A grouting micro steel pipe pile can be assembled L type retaining wall structure

Abstract

The present application belongs to retaining wall technical field, disclose a kind of grouting micro steel pipe pile can be assembled L type retaining wall structure, to solve the problem that retaining wall cannot carry out slope support in weak area.This application includes assembled bottom plate, assembled vertical plate and site-poured retaining wall, boss is formed on the assembled bottom plate, and assembled bottom plate, boss and assembled vertical plate are all provided with reserved hole, and reserved steel pipe is inserted in the reserved hole of assembled vertical plate, the lower end of the reserved steel pipe is connected on micro steel pipe, and the lower embedded connector on boss and the upper embedded connector on assembled vertical plate are connected and embedded in the first pouring body poured in later period;The micro steel pipe forms grouting micro steel pipe pile in pile hole after grouting.The present application integrates grouting micro steel pipe pile and retaining wall as a whole;Grouting micro steel pipe pile is used as the basis of L type retaining wall, improves foundation bearing capacity, so that retaining wall is more widely used.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of retaining walls, and particularly relates to a grouting micro steel pipe pile assemblable L-shaped retaining wall structure. BACKGROUND

[0002] Retaining structures are divided into two kinds of flexible and rigid. Since the flexible retaining wall has good anti-seismic performance, the flexible retaining structure is usually used in the design of retaining walls in earthquake-prone areas and high-intensity areas, and commonly used ones include cantilever retaining walls, anti-slide piles, pile-anchor structures, reinforced soil retaining walls and counterfort retaining walls.

[0003] The counterfort retaining wall refers to a retaining wall with a counterfort added at a certain distance along the vertical arm of the cantilever retaining wall to connect the vertical wall and the heel plate, and is generally a reinforced concrete structure. Its main features are simple structure, convenient construction, small wall section, light self-weight, good material strength performance, and adaptability to low bearing capacity foundation. It is suitable for areas lacking of stone materials and earthquake areas. It is generally used in high filling sections to stabilize the embankment and reduce the amount of earthwork and land occupation. The counterfort retaining wall has a small cross-sectional size, the gravity of the soil on the heel plate can effectively resist overturning and sliding, and the vertical plate and the counterfort jointly bear the bending moment and shear force generated by the earth pressure. There are many technical documents about the counterfort retaining wall in the prior art, for example, the patent with the application number 2018204130807 discloses a counterfort retaining wall, which comprises a wall surface plate, a wall heel plate, a wall toe plate and a counterfort. The wall heel plate or the wall toe plate is provided with a reserved hole, and the reserved hole is located at the position where the other engineering pile foundation and the wall heel plate or the wall toe plate of the counterfort retaining wall coincide. The other engineering pile foundation is arranged in the reserved hole. The utility model sets the reserved hole on the wall heel plate or the wall toe plate of the counterfort retaining wall, avoids drilling holes when the other engineering pile foundation is located on the wall heel plate or the wall toe plate of the counterfort retaining wall, is convenient for construction, saves engineering quantity, and avoids the damage of drilling holes to the structure of the counterfort retaining wall.

[0004] The patent with the application number 2021213476628 discloses a super-high buttress retaining wall supporting structure, which comprises a face plate, a toe plate, a heel plate and a buttress plate, all of which are reinforced concrete structures, and the back of the face plate is vertically divided into stages to set unloading plates, each stage of unloading plate forms an unloading and pressure reducing platform, the unloading plate is overlapped with the adjacent buttress plate, a plurality of PVC drainage pipes are arranged on the face plate from bottom to top, a drainage layer composed of geotextile mats and a reverse filtration gravel layer are arranged next to the back of the face plate to form a whole surface reverse filtration and drainage channel to quickly drain 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 face plate at the top of the retaining wall. According to the scheme, the unloading plates are vertically divided into stages according to a certain height at the back of the face plate of the conventional buttress retaining wall, the unloading plates are overlapped with the adjacent buttress plates, the backfill material on the unloading plates increases the self-weight of the buttress retaining wall, and the capacity of the buttress retaining wall to withstand earth pressure is improved.

[0005] The patent with the application number 2023206721785 discloses a pile-supported buttress retaining wall combined structure, which comprises a supporting pile, a bottom plate and a buttress retaining wall, the buttress retaining wall is fixedly connected with the supporting pile through the bottom plate, a drain pipe is arranged in the buttress retaining wall, one end of the drain pipe is arranged in the buttress retaining wall, and the other end of the drain pipe is arranged to protrude from the buttress retaining wall and be perpendicular to the bottom plate, the supporting pile comprises front piles, middle piles and rear piles, the front piles, the middle piles and the rear piles are sequentially embedded in the soil layer, the pile body embedding ratio is 4 / 3, and the top of the pile is fixedly connected with the bottom plate.

[0006] Like the buttress retaining wall exemplified above, although the buttress retaining wall has the advantages of convenient and fast construction, it cannot be used to support the slope in the area with weak bearing capacity of the foundation, and the main reason is that the weak bearing capacity of the foundation is prone to collapse, and the self-weight of the buttress retaining wall aggravates the collapse deformation of the stratum. SUMMARY

[0007] In order to solve the problem that the buttress retaining wall cannot be used to support the slope in the soft area, the present application provides a grouting micro steel pipe pile assembly type L-shaped retaining wall structure, which integrates the grouting micro steel pipe pile and the buttress retaining wall (i.e. L-shaped retaining wall). The grouting micro steel pipe pile is 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 grouting micro steel pipe pile can also increase the anti-sliding and anti-overturning capacity 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 pile can also improve the nature of the undisturbed soil of the slope, increase the shear strength of the slope, and thus reduce the earth pressure behind the buttress retaining wall.

[0008] To solve the technical problem, the technical scheme adopted by the present application is:

[0009] A prefabricated L-shaped retaining wall structure for grouting micro steel pipe piles is characterized by comprising a prefabricated base plate, prefabricated upright plates, and cast-in-place buttresses. The prefabricated base plate has protrusions corresponding to the prefabricated upright plates. The prefabricated base plate, protrusions, and upright plates are all provided with pre-drilled holes. The prefabricated base plate has multiple rows of pre-drilled holes, each row including at least two holes. One row of pre-drilled holes corresponds to the position of the pre-drilled holes on the upright plates, allowing the pre-drilled holes on the protrusions to align with those on the upright plates. The pre-drilled holes on the protrusions penetrate the prefabricated base plate. The pre-reserved holes of the prefabricated vertical plate penetrate the entire prefabricated vertical plate on the bottom surface of the prefabricated base plate; a pre-reserved steel pipe is inserted into the pre-reserved hole of the prefabricated vertical plate, and the lower end of the pre-reserved steel pipe is connected to the micro steel pipe of the micro steel pipe pile in the pile hole. Several grouting holes are opened on the pre-reserved steel pipe; a lower pre-embedded connector is pre-embedded in the boss, and an upper pre-embedded connector is pre-embedded in the prefabricated vertical plate. After the lower and upper pre-embedded connectors are connected, they are pre-embedded in the first casting body to be poured later; a micro steel pipe is implanted in the pile hole, and after grouting, the micro steel pipe forms a grouting micro steel pipe pile in the pile hole.

[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 hole of the prefabricated vertical plate, boss, or prefabricated base plate after casting.

[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 extends above the upper end face of the boss. The connection between the upper and lower reserved steel pipes is staggered from the connection between the upper and lower embedded connectors. The grouting holes of the reserved steel pipe are distributed on the upper reserved steel pipe. That is to say, no grouting holes are opened on the lower reserved steel pipe.

[0012] In some embodiments, the pre-reserved holes on the prefabricated base plate, except those corresponding to the pre-reserved holes on the prefabricated upright plate, are equipped with short pre-reserved steel pipes. The lower end of the short pre-reserved steel pipes is connected to the micro steel pipes of the micro steel pipe piles, and the upper end of the short pre-reserved steel pipes extends out of the upper surface of the prefabricated base plate. A plurality of reinforcing bars serving as the skeleton of the cap of the micro steel pipe piles are connected in the circumferential direction of the area where the short pre-reserved steel pipes extend out of the prefabricated base plate.

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

[0014] In some embodiments, the lower embedded connecting piece comprises lower vertical steel plates embedded on both sides of the reserved hole of the boss and a lower horizontal steel plate embedded in the fabricated bottom plate, the lower ends of the lower vertical steel plates and the lower horizontal steel plate are connected together to form an integral whole, and the upper ends of the lower vertical steel plates extend out of the upper end surface of the boss; the upper embedded connecting piece comprises an upper horizontal steel plate embedded in the fabricated vertical plate and upper vertical steel plates embedded on both sides of the reserved hole of the fabricated vertical plate, the upper ends of the upper vertical steel plates are connected with the upper horizontal steel plate, and the lower ends of the upper vertical steel plates extend out of the back of the fabricated vertical plate to be connected with the lower vertical steel plate and embedded in the first pouring body poured later.

[0015] In some embodiments, the side of the fabricated bottom plate and the fabricated vertical plate facing the soil body is in-situ poured with a reinforcing plate, the protective layer of the reserved steel pipe is synchronously poured with the reinforcing plate, the first pouring body and the buttress, and the upper vertical steel plate and the lower vertical steel plate are connected with connecting steel bars at positions corresponding to the reinforcing plate and the buttress, and the connecting steel bars are connected with the framework in the reinforcing plate and the framework of the buttress.

[0016] In some embodiments, at least part of the plurality of reserved holes on the fabricated vertical plate correspond to the positions of the buttress poured later, the reserved steel pipe is connected with connecting steel bars at positions corresponding to the reinforcing plate and the buttress, and the connecting steel bars are connected with the framework in the reinforcing plate and the framework of the buttress.

[0017] In some embodiments, the fabricated bottom plate and the fabricated vertical plate are embedded with embedded steel bars at positions corresponding to the buttress, and the embedded steel bars extend out of the fabricated bottom plate or the embedded steel bars extend out of the fabricated vertical plate to be connected with the framework of the buttress; the fabricated bottom plate and the fabricated vertical plate are embedded with embedded steel bars at positions corresponding to the reinforcing plate, and the embedded steel bars extend out of the fabricated bottom plate or the embedded steel bars extend out of the fabricated vertical plate to be connected with the framework of the reinforcing plate.

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

[0019] The grouting micro steel pipe pile of the present application can be assembled into a L-shaped retaining wall structure, which integrates the grouting micro steel pipe pile and the buttress retaining wall (i.e. L-shaped retaining wall); the grouting micro steel pipe pile is used as the foundation of the L-shaped retaining wall to improve the foundation bearing capacity, making the buttress retaining wall more widely used and solving the problem of insufficient foundation bearing capacity. The grouting micro steel pipe pile can also increase the anti-sliding and anti-overturning capacity of the buttress retaining wall, thereby improving the stability of the slope support. Meanwhile, the grouting operation of the grouting micro steel pipe pile can also improve the nature of the undisturbed soil of the slope, increase the shear strength of the slope, and thus reduce the earth pressure behind the buttress retaining wall.

[0020] The present application is mainly used for facilitating the construction of the grouting micro steel pipe pile, and facilitating the hoisting of the assembled floor and the assembled vertical plate. The structure design of the lower segment reserved steel pipe can improve the forming quality of the upper end of the micro steel pipe pile when the micro steel pipe is grouted to form the grouting micro steel pipe pile. The top part of the micro steel pipe pile is soft after grouting due to the settlement of the grout, so the top part needs to be cut off for secondary grouting, which prolongs the construction period. The structure design of the lower segment reserved steel pipe can make the grout surface float to the upper top of the lower segment reserved steel pipe during the grouting of the micro steel pipe to form the grouting micro steel pipe pile (or micro steel pipe pile), so the volume of the grout decreases during the solidification process, and the settlement occurs at the upper top of the lower segment reserved pipe, thus the micro steel pipe can be formed at one time, and the 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 soft area) in the lower segment reserved steel pipe can be synchronized with other operations in the construction site, so the present application can shorten the construction time of the micro steel pipe pile as a whole, and improve the construction efficiency.

[0021] The present application uses the short reserved steel pipe and the steel bar connected thereto as the cap of the micro steel pipe pile. Since the short reserved steel pipe and the steel pipe of the micro steel pipe pile are connected to form a whole, the connection strength between the assembled floor and the micro steel pipe pile (grouting micro steel pipe pile) can be improved. The short reserved steel pipe can improve the one-time forming quality of the micro steel pipe pile, thus shortening the construction time of the micro steel pipe pile as a whole and improving the construction efficiency.

[0022] The first pouring body of the present application serves as the connection between the convex plate of the assembled floor and the assembled vertical plate, and also serves as the connection medium between the reinforcing plate and the buttress, so that the assembled floor (including the convex plate), the assembled vertical plate, the buttress and the reinforcing plate form a whole.

[0023] Meanwhile, the framework of the reinforcing plate and the framework of the buttress are connected by the connecting steel bars, so that when the assembled vertical plate and the reinforcing plate bear the soil pressure, the soil pressure can be dispersed to the entire L-shaped retaining wall structure, and the problem of cracks and failure of the assembled vertical plate caused by excessive local pressure can be avoided. However, the buttress retaining wall in the prior art often has the problem of cracks and failure caused by excessive local pressure. The main reason is that when the soil pressure is transmitted to the vertical plate, it is only dispersed by the structural strength of the vertical plate itself. In the present application, when the assembled vertical plate bears the soil pressure, the soil pressure is directly transmitted by the assembled vertical plate on the one hand, and the first pouring body, the reinforcing plate and the embedded steel pipe can also disperse and transmit the acting force on the other hand, so that the soil pressure is transmitted to the buttress, the assembled bottom plate and the grouting micro steel pipe pile, thereby improving the supporting force of the slope soil.

[0024] Although the present application also uses upper and lower embedded parts to realize the connection between the assembled vertical plate and the assembled bottom plate (including the boss), the upper and lower embedded parts are arranged along the length direction of the assembled vertical plate, and the first pouring body, the reinforcing plate and the buttress are poured together, so that the assembled vertical plate, the assembled bottom plate and the buttress form an organic whole except for the connection between the upper and lower embedded parts. When transmitting the soil pressure of the slope, the force at the connection part (the upper and lower embedded parts) is reduced by transmitting the force through the whole structure, so as to prevent the failure of the buttress retaining wall caused by the failure of the connection part.

[0025] The grouting micro steel pipe pile assembled L-shaped retaining wall structure of the present application uses the pouring body (the first pouring body, the reinforcing plate and the buttress) to form an organic whole of the assembled bottom plate, the assembled vertical plate and the buttress, and can also use the reinforcing effect of the reserved steel pipe to improve the connection strength between the assembled vertical plate and the assembled bottom plate. Meanwhile, the lower end of the reserved steel pipe is inserted into the pile hole and connected with the micro steel pipe of the micro steel pipe pile, so that when the assembled vertical plate bears the lateral pressure of the soil, part of the acting force can be directly transmitted to the grouting micro steel pipe pile in the soil through the reserved steel pipe, thereby improving the anti-overturning and anti-sliding effect. When the reserved steel pipe is used to transmit the acting force, the acting force at the connection part of the assembled bottom plate and the assembled vertical plate is also reduced, thereby reducing the risk of damage at the connection part of the assembled bottom plate and the assembled vertical plate. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 FIG. 1 is a structural schematic view of an embodiment of the grouting micro steel pipe pile assembled L-shaped retaining wall structure of the present application;

[0027] Figure 2A sectional view structural schematic diagram of an embodiment of the present application;

[0028] Figure 3 A sectional view structural schematic diagram of an embodiment of the present application; Figure 2 A partial enlarged view schematic diagram at A in FIG. 1;

[0029] Figure 4 A sectional view structural schematic diagram of an embodiment of the present application; Figure 2 A partial enlarged view schematic diagram at B in FIG. 1;

[0030] Figure 5 A sectional view structural schematic diagram of an embodiment of the present application; Figure 2 A partial enlarged view schematic diagram at C in FIG. 1;

[0031] Figure 6 A sectional view structural schematic diagram of an embodiment of the present application; Figure 2 A partial enlarged view schematic diagram at D in FIG. 1;

[0032] In the figure, the marks are as follows: 1, assembled bottom plate, 11, boss, 12, reserved hole, 13, lower pre-buried connecting piece, 131, lower vertical steel plate, 132, lower horizontal steel plate, 14, protective layer, 15, reserved steel pipe, 151, upper section reserved steel pipe, 152, lower section reserved steel pipe, 2, assembled vertical plate, 21, upper pre-buried connecting piece, 211, upper vertical steel plate, 212, upper horizontal steel plate, 3, buttress, 4, first pouring body, 5, reinforcing plate, 6, pile hole, 7, micro steel pipe, 8, platform cap, 9, short reserved steel pipe, 91, steel bar, 10, sealing end cover. DETAILED DESCRIPTION

[0033] The present application will be further described below in conjunction with embodiments. The described embodiments are only some of the embodiments of the present application, and not all the embodiments. Based on the embodiments in the present application, other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0034] In the description of the present application, it should be noted that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as limiting the devices or elements indicated as having a particular orientation, being constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application; the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance; in addition, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0035] The grouting micro steel pipe pile can be assembled L-shaped retaining wall structure of the application, comprising an assembled bottom plate 1, an assembled vertical plate 2 and a cast-in-place buttress 3, wherein the assembled bottom plate 1 is formed with a boss 11 corresponding to the assembled vertical plate 2, the assembled bottom plate 1, the boss 11 and the assembled vertical plate 2 are all provided with a reserved hole 12, the assembled bottom plate 1 is provided with multiple rows of reserved holes 12, each row of reserved holes 12 comprises at least two 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 to say, the assembled bottom plate is provided with multiple rows of reserved holes, one row of reserved holes penetrates the boss 11 and is aligned with the reserved holes 12 on the assembled vertical plate 2), the reserved holes 12 on the boss 11 penetrate the bottom surface of the assembled bottom 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, 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 formed in 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, the lower embedded connecting piece 13 and the upper embedded connecting piece 21 are connected and embedded in the first cast body 4 cast in the later period; 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 to say, the first cast body 4 is used for casting the periphery of the upper vertical plate 211 exposed from the assembled vertical plate 2 and the lower vertical plate 131 exposed from the boss, and is used for connecting the assembled vertical plate 2 and the boss 11. Before casting the first cast body, the lower end surface of the assembled vertical plate and the upper end surface of the boss should be roughened to improve the connection fastening between the first cast body 4 and the assembled vertical plate 2 and the boss 11.

[0036] The grouting micro steel pipe pile can be assembled L-shaped retaining wall structure of the application, which integrates the grouting micro steel pipe pile and the buttress retaining wall (i.e. L-shaped retaining wall), uses the grouting micro steel pipe pile as the foundation of the L-shaped retaining wall, improves the foundation bearing capacity, makes the buttress retaining wall more widely used and solves the problem of insufficient foundation bearing capacity. The grouting micro steel pipe pile can also increase the anti-sliding and anti-overturning capacity of the buttress retaining wall, thereby improving the stability of the slope support. Meanwhile, the grouting operation of the grouting micro steel pipe pile can also improve the nature of the undisturbed soil of the slope and increase the shear strength of the slope, thereby reducing the earth 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 body. Those skilled in the art can understand and realize that the above is not described in detail. In the specific implementation process, the lower end of the micro steel pipe extends into the bearing layer by at least 0.5 m.

[0038] In some embodiments, the size of the reserved steel pipe 15 is smaller than the size of the reserved hole 12, and the reserved steel pipe 15 is connected with the prefabricated vertical plate 2, the boss 11, and the reserved hole 12 of the prefabricated bottom plate 1 through the protection layer 14 formed after pouring. The protection layer 14 is used for corrosion protection of the reserved steel pipe 15, and at the same time, the prefabricated vertical plate, the boss, and the prefabricated bottom plate are connected to form an integral 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 outer 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 and the size of the pile hole 6 are matched with each other, so that the reserved steel pipe 15 after pouring can form a pouring protection layer 14 in the prefabricated bottom plate 1, the boss 11, and the prefabricated vertical plate 2. The pouring protection layer 14 is used for protection of the reserved steel pipe, and at the same time, the prefabricated bottom plate, the boss, and the prefabricated vertical plate are connected with each other.

[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 with each other through welding or a screw rod, the lower end of the lower reserved steel pipe 152 is connected with 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 position of the upper reserved steel pipe 151 and the lower reserved steel pipe 152 is staggered with the connection position of the upper embedded connecting piece 21 and the lower embedded connecting piece 13; and the grouting holes of the reserved steel pipe 15 are distributed on the upper reserved steel pipe 151. That is, the lower reserved steel pipe 152 of the reserved steel pipe 15 does not have grouting holes.

[0041] In some embodiments, the lower reserved steel pipe 152 and the micro steel pipe 7 of the micro steel pipe pile form an integral 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 application is to facilitate the construction of the grouting micro steel pipe pile by segmenting the reserved steel pipe, and also facilitate the hoisting of the assembled floor and the assembled vertical plate. And due to the structural design of the lower segment reserved steel pipe, the micro steel pipe can improve the forming quality of the upper end of the micro steel pipe pile when the micro steel pipe is grouted to form a grouting micro steel pipe pile. Because the micro steel pipe pile is grouted, the top part of the micro steel pipe is soft due to the settlement of the grout, so it needs to be cut off for secondary grouting, which leads to a long construction period. The design of the lower segment reserved steel pipe can make the grouting grout float to the top of the lower segment reserved steel pipe, and the volume reduction and settlement during the grout solidification process occur at the top of the lower segment reserved pipe, so the micro steel pipe can be formed at one time, and the micro steel pipe pile (i.e. grouting micro steel pipe pile) with good forming quality can be obtained without secondary grouting, which improves the construction efficiency of the micro steel pipe pile. The removal operation of the settlement area (i.e. the area with soft texture) in the lower segment reserved steel pipe can be synchronized with other operations at the construction site, so the present application can shorten the construction time of the micro steel pipe pile as a whole, thereby improving the construction efficiency.

[0043] In some embodiments, the short reserved steel pipe 9 is arranged in the remaining reserved holes 12 on the assembled floor 1 except for the reserved holes 12 corresponding to the reserved holes 12 of the assembled vertical plate 2, the lower end of the short reserved steel pipe 9 is connected with the micro steel pipe 7 of the micro steel pipe pile, and the upper end of the short reserved steel pipe 9 extends out of the upper end surface of the assembled floor 1; a plurality of steel bars 91 serving as the framework of the cap 8 of the micro steel pipe pile are connected in the circumferential direction of the area of the short reserved steel pipe 9 extending out of the assembled floor 1. That is, the framework of the cap 8 is composed of the short reserved steel pipe 9 and the steel bars 91 connected to the short reserved steel pipe 9, and then the concrete is poured around the short reserved steel pipe 9 and the steel bars 91 to form the cap 8. The present application uses the short reserved steel pipe and the steel bars connected thereto as the cap of the micro steel pipe pile, and since the short reserved steel pipe and the steel pipe of the micro steel pipe pile are connected to form a whole, the connection strength of the assembled floor and the micro steel pipe pile (grouting micro steel pipe pile) can be improved.

[0044] In the specific implementation process, the number of reserved holes 12 on the assembled floor 1 is more than the number of reserved holes 12 on the assembled vertical plate 2, and the reserved steel pipe 15 (the lower segment reserved steel pipe 152 in the reserved steel pipe 15) is arranged in the reserved holes 12 corresponding to the reserved holes of the assembled vertical plate 2 on the assembled floor 1, and the short reserved steel pipe 9 is arranged in the remaining reserved holes 12 (except for the reserved holes corresponding to the reserved holes of the assembled vertical plate) on the assembled floor 1.

[0045] The short reserved steel pipe has the same effect as the lower reserved steel pipe, and the quality of the micro steel pipe pile is improved, thereby shortening the construction time of the micro steel pipe pile and improving the construction efficiency. After the micro steel pipe pile is poured, the settlement area (i.e., the area with soft texture) in the short reserved steel pipe can be operated synchronously when the assembled vertical plate is hoisted. Since the time for removing the soft texture section and the time for secondary pouring of the micro steel pipe pile are removed, the construction efficiency of the grouting micro steel pipe pile is improved, and the construction period of the entire L-shaped retaining wall structure is shortened.

[0046] In the specific implementation process, the top of the pile hole is provided with a sealing end cover, so as to prevent the grout 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 grouted. The middle part of the sealing end cover is provided with a hole for the lower reserved steel pipe and the short reserved steel pipe to pass through. 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 piece 13 includes a lower vertical steel plate 131 embedded on both sides of the reserved hole 12 of the boss 11 and a lower horizontal steel plate 132 embedded in the assembled bottom plate 1, the lower end of the lower vertical steel plate 131 and the lower horizontal steel plate 132 are connected together to form an integral 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 piece 21 includes an upper horizontal steel plate 212 embedded in the assembled vertical plate 2 and an upper vertical steel plate 211 embedded on both sides of the reserved hole 12 of the assembled vertical plate 2, 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 pouring body 4 poured later. In the process of hoisting the assembled vertical plate 2, the assembled bottom plate 1 and the assembled vertical plate 2 are first connected and stabilized by using the connection between the upper vertical steel plate 211 and the lower vertical steel plate 131, and then the first pouring body 4 is poured.

[0048] In the specific implementation process, in order to ensure the normal implantation of the reserved steel pipe, through holes are formed in the upper horizontal steel plate and the lower horizontal steel plate corresponding to the positions of the reserved steel pipe. The upper vertical steel plate of the upper embedded connecting piece and the lower vertical steel plate on the boss are connected by a screw rod and a nut.

[0049] In the specific implementation process, the upper vertical steel plate 211 is symmetrically embedded in the prefabricated vertical plate on both sides of the reserved hole of the prefabricated vertical plate, and the lower vertical steel plate 131 is symmetrically embedded in the reserved hole on both sides 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 in parallel with each other, thereby improving the connection stability of the prefabricated vertical plate and the boss on the prefabricated bottom plate, that is, only the connection of the upper vertical steel plate and the lower vertical steel plate can ensure the connection stability between the prefabricated bottom plate and the prefabricated vertical plate.

[0050] Among them, in the prefabrication process, the reinforcement framework (or referred to as the embedded steel) corresponding to the surrounding of the reserved hole, corresponding to the surrounding of the vertical plate and the horizontal steel plate on the prefabricated vertical plate and the prefabricated bottom plate is encrypted, thereby improving the strength of the prefabricated vertical plate and the prefabricated bottom plate, and preventing cracks from appearing around the reserved hole, the horizontal steel plate, and the vertical steel plate due to excessive stress.

[0051] In some embodiments, the prefabricated bottom plate 1 and the prefabricated vertical plate 2 have a reinforcing plate 5 cast on the side facing the soil body, and the protective layer 14 of the reserved steel pipe 15 is synchronously cast with the reinforcing plate 5, the first cast body 4, and the buttress 3 to form; the upper vertical steel plate 211 and the lower vertical steel plate 131 are connected with connecting steel bars corresponding to the positions of the reinforcing plate 5 and the buttress 3, and the connecting steel bars are connected with the framework in the reinforcing plate 5 and the framework of the buttress 3. Among them, the first cast body 4 serves as a connection between the boss 11 of the prefabricated bottom plate 1 and the prefabricated vertical plate 2, and simultaneously as a connecting medium between the reinforcing plate 5 and the buttress 3, thereby making the prefabricated bottom plate 1 (including the boss 11), the prefabricated vertical plate 2, the buttress 3, and the reinforcing plate 5 form an organic whole.

[0052] Meanwhile, the framework of the reinforcing plate and the framework of the buttress are connected by connecting steel bars, so that when the assembled vertical plate and the reinforcing plate bear the soil pressure, the soil pressure can be dispersed to the entire L-shaped retaining wall structure, and the problem of cracks and failure of the assembled vertical plate due to excessive local pressure does not occur. However, the buttress retaining wall in the prior art often has the problem of cracks and failure due to excessive local pressure. The main reason is that when the soil pressure is transmitted to the vertical plate, it is only dispersed by the structural strength of the vertical plate itself. In the present application, when the assembled vertical plate bears the soil pressure, the assembled vertical plate is used to transmit the soil pressure directly, and the first pouring body, the reinforcing plate and the embedded steel pipe can also disperse the action particles, so as to transmit the soil pressure to the buttress, the assembled bottom plate and the grouting micro steel pipe pile, thereby improving the supporting force of the slope soil. In the prior art, there is also an anchor rod structure on the bottom plate of the buttress retaining wall, but since the anchor rod is only connected with the bottom plate, the vertical plate (the assembled vertical plate in the present application) cannot directly transmit the force to the anchor rod, and still needs the transmission of the bottom plate, thereby causing the problem of excessive force at the connection between the bottom plate and the vertical plate.

[0053] The buttress retaining wall (also commonly known as L-shaped retaining wall) in the prior art has two construction methods, the first of which is site pouring, which has the problem of long construction period and is not suitable for some scenes. The second is an assembled structure, and the connection between the bottom plate, the vertical plate and the buttress of the existing assembled buttress retaining wall generally uses connecting pieces (or connecting pieces connected and then pouring the area of the connecting pieces). This structure makes the connection strength between the bottom plate, the vertical plate and the buttress mainly rely on the structural strength of the connecting pieces (and the pouring body or the insertion part formed by pouring around the connecting pieces to realize the connection). However, due to the fatigue of the connecting pieces and the large change of the soil pressure, the design strength of the connecting pieces is exceeded, which causes fatigue damage of the connecting pieces and failure of the entire buttress retaining wall. In addition, the connecting pieces on the prefabricated assembled vertical plate, assembled bottom plate and assembled buttress also have the problem that the strength of the connecting pieces does not reach the design strength due to uncertain factors in the manufacturing process, which accelerates the failure of the buttress retaining wall.

[0054] But the present application also utilizes the upper pre-embedded connecting piece and the lower pre-embedded piece to realize the connection between the assembled vertical plate and the assembled bottom plate (including the boss); but because the upper pre-embedded connecting piece and the lower pre-embedded piece are arranged along the length direction of the assembled vertical plate, and the first pouring body, the reinforcing plate and the buttress are poured together, the assembled vertical plate, the assembled bottom plate and the buttress form an organic whole by the pouring body (i.e. the first pouring body, the reinforcing plate and the buttress) poured on site, in addition to the connection between the upper pre-embedded connecting piece and the lower pre-embedded piece. When transmitting the pressure of the slope soil body, it is no longer only relying on the upper pre-embedded connecting piece and the lower pre-embedded piece to transmit, but through the whole structure to transmit, thereby reducing the stress at the connecting piece (the upper pre-embedded connecting piece and the lower pre-embedded piece) to prevent the problem of failure of the buttress retaining wall caused by the failure of the connecting piece.

[0055] Meanwhile, the assembled bottom plate and the boss can provide a good construction environment. On the one hand, the present application can provide a good construction environment for the pouring of the reinforcing plate, the first pouring body and the buttress; on the other hand, compared with the whole on-site pouring method in the prior art, the pouring amount of the reinforcing plate, the first pouring body and the buttress of the present application is greatly reduced. Therefore, the present application can be applied to a wider range of sites. It not only solves the problem of long construction period and limited site for pouring caused by whole pouring, but also solves the problem of low overall strength of the existing assembled buttress retaining wall and easy failure of the support after long-term use.

[0056] The grouting micro steel pipe pile assembled L-shaped retaining wall structure of the present application utilizes the pouring body (the first pouring body, the reinforcing plate and the buttress) to make the assembled bottom plate, the assembled vertical plate and the buttress form an organic whole, and can also utilize the reinforcing effect of the reserved steel pipe to improve the connection strength between the assembled vertical plate and the assembled bottom plate; at the same time, the lower end of the reserved steel pipe is inserted into the pile hole and connected with the micro steel pipe of the micro steel pipe pile, so that when the assembled vertical plate bears the lateral pressure of the soil body, part of the acting force can be directly transmitted to the grouting micro steel pipe pile in the soil body by the reserved steel pipe, thereby improving the anti-overturning and anti-sliding purposes. When transmitting the acting force by the reserved steel pipe, the acting force at the connection between the assembled bottom plate and the assembled vertical plate is also reduced, thereby reducing the risk of damage at the connection between the assembled vertical plate and the assembled bottom plate.

[0057] That is, the reserved steel pipe of the present application not only can improve the connection strength between the assembled vertical plate and the assembled bottom plate, but also can disperse the acting force at the connection (the upper pre-embedded connecting piece, the lower pre-embedded connecting piece and the first pouring body) between the assembled vertical plate and the assembled bottom plate, thereby reducing 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 lateral bending resistance of the assembled vertical plate. Finally, the slope support capacity is improved.

[0058] In some embodiments, at least a part of the plurality of reserved holes 12 on the prefabricated vertical plate 2 correspond to the positions of the later-poured buttress 3, the reserved steel pipe 15 is connected with connecting steel bars at positions corresponding to the reinforcing plate 5 and the buttress 3, and the connecting steel bars are connected with the framework in the reinforcing plate 5 and the framework of the buttress 3. In the specific implementation process, since the reinforcing plate 5 is arranged along the length direction of the prefabricated vertical plate 2, no matter how the reserved hole 12 of the prefabricated vertical plate 2 is designed, the reserved steel pipe 15 in the prefabricated vertical plate 2 will correspond to the position of the reinforcing plate 5. Among them, at least a part of the reserved holes 12 on the prefabricated vertical plate 2 correspond to the positions of the buttress 3, so as to improve the supporting force of the prefabricated vertical plate 2 by the combined action of the buttress 3 and the reserved steel pipe 15, and further improve the ability of the prefabricated vertical plate to withstand the lateral pressure of the soil body.

[0059] In some embodiments, the prefabricated bottom plate 1 and the prefabricated vertical plate 2 are pre-buried with pre-buried steel bars at positions corresponding to the buttress 3, the pre-buried steel bars extend out of the prefabricated bottom plate 1 or the prefabricated vertical plate 2, and the framework of the prefabricated bottom plate 1 and the prefabricated vertical plate 2 is connected with the framework of the buttress 3; the prefabricated bottom plate 1 and the prefabricated vertical plate 2 are pre-buried with pre-buried steel bars at positions corresponding to the reinforcing plate 5, and the pre-buried steel bars extend out of the prefabricated bottom plate or the prefabricated vertical plate and are connected with the framework of the reinforcing plate. That is, in addition to the connection of the reinforcing plate, the buttress, the upper pre-buried connecting piece, the lower pre-buried connecting piece and the connecting steel bars on the reserved steel pipe, the prefabricated bottom plate and the prefabricated vertical plate are also connected with the pre-buried steel bars in the structure of the prefabricated bottom plate and the prefabricated vertical plate, so as to connect the framework of the reinforcing plate and the buttress by using the pre-buried steel bars, and further improve the connection strength of the prefabricated bottom plate, the prefabricated vertical plate, the first pouring body, the reinforcing plate and the buttress.

[0060] The construction method of the L-shaped retaining wall structure of the present application will be introduced below. The construction method of the grouting micro steel pipe pile of the prefabricated L-shaped retaining wall structure of the present application comprises:

[0061] (1) Site leveling and measurement and setting out; the purpose of measurement and setting out is to determine the position of the pile hole of the grouting micro steel pipe pile and the placement position of the prefabricated bottom plate.

[0062] (2) Construction of the grouting micro steel pipe pile; the construction of the grouting micro steel pipe pile comprises drilling positioning according to the position of the pile hole determined in step (1), drilling by a drilling machine, implanting a micro steel pipe, filling gravel into the micro steel pipe, and grouting.

[0063] Specifically, the micro steel pipe is generally made of a seamless steel pipe, and the diameter of the seamless steel pipe can be selected according to the standard parts of engineering design (which can be understood by those skilled in the art, and will not be described here), and the seamless steel pipe should be made into a flower pipe (flower hole, or also called shotcrete hole), the diameter of the flower hole is generally 5mm-10mm, arranged in a plum blossom shape or a rectangular shape, and the flower hole spacing is generally 300mm-600mm, so that the slurry can flow out of the flower pipe hole and inject into the surrounding rock-soil body. The size of the drilling machine hole should be larger than the outer diameter of the micro steel pipe by 10-60mm.

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

[0065] In the specific implementation process, the processes of filling gravel and grouting both belong to the prior art, which can be understood by those skilled in the art, and will not be described here.

[0066] It should be noted that when filling gravel and grouting, the gravel filling should at least exceed the top of the micro steel pipe and enter the lower section reserved steel pipe and the short reserved steel pipe, and the grouting should ensure that the slurry reaches the upper end of the lower section reserved steel pipe and the short reserved steel pipe.

[0067] In the specific implementation process, after grouting, the slurry liquid level will drop, forming a section with soft texture in the lower section reserved steel pipe and the short reserved steel pipe, which needs to be removed subsequently. Therefore, in order to facilitate removal, the gravel filling should exceed the micro steel pipe and does not need to fill the entire lower section reserved steel pipe and the short reserved steel pipe. That is, the gravel filling fills both the inside of the micro steel pipe and the area between the micro steel pipe and the pile hole, which can be understood by those skilled in the art. And not filling the entire lower section reserved steel pipe and the short reserved steel pipe (i.e. not filling the entire lower section reserved steel pipe and not filling the entire short reserved steel pipe) refers to the internal space of the lower section reserved steel pipe and the short reserved steel pipe.

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

[0069] In the construction process of the grouting micro steel pipe pile of the present application, the removal of the soft texture section (the removal of the soft texture section in the lower section reserved steel pipe and the short reserved steel pipe can be synchronized with subsequent other operations) and the secondary grouting are omitted, so that the construction time of the micro steel pipe pile can be greatly shortened under the premise of ensuring the forming quality of the micro steel pipe pile.

[0070] (3) Handling and lifting of the prefabricated bottom plate; the prefabricated bottom plate is lifted to the position determined in step (1), and the lower section of the reserved steel pipe and the short reserved steel pipe are passed through the corresponding reserved holes on the prefabricated bottom plate. During the handling of the prefabricated bottom plate, the soft section in the lower section of the reserved steel pipe can be removed. Although the prefabricated bottom plate is generally handled to the construction site in advance, due to site leveling, measurement and laying of lines, and construction of the micro steel pipe pile, the prefabricated bottom plate cannot be directly lifted to the designed position, so it generally needs to be handled twice. Therefore, the soft section formed after grouting in the lower section of the reserved steel pipe can be removed without affecting the handling and lifting of the prefabricated bottom plate.

[0071] (4) Construction of the cap of the grouting micro steel pipe pile and the prefabricated bottom plate; the specific construction of the cap of the grouting micro steel pipe pile and the prefabricated bottom plate includes: connecting steel bars on the short reserved steel pipe extending out of the upper end surface of the prefabricated bottom plate, thereby forming a framework of the cap with the short reserved steel pipe and the steel bars, then supporting the formwork to pour and form the cap, and connecting and fastening the micro steel pipe pile (grouting micro steel pipe pile) and the prefabricated bottom plate with the cap.

[0072] Before connecting the steel bars on the short reserved steel pipe, the soft section formed by pouring in the short reserved steel pipe should be removed.

[0073] Lifting and connecting of the prefabricated vertical plate, and construction of the cap of the grouting micro steel pipe pile and the prefabricated bottom plate; the prefabricated vertical plate is lifted, and the upper embedded connecting piece on the prefabricated vertical plate and the lower embedded connecting piece on the boss of the prefabricated bottom plate are connected to each other, thereby connecting the prefabricated vertical plate to the prefabricated bottom plate. In the specific implementation process, after the prefabricated vertical plate and the prefabricated bottom plate are connected and fastened to each other, in order to ensure the safety of the construction, the crane should protect the prefabricated vertical plate, or other supporting methods (such as steel frame, etc.) are used to support and protect the prefabricated vertical plate. However, whether the crane or other supporting methods (such as steel frame, etc.) are used, the position of the prefabricated vertical plate should be ensured to be at the position required by the design.

[0074] In some embodiments, the prefabricated vertical plate, like the prefabricated bottom plate, generally arrives at the site in advance, and the soft section formed by pouring in the short reserved steel pipe can be removed during the second lifting of the prefabricated vertical plate. Therefore, in the actual operation process, step (4) and step (5) can partially overlap. That is, when the cap is constructed, the prefabricated vertical plate is also lifted.

[0075] (6) Bundling of the upper pre-embedded connecting piece, the lower pre-embedded connecting piece, and the reserved steel pipe upper connecting connecting steel bars, and the framework of the buttress and the reinforcing plate. In the specific implementation process, the upper pre-embedded connecting piece, the lower pre-embedded connecting piece, the reserved steel pipe, and the connecting steel bars can be used as the framework in the first pouring body, or more steel bars can be bundled as the framework according to the actual situation to improve the strength of the first pouring body.

[0076] (7) Formwork supporting, pouring, and formwork dismantling of the reinforcing plate, the first pouring body, and the buttress, so that the grouting micro steel pipe pile, the fabricated bottom plate, the reinforcing plate, and the buttress form an integral whole, and the construction of the grouting micro steel pipe pile can be completed. The fabricated L-shaped retaining wall structure.

[0077] In the specific implementation process, when pouring the reinforcing plate, the buttress, and the first pouring body, the reserved holes of the fabricated vertical plate and the boss are poured synchronously, so that the reserved steel pipe is poured synchronously to form a protective layer.

Claims

1. A cast-in-place micro steel pipe pile assemblable L-type retaining wall structure, characterized in that, The application relates to a prefabricated bottom plate (1), a prefabricated vertical plate (2) and a site-poured buttress (3), wherein the prefabricated bottom plate (1) is provided with a convex platform (11) corresponding to the prefabricated vertical plate (2), the prefabricated bottom plate (1), the convex platform (11) and the prefabricated vertical plate (2) are all provided with reserved holes (12), the prefabricated bottom plate (1) is provided with multiple rows of reserved holes (12), each row of reserved holes (12) comprises at least two reserved holes, one row of reserved holes in the multiple rows of reserved holes (12) corresponds to the position of the prefabricated vertical plate (2) so that the reserved holes (12) on the convex platform (11) can be aligned with the reserved holes (12) on the prefabricated vertical plate (2), the reserved holes (12) on the convex platform (11) penetrate the bottom surface of the prefabricated bottom plate (1), the reserved holes of the prefabricated vertical plate (2) penetrate the whole prefabricated vertical plate (2), a reserved steel pipe (15) is inserted into the reserved holes of the prefabricated vertical plate (2), the lower end of the reserved steel pipe (15) is connected to a micro steel pipe (7) of a micro steel pipe pile in a pile hole (6), a plurality of grouting holes are formed in the reserved steel pipe (15), a lower embedded connecting piece (13) is embedded in the convex platform (11), an upper embedded connecting piece (21) is embedded in the prefabricated vertical plate (2), the lower embedded connecting piece (13) and the upper embedded connecting piece (21) are connected and embedded in a first pouring body (4) poured 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, 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 prefabricated vertical plate (2), the convex platform (11) and the reserved hole (12) of the prefabricated bottom plate (1) through 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 section reserved steel pipe (151) and a lower section reserved steel pipe (152), the lower section reserved steel pipe (152) and the upper section reserved steel pipe (151) are connected to each other through welding or a screw rod, the lower end of the lower section 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 section reserved steel pipe (152) is higher than the upper end surface of the convex platform (11); the connection position of the upper section reserved steel pipe (151) and the lower section reserved steel pipe (152) is staggered with the connection position of the upper embedded connecting piece (21) and the lower embedded connecting piece (13); and the grouting holes of the reserved steel pipe (15) are distributed on the upper section reserved steel pipe (151).

4. The grouting micro steel pipe pile assemblable L-shaped retaining wall structure according to claim 3, characterized in that, Short reserved steel pipes (9) are arranged in the remaining reserved holes (12) of the prefabricated bottom plate (1) except for the reserved holes (12) corresponding to the prefabricated vertical plate (2), the lower end of the short reserved steel pipe (9) is connected to the micro steel pipe (7) of the micro steel pipe pile, and the upper end of the short reserved steel pipe (9) extends out of the upper end surface of the prefabricated bottom plate (1); a plurality of steel bars (91) serving as the framework of the cap (8) of the micro steel pipe pile are connected in the circumferential direction of the area of the short reserved steel pipe (9) extending out of the prefabricated bottom plate (1). 5.The grouting micro steel pipe pile assembled L-shaped retaining wall structure according to claim 1, 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 assemblable L-shaped retaining wall structure according to claim 1, 2, 4 or 5, characterized in that, The lower embedded connecting piece (13) comprises a lower vertical steel plate (131) embedded on both sides of the reserved hole of the boss and a lower horizontal steel plate (132) embedded in the fabricated bottom plate (1), the lower end of the lower vertical steel plate (131) and the lower horizontal steel plate (132) are connected together to form an integral 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 piece (21) comprises an upper horizontal steel plate (212) embedded in the fabricated vertical plate (2) and an upper vertical steel plate (211) embedded on both sides of the reserved hole (12) of the fabricated vertical plate, the upper end of the upper vertical steel plate (211) is connected with the upper horizontal steel plate (212), and the lower end of the upper vertical steel plate (211) extends out of the fabricated vertical plate (2) and is connected with the lower vertical steel plate (131) and embedded in the first pouring body (4) poured later. 7.The grouting micro steel pipe pile assembled L-shaped retaining wall structure according to claim 6, characterized in that, The fabricated bottom plate (1) and the fabricated vertical plate (2) are poured with a reinforcing plate (5) on the side facing the soil body, the protective layer (14) of the reserved steel pipe (15) is poured synchronously with the reinforcing plate (5), the first pouring body (4) and the buttress (3) to form; the upper vertical steel plate (211) and the lower vertical steel plate (131) are connected with connecting steel bars at positions corresponding to the reinforcing plate (5) and the buttress (3), and the connecting steel bars are connected with the framework in the reinforcing plate (5) and the framework of the buttress (3). 8.The grouting micro steel pipe pile assembled L-shaped retaining wall structure according to claim 7, characterized in that, At least part of the reserved holes (12) in the plurality of reserved holes in the fabricated vertical plate (2) correspond to the positions of the buttress (3) poured later, the reserved steel pipe (15) is connected with connecting steel bars at positions corresponding to the reinforcing plate (5) and the buttress (3), and the connecting steel bars are connected with the framework in the reinforcing plate (5) and the framework of the buttress (3). 9.The grouting micro steel pipe pile assembled L-shaped retaining wall structure according to claim 1, characterized in that, The fabricated bottom plate (1) and the fabricated vertical plate (2) are embedded with embedded steel bars at positions corresponding to the buttress (3), the embedded steel bars extend out of the fabricated bottom plate or the embedded steel bars extend out of the framework of the fabricated vertical plate and the buttress and are connected with each other; the fabricated bottom plate (1) and the fabricated vertical plate (2) are embedded with embedded steel bars at positions corresponding to the reinforcing plate (5), the embedded steel bars extend out of the fabricated bottom plate or the embedded steel bars extend out of the framework of the fabricated vertical plate and the reinforcing plate (5) and are connected with each other.

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