High fill roadbed structure of abrupt slope deep and thick covering layer section and construction method

Abstract

The invention discloses an abrupt slope deep covering layer section high fill roadbed structure and a construction method, and belongs to the technical field of roadbed construction, the abrupt slope deep covering layer section high fill roadbed structure comprises an abrupt slope and a roadbed structure arranged on the abrupt slope, the roadbed structure comprises a continuous step arranged on the slope surface of the abrupt slope, and a vertical supporting plate structure is arranged at the relatively low end of the step; a light soil fill is arranged on the side, facing the steps, of the vertical supporting plate structure, and the top of the light soil fill is used for laying a road surface; a waterproof layer is arranged on the side face, away from the vertical supporting plate structure, of the light soil fill, a drainage ditch is formed in the intersection of the lower end of the waterproof layer and the abrupt slope and communicates with a drainage pipe, and the drainage pipe penetrates through the light soil fill and downwards penetrates out of the vertical supporting plate structure. The supporting plate structure is provided with an anchoring assembly which penetrates through the light soil fill and penetrates into the abrupt slope. The light soil fill is arranged, the overall dead weight of the roadbed is reduced, the grouting capsule units can prevent the situation that the anchoring effect is lost due to stress relaxation of the pre-stressed anchor cables, and the problems of fill sliding, sedimentation and the like are avoided.

Description

Technical Field

[0001] The invention relates to the technical field of roadbed construction, and in particular to a high-fill roadbed structure and a construction method in a steep slope and thick overburden section. Background Art

[0002] At present, most highways and some municipal roads have to pass through mountainous areas. The terrain and geological conditions in mountainous areas are complex. When passing through areas with steep original ground slopes and thick overburden, there are certain risks of subsidence and stability of the subgrade when using high fill roadbed. The conventional fill slope roadbed has the problems of large subgrade area, large subsidence, and easy subsidence of the subgrade. The anti-slide pile + retaining plate support type is adopted. Due to the high fill and thick overburden, the cantilever section of the anti-slide pile is too long, resulting in a greater risk of deformation and stability of the supporting roadbed. In addition, the construction of anti-slide piles in steep slopes is difficult and the project cost is high.

[0003] The existing publicly published invention patent (a foam lightweight soil anti-skid roadbed structure for steep slope high fill) (application publication number: CN 114775348A) relies on four rows of force plates in the inclined support pipe to slidably protrude to increase the relative friction resistance between the foam lightweight soil and the roadbed casting frame, solving the problem of low adhesion of the foam lightweight soil on the roadbed casting frame, but for a deep covering layer foundation, it cannot solve the problem of overall sliding of the roadbed.

[0004] The existing publicly published invention patent (a high and steep slope roadbed structure of a gravity retaining wall combined with foam lightweight soil) (authorization announcement number: CN 219527211 U) relies on a gravity retaining wall as a retaining structure for a lightweight soil roadbed, which cannot meet the requirements of high fill roadbeds in steep slopes with thick overburden layers. There are stability problems such as high retaining walls, easy overturning, and sideslipping. Summary of the invention

[0005] In order to overcome the deficiencies of the prior art, the technical problem to be solved by the present invention is: how to improve the instability problem of the existing high fill roadbed in steep slopes with thick overburden layers, such as easy sliding and overturning.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A high fill roadbed structure in a steep slope with a deep overburden layer, comprising a steep slope and a roadbed structure arranged on the steep slope, wherein the roadbed structure comprises a continuous step arranged on the slope surface of the steep slope, a vertical support plate structure is arranged at a relatively low end of the step, a lightweight earth fill is arranged on the side of the vertical support plate structure facing the step, the lightweight earth fill completely covers the top of the step, and multiple layers of geogrids are arranged in the lightweight earth fill from top to bottom; the top of the lightweight earth fill is flush with the top of the support plate, and the top of the lightweight earth fill is used for paving the road surface; a waterproof layer is arranged on the side of the lightweight earth fill away from the vertical support plate structure, a drainage ditch is arranged at the intersection of the lower end of the waterproof layer and the steep slope, the drainage ditch is connected to a drainage pipe, and the drainage pipe passes through the lightweight earth fill and downwardly passes out of the vertical support plate structure; the support plate structure is provided with an anchoring assembly that passes through the lightweight earth fill and penetrates into the steep slope;

[0008] The above-mentioned anchoring assembly includes a plurality of supporting anchor rods of different lengths, and the plurality of supporting anchor rods are arranged at intervals from short to long from bottom to top on the above-mentioned vertical supporting structure, and the plurality of supporting anchor rods pass through the above-mentioned lightweight soil fill and penetrate into preset positions in the above-mentioned steep slope; it also includes at least one grouting anchor member, and the position of the above-mentioned grouting anchor member in the above-mentioned vertical supporting plate structure is above the plurality of supporting anchor rods, and the above-mentioned steep slope is provided with grouting holes corresponding to the above-mentioned grouting anchors, and the above-mentioned grouting anchor member passes through the above-mentioned lightweight soil fill and penetrates into the above-mentioned grouting holes; the end of the above-mentioned grouting anchor member away from the above-mentioned vertical supporting plate structure is sequentially provided with a plurality of the above-mentioned grouting capsule units, and the above-mentioned grouting capsule units are used to be embedded in the inner wall of the above-mentioned grouting hole under pressure after grouting expansion and deformation; the end of the above-mentioned grouting anchor member extending into the above-mentioned grouting hole is provided with a closed grouting structure, and the above-mentioned closed grouting structure is used to grout into the grouting hole after the above-mentioned grouting capsule unit is cast.

[0009] Furthermore, the above-mentioned grouting anchor cable comprises a steel strand structure extending into the above-mentioned steep slope, and a grouting main pipe is arranged inside the above-mentioned steel strand structure in the same extension direction as the above-mentioned steel strand; the above-mentioned grouting capsule unit comprises a plurality of grouting bags arranged around the circumference of the above-mentioned steel strand, and the plurality of grouting bags are provided with fixing rings at both ends of the above-mentioned steel strand, and the above-mentioned fixing rings press the above-mentioned grouting bags to the outside of the above-mentioned steel strand; a plurality of grouting branch pipes are connected to the outside of the above-mentioned grouting main pipe, and at least one of the above-mentioned grouting branch pipes extends into the above-mentioned grouting bag.

[0010] Furthermore, the grouting anchor cable is provided with a pressure sensor for detecting the pressure in the grouting capsule unit and the steep slope.

[0011] Furthermore, the grouting hole comprises a first channel and a second channel which are connected to each other, the inner diameter of the second channel is larger than the inner diameter of the first channel, and the grouting capsule unit is arranged in the second channel.

[0012] Furthermore, a plurality of prefabricated arch pieces are evenly arranged in the above-mentioned lightweight earth fill, and the above-mentioned prefabricated arch pieces include upper arch pieces and lower arch pieces connected to each other, and the above-mentioned upper arch pieces and the above-mentioned lower arch pieces are connected to form an arched cylindrical body with an inner cavity; the above-mentioned prefabricated arch pieces are located at the lower part of the above-mentioned lightweight earth fill.

[0013] Furthermore, the prefabricated arch plate material is a high molecular polymer material.

[0014] Furthermore, the support plate structure includes a plurality of columns spaced apart on the same straight line, a plurality of prefabricated panels spliced ​​in sequence are arranged on one side of the column close to the lightweight earth fill, the prefabricated panels are used to abut and support the lightweight earth fill, and the supporting anchor rods and the grouting anchor members are connected to the columns; a fixed foundation structure member extending into the steep slope is arranged at the lower end of the column.

[0015] The present invention also proposes a construction method for a high fill roadbed structure in a steep slope and thick overburden section, which is used to construct the high fill roadbed structure in a steep slope and thick overburden section, and comprises the following steps:

[0016] S1: digging steps on steep slopes;

[0017] S2: insert multiple support anchor rods into the steep slope foundation, drill grouting holes at the same time, insert the grouting anchor cable into the grouting holes, and then grout and anchor multiple grouting capsule units;

[0018] S3: Construction of drainage ditches and drainage pipes;

[0019] S4: Install the vertical support plate structure;

[0020] S5: After pouring a layer of lightweight soil on the side of the vertical support plate facing the above-mentioned steps, a geogrid is laid on one side, and then lightweight soil and geogrids are constructed layer by layer from bottom to top in sequence, and a waterproof layer is provided layer by layer on one side wall of the lightweight soil fill away from the vertical support plate structure;

[0021] S6: When the light soil is constructed and the grid is provided to the upper end of the support anchor rod and the grouting anchor cable, the support anchor rod and the grouting anchor cable are fixedly installed at the preset position of the vertical support plate structure;

[0022] S7: After the lightweight soil fill is poured layer by layer, the road surface is constructed on the top of the lightweight soil fill.

[0023] Furthermore, in step S2, after the grouting of the grouting capsule unit is completed, grouting is injected into the gap between the grouting hole and the grouting capsule unit through the closed casting structure.

[0024] Furthermore, in step S5, when laying the lightweight soil and geogrid layer by layer, a plurality of prefabricated arch pieces are laid in the preset layers.

[0025] The beneficial effects of the present invention are:

[0026] (1) By setting up lightweight soil fill, the overall deadweight of the roadbed is reduced, thus avoiding the problem of slippage or collapse of the high fill foundation.

[0027] (2) By setting support anchor rods and parallel grouting capsule units, the capsules are filled with grouting, and after filling, they are squeezed and embedded in the surrounding soil. When the grouting pressure exceeds the pressure of the tail closing device, the slurry fills the grouting holes and the gaps between the grouting capsule units and reinforces the surrounding soil through the closed casting structure, which can prevent the prestressed anchor cable from relaxing and losing the anchoring effect, resulting in the problem of fill sliding. At the same time, the lightweight soil can reduce the self-weight of the roadbed, thereby minimizing the load of the high fill roadbed on the foundation of the covering layer and improving the stability of the foundation structure.

[0028] (3) Prefabricated arches are installed in the lower roadbed area where the road surface load is smaller, which can reduce the amount of lightweight soil and further reduce the self-weight of the roadbed. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the structure of the present invention;

[0030] Figure 2 It is a schematic diagram of the vertical support plate structure of the present invention;

[0031] Figure 3 It is a schematic diagram of the structure of the grouting anchor cable member of the present invention;

[0032] Figure 4 It is a schematic diagram of the structure of the grouting capsule unit of the present invention;

[0033] Marked in the figure are, 1-steep slope, 2-step, 3-fixed foundation structure, 4-column, 5-prefabricated panel, 6-drainage ditch, 7-drainage pipe, 8-waterproof layer, 9-geogrid, 10-lightweight earth fill, 11-support anchor rod, 12-grouting anchor cable, 13-prefabricated arch piece, 14-pavement, 121-steel strand, 122-first channel, 123-second channel, 124-grouting branch pipe, 125-grouting bag, 126-fixing ring, 127-closed grouting structure, 128-grouting main pipe. DETAILED DESCRIPTION

[0034] The present invention is further described below in conjunction with the accompanying drawings.

[0035] like Figure 1-Figure 4As shown, the embodiment of the present application proposes a high fill roadbed structure in a steep slope and deep covering layer section, including a steep slope 1 and a roadbed structure arranged on the steep slope 1, the roadbed structure includes a continuous step 2 arranged on the slope surface of the steep slope 1, a vertical support plate structure is arranged at a relatively low end of the step 2, a light earth fill 10 is arranged on the side of the vertical support plate structure facing the step 2, the light earth fill 10 completely covers the step 2, and multiple layers of geogrids 9 are arranged at intervals from top to bottom in the light earth fill 10; The top of the light earth fill 10 is flush with the top of the support plate, and the top of the light earth fill 10 is used for paving the road surface 14; the side of the light earth fill 10 away from the vertical support plate structure is provided with a waterproof layer 8, and the intersection of the lower end of the waterproof layer 8 and the steep slope 1 is provided with a drainage ditch 6, and the drainage ditch 6 is connected to a drainage pipe 7, and the drainage pipe 7 passes through the light earth fill 10 and downwards out of the vertical support plate structure; the support plate structure is provided with an anchoring assembly that passes through the light earth fill 10 and penetrates into the steep slope 1;

[0036] The anchor assembly includes a plurality of support anchor rods 11 of different lengths, and the plurality of support anchor rods 11 are arranged at intervals from short to long from bottom to top on the vertical support structure, and the plurality of support anchor rods 11 pass through the lightweight earth fill 10 and penetrate into the preset positions in the steep slope 1; and further includes at least one grouting anchor cable 12, and the grouting anchor cable 12 is located above the plurality of support anchor rods 11 at the position of the vertical support plate structure, and the steep slope 1 is provided with grouting holes corresponding to the grouting anchor cables, The grouting anchor member 12 passes through the above-mentioned lightweight soil fill 10 and penetrates into the above-mentioned grouting hole; the above-mentioned grouting anchor member 12 is sequentially provided with a plurality of the above-mentioned grouting capsule units at one end away from the above-mentioned vertical support plate structure, and the above-mentioned grouting capsule units are used to be embedded in the inner wall of the above-mentioned grouting hole under pressure after grouting expansion and deformation; the end of the above-mentioned grouting anchor member 12 extending into the above-mentioned grouting hole is provided with a closed grouting structure 127, and the above-mentioned closed grouting structure 127 is used for grouting into the grouting hole after the above-mentioned grouting capsule unit is cast.

[0037] First of all, it should be stated that by setting the support anchor rod 11 and the parallel grouting capsule unit, the capsule is filled with grouting, and after filling, it is squeezed and embedded in the surrounding soil. After the grouting pressure exceeds the pressure of the tail closing device, the slurry fills the borehole pores and reinforces the surrounding soil through the tail, which can prevent the prestressed anchor cable from relaxing and losing the anchoring effect, resulting in the problem of fill sliding. At the same time, the fill roadbed constructed layer by layer with lightweight soil can reduce the self-weight of the roadbed, thereby minimizing the load of the high fill roadbed on the foundation of the covering layer and improving the stability of the foundation structure.

[0038] Specifically, the steep slope 1 is generally an inclined slope with an uneven surface, and the step 2 is a step 2 excavated on the surface of the steep slope 1 at a selected position and extending at a preset angle, so as to ensure uniform load acceptance and improve stability. Moreover, the lightweight soil fill 10 is generally lightweight foam soil, which is poured and filled by grouting layer by layer. During the grouting process, multiple layers of geogrids 9 are simultaneously set layer by layer.

[0039] In this embodiment, the above-mentioned support anchor rods 11 include three support anchor rods 11, and the lengths of the three support anchor rods 11 are 12m, 16m and 18m from bottom to top respectively. Specifically, a 12m long anchor rod and 16m and 18m long anchor bundles are constructed on the covering layer foundation of the above-mentioned steep slope 1, and the three support anchor rods 11 are arranged parallel to each other to achieve a stable tension support effect; at the same time, the length of the grouting anchor cable 12 is specifically a 30m long anchor cable, and a grouting hole is drilled in the covering layer foundation of the steep slope 1, and one end of the grouting anchor cable 12 with the grouting capsule unit is placed in the grouting hole, and then grouting anchoring is achieved.

[0040] Moreover, the grouting anchor cable 12 comprises a steel strand 121 structure extending into the steep slope 1, and a grouting main pipe 128 is arranged inside the steel strand 121 structure in the same extending direction as the steel strand 121; the grouting capsule unit comprises a plurality of grouting bags 125 arranged circumferentially along the steel strand 121, and both ends of the plurality of grouting bags 125 on the steel strand 121 are provided with fixing rings 126, and the fixing rings 126 press the grouting bags 125 tightly and connect them to the outside of the steel strand 121; the outside of the grouting main pipe 128 is connected to a plurality of grouting distribution Tube 124, at least one of the above-mentioned grouting branch pipes 124 extends into the above-mentioned grouting bag 125; in this embodiment, the steel strand 121 is an existing anchor cable tensioning steel strand 121 structure, and the steel strand 121 is specifically formed in a tubular shape, and a grouting main pipe 128 is arranged in the center of the steel strand 121, and the grouting bag 125 is stably fixed to the outer wall of the steel strand 121 through a fixing ring 126, and in this embodiment, a grouting capsule unit includes four grouting bags 125 arranged around the outside of the steel strand 121, and a plurality of grouting capsule units are arranged in sequence along the extension direction of the steel strand 121.

[0041] The above-mentioned grouting branch pipe 124 is connected to the above-mentioned grouting main pipe 128 and extends into the corresponding grouting bag 125, and a sealing kit is provided at the connection between the grouting branch pipe 124 and the grouting bag 125 to avoid the problem of concrete leakage during the grouting process.

[0042] In order to ensure an accurate pouring process, the grouting anchor 12 is provided with a pressure sensor for detecting the pressure inside the grouting capsule unit and the steep slope 1. By detecting the pressure value between the grouting capsule unit and the inner wall of the grouting hole during the pouring process, it can be confirmed whether the grouting is in place, thereby ensuring the controllability of the grouting process.

[0043] Moreover, the above-mentioned grouting hole includes a first channel 122 and a second channel 123 that are connected. The inner diameter of the second channel 123 is larger than the inner diameter of the above-mentioned first channel 122. The above-mentioned grouting capsule unit is arranged in the above-mentioned second channel 123. When the pouring of the grouting capsule unit is completed and the second channel 123 is poured through the closed pouring structure, the gap formed by the grouting capsule unit and the inner wall of the second channel 123 is poured and filled. At this time, the grouting capsule unit, the steel strand 121 and the concrete in the second channel 123 form a stable anchoring overall structure, and the outer diameter of the overall structure is larger than the inner diameter of the first channel 122, so as to achieve a stable anchoring effect, and prevent the stress relaxation of the prestressed anchor cable and the loss of the anchoring effect.

[0044] The above-mentioned closed grouting structure 127 is specifically a sealing connection sleeve installed at the tail of the grouting main pipe 128. Under a certain pressure range, the sealing connection sleeve will fall off under force. That is to say, when the grouting main pipe 128 fills each grouting bag 125 with slurry, the pressure in the grouting main pipe 128 gradually increases. At this time, the closed grouting structure 127 is flushed open, and grouting is implemented into the second channel 123 to fill the gap formed by the grouting bag 125 and the inner wall of the second channel 123, thereby improving the anchoring effect.

[0045] The above-mentioned lightweight earth fill 10 is poured and filled layer by layer from the steps upwards, and in order to reduce the amount of lightweight earth and further reduce the deadweight, a plurality of prefabricated arch pieces 13 are evenly arranged in the above-mentioned lightweight earth fill 10, and the above-mentioned prefabricated arch pieces 13 include an upper arch piece and a lower arch piece that are connected to each other, and the upper arch piece and the lower arch piece are connected to form an ellipsoid with an inner cavity; the above-mentioned prefabricated arch piece 13 is located at the lower part of the above-mentioned lightweight earth fill 10, that is, the upper and lower sides of the ellipsoid formed by the upper arch piece and the lower arch piece have good compressive resistance, and the material of the above-mentioned prefabricated arch piece 13 is a polymer material, specifically carbon fiber, which has the effect of light weight and high strength. The prefabricated arch piece 13 can greatly reduce the amount of lightweight earth, further reduce the deadweight of the fill foundation structure, and reduce the risk of slippage and settlement of the fill roadbed structure.

[0046] The support plate structure includes a plurality of columns 4 arranged at intervals on the same straight line. A plurality of prefabricated panels 5 spliced ​​in sequence are arranged on one side of the column 4 close to the lightweight earth fill 10. The prefabricated panels 5 are used to abut and support the lightweight earth fill 10, and the support anchor rods 11 and the grouting anchor members 12 are connected to the columns 4. A fixed foundation structure member 3 extending into the steep slope 1 is arranged at the lower end of the column 4, and the fixed foundation structure member 3 is an existing pile foundation anchoring structure, and a stable installation effect of the column 4 is achieved by drilling and grouting anchoring, and the gaps between adjacent prefabricated panels 5 are caulking treated with asphalt mastic to ensure sealing and waterproofing effects.

[0047] This embodiment also proposes a construction method for a high fill roadbed structure in a steep slope and thick overburden section, which is used to construct the high fill roadbed structure in the steep slope and thick overburden section, and includes the following steps:

[0048] S1: Excavate steps on the steep slope 1; clear the surface of the original steep slope 1 and excavate step 2, with the specific excavation size being 0.5m×1.0m in height×width.

[0049] S2: Insert multiple support anchor rods 11 into the foundation of the steep slope 1, and drill grouting holes at the same time. After the grouting anchor cable 12 is inserted into the grouting holes, grouting and anchoring are performed to multiple grouting capsule units; drill holes in sequence to anchor multiple support anchor rods 11 inside the steep slope 1, and extend the outwardly extending part to the position where the vertical support plate structure is set, so as to facilitate subsequent fixed installation; drill grouting holes again, the inner diameter of the first channel 122 of the grouting hole is smaller than the inner diameter of the second channel 123, and after one end of the grouting anchor cable 12 with the grouting capsule unit is extended into the second channel 123 into place, grouting is started, and the slurry enters each grouting branch pipe 124 under the action of high pressure along the grouting main pipe 128, and enters each grouting bag 125 to achieve the effect of filling and deforming the grouting bag 125 and squeezing the soil layer on the inner wall of the second channel 123 to achieve the effect of embedding into the soil layer, thereby improving the stability of the anchoring.

[0050] After the grouting of the grouting capsule unit is completed, grouting is injected into the gap between the grouting hole and the grouting capsule unit through the closed casting structure. Specifically, through the closed grouting structure 127, under a certain grouting pressure, the closed grouting structure 127 at the tail end of the grouting main pipe 128 is opened to achieve the effect of direct grouting into the second channel 123.

[0051] S3: construct drainage ditch 6 and drainage pipe 7; after the drainage ditch 6 is opened, the drainage pipe 7 is connected to the drainage ditch 6 and the other end is extended downward along the step 2 to a position on the side of the vertical support plate structure away from the lightweight earth fill 10, so as to facilitate drainage and avoid affecting the waterproof performance of the lightweight earth fill 10 structure.

[0052] S4: Install the vertical support plate structure; first install the fixed base structure 3 on the steep slope 1, install the corresponding columns 4, and then install the prefabricated panels 5 on the surface of multiple columns 4 in sequence, and then fix them, and then install them upward from bottom to top.

[0053] S5: After pouring a layer of lightweight soil on one side of the vertical support plate toward the above-mentioned step 2, a geogrid 9 is laid on one side, and then the lightweight soil and geogrid 9 are constructed layer by layer from bottom to top in sequence. At the same time, a waterproof layer 8 is arranged layer by layer on the side wall of the lightweight soil fill 10 away from the vertical support plate structure. The waterproof layer 8 can specifically be a concrete layer; when laying the lightweight soil and geogrid 9 layer by layer, a plurality of prefabricated arch pieces 13 are laid in the preset layer, and the prefabricated arch pieces 13 are arranged in the middle and lower layers of the above-mentioned lightweight soil fill 10. The upper layer of the lightweight soil fill 10 is layered with lightweight foam soil and geogrid 9 to ensure the supporting strength and stability of the road surface 14.

[0054] S6: When the lightweight soil is constructed and the grid is provided to the upper end of the supporting anchor rod 11 and the grouting anchor cable 12, the supporting anchor rod 11 and the grouting anchor cable 12 are fixedly installed at the preset position of the vertical support plate structure.

[0055] S7: After the lightweight earth fill 10 is poured layer by layer, a road surface 14 is constructed on the top of the lightweight earth fill 10, and safety facilities such as guardrails and signs are set on both sides of the road surface 14.

[0056] In summary, the embodiments of the present application propose a high fill roadbed structure and construction method for steep slope and thick covering layer areas. A foam lightweight soil high fill roadbed is set on the steep slope 1 and the thick covering layer foundation, which can reduce the self-weight of the roadbed. A prefabricated arch piece 13 is set in the lower roadbed to reduce the amount of lightweight soil and further reduce the self-weight of the roadbed, which can greatly reduce the risk of roadbed settlement, improve the stability of the roadbed, and reduce the project cost. The construction processes of foam lightweight soil, anchor rods, anchor cables, etc. are mature in technology and reliable in quality. Among them, foam lightweight soil filling, prefabricated panels 5, prefabricated arch plates 13, etc. can be prepared in advance, and the construction is convenient. In the thick covering layer foundation, a parallel grouting capsule unit is used to prevent the stress relaxation of the prestressed anchor cable and the loss of the anchoring effect. Moreover, on the whole, the construction risk of the present invention is relatively small, the quality is reliable, the construction speed is fast, and the project investment is relatively small.

Claims

1. A high fill roadbed structure in a steep slope with a thick overburden layer, comprising a steep slope (1) and a roadbed structure arranged on the steep slope (1), characterized in that: The roadbed structure comprises a continuous step (2) arranged on the slope surface of the steep slope (1); a vertical support plate structure is arranged at a relatively low end of the step (2); a lightweight earth fill (10) is arranged on the side of the vertical support plate structure facing the step (2); the lightweight earth fill (10) completely covers the top of the step (2); multiple layers of geogrids (9) are arranged at intervals from top to bottom in the lightweight earth fill (10); the top position of the lightweight earth fill (10) is flush with the top position of the support plate, and the The top of the lightweight earth fill (10) is used for paving a road surface (14); a waterproof layer (8) is provided on the side of the lightweight earth fill (10) away from the vertical support plate structure; a drainage ditch (6) is provided at the intersection of the lower end of the waterproof layer (8) and the steep slope (1); the drainage ditch (6) is connected to a drainage pipe (7); the drainage pipe (7) passes through the lightweight earth fill (10) and passes downward out of the vertical support plate structure; the support plate structure is provided with an anchoring assembly that passes through the lightweight earth fill (10) and penetrates into the steep slope (1); The anchor assembly comprises a plurality of support anchor rods (11) of different lengths, wherein the plurality of support anchor rods (11) are arranged in a spaced manner from short to long from bottom to top on the vertical support structure, and the plurality of support anchor rods (11) pass through the lightweight earth fill (10) and penetrate into a preset position in the steep slope (1); and further comprises at least one grouting anchor cable (12), wherein the grouting anchor cable (12) is located above the plurality of support anchor rods (11) at the position of the vertical support plate structure, and the steep slope (1) is provided with a grouting anchor cable corresponding to the grouting anchor cable. A hole is formed, wherein the grouting anchor member (12) passes through the lightweight soil fill (10) and penetrates into the grouting hole; a plurality of grouting capsule units are sequentially arranged at one end of the grouting anchor member (12) away from the vertical support plate structure, and the grouting capsule units are used to be embedded in the inner wall of the grouting hole under pressure after grouting expansion and deformation; a closed grouting structure (127) is arranged at the end of the grouting anchor member (12) extending into the grouting hole, and the closed grouting structure (127) is used to grout into the grouting hole after the grouting capsule unit is poured.

2. The high fill roadbed structure for steep slope and thick overburden layer according to claim 1 is characterized in that: The grouting anchor cable (12) comprises a steel strand (121) structure extending into the steep slope (1), wherein a grouting main pipe (128) is arranged inside the steel strand (121) structure in the same direction as the extension direction of the steel strand (121); the grouting capsule unit comprises a plurality of grouting bags (125) arranged around the circumference of the steel strand (121), and both ends of the plurality of grouting bags (125) on the steel strand (121) are provided with fixing rings (126), and the fixing rings (126) press the grouting bags (125) to connect them to the outside of the steel strand (121); and a plurality of grouting branch pipes (124) are arranged on the outside of the grouting main pipe (128), and at least one of the grouting branch pipes (124) extends into the grouting bag (125).

3. The high fill roadbed structure for steep slope and thick overburden layer according to claim 1 is characterized in that: The grouting anchor cable member (12) is provided with a pressure sensor for detecting the pressure inside the grouting capsule unit and the steep slope (1).

4. The high fill roadbed structure for steep slope and thick overburden layer according to claim 1 is characterized in that: The grouting hole comprises a first hole (122) and a second hole (123) which are connected to each other, the inner diameter of the second hole (123) is larger than the inner diameter of the first hole (122), and the grouting capsule unit is arranged in the second hole (123).

5. The high fill roadbed structure for steep slope and thick overburden area according to claim 1 is characterized in that: A plurality of prefabricated arch pieces (13) are evenly arranged in the lightweight earth fill (10), the prefabricated arch pieces (13) comprising an upper arch piece and a lower arch piece connected to each other, the upper arch piece and the lower arch piece being connected to form an ellipsoid having an inner cavity; the prefabricated arch piece (13) is located at the lower part of the lightweight earth fill (10).

6. The high fill roadbed structure for steep slope and thick overburden layer according to claim 5 is characterized in that: The material of the prefabricated arch piece (13) is a high molecular polymer material.

7. The high fill roadbed structure for steep slope and thick overburden area according to claim 1 is characterized in that: The support plate structure comprises a plurality of columns (4) arranged at intervals on the same straight line, a plurality of prefabricated panels (5) which are sequentially spliced ​​are arranged on one side of the column (4) close to the light earth fill (10), the prefabricated panels (5) are used to abut against and support the light earth fill (10), and the support anchor rods (11) and the grouting anchor cable members (12) are connected to the columns (4); a fixed foundation structure member (3) which extends into the steep slope (1) is arranged at the lower end of the column (4).

8. A construction method for a high fill roadbed structure in a steep slope with a thick overburden layer, characterized in that: The method is used for constructing a high fill roadbed structure in a steep slope and thick overburden section as described in claims 1 to 7, comprising the following steps: S1: Excavating steps on the steep slope (1); S2: inserting a plurality of support anchor rods (11) into the foundation of the steep slope (1), drilling grouting holes at the same time, inserting the grouting anchor cable members (12) into the grouting holes, and then grouting and anchoring the plurality of grouting capsule units; S3: Construction of drainage ditches (6) and drainage pipes (7); S4: Install the vertical support plate structure; S5: After pouring a layer of lightweight soil on one side of the vertical support plate toward the step (2), a geogrid (9) is laid on one side, and then the lightweight soil and geogrid (9) are constructed layer by layer from bottom to top in sequence, and at the same time, a waterproof layer (8) is arranged layer by layer on a side wall of the lightweight soil fill (10) away from the vertical support plate structure; S6: When the lightweight soil is constructed and the grid is provided to the upper end position of the support anchor rod (11) and the grouting anchor cable member (12), the support anchor rod (11) and the grouting anchor cable member (12) are fixedly installed at the preset position of the vertical support plate structure; S7: After the lightweight earth fill (10) is poured layer by layer, a road surface (14) is constructed on the top of the lightweight earth fill (10).

9. The construction method of high fill roadbed structure in steep slope and thick overburden section according to claim 8 is characterized in that: In step S2, after the grouting of the grouting capsule unit is completed, grouting is injected into the gap between the grouting hole and the grouting capsule unit through the closed casting structure.

10. The construction method of high fill roadbed structure in steep slope and thick overburden section according to claim 8, characterized in that: In step S5, when laying the lightweight soil and geogrid (9) layer by layer, a plurality of prefabricated arch pieces (13) are laid in a preset layer.

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