A suspended roadbed structure and construction method

Abstract

The application discloses a kind of overhanging roadbed structure and construction method, belong to high fill section deep soft soil roadbed engineering technical field.The roadbed structure includes pipe pile support structure, leveling layer, shear layer and pavement structure layer, the leveling layer and shear layer are both foam concrete pouring layer, the pipe pile contains one or more lengths, and can be spliced.The construction method includes that after pipe pile is implanted foundation, first rough leveling is carried out by pipe pile, then fine leveling is carried out by leveling layer, the leveling layer and shear layer are both poured and constructed by the working face of temporary platform, batten board construction and the formwork of rigid bar piece, the leveling layer, shear layer and reinforced layer are used to transmit structure dead load and live load to pile cap and pipe pile.The roadbed structure and construction method of the application do not need to cut pile, have excellent structure durability and are economical and practical.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high filling section deep soft soil subgrade engineering, in particular to a suspended subgrade structure and a construction method, which are suitable for highway subgrade construction. BACKGROUND

[0002] With the densification of the national road network, more and more road projects are on complex strata, and high filling section deep soft soil subgrade engineering is one of the most common types. For high filling section deep soft soil subgrade engineering, composite foundation method (cement mixing pile composite foundation, CFG pile composite foundation, and prefabricated pipe pile composite foundation, etc.) is often used for reinforcement. When the settlement requirement of this type of section is strict (such as the section belongs to the highway section or the road and bridge connection section), the method of combining composite foundation method with light embankment (foamed concrete subgrade structure) is further used. In the following, the high filling section deep soft soil subgrade engineering with strict settlement requirement is referred to as "S engineering".

[0003] Among the composite foundation methods, the prefabricated pipe pile composite foundation is favored by engineering technicians because of its convenient construction and deep soft soil reinforcement depth. Therefore, in the S engineering, the method of combining prefabricated pipe pile composite foundation with foamed concrete subgrade is often used. For example, the Chinese patent "Deep soft soil foundation treatment structure" (CN217352404U) disclosed on September 2, 2022 proposes a "reinforced concrete prefabricated pipe pile + reinforced concrete prefabricated pile cap + cushion + foamed concrete subgrade" combined foundation treatment structure, which replaces the traditional filled subgrade with foamed concrete subgrade to reduce the upper load, and then transfers most of the upper load to the stable stratum below the soft soil layer through "reinforced concrete prefabricated pipe pile + reinforced concrete prefabricated pile cap + cushion", thereby achieving the effect of strictly controlling the settlement. However, this method still has the following shortcomings:

[0004] (1) The structure requires the pile top elevation of the reinforced concrete prefabricated pipe pile to be uniform, but in actual construction, due to the undulation of the stratum itself, the embedded length of the reinforced concrete prefabricated pipe pile is difficult to control, and the pile top elevation after construction is uneven, which needs to be made to meet the design requirements by cutting the pile, which will inevitably damage the performance of the reinforced concrete prefabricated pipe pile itself.

[0005] (2) The foamed concrete subgrade has a small dry density (the dry density commonly used in subgrade engineering is 300kg / m -3 ~ 900kg / m -3 ), and only relies on the friction force generated by its own weight to contact with the composite foundation, so the connection between the upper and lower parts is poor. Factors such as rainwater accumulation can easily have a negative impact on the stability of the subgrade structure.

[0006] (3) In this structure, foamed concrete is poured from the top of the cushion to the bottom of the pavement base, which requires a large amount of foamed concrete and has relatively poor economy. SUMMARY

[0007] The technical problem to be solved by the present application is the problem existing in the prior art, and specifically, the present application starts from strengthening the integrity of the foam concrete roadbed structure and the prefabricated pipe pile, and proposes a suspended roadbed structure and a construction method, which can effectively solve the above technical problems and produce relatively large economic benefits.

[0008] The purpose of the present application is achieved, and the present application provides a suspended roadbed structure, which comprises, from bottom to top, a pipe pile support structure, a leveling layer, a shear layer and a pavement structure layer, the leveling layer and the shear layer are both foam concrete pouring layers, a plurality of reinforcing layers parallel to the shear layer are uniformly arranged in the shear layer, and the foam concrete pouring layer is poured in a block and layer manner, and expansion joints are left between adjacent blocks.

[0009] The pipe pile support structure is composed of a plurality of uniformly distributed pipe piles, a pile cap is welded at the top of each pipe pile, one end of the pipe pile is vertically inserted into the bearing layer below the ground, and the other end is vertically suspended above the ground, and the elevation of the pipe pile meets the following design requirements: when the pipe pile is inserted into the bearing layer, the top end surface of the pile cap is located in the leveling layer.

[0010] Preferably, a protective layer is formed on the side surface of the leveling layer, on the side surface of the shear layer and on the lower plane of the leveling layer by spraying cement mortar.

[0011] Preferably, the reinforcing material of the reinforcing layer is a geosynthetic material or a steel mesh.

[0012] Preferably, the spacing of the pipe piles, the cross-sectional area of the pile cap, the thickness of the leveling layer, the thickness of the shear layer, the bulk density of the foam concrete, the compressive strength of the foam concrete, the tensile strength of the foam concrete and the shear strength of the foam concrete should meet the requirement that the leveling layer and the shear layer do not fail under normal working conditions of the roadbed.

[0013] Preferably, the failure of the leveling layer and the shear layer refers to the maximum compressive stress in the leveling layer and the shear layer in the three-dimensional finite element numerical simulation results of a suspended roadbed structure being less than the compressive strength of the foam concrete, the maximum tensile stress being less than the tensile strength of the foam concrete, and the maximum shear stress being less than the shear strength of the foam concrete.

[0014] Preferably, the pipe pile comprises a reinforced pipe pile and a main pipe pile, the lengths h0 of the two types of pipe piles are the same and meet the following requirements: when the pipe pile is inserted into the bearing layer, the calculated elevation of the pile top elevation plus the pile cap thickness value is located between the upper plane of the leveling layer and a lowest reference surface; the lowest reference surface is lower than the lower plane of the leveling layer, the vertical distance between the lowest reference surface and the lower plane of the leveling layer is h2, the thickness of the leveling layer is h1, h2+h1

[0015] When the pipe pile is inserted into the bearing stratum, the pile top elevation plus the pile cap thickness value of the calculated elevation is located in the leveling layer, the reinforced pipe pile is taken as the pipe pile of the N columns on both sides of the pipe pile support structure, and the main pipe pile is taken as the pipe pile of the pipe pile support structure other than the N columns on both sides;

[0016] When the pipe pile is inserted into the bearing stratum, the pile top elevation plus the pile cap thickness value of the calculated elevation is located between the lower plane lower than the leveling layer and the lowest reference surface, splicing is performed, and specifically: if the pipe pile is the pipe pile of the N columns on both sides of the pipe pile support structure, the pipe pile is composed of the reinforced pipe pile and M reinforced joint pipe piles welded on the top of the reinforced pipe pile; if the pipe pile is the pipe pile of the pipe pile support structure other than the N columns on both sides, the pipe pile is composed of the main pipe pile and M main joint pipe piles welded on the top of the main pipe pile; the length h3 of the reinforced joint pipe pile and the main joint pipe pile is h1.

[0017] Preferably, the reinforced pipe pile, the main pipe pile, the reinforced joint pipe pile, the main joint pipe pile and the pile cap are all reinforced concrete structures and are produced by a prefabrication process, wherein pre-buried welding points are arranged on the pile cap located on the outermost pipe pile of the pipe pile support structure and on the pile cap located on the pipe pile on the block pouring boundary line.

[0018] The cross-sectional area of the reinforced pipe pile is greater than that of the main pipe pile.

[0019] The application also provides a construction method of the suspended roadbed structure, and the construction method comprises the following steps:

[0020] Step 7.1, determining the pipe pile layout range boundary line

[0021] The pipe pile layout range boundary line is determined according to the road center line and the leveling layer width, and specifically: the center line of the road is taken as the center to offset by one-half of the leveling layer width on both sides, and then projected to the ground, and the projection range is the pipe pile layout range boundary line;

[0022] Step 7.2, determining the pipe pile layout position

[0023] The pipe pile layout position is determined according to the pipe pile layout range, the pipe pile spacing and the pipe pile layout form, and is marked on site by measuring and laying out, wherein the projection on the outermost pre-buried welding point horizontal plane of the pile cap farthest from the road center line is located on the outside of the pipe pile layout range boundary line;

[0024] Step 7.3, installation and adjustment of the pipe pile

[0025] The installation and adjustment of the pipe pile are performed according to the design parameters of the leveling layer, and the design parameters of the leveling layer include the thickness of the leveling layer and the elevation of the lower plane thereof;

[0026] The installation of the pipe pile is to drive each pipe pile into the bearing layer by a mechanical device, and the adjustment is the adjustment when the pipe pile does not meet the design requirements after being inserted into the bearing layer, specifically, the field splicing;

[0027] Step 7.4, installation of the temporary platform

[0028] The temporary platform is composed of two identical rectangular plates, a part-circular notch is opened at the center position of the long side of the rectangular plate, and the shape of the notches of the two rectangular plates is matched with the outer diameter of the pipe pile after being aligned in space, and a through hole parallel to the short side and passing through the plate is opened at both ends of the long side of each rectangular plate;

[0029] After the notches of the two rectangular plates are aligned in space and clamped on the pipe pile, two threaded rods are respectively inserted through the corresponding through holes of the two rectangular plates, and are locked by nuts, that is, the two rectangular plates are combined into a temporary platform that is sleeved on the pipe pile, and the top surface of the temporary platform plus twice the thickness of the lapping plate is flush with the lower plane of the leveling layer;

[0030] Step 7.5, laying of the lapping plate

[0031] A layer of lapping plate is laid between adjacent temporary platforms, that is, a lapping layer composed of lapping plates is formed, and then a layer of lapping plate is laid on the upper part to form a second lapping layer, and the second lapping layer is ensured to be flush with the lower plane of the leveling layer, and the gap between adjacent temporary platforms is completely covered by the lapping plate, and then a layer of impermeable geotextile is laid on the second lapping layer;

[0032] Step 7.6, fixing of the lateral formwork of the foamed concrete pouring layer

[0033] The foamed concrete pouring layer is poured in a block-by-block and layer-by-layer manner, the length of each foamed concrete layer is parallel to the driving direction of the road, the width is perpendicular to the driving direction of the road, and when the blocks are divided, the division line falls on the row or column formed by the pile caps, and the corresponding positions of the upper end surface and the lower end surface of the pile cap are provided with pre-buried welding points;

[0034] A rigid rod is welded on each pre-buried welding point adjacent to the foamed concrete block pouring division line in the horizontal projection, and the bottom end of the lower rigid rod is flush with the upper end surface of the temporary platform, and the top end of the upper rigid rod is flush with the upper plane of the shear layer, that is, a complete formwork support is formed on the division line of each foamed concrete layer by the plurality of rigid rods;

[0035] According to the designed layer height of the pouring layer, the matching lateral formwork is fixed on the rigid rod layer by layer, that is, the pouring formwork of each foamed concrete layer is formed;

[0036] Step 7.7, pouring of the leveling layer and the shear layer

[0037] Firstly, the leveling layer is poured;

[0038] Then, the shearing layer is poured, and in the pouring process, according to the number of layers A of the reinforced layer, the process of pouring foam concrete-laying reinforced material to form the reinforced layer-pouring foam concrete is repeated A times;

[0039] In the layered pouring of the shearing layer foam concrete of the leveling layer and the shearing layer, after each layer is poured, the lateral formwork on both sides of the layer, which has been poured with foam concrete, is removed, and polystyrene material is filled into the gap left after the removal of the lateral formwork to form a expansion joint;

[0040] Step 7.8, construction of the pavement structure layer and removal of the temporary component

[0041] Firstly, the pavement structure layer is constructed, and secondly, the road maintenance is carried out, and after the road maintenance is completed, the temporary platform, the deck and the remaining lateral formwork are removed, and cement mortar is sprayed on the side surface of the leveling layer, the side surface of the shearing layer and the lower plane of the leveling layer to form a protective layer.

[0042] Compared with the prior art, the beneficial effects of the present application are embodied in:

[0043] (1) The suspended roadbed structure provided by the present application uses the reinforced joint pipe pile and the main joint pipe pile to coarsely adjust the elevation of the pile top, and then finely adjusts the elevation through the leveling layer, thereby avoiding the problem of cutting the pile;

[0044] (2) The pipe pile support structure of the present application is embedded into the foundation and the roadbed at both ends, which strengthens the connection performance of the roadbed and the foundation, and suspends the roadbed to avoid the negative impact of rainwater accumulation on the stability of the roadbed;

[0045] (3) Although the foam concrete is suspended in the present application, the length of the pipe pile is increased, but a large amount of foam concrete is saved, which obviously saves the engineering cost and has relatively great economic value. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 It is a structural schematic view of the suspended roadbed of the present application;

[0047] Figure 2 It is a three-dimensional structure view of the suspended roadbed structure of the present application in the construction process;

[0048] Figure 3 It is a schematic view of the pile cap pre-buried welding point and the flange plate in the embodiment of the present application;

[0049] Figure 4 It is a schematic view of the temporary platform structure in the embodiment of the present application;

[0050] Figure 5A schematic diagram of a foamed concrete block position in the embodiment of the present application.

[0051] Wherein: 1. bearing layer; 2. ground; 3. leveling layer, 4. temporary platform; 41, rectangular plate; 42. threaded rod; 43. nut; 5. pile cap; 6. reinforced layer; 7. shear layer; 8. pavement structure layer; 9. lap plate; 10. rigid rod; 11. protective layer; 12. pre-buried welding point; 13. reinforced pipe pile; 14. main pipe pile; 15. reinforced joint pipe pile; 16. main joint pipe pile; 17. lateral formwork; 18. expansion joint; 19. flange. DETAILED DESCRIPTION

[0052] The present application will be further described below in conjunction with specific embodiments and drawings.

[0053] Figure 1 A schematic diagram of a suspended roadbed structure of the present application, from bottom to top, comprises a pipe pile support structure, a leveling layer 3, a shear layer 7 and a pavement structure layer 8, the leveling layer 3 and the shear layer 7 are both foamed concrete pouring layers, the shear layer 7 is also uniformly provided with a plurality of reinforced layers 6 parallel to the shear layer 7, the foamed concrete pouring layer is poured in a block-by-block and layer-by-layer manner, and expansion joints 18 are left between adjacent blocks. Figure 1 It can be seen that the suspended roadbed structure comprises, from bottom to top, a pipe pile support structure, a leveling layer 3, a shear layer 7 and a pavement structure layer 8, the leveling layer 3 and the shear layer 7 are both foamed concrete pouring layers, the shear layer 7 is also uniformly provided with a plurality of reinforced layers 6 parallel to the shear layer 7, the foamed concrete pouring layer is poured in a block-by-block and layer-by-layer manner, and expansion joints 18 are left between adjacent blocks.

[0054] The pipe pile support structure is composed of a plurality of uniformly distributed pipe piles, a pile cap 5 is welded to the top of each pipe pile, one end of the pipe pile is vertically inserted into the bearing layer 1 below the ground 2, and the other end is vertically suspended above the ground 2, and the elevation of the pipe pile meets the following design requirements: when the pipe pile is inserted into the bearing layer 1, the top end surface of the pile cap 5 is located in the leveling layer 3.

[0055] In this embodiment, a protective layer 11 is formed on the side surface of the leveling layer 3, on the side surface of the shear layer 7, and on the lower plane of the leveling layer 3 by spraying cement mortar.

[0056] In this embodiment, the reinforcing material of the reinforced layer 6 is geosynthetic material or steel mesh.

[0057] In this embodiment, the spacing of the pipe piles, the cross-sectional area of the pile cap 5, the thickness of the leveling layer 3, the thickness of the shear layer 7, the bulk density of the foamed concrete, the compressive strength of the foamed concrete, the tensile strength of the foamed concrete and the shear strength of the foamed concrete should meet the requirement that the leveling layer 3 and the shear layer 7 do not fail under normal working conditions of the roadbed.

[0058] The maximum compressive stress in the leveling layer 3 and the shear layer 7 is less than the compressive strength of the foam concrete, the maximum tensile stress is less than the tensile strength of the foam concrete, and the maximum shear stress is less than the shear strength of the foam concrete.

[0059] In the embodiment, the pipe pile includes a reinforced pipe pile 13 and a main pipe pile 14, and the lengths h0 of the two pipe piles are the same and satisfy: when the pipe pile is inserted into the bearing stratum 1, the calculated elevation of the pile top elevation plus the thickness value of the pile cap 5 is located between the upper plane of the leveling layer 3 and a lowest reference surface; the lowest reference surface is lower than the lower plane of the leveling layer 3, the vertical distance between the lowest reference surface and the lower plane of the leveling layer 3 is h2, the thickness of the leveling layer 3 is h1, and h2+h1

[0060] When the pipe pile is inserted into the bearing stratum 1, the calculated elevation of the pile top elevation plus the thickness value of the pile cap 5 is located in the leveling layer 3, the reinforced pipe pile 13 is taken as the pipe pile on the two sides of the N columns of the pipe pile support structure, and the main pipe pile 14 is taken as the pipe pile other than the two sides of the N columns of the pipe pile support structure.

[0061] When the pipe pile is inserted into the bearing stratum 1, the calculated elevation of the pile top elevation plus the thickness value of the pile cap 5 is located between the lower plane of the leveling layer 3 and the lowest reference surface, splicing is performed, and specifically: if the pipe pile is the pipe pile on the two sides of the N columns of the pipe pile support structure, the pipe pile is composed of the reinforced pipe pile 13 and M reinforced joint pipe piles 15 welded on the top of the reinforced pipe pile 13; if the pipe pile is the pipe pile other than the two sides of the N columns of the pipe pile support structure, the pipe pile is composed of the main pipe pile 14 and M main joint pipe piles 16 welded on the top of the main pipe pile 14; the lengths h3 of the reinforced joint pipe pile 15 and the main joint pipe pile 16 are h1.

[0062] The pipe pile on the two sides of the N columns of the pipe pile support structure refers to 2N pipe pile columns parallel to the driving direction of the road formed from the two sides of the road to the center of the road. Figure 1 and Figure 2 It can be seen that, in the example, N=1, so Figure 1 and Figure 2 In the example, only the pipe piles on the outermost columns of the pipe pile support structure adopt the reinforced pipe pile 13.

[0063] In the embodiment, the reinforced pipe pile 13, the main pipe pile 14, the reinforced joint pipe pile 15, the main joint pipe pile 16, and the pile cap 5 are all reinforced concrete structures and are produced by a prefabrication process, wherein the pile cap 5 on the outermost pipe pile of the pipe pile support structure and the pile cap 5 on the pipe pile at the pouring boundary of the block are provided with pre-embedded welding points 12.

[0064] The reinforcing pipe pile 13 has a larger cross-sectional area than the main pipe pile 14.

[0065] In the embodiment, the length of the reinforcing pipe pile 13 and the main pipe pile 14 is 5 m-30 m, the length of the reinforcing joint pipe pile 15 and the main joint pipe pile 16 is 0.5 m-5.0 m, the outer diameter of the reinforcing pipe pile 13 and the reinforcing joint pipe pile 15 is 400 mm-1400 mm, and the wall thickness is 95 mm-150 mm, and the outer diameter of the main pipe pile 14 and the main joint pipe pile 16 is 300 mm-1300 mm, and the wall thickness is 60 mm-150 mm.

[0066] In the embodiment, the two end faces of the reinforcing pipe pile 13 and the main pipe pile 14, the two end faces of the reinforcing joint pipe pile 15 and the main joint pipe pile 16, and the bottom end face of the pile cap 5 are embedded with flanges 19, which are used for welding between the pipe piles and the pile cap 5, between the reinforcing pipe piles 13 and the reinforcing pipe piles 13, between the reinforcing pipe pile 13 and the reinforcing joint pipe pile 15, between the reinforcing joint pipe pile 15 and the reinforcing joint pipe pile 15, between the main pipe piles 14 and the main pipe piles 14, between the main pipe pile 14 and the main joint pipe pile 16, and between the main joint pipe pile 16 and the main joint pipe pile 16. Figure 3 The position of the flange 19 at the bottom end face of the pile cap 5 in the embodiment is shown, and the position of the embedded welding point 12 on the pile cap 5 is also shown. Figure 3 It can be seen that the pile cap 5 is a column with a rectangular cross section.

[0067] The construction method of the suspension type roadbed structure provided by the application comprises the following steps:

[0068] Step 7.1, determining the pipe pile layout range boundary line

[0069] The pipe pile layout range boundary line is determined according to the road center line and the width of the leveling layer 3, specifically: the road center line is taken as the center to offset one-half of the width of the leveling layer 3 on both sides, and then the projection on the ground 2 is obtained, and the projection range is the pipe pile layout range boundary line.

[0070] Step 7.2, determining the pipe pile layout position

[0071] The pipe pile layout position is determined according to the pipe pile layout range, the pipe pile spacing, and the pipe pile layout form, and is marked on the site by measurement and setting out, wherein the projection on the horizontal plane of the outermost embedded welding point 12 on the pile cap 5 of the pipe pile farthest from the road center line is located on the outside of the pipe pile layout range boundary line.

[0072] Step 7.3, installation and adjustment of the pipe pile

[0073] The installation and adjustment of the pipe pile are carried out according to the design parameters of the leveling layer 3, the design parameters of the leveling layer 3 including the thickness of the leveling layer 3 and the elevation of the lower plane thereof;

[0074] The installation of the pipe pile is that each pipe pile is driven into the bearing stratum 1 by a mechanical device, and the adjustment is the adjustment carried out when the pipe pile does not meet the design requirements after being inserted into the bearing stratum 1, specifically, the field splicing;

[0075] Step 7.4, installation of the temporary platform 4

[0076] Figure 2 A three-dimensional structural view of the suspended roadbed structure in the construction process of the present application, Figure 4 A schematic view of the temporary platform structure in the embodiment of the present application. Figure 2 And Figure 4 As can be seen, the temporary platform 4 is composed of two identical rectangular plates 41, a part-circular-shaped notch is formed at the center position of the long side of the rectangular plate 41, and the shape of the notches of the two rectangular plates 41 after being aligned in space is matched with the outer diameter of the pipe pile, and a through hole parallel to the short side and passing through the plate body is formed at each end of the long side of each rectangular plate 41.

[0077] After the notches of the two rectangular plates 41 are aligned in space and clamped on the pipe pile, two threaded rods 42 are respectively inserted through the corresponding through holes of the two rectangular plates 41, and are locked by nuts 43, that is, the two rectangular plates 41 are combined into a temporary platform 4 which is sleeved on the pipe pile, and the top surface of the temporary platform 4 plus twice the thickness of the furring 9 is flush with the lower plane of the leveling layer 3.

[0078] Step 7.5, laying of the furring 9

[0079] A layer of furring 9 is laid between adjacent temporary platforms 4, that is, a furring layer is formed, and then a second layer of furring 9 is laid on the upper part, forming a second furring layer, and ensuring that the second furring layer is flush with the lower plane of the leveling layer 3, and the gap between adjacent temporary platforms 4 is completely covered by the furring 9; then, a layer of anti-seepage geotextile is laid on the second furring layer.

[0080] Step 7.6, fixing of the lateral formwork 17 of the foamed concrete pouring layer

[0081] The foamed concrete pouring layer is poured in a block-by-block and layer-by-layer manner, the length of each block of foamed concrete layer is parallel to the driving direction of the road, the width is perpendicular to the driving direction of the road, and when the blocks are divided, the dividing line falls on the row or column formed by the pile cap 5, and the corresponding positions of the upper end surface and the lower end surface of the pile cap 5 are provided with pre-embedded welding points 12.

[0082] A rigid rod 10 is welded on each horizontal projection adjacent to the partition line between the foam concrete blocks, and the bottom end of the lower rigid rod 10 is leveled with the upper end surface of the temporary platform 4, and the top end of the upper rigid rod 10 is leveled with the upper surface of the shear layer 7, that is, a complete formwork support is formed on the partition line of each foam concrete layer by the plurality of rigid rods 10;

[0083] According to the layer height of the designed layer-by-layer pouring, the matching lateral formwork 17 is fixed on the rigid rod 10 layer by layer, that is, the pouring formwork of each foam concrete layer is formed.

[0084] In the embodiment, the single-layer pouring thickness of the foam concrete is 0.3m-1.0m. The rigid rod 10 is a circular steel pipe with an outer diameter of 1cm-3cm or a square steel pipe with an outer side length of 1cm-3cm.

[0085] Figure 5 It is a schematic diagram of the foam concrete block position in the embodiment of the application.

[0086] Step 7.7, leveling and pouring of the leveling layer 3 and the shear layer 7

[0087] First, the pouring of the leveling layer 3 is performed;

[0088] Then, the pouring of the shear layer 7 is performed. Specifically, during the pouring process, according to the number A of the reinforced layers 6, the process of pouring foam concrete and laying reinforcing materials A times to form the reinforced layer 6 is repeated.

[0089] During the layer-by-layer pouring of the leveling layer 3 and the shear layer 7, after pouring each layer, the lateral formwork 17 on both sides of the layer which has been poured with foam concrete is removed, and polystyrene material is filled into the gap left after the removal of the lateral formwork 17 to form a expansion joint 18.

[0090] In the embodiment, A=1, that is, the reinforced layer 6 is one layer. The specific pouring process is as follows:

[0091] Pouring 0.5m-thick foam concrete on the leveling layer 3;

[0092] Laying a layer of reinforcing material to form the first layer of the reinforced layer 6;

[0093] Pouring foam concrete again.

[0094] Step 7.8, construction of the pavement structure layer 8 and removal of the temporary components

[0095] First, the construction of the road surface structure layer is carried out, and then the road maintenance is carried out. After the road maintenance is completed, the temporary platform 4, the boarding 9 and the remaining lateral formwork 17 are removed, and the cement mortar is sprayed on the side surface of the leveling layer 3, the side surface of the shear layer 7 and the lower surface of the leveling layer 3 to form the protective layer 11.

Claims

1. A suspended embankment structure, characterized by, From bottom to top, the pipe pile support structure, the leveling layer (3), the shear layer (7) and the pavement structure layer (8) are sequentially included, the leveling layer (3) and the shear layer (7) are both foam concrete pouring layers, a plurality of reinforcing layers (6) parallel to the shear layer (7) are uniformly arranged in the shear layer (7), and the foam concrete pouring layer is poured in a block and layer manner, and expansion joints (18) are left between adjacent blocks. The pipe pile support structure is composed of a plurality of uniformly distributed pipe piles, a pile cap (5) is welded at the top of each pipe pile, one end of the pipe pile is vertically inserted into the bearing layer (1) below the ground (2), one end is vertically suspended above the ground (2), and the elevation of the pipe pile meets the following design requirements: when the pipe pile is inserted into the bearing layer (1), the top end surface of the pile cap (5) is located in the leveling layer (3). A protective layer (11) is formed on the side surface of the leveling layer (3), the side surface of the shear layer (7) and the lower plane of the leveling layer (3) by spraying cement mortar. The reinforcing material of the reinforcing layer (6) is a geosynthetic material or a steel mesh. The spacing of the pipe piles, the cross-sectional area of the pile cap (5), the thickness of the leveling layer (3), the thickness of the shear layer (7), the bulk density of the foam concrete, the compressive strength of the foam concrete, the tensile strength of the foam concrete and the shear strength of the foam concrete should meet the requirements that the leveling layer (3) and the shear layer (7) do not fail under normal working conditions of the subgrade. The failure of the leveling layer (3) and the shear layer (7) refers to the maximum compressive stress in the leveling layer (3) and the shear layer (7) being less than the compressive strength of the foam concrete, the maximum tensile stress being less than the tensile strength of the foam concrete, and the maximum shear stress being less than the shear strength of the foam concrete in the three-dimensional finite element numerical simulation results of the suspended subgrade structure. The pipe pile includes a reinforced pipe pile (13) and a main pipe pile (14), the lengths h0 of the two types of pipe piles are the same and meet the following requirements: when the pipe pile is inserted into the bearing layer (1), the calculated elevation of the pile top elevation plus the thickness of the pile cap (5) is located between the upper plane of the leveling layer (3) and a lowest reference surface; the lowest reference surface is lower than the lower plane of the leveling layer (3), the vertical distance between the lowest reference surface and the lower plane of the leveling layer (3) is h2, the thickness of the leveling layer (3) is h1, h2+h1 When the pipe pile is inserted into the bearing layer (1), the calculated elevation of the pile top elevation plus the thickness of the pile cap (5) is located in the leveling layer (3), the reinforced pipe pile (13) is taken as the pipe pile on both sides of the N columns of the pipe pile support structure, and the main pipe pile (14) is taken as the pipe pile of the pipe pile support structure other than the N columns on both sides. When the pipe pile is inserted into the bearing stratum (1), the calculated elevation of the pile top elevation plus the thickness value of the pile cap (5) is located between the lower plane of the leveling layer (3) and the lowest reference surface, and the splicing is carried out, specifically: if the pipe pile is N columns of pipe piles on both sides of the pipe pile support structure, the pipe pile is composed of a reinforced pipe pile (13) and M reinforced joint pipe piles (15) welded on the top of the reinforced pipe pile (13); if the pipe pile is a pipe pile other than N columns of pipe piles on both sides of the pipe pile support structure, the pipe pile is composed of a main pipe pile (14) and M main joint pipe piles (16) welded on the top of the main pipe pile (14); the length h3 of the reinforced joint pipe pile (15) and the main joint pipe pile (16) is h1; The reinforced pipe pile (13), the main pipe pile (14), the reinforced joint pipe pile (15), the main joint pipe pile (16) and the pile cap (5) are all reinforced concrete structures and are produced by prefabrication process, wherein the pile cap (5) on the outermost pipe pile of the pipe pile support structure and the pile cap (5) on the pipe pile located on the block pouring boundary line are provided with pre-embedded welding points (12); The cross-sectional area of the reinforced pipe pile (13) is greater than that of the main pipe pile (14).

2. A method of constructing a suspended roadbed structure using the suspended roadbed structure according to claim 1, characterized by, The construction method comprises the following steps: Step 7.1, determining the pipe pile layout range boundary The pipe pile layout range boundary is determined according to the road center line and the width of the leveling layer (3), specifically: taking the center line of the road as the center, offsetting half of the width of the leveling layer (3) on both sides, and then projecting to the ground (2), the projection range is the pipe pile layout range boundary; Step 7.2, determining the pipe pile layout position The pipe pile layout position is determined according to the pipe pile layout range, the pipe pile spacing and the pipe pile layout form, and is marked on site by measuring and laying out, wherein the projection of the outermost pre-embedded welding point (12) on the horizontal plane of the pile cap (5) farthest from the road center line is located outside the pipe pile layout range boundary; Step 7.3, installation and adjustment of the pipe pile The installation and adjustment of the pipe pile are carried out according to the design parameters of the leveling layer (3), which include the thickness of the leveling layer (3) and the elevation of its lower plane; The installation of the pipe pile is to drive each pipe pile into the bearing stratum (1) by a mechanical device, and the adjustment is carried out when the pipe pile inserted into the bearing stratum (1) does not meet the design requirements, specifically, the on-site splicing; Step 7.4, installation of the temporary platform (4) The temporary platform (4) is composed of two identical rectangular plates (41), a part of the circular-shaped notch is opened at the center position of the long side of the rectangular plate (41), and the shape of the aligned notches of the two rectangular plates (41) is matched with the outer diameter of the pipe pile, and a through hole parallel to the short side and passing through the plate is opened at both ends of the long side of each rectangular plate (41); After the two rectangular plates (41) are clamped on the pipe pile with the notches aligned, two threaded rods (42) are respectively inserted through the corresponding through holes of the two rectangular plates (41), and then the threaded rods (42) are locked by nuts (43), so that the two rectangular plates (41) are combined into a temporary platform (4) sleeved on the pipe pile, and the top surface of the temporary platform (4) is flush with the lower surface of the leveling layer (3) after adding the thickness of two layers of the furring (9); Step 7.5, laying of the furring (9) A layer of furring (9) is laid between adjacent temporary platforms (4) to form a furring layer, and then a second layer of furring (9) is laid on the upper part of the furring layer to form a second furring layer, so that the second furring layer is flush with the lower surface of the leveling layer (3), and the gap between adjacent temporary platforms (4) is completely covered by the furring (9), and then a layer of anti-seepage geotextile is laid on the second furring layer; Step 7.6, fixing of the lateral formwork (17) for the foamed concrete pouring layer The foamed concrete pouring layer is poured in a block-by-block and layer-by-layer manner, each block of foamed concrete layer has a length parallel to the driving direction of the road and a width perpendicular to the driving direction of the road, and when the blocks are divided, the division line falls on the row or column formed by the pile caps (5), and the corresponding positions of the upper end surface and the lower end surface of the pile caps (5) are provided with pre-embedded welding points (12); A rigid rod member (10) is welded to each pre-embedded welding point (12) adjacent to the division line of the foamed concrete block pouring, and the bottom end of the lower rigid rod member (10) is flush with the upper end surface of the temporary platform (4), and the top end of the upper rigid rod member (10) is flush with the upper surface of the shear-resistant layer (7), so that a complete formwork support is formed on the division line of each block of foamed concrete layer by the plurality of rigid rod members (10); According to the designed layer height of the layer-by-layer pouring, the corresponding lateral formwork (17) is fixed on the rigid rod member (10) in a layer-by-layer manner to form the pouring formwork of each block of foamed concrete layer; Step 7.7, pouring of the leveling layer (3) and the shear-resistant layer (7) First, the leveling layer (3) is poured; Then, the shear-resistant layer (7) is poured, and specifically, during the pouring process, according to the number A of the reinforcing layers (6), the process of pouring foamed concrete and laying reinforcing materials is repeated A times to form the reinforcing layer (6). During the layer-by-layer pouring of the foamed concrete of the leveling layer (3) and the shear-resistant layer (7), after pouring each layer, the lateral formwork (17) on both sides of the layer, which has been poured with foamed concrete, is removed, and polystyrene material is filled into the gap left after the removal of the lateral formwork (17) to form a expansion joint (18). Step 7.8, construction of the pavement structure layer (8) and removal of the temporary components First, the pavement structure layer is constructed, and then the road is maintained, and after the road maintenance is completed, the temporary platform (4), the furring (9), and the remaining lateral formwork (17) are removed, and cement mortar is sprayed on the side surfaces of the leveling layer (3) and the shear-resistant layer (7) and on the lower surface of the leveling layer (3) to form a protective layer (11).

Images