical plate itself; while in the present invention, when the soil pressure borne by the assembled vertical plate is directly transmitted by the assembled vertical plate, on the one hand, the first casting body and the reinforcement plate and the embedded steel pipe cast in one piece can disperse and transmit the effect particles, thereby transmitting the soil pressure to the buttress, the assembled bottom plate and the grouting micro steel pipe piles, thereby improving the support force on the slope soil. There is also a structure in the prior art for constructing anchor rods on the bottom plate of a buttress retaining wall. However, since the anchor rods are only connected to the bottom plate, when transmitting the force, the vertical plate (the assembled vertical plate in the present invention) cannot directly transmit the force to the anchor rods, but still requires the transmission function of the bottom plate, which leads to the problem of excessive force at the connection between the bottom plate and the vertical plate.

[0053] There are two main construction methods for buttress retaining walls (also often called L-shaped retaining walls) in the prior art. The first is on-site casting. The on-site casting method has the problem of long construction period and is not applicable in some scenarios. The second is also an assembled structure. For the existing assembled wall retaining wall, the bottom plate, the vertical plate and the buttress are generally connected by connectors (or the area of ​​the connector is cast after the connector is connected). This structure makes the connection strength between the bottom plate, the vertical plate and the buttress mainly rely on the structural strength of the connector (and the casting body formed by the outer casting of the connector or the plug-in component to achieve the connection). However, due to the fatigue of the connector itself and the large change in soil pressure, the design strength of the connector is exceeded; thus, the fatigue damage of the connector causes the failure of the entire buttress retaining wall. In addition, during the manufacturing process of the prefabricated assembled vertical plate, assembled bottom plate, and assembled buttress connectors, there are also uncertain factors in the manufacturing process that cause the strength of the connector to not reach the design strength, thereby accelerating the failure of the buttress retaining wall.

[0054] Although the present invention also uses upper embedded connectors and lower embedded parts to achieve the connection between the assembled vertical plate and the assembled bottom plate (including the boss); however, since the upper embedded connectors and the lower embedded parts are arranged along the length direction of the assembled vertical plate, and the first cast body, the reinforcement plate and the buttress are cast together, in addition to the connection between the upper embedded connectors and the lower embedded parts, the assembled vertical plate, the assembled bottom plate and the buttress also use the cast bodies cast on site (i.e., the first cast body, the reinforcement plate and the buttress) to form an organic whole. When transmitting the slope soil pressure, it is no longer just transmitted by the upper embedded connectors and the lower embedded parts, but transmitted through the overall structure to reduce the force at the connectors (upper embedded connectors and lower embedded parts) to prevent the problem of failure of the buttress retaining wall caused by failure of the connectors.

[0055] At the same time, the use of assembled bottom plates and protrusions can provide a good construction environment. On the one hand, the present invention can provide a good construction environment for the casting of reinforcement plates, first casting bodies and buttresses; on the other hand, compared with the overall on-site casting method in the prior art, the casting amount of the reinforcement plates, first casting bodies and buttresses of the present invention is greatly reduced. Therefore, the present invention can be applied to a wider range of sites. It not only solves the problems of long construction period caused by overall casting and limited site for continuous casting, but also solves the problems of low overall strength of existing assembled buttress retaining walls and easy support failure after long-term use.

[0056] The grouting micro steel pipe pile assembled L-shaped retaining wall structure of the present invention utilizes the casting body (first casting body, reinforcement plate and buttress) to make the assembled base plate, assembled vertical plate and buttress form an organic whole, and can also utilize the reinforcement effect of the reserved steel pipe to improve the connection strength between the assembled vertical plate and the assembled base plate; at the same time, the lower end of the reserved steel pipe is inserted into the pile hole and interconnected with the micro steel pipe of the micro steel pipe pile, so that when the assembled vertical plate is subjected to the lateral pressure of the soil body, part of the force can be directly transmitted to the grouting micro steel pipe pile in the soil body by the reserved steel pipe, thereby achieving the purpose of improving the anti-overturning and anti-slip. When the reserved steel pipe is used to transmit the force, the force at the connection between the assembled base plate and the assembled vertical plate is also reduced, reducing the risk of damage to the connection between the assembled vertical plate and the assembled base plate.

[0057] That is to say, the reserved steel pipe of the present invention can not only improve the connection strength between the assembled vertical plate and the assembled bottom plate, but also disperse the force at the connection between the assembled vertical plate and the assembled bottom plate (upper embedded connector, lower embedded connector and first cast body), reduce the risk of fatigue damage at the connection between the assembled vertical plate and the assembled bottom plate; at the same time, it can also improve the anti-lateral bending ability of the assembled vertical plate. Ultimately, the slope support capacity is improved.

[0058] In some embodiments, at least a portion of the multiple reserved holes 12 on the prefabricated vertical plate 2 correspond to the positions of the buttresses 3 to be cast later, and the reserved steel pipes 15 are connected with connecting steel bars at the positions corresponding to the reinforcing plates 5 and the buttresses 3, and the connecting steel bars are connected to the skeleton in the reinforcing plates 5 and the skeleton of the buttresses 3. In the specific implementation process, since the reinforcing plates 5 are arranged along the length direction of the prefabricated vertical plate 2, no matter how the reserved holes 12 of the prefabricated vertical plate 2 are designed, the reserved steel pipes 15 in the prefabricated vertical plate 2 will correspond to the positions of the reinforcing plates 5. Among them, at least a portion of the reserved holes 12 on the prefabricated vertical plate 2 correspond to the positions of the buttresses 3, so that the buttresses 3 and the reserved steel pipes 15 work together to improve the supporting force on the prefabricated vertical plate 2, thereby improving the ability of the prefabricated vertical plate to withstand the lateral pressure of the soil.

[0059] In some embodiments, embedded steel bars are embedded in the positions of the assembled base plate 1 and the assembled vertical plate 2 corresponding to the buttress 3, and the embedded steel bars extend out of the assembled base plate 1 or the embedded steel bars extend out of the assembled vertical plate 2 and are connected to the skeleton of the buttress 3; embedded steel bars are embedded in the positions of the assembled base plate 1 and the assembled vertical plate 2 corresponding to the reinforcing plate 5, and the embedded steel bars extend out of the assembled base plate or the embedded steel bars extend out of the assembled vertical plate and are connected to the skeleton of the reinforcing plate. That is to say, in addition to connecting the reinforcing plate and the buttress with the upper embedded connector, the lower embedded connector and the connecting steel bars on the reserved steel pipe, embedded steel bars are also connected to the structures of the assembled base plate and the assembled vertical plate themselves, so that the embedded steel bars are used to connect with the skeleton of the reinforcing plate and the buttress, thereby improving the connection strength between the assembled base plate, the assembled vertical plate and the first cast body, the reinforcing plate and the buttress.

[0060] The construction method of the L-shaped retaining wall structure of the present invention is introduced below. The construction method of the L-shaped retaining wall structure of the present invention that can be assembled by grouting micro steel pipe piles includes:

[0061] (1) The site is leveled and the layout is measured; the purpose of the measurement is to determine the location of the pile holes for the grouting micro steel pipe piles and the placement of the prefabricated base plate.

[0062] (2) Construction of grouting micro steel pipe piles; The construction of grouting micro steel pipe piles specifically includes drilling positioning according to the position of the pile hole determined in step (1) - drilling with a drilling rig - implanting the micro steel pipe - filling the micro steel pipe with gravel - grouting.

[0063] Specifically, micro steel pipes are generally made of seamless steel pipes. The diameter of seamless steel pipes can be selected from standard parts according to engineering design (technical personnel in this field can understand and comprehend, so I will not repeat them here). Seamless steel pipes should be made into flower pipes (flower holes, or grouting holes). The diameter of the flower holes is usually 5mm-10mm, arranged in plum blossom or rectangular shape, and the flower hole spacing is usually 300mm-600mm, so that the slurry can flow out of the flower pipe pores and be injected into the surrounding rock and soil. The size of the drill hole should be 10-60mm larger than the outer diameter of the micro steel pipe.

[0064] Among them, the micro steel pipes implanted in the pile holes corresponding to the reserved holes of the prefabricated vertical plates in each pile hole should first be connected to the lower section of the embedded steel pipe, and then the micro steel pipe connected to the lower section of the reserved steel pipe should be implanted into the pile hole; and the micro steel pipes configured in the remaining pile holes in each pile hole should first be connected to the short reserved steel pipe and then implanted into the corresponding pile holes.

[0065] In the specific implementation process, the process of filling gravel and grouting belongs to the existing technology, which can be understood by technicians in this field and will not be described in detail here.

[0066] It should be noted that when filling gravel and grouting are performed in the present invention, the gravel filling at least exceeds the top of the micro steel pipe and enters the lower reserved steel pipe and the short reserved steel pipe, while grouting needs to ensure that the slurry reaches the upper end of the lower reserved steel pipe and the short reserved steel pipe.

[0067] In the specific implementation process, since the slurry level will drop after grouting, a softer section will be formed in the lower reserved steel pipe and the short reserved steel pipe, which needs to be removed later. Therefore, in order to facilitate removal, when filling gravel, the gravel filling exceeds the micro steel pipe and it is not necessary to fill the entire lower reserved steel pipe and the short reserved steel pipe. That is to say, the gravel filling not only fills the inside of the micro steel pipe, but also fills the area between the micro steel pipe and the pile hole, which can be understood and understood by technicians in this field. Not filling the lower reserved steel pipe and the short reserved steel pipe (that is, not filling the entire lower reserved steel pipe and not filling the entire short reserved steel pipe) refers to the internal space of the lower reserved steel pipe and the short reserved steel pipe.

[0068] After implanting a micro steel pipe connected to a lower section reserved steel pipe or a short reserved steel pipe into the pile hole, a sealing end cover should be installed after filling the gravel between the micro steel pipe and the pile hole to seal and protect the top of the pile hole.

[0069] During the construction process of the grouting micro steel pipe pile of the present invention, the removal of the softer sections (the removal of the softer sections in the lower reserved steel pipe and the short reserved steel pipe can be carried out simultaneously with other subsequent operations) and the secondary grouting are omitted. Therefore, under the premise of ensuring the molding quality of the micro steel pipe pile, the construction time of the micro steel pipe pile can be greatly shortened.

[0070] (3) Transportation and hoisting of prefabricated assembled base plates; hoist the assembled base plate to the position determined in step (1), and allow the lower reserved steel pipe and the short reserved steel pipe to pass through the corresponding reserved holes on the assembled base plate. During the transportation of the assembled base plate, the softer section in the lower reserved steel pipe can be removed. Although the assembled base plate is generally transported to the construction site in advance, due to site leveling, measurement and layout, and the construction of micro steel pipe piles, the assembled base plate will not be directly hoisted to the designed position, so it generally requires secondary transportation. Therefore, when it does not affect the transportation and hoisting of the assembled base plate, the softer section formed after grouting in the lower reserved steel pipe can be removed.

[0071] (4) Construction of the cap of the grouting micro steel pipe pile and the prefabricated base plate; The specific construction of the cap of the grouting micro steel pipe pile and the prefabricated base plate includes: connecting steel bars to the short reserved steel pipe extending from the upper end surface of the prefabricated base plate, thereby forming the skeleton of the cap with the short reserved steel pipe and the steel bars, and then casting to form the cap by supporting the formwork, and using the cap to connect and fasten the micro steel pipe pile (grouting micro steel pipe pile) and the prefabricated base plate.

[0072] Among them, before connecting the steel bars to the short reserved steel pipe, the softer section formed by pouring inside the short reserved steel pipe should be removed.

[0073] (5) The hoisting and connection of the prefabricated vertical panels, and the construction of the caps of the grouting micro steel pipe piles and the prefabricated base plate; the prefabricated vertical panels are hoisted, and the upper embedded connectors on the prefabricated vertical panels and the lower embedded connectors on the bosses of the prefabricated base plate are connected to each other, thereby connecting the prefabricated vertical panels to the prefabricated base plate. In the specific implementation process, after the prefabricated vertical panels and the prefabricated base plate are connected and tightened to each other, in order to ensure the safety of the construction, the prefabricated vertical panels should be protected by a crane, or other support methods should be used to support and protect the prefabricated vertical panels. However, whether a crane or other support methods (such as steel frames, etc.) are used, ensure that the position of the prefabricated vertical panels is in the position required by the design.

[0074] In some embodiments, the assembled vertical plate is similar to the assembled bottom plate, and is generally delivered to the site in advance. When the assembled vertical plate is hoisted for the second time, the softer section formed by casting in the short reserved steel pipe can be removed. Therefore, in the actual operation process, step (4) and step (5) can be partially overlapped. That is, when the platform cap is being constructed, the assembled vertical plate is also being hoisted at the same time.

[0075] (6) The upper embedded connectors, the lower embedded connectors, the reserved steel pipes, and the connecting steel bars, as well as the tying of the framework of the buttresses and the reinforcement plates. In the specific implementation process, the upper embedded connectors, the lower embedded connectors, the reserved steel pipes, and the connecting steel bars can be used as the framework in the first cast unit. More steel bars can also be tied as the framework according to the actual situation to improve the strength of the first cast unit.

[0076] (7) The formwork, casting and demolding of the reinforcement plate, the first casting body and the buttresses make the grouting micro steel pipe piles, the assembled base plate, the reinforcement plate and the buttresses form a whole, thus completing the construction of the grouting micro steel pipe pile assembled L-shaped retaining wall structure.

[0077] In the specific implementation process, when pouring the reinforcement plate, buttress and the first pouring body, the reserved holes of the assembled vertical plate and the boss are poured simultaneously, so that the reserved steel pipes are poured simultaneously to form a protective layer.

Claims

1. A grouting micro steel pipe pile assembled L-shaped retaining wall structure, characterized in that: The invention comprises an assembled base plate (1), an assembled vertical plate (2) and a buttress (3) cast on site, wherein a boss (11) corresponding to the assembled vertical plate (2) is formed on the assembled base plate (1), and the assembled base plate (1), the boss (11) and the assembled vertical plate (2) are all provided with reserved holes (12), and the assembled base plate (1) is provided with a plurality of rows of reserved holes (12), and each row of reserved holes (12) includes at least two reserved holes; one row of reserved holes in the plurality of rows of reserved holes (12) corresponds to the position of the assembled vertical plate (2) so that the reserved holes (12) on the boss (11) can be aligned with the reserved holes (12) on the assembled vertical plate (2), and the reserved holes (12) on the boss (11) penetrate the bottom surface of the assembled base plate (1). The reserved hole of the assembled vertical plate (2) runs through the entire assembled vertical plate (2); a reserved steel pipe (15) is inserted into the reserved hole of the assembled vertical plate (2); the lower end of the reserved steel pipe (15) is connected to the micro steel pipe (7) of the micro steel pipe pile in the pile hole (6); and a plurality of grouting holes are opened on the reserved steel pipe (15); a lower embedded connecting piece (13) is embedded in the boss (11); an upper embedded connecting piece (21) is embedded in the assembled vertical plate (2); the lower embedded connecting piece (13) and the upper embedded connecting piece (21) are connected and embedded in the first casting body (4) cast later; a micro steel pipe (7) is implanted in the pile hole (6); and the micro steel pipe (7) forms a grouting micro steel pipe pile in the pile hole (6) after grouting.

2. The grouting micro steel pipe pile assembled L-shaped retaining wall structure according to claim 1 is characterized in that: The size of the reserved steel pipe (15) is smaller than the size of the reserved hole (12), and a protective layer (14) is formed between the reserved steel pipe (15) and the reserved hole (12) of the assembled vertical plate (2), the boss (11), and the assembled bottom plate (1) after pouring.

3. The grouting micro steel pipe pile assembled L-shaped retaining wall structure according to claim 1 or 2, characterized in that: The reserved steel pipe (15) comprises an upper reserved steel pipe (151) and a lower reserved steel pipe (152); the lower reserved steel pipe (152) and the upper reserved steel pipe (151) are connected to each other by welding or screws; the lower end of the lower reserved steel pipe (152) is connected to the micro steel pipe (7) of the micro steel pipe pile; the upper end of the lower reserved steel pipe (152) is higher than the upper end surface of the boss (11); the connection between the upper reserved steel pipe (151) and the lower reserved steel pipe (152) is staggered with the connection between the upper embedded connector (21) and the lower embedded connector (13); and the grouting holes of the reserved steel pipe (15) are distributed on the upper reserved steel pipe (151).

4. The grouting micro steel pipe pile assembled L-shaped retaining wall structure according to claim 3 is characterized in that: The remaining reserved holes (12) on the assembled base plate (1) except for the reserved holes (12) corresponding to the assembled vertical plates (2) are provided with short reserved steel pipes (9), the lower ends of the short reserved steel pipes (9) are connected to the micro steel pipes (7) of the micro steel pipe piles, and the upper ends of the short reserved steel pipes (9) extend out of the upper end surface of the assembled base plate (1); the circumferential direction of the area where the short reserved steel pipes (7) extend out of the assembled base plate (1) is connected to a plurality of steel bars (91) serving as the skeleton of the caps (8) of the micro steel pipe piles.

5. The grouting micro steel pipe pile assembled L-shaped retaining wall structure according to claim 1 is characterized in that: The top of the pile hole (6) is provided with a sealing end cover (10).

6. The grouting micro steel pipe pile assembled L-shaped retaining wall structure according to any one of claims 1 to 5, characterized in that: The lower embedded connection piece (13) comprises a lower vertical steel plate (131) embedded in both sides of the reserved hole of the boss and a lower horizontal steel plate (132) embedded in the assembled base plate (1), the lower end of the lower vertical steel plate (131) and the lower horizontal steel plate (132) are connected to each other to form a whole, and the upper end of the lower vertical steel plate (131) extends out of the upper end surface of the boss (11); the upper embedded connection piece (21) includes The invention comprises an upper horizontal steel plate (212) embedded in the assembled vertical plate (2) and an upper vertical steel plate (211) embedded in both sides of the reserved hole (12) of the assembled vertical plate, wherein the upper end of the upper vertical steel plate (211) is connected to the upper horizontal steel plate (212), and the lower end of the upper vertical steel plate (211) extends out of the assembled vertical plate (2) and is connected to the lower vertical steel plate (131) and embedded in the first casting body (4) cast later.

7. The grouting micro steel pipe pile assembled L-shaped retaining wall structure according to claim 6 is characterized in that: A reinforcement plate (5) is cast on site on the side of the assembled bottom plate (1) and the assembled vertical plate (2) facing the soil, and the protective layer (14) of the reserved steel pipe (15) is cast and formed synchronously with the reinforcement plate (5), the first cast body (4) and the buttress (3); connecting steel bars are connected to the positions corresponding to the reinforcement plate (5) and the buttress (3) on the upper vertical steel plate (211) and the lower vertical steel plate (131), and the connecting steel bars are connected to the frame inside the reinforcement plate (5) and the frame of the buttress (3).

8. The grouting micro steel pipe pile assembled L-shaped retaining wall structure according to claim 7 is characterized in that: At least a portion of the reserved holes (12) among the plurality of reserved holes on the assembled vertical plate (2) correspond to the positions of the buttresses (3) cast later, and connecting steel bars are connected to the positions of the reserved steel pipes (15) corresponding to the reinforcing plates (5) and the buttresses (3), and the connecting steel bars are connected to the framework inside the reinforcing plates (5) and the framework of the buttresses (3).

9. The grouting micro steel pipe pile assembled L-shaped retaining wall structure according to claim 1, characterized in that: Pre-embedded steel bars are embedded in the assembled base plate (1) and the assembled vertical plate (2) at positions corresponding to the buttress (3), and the embedded steel bars extend out of the assembled base plate or the embedded steel bars extend out of the assembled vertical plate and are connected to the frame of the buttress; pre-embedded steel bars are embedded in the assembled base plate (1) and the assembled vertical plate (2) at positions corresponding to the reinforcement plate (5), and the embedded steel bars extend out of the assembled base plate or the embedded steel bars extend out of the assembled vertical plate and are connected to the frame of the reinforcement plate (5).

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