A deep foundation pit advance support structure crossing a subway line and a construction method thereof

Abstract

A kind of deep foundation pit advance support structure crossing subway line and its construction method, including subway line area (1), it is characterized by: the deep foundation pit crossing construction area is just above the subway line area (1), one or more rows of concrete piles (4) are respectively arranged in left piling area (2) and right piling area (3), one or more rows of parallel distribution arc-shaped protective arches (6) crossing subway line area (1) are erected above between left concrete pile (4) and right concrete pile (4), two rows of support piles (13) are vertically fixed on arc-shaped protective arch (6) or arc surface connecting component (8), the present application has reasonable structure, uses deep foundation pit advance support structure, can carry out deep foundation pit advance support around the peripheral soil of subway line area, stress is uniform, the safety of subway line is guaranteed to the greatest extent, construction efficiency has been improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a deep foundation pit advance support structure and a construction method thereof, in particular to a deep foundation pit advance support structure and a construction method thereof for crossing a subway line, and belongs to the technical field of underground engineering. BACKGROUND

[0002] In recent years, with the development of cities, more and more cities build subways and underground comprehensive pipe galleries underground. Due to the crisscrossing of subways and underground comprehensive pipe galleries, it is inevitable to cross the built subway lines or subway lines under construction. Urban underground rail transit is also developing rapidly, and the number of subway lines under construction and operation is increasing, and the underground traffic network is gradually formed. It is very important to ensure the stability of the soil of the subway line and the safety of the subway line. More importantly, some subway lines cross rivers, lakes and other soft soil layers with high water content, and the structures such as subway tunnel segments located below are very sensitive to changes in soil stress. The construction difficulty of crossing the subway line is highlighted, which has become one of the important technical obstacles restricting the construction of new subway lines and underground comprehensive pipe galleries.

[0003] If the deep foundation pit crossing the subway line is constructed by using the traditional ordinary construction method, the stability of the soil of the subway line and the safety of the subway line cannot be guaranteed. Especially for the construction of deep foundation pit subway lines or underground comprehensive pipe galleries, the construction difficulty is multiplied. The traditional underground comprehensive pipe gallery structure has a great safety hazard. The supporting pile cannot be effectively fixed and supported in the part crossing the subway line below, and the bearing capacity of the part crossing the subway line below is limited. The traditional construction method is easy to cause damage to the soil stress structure of the subway line below. The construction difficulty of the deep foundation pit support crossing the subway line has not been solved for a long time, and there is a lack of a deep foundation pit support structure which is convenient to construct, has good safety, and can guarantee the safety and stability of the subway line to solve the above technical problems. SUMMARY

[0004] The first object of the present application is to solve the defects and deficiencies that the deep foundation pit crossing the subway line cannot guarantee the stability of the soil of the subway line and the safety of the subway line, the construction difficulty is large, and the traditional underground comprehensive pipe gallery structure has a great safety hazard, the supporting pile cannot be effectively fixed and supported in the part crossing the subway line below, and the safety performance is poor. The present application provides a deep foundation pit advance support structure which is reasonable in structure, can perform deep foundation pit advance support around the peripheral soil of the subway line area, is uniform in stress, maximizes the safety of the subway line, effectively solves the problem of fixed support of the supporting pile, and improves the construction efficiency.

[0005] The second object of the present application is to provide a deep foundation pit advanced support construction method for crossing a subway line, which is reasonable in process, simple in construction, ensures the safety of the subway line below, and solves the construction problem of deep foundation pit support for crossing the subway line, and improves the construction quality.

[0006] To achieve the first object, the technical solution of the present application is a deep foundation pit advanced support structure for crossing a subway line, comprising a subway line area, characterized in that: the area directly above the subway line area is a deep foundation pit crossing construction area, one side of the periphery of the subway line area is a left piling area, the other side of the periphery of the subway line area is a right piling area, one or more rows of concrete piles are arranged in the left piling area and the right piling area respectively, the concrete piles on the same side are arranged as an integral structure, and one or more rows of arc-shaped protective arches for crossing the subway line area are arranged above the concrete piles on the left side and the concrete piles on the right side, the adjacent arc-shaped protective arches are connected and fixed through arc surface connecting members, two rows of support piles are vertically fixed on the arc-shaped protective arches or the arc surface connecting members, and a continuous retaining wall is arranged between the support piles on the same side through concrete pouring.

[0007] Further, a plurality of arc-shaped steel frames are arranged on the periphery of the soil above the subway line area, a bottom formwork is arranged on the arc-shaped steel frame, and the span of the arranged arc-shaped steel frame is greater than the maximum width of the subway line area.

[0008] Further, an end anchoring seat is arranged on the outer side of the concrete pile, the end of the arc-shaped protective arch is fixed on the end anchoring seat, a tensioning hole is arranged in the end anchoring seat, and a tensioning anchoring seat is arranged at the outer end of the tensioning hole.

[0009] Further, a plurality of prestressed steel bars or prestressed steel cables are arranged in the arc-shaped protective arch, and the span of the arc-shaped protective arch is greater than the maximum width of the subway line area.

[0010] Further, the arc-shaped protective arch and the arc surface connecting member are longitudinally and transversely staggered to form a plurality of arc surface window holes with equal intervals, a support pile fixing seat is fixed on the arc surface window hole along the distribution direction of the two rows of parallel support piles, and a support pile is vertically fixed on the support pile fixing seat.

[0011] Further, the support pile fixing seat comprises an upper fixing frame, a lower fixing frame, a tensioning screw and a flange fixing seat, the upper fixing frame is located at the upper part of the arc-shaped protective arch and the arc surface connecting member, the lower fixing frame is located at the bottom of the arc-shaped protective arch and the arc surface connecting member, the upper fixing frame and the lower fixing frame are connected and fixed through the tensioning screw and the locking nut, the flange fixing seat is fixedly arranged on the upper fixing frame, and the support pile is vertically fixed on the flange fixing seat.

[0012] Further, the lower part or the middle part of the support pile is connected and fixed with the arc-shaped protective arch or the arc surface connecting member through the fixing inclined struts, the top ends of the support piles located on the same side are fixedly provided with the crown beams which are horizontally distributed, and the horizontal support rods are fixedly arranged between the two rows of parallel support piles.

[0013] Further, the upper surface circular arc surface of the arc-shaped protective arch is provided with a backfill area, and the upper surface of the backfill area is horizontal.

[0014] To achieve the above-mentioned second object, the technical solution of the present application is: a deep foundation pit advanced support construction method for crossing a subway line, characterized in that it comprises the following steps:

[0015] a. First, the outer contour of the subway line area is calibrated, and the specific position crossing the subway line area is determined;

[0016] b. Then, the left piling area is selected on one side of the outer periphery of the subway line area, and the right piling area is selected on the other side of the outer periphery of the subway line area;

[0017] c. Then, one or more rows of concrete piles are arranged in the left piling area and the right piling area respectively, and end anchoring seats are arranged outside the concrete piles;

[0018] d. Then, the arc-shaped protective arches crossing the subway line area are arranged on the concrete piles, and the adjacent arc-shaped protective arches are connected and fixed through the arc surface connecting members;

[0019] e. Then, a plurality of support pile fixing seats are fixedly arranged on the straight line along which the two rows of support piles are distributed in the arc surface window hole, the support piles are vertically fixed on the support pile fixing seats, and a continuous retaining wall is arranged between the support piles located on the same side through concrete pouring;

[0020] f. Finally, the backfill area is arranged on the upper surface circular arc surface of the arc-shaped protective arch, and the deep foundation pit advanced support construction operation is completed.

[0021] Further, the top ends of the support piles located on the same side in the step e or the step f are fixedly provided with the crown beams which are horizontally distributed, and the horizontal support rods are fixedly arranged between the two rows of parallel support piles.

[0022] The beneficial effects of the present application are:

[0023] 1、The present application adopts the arc-shaped protective arch as the protective main structure, and carries out the deep foundation pit advance support around the peripheral soil of the subway line area, so that the load of the structures, backfill soil and construction machines above the subway line area is shared to the piling area outside the bottom subway line area, and the safety of the subway line is ensured to the maximum extent.

[0024] 2、The present application forms a plurality of equidistant arc surface window holes by the longitudinal and transverse intersection of the arc-shaped protective arch and the arc surface connecting member, and different support piles with different span angles can be conveniently installed by selecting different arc surface window hole positions, and the support piles are fixed on the arc-shaped protective arch through the support pile fixing seat, so that the fixed support problem of the support piles is effectively solved.

[0025] 3、The present application has reasonable structure, fundamentally solves the construction difficulty of the deep foundation pit support crossing the subway line, avoids the destruction of the stress structure of the soil body under the subway line, avoids the adverse effects of the excitation force generated in the construction process on the subway line, and can cross the subway line at different angles according to the needs, and the construction efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is the end surface structure schematic diagram of the arc-shaped protective arch of the present application.

[0027] Figure 2 is the top view of the arc-shaped protective arch of the present application.

[0028] Figure 3 is the structure schematic diagram of the arc-shaped protective arch when the arc-shaped steel frame is installed.

[0029] Figure 4 is the end surface schematic diagram of the arc-shaped protective arch after the support pile is arranged.

[0030] Figure 5 is the structure schematic diagram of the arc-shaped protective arch after the support pile is arranged.

[0031] Figure 6 is the bottom fixed structure schematic diagram of the support pile of the present application.

[0032] Figure 7 is the structure schematic diagram of the continuous retaining wall of the present application.

[0033] Figure 8 is the structure schematic diagram of the support structure of the present application.

[0034] Fig. The subway line area 1, left piling area 2, right piling area 3, concrete pile 4, end anchorage 5, arc-shaped protective arch 6, prestressed steel bar 7, arc surface connecting member 8, arc surface window hole 9, arc-shaped steel frame 10, bottom formwork 11, support pile fixing seat 12, support pile 13, fixed diagonal brace 14, crown beam 15, continuous retaining wall 16, horizontal support rod 17, upper fixed frame 18, lower fixed frame 19, tensioning screw 20, flange fixing seat 21, backfill area 22. DETAILED DESCRIPTION

[0035] The application is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0036] Reference Figures 1 to 8 , a deep foundation pit advanced support structure crossing a subway line, comprising a subway line area 1, characterized in that: the underground deep foundation pit crossing construction area is directly above the subway line area 1, the left piling area 2 is on one side of the periphery of the subway line area 1, and the right piling area 3 is on the other side of the periphery of the subway line area 1, one or more rows of concrete piles 4 are arranged in the left piling area 2 and the right piling area 3 respectively, the concrete piles 4 on the same side are cast and arranged as a whole structure, one or more rows of arc-shaped protective arches 6 crossing the subway line area 1 are arranged above the concrete piles 4 on the left side and the concrete piles 4 on the right side, the adjacent arc-shaped protective arches 6 are connected and fixed through arc surface connecting members 8, two rows of support piles 13 are vertically fixed on the arc-shaped protective arches 6 or the arc surface connecting members 8, and continuous retaining walls 16 are arranged between the support piles 13 on the same side through concrete casting.

[0037] A plurality of arc-shaped steel frames 10 are arranged on the soil on the periphery above the subway line area 1, the bottom formwork 11 is installed on the arc-shaped steel frame 10, and the span of the arranged arc-shaped steel frame 10 is greater than the maximum width of the subway line area 1.

[0038] End anchorage seats 5 are arranged on the outer sides of the concrete piles 4, the ends of the arc-shaped protective arches 6 are fixed on the end anchorage seats 5, the inside of the end anchorage seat 5 is provided with a tensioning hole, and the outer end of the tensioning hole is provided with a tensioning anchorage seat.

[0039] A plurality of prestressed steel bars 7 or prestressed steel cables are arranged in the arc-shaped protective arch 6, and the span of the arc-shaped protective arch 6 is greater than the maximum width of the subway line area 1.

[0040] The arc-shaped protective arch 6 and the arc surface connecting member 8 are longitudinally and transversely staggered to form a plurality of arc surface window holes 9 with equal intervals, the support pile fixing seats 12 are fixed along the distribution direction of the two rows of mutually parallel support piles 13 on the arc surface window holes 9, and the support piles 13 are vertically fixed on the support pile fixing seats 12.

[0041] The support pile fixing seat 12 comprises an upper fixing frame 18, a lower fixing frame 19, a tensioning screw 20 and a flange fixing seat 21, the upper fixing frame 18 is located at the upper part of the arc-shaped protective arch 6 and the cambered connecting member 8, the lower fixing frame 19 is located at the bottom of the arc-shaped protective arch 6 and the cambered connecting member 8, the upper fixing frame 18 and the lower fixing frame 19 are connected and fixed through the tensioning screw 20 and the locking nut, the flange fixing seat 21 is fixedly arranged on the upper fixing frame 18, and the support pile 13 is vertically fixed on the flange fixing seat 21.

[0042] The lower part or the middle part of the support pile 13 is connected and fixed with the arc-shaped protective arch 6 or the cambered connecting member 8 through the fixed inclined support 14, the top ends of the support piles 13 located on the same side are fixedly provided with the crown beams 15 which are horizontally distributed, and the horizontal support rods 17 are fixedly arranged between the two rows of parallel support piles 13.

[0043] The upper surface of the arc-shaped protective arch 6 is provided with a backfill area 22, and the upper surface of the backfill area 22 is horizontal.

[0044] A deep foundation pit advance support construction method for crossing a subway line, characterized by comprising the following steps:

[0045] a. First, the outer contour of the subway line area 1 is calibrated, and the specific position crossing the subway line area 1 is determined;

[0046] b. Then, the left piling area 2 is selected on one side of the outer periphery of the subway line area 1, and the right piling area 3 is selected on the other side of the outer periphery of the subway line area 1;

[0047] c. Then, one or more rows of concrete piles 4 are arranged in the left piling area 2 and the right piling area 3 respectively, and end anchoring seats 5 are arranged outside the concrete piles 4;

[0048] d. Then, the arc-shaped protective arch 6 crossing the subway line area 1 is arranged on the concrete piles 4, and the adjacent arc-shaped protective arches 6 are connected and fixed through the cambered connecting members 8;

[0049] e. Then, a plurality of support pile fixing seats 12 are fixedly arranged on the straight line along which the two rows of support piles 13 are distributed in the cambered window hole 9, the support piles 13 are vertically fixed on the support pile fixing seats 12, and the continuous retaining walls 16 are arranged between the support piles 13 located on the same side through concrete pouring;

[0050] f. Finally, the backfill area 22 is arranged on the upper surface of the arc-shaped protective arch 6, and the deep foundation pit advance support construction operation is completed.

[0051] The top end of the support pile 13 on the same side in the step e or step f is fixedly provided with a crown beam 15 in horizontal distribution, and a horizontal support rod 17 is fixedly arranged between the two rows of parallel support piles 13.

[0052] Referring to Figure 1 The present application is directed to the advanced support of deep foundation pit across the built subway line or the subway line under construction, which can maximize the absolute safety of the subway line area 1 and avoid the adverse effects on the subway line caused by the construction of underground comprehensive pipe gallery directly above the subway line area 1. The present application adopts an arc-shaped protective arch as the main protective structure, which is equivalent to erecting a protective arch around the peripheral soil of the subway line area 1. The weight of backfilling, support structure and structure in the area above the subway line area 1 will not directly act on the subway line area 1. The specific structure is as follows:

[0053] The area directly above the subway line area 1 is a deep foundation pit crossing construction area, one side of the peripheral subway line area 1 is a left piling area 2, and the other side of the peripheral subway line area 1 is a right piling area 3. The left piling area 2 and the right piling area 3 are located outside the subway line protection area and are symmetrically arranged. One or more rows of concrete piles 4 are arranged in the left piling area 2 and the right piling area 3 respectively. The concrete piles 4 are cast-in-place piles or concrete mixing piles. The concrete piles 4 on the same side are cast as a whole structure, which serves as the support foundation for the arc-shaped protective arch structure and the load bearing weight above.

[0054] One or more rows of arc-shaped protective arches 6 are erected between the left concrete piles 4 and the right concrete piles 4. The arc-shaped protective arch 6 spans the subway line area 1, and the span of the arc-shaped protective arch 6 is greater than the maximum width of the subway line area 1. The adjacent arc-shaped protective arches 6 are connected and fixed by arc surface connecting members 8. The multiple arc-shaped protective arches 6 can also be cast as a whole structure to avoid the adverse effects of the excitation force generated during construction on the subway line. The outer side of the concrete pile 4 is provided with an end anchoring seat 5, and the end of the arc-shaped protective arch 6 is fixed on the end anchoring seat 5. The inside of the end anchoring seat 5 is provided with a tensioning hole, and the outer end of the tensioning hole is provided with a tensioning anchoring seat. The arc-shaped protective arch 6 is provided with a plurality of prestressed steel bars 7 or prestressed steel cables. The prestressed steel bars 7 or prestressed steel cables are fixed on the end anchoring seat 5 after prestressed tensioning.

[0055] In order to facilitate the fixing of the support pile 13 on the arc-shaped protective arch 6, the arc-shaped protective arch 6 and the cambered surface connecting member 8 are longitudinally and transversely staggered to form a plurality of equidistant cambered surface window holes 9, which are longitudinally and transversely distributed along the cambered surface. The cambered surface window hole 9 is fixedly provided with a support pile fixing seat 12 along the distribution direction of the two rows of parallel support piles 13, and the support pile fixing seat 12 comprises an upper fixing frame 18, a lower fixing frame 19, a tensioning screw 20 and a flange fixing seat 21. The upper fixing frame 18 is located at the upper part of the arc-shaped protective arch 6 and the cambered surface connecting member 8, and the lower fixing frame 19 is located at the bottom of the arc-shaped protective arch 6 and the cambered surface connecting member 8. The upper fixing frame 18 and the lower fixing frame 19 are connected and fixed by the tensioning screw 20 and the locking nut, and the flange fixing seat 21 is fixedly arranged on the upper fixing frame 18. The flange fixing seat 21 is vertically fixed with the support pile 13.

[0056] The crossing subway line area 1 can not only be vertically crossed, but also be crossed at a certain angle with the axis of the subway line. By selecting different hole positions of the cambered surface window hole 9, support piles 13 with different crossing angles can be conveniently installed. The support piles 13 are arranged in two rows in parallel, and a continuous retaining wall 16 is arranged between the support piles 13 on the same side by pouring concrete. The top end of the support piles 13 on the same side is fixedly provided with a crown beam 15 which is horizontally distributed. The two rows of parallel support piles 13 are fixedly provided with a horizontal support rod 17.

[0057] The specific steps of the deep foundation pit advanced support construction method for crossing the subway line of the present application are as follows: first, the outer contour of the subway line area 1 is calibrated, and the specific position of the crossing subway line area 1 is determined. Then, the left piling area 2 is selected on one side of the outer periphery of the subway line area 1, and the right piling area 3 is selected on the other side of the outer periphery of the subway line area 1. Then, one or more rows of concrete piles 4 are arranged in the left piling area 2 and the right piling area 3, respectively, and end anchoring seats 5 are arranged outside the concrete piles 4. Then, the arc-shaped protective arch 6 crossing the subway line area 1 is arranged on the concrete piles 4, and the adjacent arc-shaped protective arches 6 are connected and fixed by the cambered surface connecting member 8. Then, a plurality of support pile fixing seats 12 are fixedly arranged in the cambered surface window hole 9 along the straight line where the two rows of support piles 13 are distributed, and the support piles 13 are vertically fixed on the support pile fixing seat 12. Meanwhile, a continuous retaining wall 16 is arranged between the support piles 13 on the same side by pouring concrete. Finally, a backfill area 22 is arranged on the upper surface of the arc-shaped protective arch 6, and the deep foundation pit advanced support construction operation is completed.

[0058] The above further describes the present application in detail in connection with the specific embodiments, and should not be considered as limiting the specific embodiments of the present application. For those skilled in the art of the present application, various simple replacements, improvements and changes can be made without departing from the concept of the present application, and all the simple replacements, improvements and changes should be considered as falling within the protection scope of the present application.

Claims

1. A deep foundation pit pre-support structure spanning a subway line, including the subway line area (1), characterized in that: The area directly above the subway line area (1) is the underground deep foundation pit crossing construction area. The outer perimeter of one side of the subway line area (1) is the left piling area (2), and the outer perimeter of the other side of the subway line area (1) is the right piling area (3). One or more rows of concrete piles (4) are respectively set in the left piling area (2) and the right piling area (3). The concrete piles (4) on the same side are cast as an integral structure. One or more parallel arc-shaped protective arches (6) are erected above the concrete piles (4) on the left side and the concrete piles (4) on the right side, crossing the subway line area (1). Adjacent arc-shaped protective arches (6) are connected and fixed by arc-shaped connecting members (8). Two rows of support piles (13) are vertically fixed on the arc-shaped protective arches (6) or the arc-shaped connecting members (8). A continuous retaining wall (16) is set between the support piles (13) on the same side by concrete pouring. Multiple equally spaced arc-shaped window holes (9) are formed by the interlacing of the arc-shaped connecting member (8). Support pile fixing seats (12) are fixedly installed on the arc-shaped window holes (9) along the distribution direction of two rows of parallel support piles (13). Support piles (13) are vertically fixed on the support pile fixing seats (12). The support pile fixing seats (12) include an upper fixing frame (18), a lower fixing frame (19), a tie rod (20), and a flange fixing seat (21). The upper fixing frame (18) is located at the top of the arc-shaped protective arch (6) and the arc-shaped connecting member (8). The lower fixing frame (19) is located at the bottom of the arc-shaped protective arch (6) and the arc-shaped connecting member (8). The upper fixing frame (18) and the lower fixing frame (19) are connected and fixed by the tie rod (20) and the locking nut. A flange fixing seat (21) is fixedly installed on the upper fixing frame (18). Support piles (13) are vertically fixed on the flange fixing seat (21).

2. The pre-support structure for deep foundation pits crossing subway lines according to claim 1, characterized in that: Multiple spliced ​​and fixed arc-shaped steel frames (10) are erected on the soil outside the subway line area (1). The bottom template (11) is installed on the arc-shaped steel frames (10). The span of the erected arc-shaped steel frames (10) is greater than the maximum width of the subway line area (1).

3. The pre-support structure for deep foundation pits crossing subway lines according to claim 1, characterized in that: An end anchorage (5) is provided on the outside of the concrete pile (4), and the end of the arc-shaped protective arch (6) is fixed on the end anchorage (5). A tensioning hole is provided inside the end anchorage (5), and a tensioning anchorage is provided at the outer end of the tensioning hole.

4. The pre-support structure for deep foundation pits crossing subway lines according to claim 1, characterized in that: The arc-shaped protective arch (6) is equipped with multiple prestressed steel bars (7) or prestressed steel cables inside, and the span of the arc-shaped protective arch (6) is greater than the maximum width of the subway line area (1).

5. The pre-support structure for deep foundation pits crossing subway lines according to claim 1, characterized in that: The lower or middle part of the support pile (13) is connected and fixed to the arc-shaped protective arch (6) or the arc-shaped connecting member (8) by a fixed diagonal brace (14). The top of the support pile (13) on the same side is fixedly provided with a horizontally distributed crown beam (15). A horizontal support rod (17) is fixedly provided between the two rows of parallel support piles (13).

6. The pre-support structure for deep foundation pits crossing subway lines according to claim 3, characterized in that: The upper surface of the arc-shaped protective arch (6) is provided with a backfill area (22), and the upper surface of the backfill area (22) is set to be horizontal.

7. A construction method for a deep foundation pit pre-support structure crossing a subway line as described in claim 6, characterized in that... Includes the following steps: a. First, mark the outer outline of the subway line area (1) and determine the specific location that crosses the subway line area (1); b. Then select the left piling area (2) on one side of the subway line area (1) and the right piling area (3) on the other side of the subway line area (1). c. Subsequently, one or more rows of concrete piles (4) are set in the left pile driving area (2) and the right pile driving area (3), and end anchorages (5) are set on the outside of the concrete piles (4). d. Next, an arc-shaped protective arch (6) spanning the subway line area (1) is erected on the concrete pile (4), and adjacent arc-shaped protective arches (6) are connected and fixed by arc-shaped connecting components (8); e. Then, multiple support pile fixing seats (12) are fixedly installed in the arc window hole (9) along the straight line of the two rows of support piles (13). Support piles (13) are vertically fixed on the support pile fixing seats (12). At the same time, a continuous retaining wall (16) is set between the support piles (13) on the same side by concrete pouring. f. Finally, a backfill area (22) is set on the upper arc surface of the arc-shaped protective arch (6) to complete the deep foundation pit advanced support construction operation.

8. The construction method for a deep foundation pit pre-support structure crossing a subway line according to claim 7, characterized in that: In step e or step f, a horizontally distributed crown beam (15) is fixedly installed at the top of the support piles (13) located on the same side, and a horizontal support rod (17) is fixedly installed between the two rows of parallel support piles (13).

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