Construction method of widening embankment with cast-in-place concrete full-protection foam lightweight soil

Abstract

The present invention relates to a construction method of a cast-in-place concrete fully protected foam lightweight soil widened embankment, and the construction of the standard section widened embankment and the bridgehead section widened embankment are carried out simultaneously. The construction of the standard section widened embankment includes the following steps: excavation of the standard section widened embankment foundation trench, processing of prefabricated components, construction of prefabricated cantilever reinforced concrete retaining wall, replacement of gravel construction, pouring of foam concrete, construction of lime soil leveling layer, construction of prefabricated concrete inner wall, and cast-in-place concrete full protection construction. The beneficial effects of the present invention are: installing the prefabricated concrete inner wall below the drainage hole of the prefabricated cantilever reinforced concrete retaining wall, and then installing the prefabricated side ditch outer wall; the winch pulls the suspension rod to drive the mobile steel formwork to perform cast-in-place concrete full protection construction; the mobile operating platform structure is fixedly connected to the prefabricated cantilever reinforced concrete retaining wall through an anti-overturning pull rod, thereby improving the construction efficiency and construction quality of the new widened embankment.

Description

Technical Field

[0001] The invention belongs to the technical field of roadbed engineering, and in particular relates to a construction method for a cast-in-place concrete full-protection foam lightweight soil widened embankment. Background Art

[0002] With the rapid development of my country's economy, along with the rapid development of my country's transportation industry, and in order to meet the growing traffic demand, more and more embankment widening projects are being carried out on the basis of keeping existing roads open to traffic. Due to the settlement difference between the embankment and the structure and the uneven settlement of the new and old embankments, the new widened embankment is prone to cause vehicle jumping, structure damage and roadbed instability. In addition, the construction process of the new widened embankment is likely to increase the traffic burden on other roads and seriously affect the local transportation and economy. Therefore, improving its construction efficiency is also a top priority. From the perspective of the widened highways that have been delivered for use, especially the expressways, the effect after completion and operation is not good. There are still many problems in widening the embankment section of the highway. It is of great significance to develop an economical and safe way to widen the embankment.

[0003] In summary, for the construction of cast-in-place concrete fully protected foam lightweight soil widened embankment, it is very important to seek a new cast-in-place concrete fully protected foam lightweight soil widened embankment with fast construction speed, simple operation, and high construction quality reliability and its construction method. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a construction method for a cast-in-place concrete fully protected foam lightweight soil widened embankment.

[0005] The construction method of the cast-in-place concrete full-protection foam lightweight soil embankment widening method simultaneously carries out the construction of the standard section embankment widening method and the bridgehead section embankment widening method, wherein the construction method of the standard section embankment widening method specifically includes the following steps:

[0006] Step 1: Excavate the standard section in a stepped manner to widen the embankment foundation trench, and install the prefabricated cantilever reinforced concrete retaining wall;

[0007] Step 2: Backfill, replace with gravel and soil and compact;

[0008] Step 3: Install galvanized steel wire mesh and pour foam concrete; construct lime soil leveling layer and lay HPDE waterproof geomembrane;

[0009] Step 4: Install the prefabricated concrete inner wall below the drain hole of the prefabricated cantilever reinforced concrete retaining wall, and then install the prefabricated side ditch outer wall;

[0010] Step 5: Build the mobile formwork system. Install a winch on the top of the square steel beam and a slide trough on the top of the square steel beam. Fix the hanger to the embedded slide bar, and the winch pulls the hanger to drive the mobile steel formwork to carry out full protection construction of cast-in-place concrete. The mobile operating platform structure is fixedly connected to the prefabricated cantilever reinforced concrete retaining wall through an anti-overturning tie rod. After the construction is completed, the connection is removed and moved, and then re-fixed.

[0011] As a preferred embodiment, the construction method of widening the embankment at the bridgehead section specifically includes the following steps:

[0012] Step 1: Drive steel sheet piles, excavate the bridgehead section to widen the embankment foundation trench, and carry out gravel cushion construction;

[0013] Step 2: construct the cantilever retaining wall at the bridge head;

[0014] Step 3: Replace the gravel and clay and compact them;

[0015] Step 4: Install galvanized steel wire mesh at the designed location, pour foam concrete and maintain;

[0016] Step 5: Remove the steel sheet piles and backfill the empty grooves of the steel sheet piles;

[0017] Step 6: construct lime soil leveling layer and lay HPDE waterproof geomembrane. The construction method of cast-in-place concrete full-protection foam lightweight soil widening embankment according to claim is characterized in that after completing the construction of standard section widening embankment and bridgehead section widening embankment, the pavement structure and concrete guardrail are constructed.

[0018] As a preference, after completing the construction of the standard section widened embankment and the bridgehead section widened embankment, the pavement structure and concrete guardrail construction are carried out.

[0019] Preferably, during the construction of the standard section widened embankment, the prefabricated cantilever reinforced concrete retaining wall, the prefabricated concrete inner wall and the prefabricated ditch outer wall are all factory-prefabricated components, wherein the prefabricated cantilever reinforced concrete retaining wall is provided with embedded parts and drainage holes, the prefabricated ditch outer wall is L-shaped, and the prefabricated concrete inner wall includes an inclined panel, a lap groove, an upper lap plate and a lower lap plate.

[0020] Preferably, during the construction of the standard section widening embankment, the mobile formwork system includes a counterweight block, a counterweight rod, a winch, a steel wire rope, a mobile steel formwork, a base, a square steel longitudinal beam, a square steel cross beam, a hanger, a pull ring, a steel wire rope, an adjustable screw, a slide groove, an embedded slide rod, a small pulley and a triangular cross beam pad; the square steel longitudinal beam, square steel cross beam and triangular cross beam pad are all bolted and connected, and the triangular cross beam pad is supported on the top of the prefabricated cantilever reinforced concrete retaining wall. After the assembly is completed at the construction position, the lifting base is fixed to the square steel cross beam, and a winch is installed on the upper part of the base, wherein a counterweight rod is arranged on the base, and a counterweight block is placed on the upper part of the counterweight rod; a slide groove is arranged on the upper part of the square steel longitudinal beam; the hanger is welded and fixed to the embedded slide rod, a small pulley is arranged on the embedded slide rod, and a pull ring is arranged in the middle of the hanger; the mobile steel formwork and the hanger are connected and fixed by an adjustable screw.

[0021] Preferably, during the construction of the standard section widened embankment, the height of the movable steel formwork is adjusted according to the construction needs through an adjustable screw; the winch connects the pull ring set in the middle of the hanger through a steel wire rope to pull the hanger to move, thereby driving the movable steel formwork to carry out full protection construction of cast-in-place concrete; after the construction is completed, the counterweight block is removed, and the entire formwork system is moved as a whole by the crane, and the above steps are repeated.

[0022] Preferably, during the construction of the standard section widened embankment, the mobile operating platform structure includes a steel support, an operating platform and a safety net; the steel support with a pulley is hoisted as a whole, and the steel support is fixedly connected to the embedded parts on the prefabricated cantilever reinforced concrete retaining wall through an anti-overturning rod, and an operating platform and a safety net are arranged on the top of the steel support; after the construction is completed, the anti-overturning rod and the embedded parts on the prefabricated cantilever reinforced concrete retaining wall are removed and the next construction is moved and re-fixed in the above manner.

[0023] A cast-in-place concrete fully protected foamed lightweight soil widened embankment obtained by any of the above-mentioned methods.

[0024] The beneficial effects of the present invention are:

[0025] 1) The present invention solves the problems of uneven settlement and construction efficiency of newly widened embankments. Compared with traditional construction technologies, it has the advantages of shortening construction period, high construction efficiency, and a high proportion of comprehensive cost savings.

[0026] 2) The present invention installs a prefabricated concrete inner wall below the drainage hole of the prefabricated cantilever reinforced concrete retaining wall, and then installs a prefabricated ditch outer wall; a winch pulls the suspension rod to drive the mobile steel formwork to perform full protection construction of cast-in-place concrete; the mobile operating platform structure is fixedly connected to the prefabricated cantilever reinforced concrete retaining wall through an anti-overturning tie rod, thereby improving the construction efficiency and quality of the new widened embankment.

[0027] 3) The new widened embankment of the present invention adopts the original roadbed steel sheet pile protection technology, which can effectively reduce soil sliding and improve the excavation efficiency of the foundation trench. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the cross section of a widened embankment made of fully protected foamed lightweight soil with cast-in-place concrete;

[0029] Figure 2 This is a schematic diagram of the excavation section of the foundation trench of the standard section widened embankment;

[0030] Figure 3 This is a schematic diagram of the excavation section of the widened embankment foundation trench at the bridgehead section;

[0031] Figure 4 It is a schematic diagram of the inner wall of the precast concrete block;

[0032] Figure 5 This is a quick installation diagram of the mobile operating platform;

[0033] Figure 6 It is a plan view of the fully protected mobile formwork system for cast-in-place concrete;

[0034] Figure 7 It is a cross-sectional diagram of a fully protected mobile formwork system for cast-in-place concrete;

[0035] Figure 8 It is a construction process flow chart of the present invention.

[0036] In the figure: 1-concrete guardrail, 2-pavement structure, 3-HPDE waterproof geomembrane, 4-cast-in-place concrete full protection, 5-prefabricated cantilever reinforced concrete retaining wall, 6-foam concrete, 7-sluice hole, 8-prefabricated concrete inner wall, 9-dry stone, 10-prefabricated ditch outer wall, 11-backfill soil, 12-replacement gravel, 13-soil, 14-lime soil leveling layer, 15-galvanized steel wire mesh, 16-old roadbed slope line, 17-green belt, 18-curbstone, 19-old roadbed, 20-steel sheet pile, 21-gravel cushion, 22-concrete guardrail foundation, 23 -Cantilever retaining wall at bridge head, 24-clay, 25-inclined panel, 26-lap groove, 27-upper slab, 28-lower slab, 29-counterweight block, 30-counterweight rod, 31-winch, 32-steel wire rope, 33-mobile steel formwork, 34-safety net, 35-operating platform, 36-anti-overturning pull rod, 37-embedded parts, 38-steel bracket, 39-pulley, 40-base, 41-square steel longitudinal beam, 42-square steel cross beam, 43-suspender rod, 44-pull ring, 46-adjustable screw, 47-slide groove, 48-embedded slide rod, 49-small pulley, 50-triangular cross beam pad. DETAILED DESCRIPTION

[0037] The present invention is further described below in conjunction with embodiments. The description of the following embodiments is only used to help understand the present invention. It should be noted that for ordinary persons in the art, without departing from the principle of the present invention, the present invention can also be modified in some ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0038] Embodiment 1

[0039] As an example, Figure 8 As shown in the figure, a construction method of a cast-in-place concrete fully protected foam lightweight soil embankment widening is used, and the construction of the standard section embankment widening and the bridgehead section embankment widening is carried out simultaneously:

[0040] Construction preparation: geological survey, site leveling, and related construction machinery, personnel training, material preparation, traffic diversion, etc.

[0041] Then the construction of the standard section widening embankment and the bridgehead section widening embankment was carried out simultaneously:

[0042] The construction method of the standard section widening embankment specifically includes the following steps:

[0043] Step 1, prefabricated component processing: prefabricated cantilever reinforced concrete retaining wall 5, prefabricated concrete inner wall 8, prefabricated side ditch outer wall 10 are all prefabricated components in the factory, wherein the prefabricated cantilever reinforced concrete retaining wall 5 is provided with embedded parts 37 and drainage holes 7, the prefabricated side ditch outer wall 10 is L-shaped, and the prefabricated concrete inner wall 8 is composed of an inclined panel 25, a lap groove 26, an upper lap plate 27, and a lower lap plate 28;

[0044] Prefabricated cantilever reinforced concrete retaining wall construction: The standard section widening embankment foundation trench is excavated in a stepped manner. After the trench is cleared, the prefabricated cantilever reinforced concrete retaining wall 5 is installed first;

[0045] Step 2: Replacement of gravel: backfilling of the replacement gravel 12 and soil 13 and compaction;

[0046] Step 3: Foam concrete pouring: install galvanized steel wire mesh 15 at the designed position, pour foam concrete and maintain;

[0047] Lime soil leveling layer construction: After the foam concrete curing is completed, the lime soil leveling layer 14 is constructed and the HPDE waterproof geomembrane 3 is laid;

[0048] Step 4: Precast concrete inner wall construction: then install the precast concrete inner wall 8, the precast ditch outer wall 10, the backfill soil 11, and the dry-laid stone 9 in sequence, wherein the precast concrete inner wall 8 is located below the drainage hole 7;

[0049] Step 5: Cast-in-place concrete full protection construction; the square steel longitudinal beam 41, square steel cross beam 42 and triangular cross beam pad 50 described in the cast-in-place concrete full protection 4 mobile formwork technology are all bolted and fixedly connected, and the triangular cross beam pad 50 is supported on the top of the prefabricated cantilever reinforced concrete retaining wall 5. After the assembly is completed at the construction position, the hoisting base 40 is fixed to the square steel cross beam 42, and a winch 31 is installed on the upper part of the base 40, wherein a counterweight rod 30 is arranged on the base 40, and a counterweight block 29 is placed on the upper part of the counterweight rod 30 to improve its stability; a slide groove 47 is arranged on the upper part of the square steel longitudinal beam 41; the hoisting rod 43 and the inner The embedded slide bar 48 is welded and fixed, and a small pulley 49 is arranged on the embedded slide bar 48 to reduce the movement resistance of the embedded slide bar 48 in the slide groove, wherein a pull ring 44 is arranged in the middle of the suspension rod 48; the movable steel template 33 is connected and fixed to the suspension rod 43 by an adjustable screw 46, and the height of the movable steel template 33 is adjusted according to the construction needs; the winch 31 is connected to the suspension rod 48 by a pull ring 44 arranged in the middle of the suspension rod 48 through a steel wire rope 32 to pull the suspension rod 43 to move and then drive the movable steel template 33 to perform cast-in-place concrete full protection 4 construction; after the construction is completed, the counterweight block 29 is removed, and the entire template system is moved as a whole by the crane, and the above steps are repeated;

[0050] The mobile operating platform structure consists of a steel support 38, an operating platform 35, and a safety net 34. After the steel support 38 is processed in the factory, the pulley 39 is installed on site and then hoisted as a whole. The steel support 38 is fixedly connected to the embedded parts 37 on the prefabricated cantilever reinforced concrete retaining wall 5 through the anti-overturning rod 36, and the operating platform 35 and the safety net 34 are set on the top of the steel support 38. After the construction is completed, the anti-overturning rod 36 and the embedded parts 37 on the prefabricated cantilever reinforced concrete retaining wall 5 are removed and fixedly connected, and the steel support 38 is moved to the next construction site and re-fixed in the above-mentioned manner.

[0051] The construction method of widening the embankment at the bridgehead section specifically includes the following steps:

[0052] Step 1: Construction of gravel cushion layer: After the steel sheet piles 20 are driven, the foundation trench of the bridge head section is excavated to effectively reduce soil sliding, improve the excavation efficiency of the foundation trench, and then the gravel cushion layer 21 is constructed;

[0053] Step 2: Construction of the bridge head cantilever retaining wall: The bridge head cantilever retaining wall 23 is constructed using a cast-in-place concrete structure;

[0054] Step 3: Replacement of gravel: Replacement of gravel 12 and clay 24 and compaction;

[0055] Step 4: Foam concrete pouring: install galvanized steel wire mesh 15 at the designed position, pour foam concrete and maintain;

[0056] Step 5: Removal of steel sheet piles: After the foam concrete 6 is poured, the steel sheet piles 20 are removed and the empty grooves of the steel sheet piles 20 are backfilled;

[0057] Step 6: Construction of lime soil leveling layer: After the foam concrete is cured, the lime soil leveling layer 14 is constructed and the HPDE waterproof geomembrane 3 is laid.

[0058] After completing the construction of the standard section widened embankment and the bridgehead section widened embankment, the pavement structure construction is carried out: finally, the pavement structure 2 and concrete guardrail 1 are constructed.

[0059] Embodiment 2

[0060] As another embodiment, the cast-in-place concrete fully protected foam lightweight soil widened embankment obtained by the method in embodiment 1 includes: concrete guardrail 1, pavement structure 2, HPDE waterproof geomembrane 3, cast-in-place concrete full protection 4, prefabricated cantilever reinforced concrete retaining wall 5, foam concrete 6, drainage hole 7, prefabricated concrete inner wall 8, dry masonry 9, prefabricated ditch outer wall 10, backfill soil 11, replacement gravel 12, soil 13, lime soil leveling layer 14, galvanized steel wire mesh 15, old roadbed slope line 16, green belt 17, curbstone 18, old roadbed 19, steel sheet pile 20, gravel cushion 21, Concrete guardrail foundation 22, bridge head cantilever retaining wall 23, clay 24, inclined panel 25, lap groove 26, upper slat 27, lower slat 28, counterweight block 29, counterweight rod 30, winch 31, wire rope 32, mobile steel formwork 33, safety net 34, operating platform 35, anti-overturning pull rod 36, embedded parts 37, steel bracket 38, pulley 39, base 40, square steel longitudinal beam 41, square steel cross beam 42, suspension rod 43, pull ring 44, adjustable screw 46, slide 47, embedded slide rod 48, small pulley 49, triangular cross beam pad 50; also includes a mobile formwork system and a mobile operating platform;

[0061] The mobile formwork system includes a mobile steel formwork 33, a base 40, a square steel longitudinal beam 41, a square steel cross beam 42, a suspension rod 43 and an embedded sliding rod 48; a winch 31 is installed on the upper part of the square steel cross beam 42; a slide groove 47 is arranged on the upper part of the square steel longitudinal beam 41; the suspension rod 43 is welded and fixed to the embedded sliding rod 48, and a small pulley 49 is arranged on the embedded sliding rod 48; the mobile steel formwork 33 is connected and fixed to the suspension rod 43 by an adjustable screw 46; the winch 31 is connected to the suspension rod 43 by a steel wire rope 32;

[0062] The mobile operating platform structure includes a steel bracket 38 and an operating platform 35 ; the steel bracket 38 is fixedly connected to the prefabricated cantilever reinforced concrete retaining wall 5 , and the operating platform 35 is arranged on the top of the steel bracket 38 .

[0063] The bottom of the steel sheet pile 20 penetrates the old roadbed 19 and enters the soil 13. After the steel sheet pile 20 is driven, the foundation trench of the bridgehead section widened embankment is excavated, which can effectively reduce soil sliding and improve the excavation efficiency of the foundation trench. A crushed stone cushion layer 21 and a bridgehead cantilever retaining wall 23 are arranged in the foundation trench of the bridgehead section widened embankment in sequence. Replacement crushed stone 12 and clay 24 are also arranged in the foundation trench of the bridgehead section widened embankment. Foam concrete 6 is poured between the bridgehead cantilever retaining wall 23 and the old roadbed 19.

[0064] The prefabricated cantilever reinforced concrete retaining wall 5, prefabricated concrete inner wall 8, and prefabricated side ditch outer wall 10 are all factory prefabricated components, wherein the prefabricated cantilever reinforced concrete retaining wall 5 is provided with embedded parts 37 and drainage holes 7, the prefabricated side ditch outer wall 10 is L-shaped, and the prefabricated concrete inner wall 8 is composed of an inclined panel 25, a lap groove 26, an upper lap plate 27, and a lower lap plate 28, wherein the prefabricated concrete inner wall 8 is located below the drainage hole 7.

[0065] The mobile operating platform rapid installation technology is as follows: the mobile operating platform structure is composed of a steel support 38, an operating platform 35, and a safety net 34; after the steel support 38 is processed in the factory, the pulley 39 is installed on site and then hoisted as a whole. The steel support 38 is fixedly connected to the embedded parts 37 on the prefabricated cantilever reinforced concrete retaining wall 5 through the anti-overturning rod 36, and the operating platform 35 and the safety net 34 are arranged on the top of the steel support 38; the anti-overturning rod 36 and the embedded parts 37 on the prefabricated cantilever reinforced concrete retaining wall 5 can be removed and moved to the next construction location, and then re-fixed to achieve mobile rapid installation.

[0066] The cast-in-place concrete full-protection 4 mobile formwork technology, the mobile formwork system is composed of a counterweight block 29, a counterweight rod 30, a winch 31, a wire rope 32, a mobile steel formwork 33, a base 40, a square steel longitudinal beam 41, a square steel cross beam 42, a hanger 43, a pull ring 44, an adjustable screw 46, a slide 47, an embedded slide rod 48, a small pulley 49, and a triangular cross beam pad 50; the square steel longitudinal beam 41, the square steel cross beam 42, and the triangular cross beam pad 50 are all bolted and fixed, and the triangular cross beam pad 50 is supported on the top of the prefabricated cantilever reinforced concrete retaining wall 5 and assembled at the construction position. The base 40 is fixed to the square steel crossbeam 42, and a winch 31 is installed on the upper part of the base 40, wherein a counterweight rod 30 is arranged on the base 40, and a counterweight block 29 is placed on the upper part of the counterweight rod 30 to improve its stability; a slide groove 47 is arranged on the upper part of the square steel longitudinal beam 41; the suspension rod 43 is welded and fixed to the embedded sliding rod 48, and a small pulley 49 is arranged on the embedded sliding rod 48 to reduce the movement resistance of the embedded sliding rod 48 in the slide groove, wherein a pull ring 44 is arranged in the middle part of the suspension rod 43; the movable steel formwork 33 is connected and fixed to the suspension rod 43 by an adjustable screw 46, and the height of the movable steel formwork 33 is adjusted according to construction needs; the winch 31 is connected to the suspension rod 43 by a steel wire rope 32, and a pull ring 44 is arranged in the middle part of the suspension rod 43 to pull the suspension rod 43 to move, thereby driving the movable steel formwork 33 to perform cast-in-place concrete full protection 4 construction; after removing the counterweight block 29, the entire formwork system can be moved by the crane.

Claims

1. A construction method for widening an embankment by using cast-in-place concrete with full protection and foamed lightweight soil, characterized in that: The construction of the standard section widening embankment and the bridgehead section widening embankment is carried out simultaneously, wherein the construction method of the standard section widening embankment specifically includes the following steps: Step 1: step-by-step excavation of standard sections to widen the embankment foundation trench, and install prefabricated cantilever reinforced concrete retaining wall (5); Step 2: backfilling and replacing the gravel (12) and soil (13) and compacting them; Step 3: Install galvanized steel wire mesh (15), pour foam concrete (6); construct lime soil leveling layer (14), and lay HPDE waterproof geomembrane (3); Step 4: Install the prefabricated concrete inner wall (8) below the drainage hole (7) of the prefabricated cantilever reinforced concrete retaining wall (5), and then install the prefabricated side ditch outer wall (10); Step 5: Building a mobile formwork system. A winch (31) is installed on the upper part of the square steel cross beam (42), and a slide groove (47) is arranged on the upper part of the square steel longitudinal beam (41); the suspension rod (43) is fixed to the embedded slide rod (48), and the winch (31) pulls the suspension rod (43) to drive the mobile steel formwork (33) to perform cast-in-place concrete full protection (4) construction; the mobile operating platform structure is fixedly connected to the prefabricated cantilever reinforced concrete retaining wall (5) through the anti-overturning pull rod (36), and after the construction is completed, the connection is removed and moved, and then fixed again; the mobile formwork system includes a counterweight block (29), a counterweight rod (30), a winch (31), a steel wire rope (32), a mobile steel formwork (33), a base (40), a square steel longitudinal beam (41), a square steel cross beam (42), a suspension rod (43), a pull ring (44), an adjustable screw (46), a slide groove (47), an embedded slide rod (48), a small pulley (4 9) and a triangular crossbeam pad (50); the square steel longitudinal beam (41), the square steel crossbeam (42), and the triangular crossbeam pad (50) are all connected by bolts, and the triangular crossbeam pad (50) is supported on the top of the prefabricated cantilever reinforced concrete retaining wall (5). After assembly at the construction location, the hoisting base (40) is fixed to the square steel crossbeam (42), and a winch (31) is installed on the upper part of the base (40), wherein a counterweight rod (30) is arranged on the base (40), and a counterweight block (29) is placed on the upper part of the counterweight rod (30); a slide groove (47) is arranged on the upper part of the square steel longitudinal beam (41); the suspension rod (43) is welded and fixed to the embedded sliding rod (48), a small pulley (49) is arranged on the embedded sliding rod (48), and a pull ring (44) is arranged in the middle of the suspension rod (43); the movable steel template (33) and the suspension rod (43) are connected and fixed by an adjustable screw rod (46).

2. The construction method of cast-in-place concrete full-protection foam lightweight soil widening embankment according to claim 1 is characterized in that: The construction method of widening the embankment at the bridgehead section specifically includes the following steps: Step 1: driving steel sheet piles (20), excavating the bridge head section to widen the embankment foundation trench, and constructing a crushed stone cushion layer (21); Step 2: constructing a cantilever retaining wall at the bridge head (23); Step 3: Replace the gravel (12) and clay (24) and compact them; Step 4: Install the galvanized steel wire mesh (15) at the designed position, pour the foamed concrete (6) and maintain it; Step 5: removing the steel sheet piles (20) and backfilling the empty slots of the steel sheet piles (20); Step 6: construct a lime soil leveling layer (14) and lay a HPDE waterproof geomembrane (3).

3. The construction method of cast-in-place concrete full-protection foam lightweight soil widening embankment according to claim 2 is characterized in that: After the construction of the standard section widened embankment and the bridgehead section widened embankment is completed, the pavement structure (2) and the concrete guardrail (1) are constructed.

4. The construction method of cast-in-place concrete full-protection foam lightweight soil widening embankment according to claim 1 is characterized in that: During the construction of the standard section widening embankment, the prefabricated cantilever reinforced concrete retaining wall (5), the prefabricated concrete inner wall (8), and the prefabricated side ditch outer wall (10) are all factory prefabricated components, wherein the prefabricated cantilever reinforced concrete retaining wall (5) is provided with embedded parts (37) and drainage holes (7), the prefabricated side ditch outer wall (10) is L-shaped, and the prefabricated concrete inner wall (8) includes an inclined panel (25), a lap groove (26), an upper lap plate (27), and a lower lap plate (28).

5. The construction method of cast-in-place concrete full-protection foam lightweight soil widening embankment according to claim 1 is characterized in that: During the construction of the standard section widening embankment, the height of the movable steel formwork (33) is adjusted according to construction needs through the adjustable screw rod (46); the hoist (31) is connected to the pull ring (44) provided in the middle of the suspension rod (43) through the steel wire rope (32) to pull the suspension rod (43) to move, thereby driving the movable steel formwork (33) to perform cast-in-place concrete full protection (4) construction; after the construction is completed, the counterweight block (29) is removed, and the entire formwork system is moved as a whole by the crane, and the above steps are repeated.

6. The construction method of cast-in-place concrete full-protection foam lightweight soil widening embankment according to claim 1 is characterized in that: During the construction of the standard section widening embankment, the mobile operating platform structure includes a steel support (38), an operating platform (35) and a safety net (34); the steel support (38) with a pulley (39) is hoisted as a whole, and the steel support (38) is fixedly connected to the embedded parts (37) on the prefabricated cantilever reinforced concrete retaining wall (5) through an anti-overturning tie rod (36), and the operating platform (35) and the safety net (34) are arranged on the top of the steel support (38); after the construction is completed, the anti-overturning tie rod (36) and the embedded parts (37) on the prefabricated cantilever reinforced concrete retaining wall (5) are removed and the steel support (38) is moved to the next construction and re-fixed in the above manner.

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