High fill roadbed structure and construction method in steep slope and thick overburden area

Abstract

The present invention discloses a high fill roadbed structure and a construction method in a steep slope and deep covering layer section in the field of roadbed construction technology, comprising a steep slope and a roadbed structure arranged on the steep slope, the roadbed structure comprising a continuous step arranged on the slope surface of the steep slope, a vertical support plate structure being provided at a relatively low end of the step, a lightweight earth fill being provided on the side of the vertical support plate structure facing the step, and the top of the lightweight earth fill being used for paving the road surface; a waterproof layer being provided on the side of the lightweight earth fill away from the vertical support plate structure, a drainage ditch being provided at the intersection of the lower end of the waterproof layer and the steep slope, the drainage ditch being connected to a drainage pipe, the drainage pipe passing through the lightweight earth fill in a downward direction and out of the vertical support plate structure; the support plate structure being provided with an anchoring assembly passing through the lightweight earth fill and penetrating into the steep slope; the lightweight earth fill being provided to reduce the overall dead weight of the roadbed, and the grouting capsule unit being able to prevent the stress of the prestressed anchor cable from relaxing and losing the anchoring effect, thereby avoiding problems such as sliding and settling of the fill.

Description

Technical Field

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

[0002] Currently, most highways and some municipal roads must pass through mountainous areas with complex topography and geology. When using high-fill roadbeds to pass through areas with steep original ground slopes and thick overburden, there are certain risks of subsidence and stability. Conventional fill-slope roadbeds have the disadvantages of large roadbed footprints, high subsidence, and the susceptibility to roadbed sideways slippage and instability. Using anti-slip piles + retaining wall support, due to the high fill and thick overburden, the anti-slip pile cantilever section is too long, resulting in greater risks of deformation and stability of the retaining roadbed. Furthermore, anti-slip pile construction on steep slopes is difficult and the project cost is high.

[0003] An 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 slidable protrusions in the inclined support tube to increase the relative friction resistance between the foam lightweight soil and the roadbed casting frame, solving the problem of the foam lightweight soil's low adhesion to the roadbed casting frame. However, it cannot solve the problem of overall roadbed sliding for deep overburden foundations.

[0004] The existing publicly published invention patent (a high-steep slope roadbed structure combining a gravity retaining wall and foam lightweight soil) (authorization announcement number: CN 219527211 U) relies on a gravity retaining wall as the retaining structure of the lightweight soil roadbed. It cannot meet the requirements of high fill roadbeds in areas with steep slopes and thick overburden. It has stability issues such as tall retaining walls, easy overturning, and sideslip. Summary of the Invention

[0005] In order to overcome the deficiencies of the prior art, the present invention aims to solve the following technical problem: 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 comprises a steep slope and a roadbed structure arranged on the steep slope, the roadbed structure comprising a continuous step arranged on the slope surface of the steep slope, a vertical support plate structure being provided at a relatively low end of the step, a lightweight soil fill being provided on the side of the vertical support plate structure facing the step, the lightweight soil fill completely covering the step, and multiple layers of geogrids being arranged at intervals from top to bottom in the lightweight soil fill; the top of the lightweight soil fill is flush with the top of the support plate, and the top of the lightweight soil fill is used for paving the road surface; a waterproof layer is provided on the side of the lightweight soil fill away from the vertical support plate structure, a drainage ditch is provided 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 soil fill in a downward direction and out of the vertical support plate structure; the support plate structure is provided with an anchoring assembly that passes through the lightweight soil fill and penetrates into the steep slope;

[0008] The above-mentioned anchor assembly includes a plurality of support anchor rods of different lengths, and the plurality of support anchor rods are arranged at intervals from short to long from bottom to top in the above-mentioned vertical support structure, and the plurality of support 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 support plate structure is above the plurality of support 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 support 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 the action of 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 the grouting hole after the above-mentioned grouting capsule unit is cast.

[0009] Furthermore, the above-mentioned grouting anchor cable includes 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 includes 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 includes a first channel and a second channel that 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 an upper arch piece and a lower arch piece connected to each other, and the above-mentioned upper arch piece and the above-mentioned lower arch piece 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, and a plurality of prefabricated panels spliced ​​in sequence are provided on the side of the column close to the lightweight earth fill, and 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; the lower end of the column is provided with a fixed foundation structure member extending into the steep slope.

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

[0016] S1: Excavating 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 the 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 the lightweight soil and the geogrid are constructed layer by layer from bottom to top in sequence. At the same time, a waterproof layer is laid layer by layer on the side wall of the lightweight soil fill away from the vertical support plate structure;

[0021] S6: When the lightweight soil is constructed and the grid is provided to the upper end position of the support anchor rod and the grouting anchor member, the support anchor rod and the grouting anchor member 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 performed 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 pores between the grouting hole and the grouting capsule unit through the closed casting structure and reinforces the surrounding soil, which can prevent the stress relaxation of the prestressed anchor cable and the loss of 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 covering layer foundation and improving the stability of the foundation structure.

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

[0029] Figure 1 It is a schematic structural diagram 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 This is a schematic diagram of the structure of the grouting anchor cable of the present invention;

[0032] Figure 4 This 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-precast panel, 6-drainage ditch, 7-drainage pipe, 8-waterproof layer, 9-geogrid, 10-lightweight earth fill, 11-support anchor rod, 12-grouting anchor, 13-precast 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 will be further described below with reference to the accompanying drawings.

[0035] like Figure 1-Figure 4As shown, the embodiment of the present application proposes a high fill roadbed structure for a steep slope with a deep overburden layer, comprising a steep slope 1 and a roadbed structure arranged on the steep slope 1, wherein the roadbed structure comprises a continuous step 2 arranged on the slope surface of the steep slope 1, a vertical support plate structure is provided at a relatively low end of the step 2, a lightweight earth fill 10 is provided 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, and multiple layers of geogrids 9 are arranged at intervals from top to bottom in the lightweight earth fill 10; The top of the lightweight earth fill 10 is flush with the top of the support plate, and the top of the lightweight earth fill 10 is used to pave the 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, and 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, which passes through the lightweight earth fill 10 and downwardly passes through 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;

[0036] The above-mentioned anchor assembly includes a plurality of support anchor rods 11 of different lengths, and the plurality of support anchor rods 11 are arranged from short to long from bottom to top in the above-mentioned vertical support structure, and the plurality of support anchor rods 11 pass through the above-mentioned lightweight soil fill 10 and penetrate into the preset position in the above-mentioned steep slope 1; and further includes at least one grouting anchor member 12, and the grouting anchor member 12 is located above the plurality of support anchor rods 11 in the position of the above-mentioned vertical support plate structure, and the above-mentioned 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 enters 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 unit is 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 to grout the grouting hole after the above-mentioned grouting capsule unit is cast.

[0037] First, it should be noted that by providing support anchors 11 and parallel grouting capsule units, the capsules are filled with grout and, after being filled, squeezed into the surrounding soil. When the grouting pressure exceeds the pressure of the tail closure device, the slurry passes through the tail to fill the drilled pores and reinforce the surrounding soil, preventing the prestressed anchor cables from relaxing and losing their anchoring effect, which can cause fill slippage. At the same time, the lightweight soil used in the layered fill roadbed can reduce the weight of the roadbed, thereby minimizing the load of the high fill roadbed on the overburden foundation and improving the stability of the foundation structure.

[0038] Specifically, the above-mentioned 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 to ensure uniform load acceptance and improve stability. In addition, 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 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 from bottom to top are 12m, 16m and 18m 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 tensioning 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 includes a steel strand 121 structure extending into the steep slope 1, and a grouting main pipe 128 is provided inside the steel strand 121 structure in the same extending direction as the steel strand 121; the grouting capsule unit includes a plurality of grouting bags 125 arranged around the circumference of the steel strand 121, and the plurality of grouting bags 125 are provided with fixing rings 126 at both ends of the steel strand 121, 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 holes 126. 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 multiple 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 above-mentioned grouting anchor 12 is provided with a pressure sensor for detecting the pressure inside the above-mentioned 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 to each other. 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, thereby achieving a stable anchoring effect and preventing 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 the slurry in each grouting bag 125, the pressure in the grouting main pipe 128 gradually increases. At this time, the closed grouting structure 127 is flushed open, and grouting is realized 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 soil fill 10 is poured and filled layer by layer from the steps upwards, and in order to reduce the amount of lightweight soil and further reduce the deadweight, a plurality of prefabricated arch pieces 13 are evenly arranged in the above-mentioned lightweight soil 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 above-mentioned upper arch piece and the above-mentioned 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 soil 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 soil, further reduce the deadweight of the fill foundation structure, and reduce the risk of slippage and settlement of the fill roadbed structure.

[0046] The above-mentioned 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 provided on the side of the above-mentioned columns 4 close to the above-mentioned lightweight earth fill 10. The above-mentioned prefabricated panels 5 are used to abut and support the lightweight earth fill 10, and the above-mentioned support anchor rods 11 and the above-mentioned grouting anchor members 12 are connected to the above-mentioned columns 4; the lower end of the above-mentioned columns 4 is provided with fixed foundation structural members 3 extending into the above-mentioned steep slope 1, and the fixed foundation structural members 3 are existing pile foundation anchoring structures, and the stable installation effect of the columns 4 is achieved by drilling and grouting anchoring, and the gaps between adjacent prefabricated panels 5 are treated by asphalt mastic caulking 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 area, which is used to construct the high-fill roadbed structure in the steep slope and thick overburden area, including 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 parts 12 are 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 outward-extending parts to the position where the vertical support plate structure is set, so as to facilitate subsequent fixed installation; drill grouting holes again, and the inner diameter of the first channel 122 of the grouting hole is smaller than the inner diameter of the second channel 123. After one end of the grouting anchor part 12 with the grouting capsule unit is inserted into the second channel 123 and into place, grouting is started. 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 fill and deform the grouting bag 125 and then squeeze 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, the closed grouting structure 127 is used. Under a certain grouting pressure, the closed grouting structure 127 at the 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 from bottom to top.

[0053] S5: After pouring a layer of lightweight soil on the side of the vertical support plate toward the above-mentioned step 2, geogrid 9 is laid on one side, and then 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 lightweight soil and geogrid 9 layer by layer, a plurality of prefabricated arch pieces 13 are laid in the preset layer. 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 position of the support anchor rod 11 and the grouting anchor member 12, the support anchor rod 11 and the grouting anchor member 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 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 embodiment of the present application proposes a high fill roadbed structure and construction method for steep slope and deep covering layer areas. A foam lightweight soil high fill roadbed is set on the steep slope 1 and deep covering layer foundation, which can reduce the self-weight of the roadbed. Prefabricated arch pieces 13 are 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 roadbed stability, and reduce 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 pieces 13, etc. can be prepared in advance, and construction is convenient. In the deep 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, the construction risk of the present invention as a whole 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) provided on the slope surface of the steep slope (1), a vertical support plate structure being provided at a relatively low end of the step (2), a lightweight earth fill (10) being provided on the side of the vertical support plate structure facing the step (2), the lightweight earth fill (10) completely covering the top of the step (2), and multiple layers of geogrids (9) being provided in the lightweight earth fill (10) at intervals from top to bottom; 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 downwardly passes through 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 at intervals from short to long from bottom to top on the vertical support plate 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 member (12), wherein the grouting anchor member (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 member (12) opposite to the grouting anchor member (12). The grouting hole is provided with a corresponding grouting hole, the grouting anchor cable (12) passes through the lightweight soil fill (10) and penetrates the grouting hole; a plurality of grouting capsule units are sequentially provided at one end of the grouting anchor cable (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 the action of pressure after grouting expansion and deformation; the end of the grouting anchor cable (12) extending into the grouting hole is provided with a closed grouting structure (127), and the closed grouting structure (127) is used to grout the grouting hole after the grouting capsule unit is poured; The grouting anchor cable (12) comprises a steel strand (121) structure extending into the steep slope (1), wherein a grouting main pipe (128) extending in the same direction as the steel strand (121) is provided inside the steel strand (121); the grouting capsule unit comprises a plurality of grouting bags (125) arranged circumferentially around the steel strand (121), wherein both ends of the plurality of grouting bags (125) on the steel strand (121) are provided with fixing rings (126), wherein 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 provided on the outside of the grouting main pipe (128), wherein at least one of the grouting branch pipes (124) extends into the grouting bag (125).

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

3. The high fill roadbed structure for steep slope and thick overburden area 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). The grouting capsule unit is arranged in the second hole (123).

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

5. The high fill roadbed structure for steep slope and thick overburden area according to claim 4 is characterized in that: The material of the prefabricated arch piece (13) is a high molecular polymer material.

6. The high fill roadbed structure for steep slope and thick overburden area according to claim 1, 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 columns (4) close to the light earth fill (10), the prefabricated panels (5) are used to abut 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) extending into the steep slope (1) is provided at the lower end of the columns (4).

7. A construction method for a high fill roadbed structure in a steep slope with a thick overburden layer, characterized in that: The method for constructing a high fill roadbed structure on a steep slope with a thick overburden layer as claimed in any one of claims 1 to 6 comprises 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 (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 laid 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 top of the lightweight earth fill (10).

8. The construction method of a high fill roadbed structure in a steep slope and thick overburden area according to claim 7 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.

9. The construction method of a high fill roadbed structure in a steep slope and thick overburden area according to claim 7, 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 the preset layer.

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