CN112411288A

CN112411288A - Geotextile-containing light soil widened embankment anti-floating structure and construction method thereof

Info

Publication number: CN112411288A
Application number: CN202011286588.3A
Authority: CN
Inventors: 张振; 秦粮凯; 叶观宝; 沈鸿辉
Original assignee: Tongji University
Current assignee: Tongji University
Priority date: 2020-11-17
Filing date: 2020-11-17
Publication date: 2021-02-26

Abstract

The invention provides a light soil widening embankment anti-floating structure containing geotextiles and a construction method thereof, belonging to the technical field of roadbed engineering. The widened embankment anti-floating structure includes the original subgrade, the widened subgrade, an anchor rod with a fixed end, a geocell, a waterproof layer, a sand cushion layer, an anti-seepage membrane and a discarded scaffolding fastener. A stepped step is arranged between the original roadbed and the widened roadbed; the anchor rod is a waste steel pipe, and the anchor rod is provided with a fixed end, and the fixed end is embedded in the original roadbed or a hard roadbed In order to meet the anti-floating requirements, the diameter of the fixed end is 3 to 5 times the diameter of the steel pipe; a layer of sand cushioning layer is laid on the surface of the original roadbed or hard roadbed, and a multi-layer sand cushion layer is arranged above the cushioning layer. For geocells, each layer of geocells is filled with foamed light soil, and one end of the other geocells is fixed on the stepped structure of the embankment to be widened, and so on.

Description

Geotextile-containing light soil widened embankment anti-floating structure and construction method thereof

Technical Field

The invention relates to the technical field of roadbeds, in particular to a light soil widened embankment anti-floating structure containing geotextile and a construction method thereof.

Background

The urban group integrated development brings high-strength transportation demands, and the original highway can not meet the demands of travel and logistics, so that the contradiction between supply and demand of transportation is made obvious and is further aggravated. Highway widening is one of the main ways of expanding the capacity of existing roads and improving service capacity. The widening and expanding of the roadbed not only needs to reinforce the original roadbed defects and improve the bearing capacity of the roadbed defects, but also needs to solve the problem of uneven settlement of the old roadbed and the new roadbed defects caused by excessive uneven settlement. If the uneven settlement is too large, longitudinal cracks of the road surface may appear at the joint of the old and new road beds.

The bubble lightweight concrete can effectively reduce the sedimentation influence of dead weight load on a new roadbed and an old roadbed due to low density. But easily cause anti floating destruction to the low-lying highway section of easy ponding, in order to balance the buoyancy that groundwater produced, set up anti floating measure in widening the road bed to satisfy the whole anti floating stability of road bed.

Disclosure of Invention

In order to overcome the defects in the background art, the invention discloses a light soil widened embankment anti-floating structure containing geotextile and a construction method thereof. The technical measure of the invention is that the problems of poor overall stability of the roadbed in the existing roadbed widening and reforming process can be effectively solved by adopting old roadbed excavation steps, geosynthetic material reinforcement, bubble lightweight concrete filler and the like. The foamed lightweight concrete is used as a widened roadbed filling material, so that the influence of self-weight load on settlement can be effectively reduced; one end of an anchor rod is fixed in the road bed, so that the anti-floating capacity of the anchor rod can be improved; the local hardening area can effectively increase the action range of the anti-floating anchor rod, so that the anchor rod can fully exert the anti-floating capacity.

In order to achieve the purpose, the invention adopts the following technical scheme:

a light soil widened embankment anti-floating structure containing geotextile comprises an original roadbed (1), a new roadbed, a roadbed (13), anchor rod piles (8), geocell chambers (7) and clay covered edges (6), wherein the anchor rod piles (8), the geocell chambers (7) and the clay covered edges form the new roadbed; the new roadbed is the widened roadbed, and light soil filling materials are filled in the new roadbed; the soil engineering anti-seepage waterproof sand bed further comprises a waterproof layer (2), a soil engineering anti-seepage film (3) and a sand cushion layer (10); also comprises a drainage groove (11); the anchor rod piles (8) are a plurality of and are indirectly separated, and each anchor rod pile (8) is vertically distributed in the widened roadbed; the geocell (7) is distributed in the widened roadbed in a multi-layer mode; a step-shaped step is arranged between the original roadbed and the widened roadbed; the waterproof layer (2) is positioned on the vertical surface of the step-shaped step and is fixed between the widened roadbed and the old roadbed (1); the stone building layer (10) is arranged on the outer side of the widened roadbed and plays a role in protecting the outer surface of the roadbed.

Preferably, the anchor rod pile is a waste anchor rod, a fixed end is arranged at the bottom of the anchor rod, and the fixed end is embedded in an original roadbed or a hard roadbed.

Preferably, the diameter of the fixed end is 3-5 times of the outer diameter of the anchor rod; the anchor rods are embedded in the light soil filling material.

Preferably, the cell sheets of the geocell are distributed in a square shape, and the side length of each square hole is 5cm, so that a net-shaped structure is formed; the crossing department of geotechnological check room and stock is equipped with local sclerosis district to set up discarded scaffold fastener directly over local sclerosis district, prevent the come-up.

Preferably, a sand cushion layer is laid on the roadbed, a plurality of layers of geocell chambers are arranged above the sand cushion layer, foamed light soil is filled above each layer of geocell chamber, the lowest geocell chamber is laid on the sand cushion layer, one ends of the geocell chambers of the other layers are fixed on a step-shaped structure of the embankment to be widened, the other ends of the geocell chambers are fixed on the foamed light soil below the geocell chambers, the foamed light soil is located at one end, opposite to the embankment to be widened, of the filled clay edge, the top surface of the foamed light soil at the top layer is flush with the top surface of the embankment to be widened, and an impermeable membrane is laid.

Preferably, the step surface of the step-shaped structure is an inward-inclined step surface, and the inward-inclined gradient is 3% -5%.

Preferably, a drainage channel is arranged on the sand cushion layer on the outer side of the clay edge covering.

Preferably, the waterproof layer is located on the vertical surface of the stepped step and fixed between the widened roadbed and the old roadbed.

Preferably, the geotextile-containing lightweight soil widened embankment anti-floating structure and the construction method thereof comprise the following steps:

step 1: and excavating the embankment to be widened into step-shaped steps. The inner inclination of the step surface is 3-5%, the width of the step surface is 1.0-2.0 m, the height is 0.5-1.0 m, and the surface of the step is roughened.

Step 2: and reinforcing the roadbed at the side, needing to be widened, of the embankment to be widened to ensure that the bearing capacity of the roadbed to be widened is not lower than 8OkPa, and leveling the surface of the roadbed to be widened to ensure that the camber transverse gradient of the surface of the embankment to be widened is 3-5%.

And step 3: and (4) drilling on the road bed by using the high-pressure rotary jet drilling machine to form an enlarged head hole, wherein when the drilling depth reaches the designed depth, the high-pressure rotary jet drilling machine stops and withdraws the drill bit and the drill rod from the formed hole. And then, a waste steel pipe with a certain length is fixed at the center of the enlarged head hole, and the outer diameter of the waste steel pipe is 48 mm. And then grouting into the enlarged head hole, and vibrating by a vibrator to uniformly mix the water slurry, the medium sand and the broken stones to form a fixed end.

And 4, step 4: when the concrete slurry is solidified to reach 75% of the designed strength, a sand cushion layer with the thickness of about 15cm is paved on the surface layer of the roadbed, compaction and leveling are carried out, the maximum grain diameter is not more than 5cm, and the compaction degree is not less than 91%.

And 5: the waterproof layer is laid on the vertical surface of each step, then the geocell at the bottom layer is directly laid on the sand bedding layer, then the foam light soil is filled above the geocell, the foam light soil is poured to be flush with the first step, and after certain strength is reached, the geocell is laid.

Step 6: the reinforcing bars are fixed at preset positions at the joint of the reinforcing bars and the anchor rods, concrete is poured, after certain strength is achieved, a local hardening area is formed, and waste scaffold fasteners are fixed right above the local hardening area to prevent floating.

And 7: and (5) repeating the step (5) and the step (6) in the construction of other steps, wherein one end of the geocell is fixed on a step-shaped structure formed by the embankment to be widened, the other end of the geocell is fixed on the foamed light soil below the geocell, the foamed light soil is positioned at one end, opposite to the embankment to be widened, of the opposite side, the clay is filled and covered, the top surface of the foamed light soil at the topmost layer is flush with the top surface of the embankment to be widened.

The light soil widened embankment anti-floating structure containing the geotextile, provided by the invention, not only effectively reduces differential settlement and pavement cracking between new and old roadbeds and prolongs the service life of roadbeds and pavements, but also solves the problem of anti-floating stability of the light soil widened embankment. The invention also discloses a construction method of the anti-floating structure, and provides reference for workers in the field of roadbed engineering.

Drawings

FIG. 1 is a schematic partial cross-sectional view of an embodiment of the present invention.

Fig. 2 is a schematic view of a geocell layer of the present invention.

FIG. 3 is a schematic view of a localized hardening zone of the present invention.

FIG. 4 is a diagram of the local hardening zone reinforcement of the present invention.

Figure 5 is a schematic view of a discarded scaffold fastener of the present invention.

Reference numbers in the figures: 1. an original roadbed; 2. a waterproof layer; 3. a geotechnical impermeable film; 4. a discarded scaffold fastener; 5. a localized hardened zone; 6. clay edge covering; 7. a geocell; 8. anchor rod piles; 9. a fixed end; 10. a sand bedding layer; 11. a water discharge tank; 12. an impermeable layer; 13. a road bed;

14. an outer contour line; 15. reinforcing bars; 16. an inner contour;

17. fixing the bolt; 18. a connecting member.

Detailed Description

The present invention will be further described with reference to fig. 1 to 5. It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

A light soil widened embankment anti-floating structure containing geotextile and a construction method thereof belong to the technical field of roadbed engineering. The widened embankment anti-floating structure comprises an original roadbed, a widened roadbed, an anchor rod with a fixed end, a geocell, a waterproof layer, a sand cushion layer, an impermeable film and an abandoned scaffold fastener. A step-shaped step is arranged between the original roadbed and the widened roadbed; the anchor rod is a waste steel pipe and is provided with a fixed end, and the fixed end is embedded in an original roadbed or a hard roadbed; in order to meet the anti-floating requirement, the diameter of the fixed end is 3-5 times of that of the steel pipe; laying a sand cushion layer on the surface of an original roadbed or a hard roadbed, wherein a plurality of layers of geocell are arranged above the sand cushion layer, foam light soil is filled above each layer of geocell, one end of each geocell of the other layers is fixed on a step-shaped structure arranged on the embankment to be widened, the other end of each geocell of the other layers is fixed on the foam light soil below the geocell, the top surface of the foam light soil at the topmost layer is flush with the top surface of the embankment to be widened, and a geotechnical impermeable membrane is laid; at the intersection of the anchor rod and the geocell, local hardening treatment is carried out on the geocell, and a waste scaffold fastener is arranged right above the hardening treatment; the waterproof layer is located on the vertical surface of the step-shaped step and fixed between the new roadbed and the old roadbed.

A light soil widened embankment anti-floating structure containing geotextile and a construction method thereof are disclosed, the method comprises the following steps:

the light soil widened embankment anti-floating structure comprises an original roadbed (1), a waterproof layer (2), a geotechnical anti-seepage film (3), a local hardening area (5), clay covered edges (6), geotechnical cells (7), anchor rods (8), a sand cushion layer (10), a drainage channel (11), an anti-seepage layer (12) and a roadbed (13). And a step-shaped step is arranged between the original roadbed and the widened roadbed.

And step two, the anchor rod pile (8) is a waste anchor rod, a fixed end (9) is arranged at the bottom of the anchor rod (8), and the fixed end (9) is embedded in the original roadbed (1) or the hard roadbed (13).

Thirdly, the diameter of the fixed end (9) is 3-5 times of the outer diameter of the anchor rod (8); the anchor rods (8) are pre-buried in the light soil filling material.

Step four, the grid cell sheets of the geocell (7) are distributed in a square shape, the side length of the square hole is 5cm, and a net-shaped structure is formed; geocell (7) are equipped with local hardening district (5) with crossing department of stock (8) to set up discarded scaffold fastener (4) directly over local hardening district (5), prevent the come-up.

And fifthly, paving a sand cushion layer (10) on the roadbed (13), arranging a plurality of layers of geocell chambers (7) above the sand cushion layer (10), filling foamed light soil above each layer of geocell chamber, paving the lowest geocell chamber on the sand cushion layer, fixing one ends of the geocell chambers of other layers on a step-shaped structure of the embankment to be widened, fixing the other ends of the geocell chambers on the foamed light soil below the geocell chambers, filling clay covered edges (6) at one ends of opposite sides of the embankment to be widened, leveling the top surface of the foamed light soil at the top layer with the top surface of the embankment to be widened, and paving a geotechnical impermeable membrane (3).

Step six, adopting an inward-inclined step surface as the step surface of the step-shaped structure, wherein the inward-inclined gradient is 3% -5%.

And seventhly, arranging a drainage channel (11) on the sand cushion layer on the outer side of the clay covered edge (6).

And step eight, the waterproof layer (2) is positioned on the vertical surface of the step-shaped step and fixed between the widened roadbed and the old roadbed (1).

Further, the invention also discloses a light soil widened embankment anti-floating structure containing geotextile and a construction method thereof, and the light soil widened embankment anti-floating structure comprises the following steps:

The above embodiments and drawings are not intended to limit the form and style of the present invention, and any suitable changes or modifications thereof by those skilled in the art should be considered as not departing from the scope of the present invention. On the basis of the technical scheme of the invention, various modifications or changes which can be made by a person skilled in the art without creative efforts are still within the protection scope of the invention.

Claims

1. An anti-floating structure of a light-weight soil widening embankment containing a geotextile, comprising an original roadbed (1), a new roadbed, a roadbed (13), an anchor pile (8), a geocell (7) and a clay edging (6), the structures of the anchor rod (8), the geocell (7) and the clay edging form a new roadbed; the new roadbed is to widen the roadbed, which is filled with light soil filling materials;

It also includes a waterproof layer (2), a geotechnical impermeable membrane (3), and a sand cushion layer (10);

Also includes a drainage channel (11);

The anchor piles (8) are divided indirectly, and each anchor pile (8) is vertically distributed in the widened subgrade; the geocells (7) are multi-layered and distributed horizontally in the widened subgrade;

A stepped step is arranged between the original roadbed and the widened roadbed; the waterproof layer (2) is located on the vertical surface of the stepped step and is fixed between the widened roadbed and the old roadbed (1). The masonry layer (10) is arranged on the outer side of the widened roadbed to protect the outer surface of the road surface.

2. The lightweight soil widening embankment anti-floating structure containing geotextile according to claim 1, characterized in that: the bottom of the anchor pile (8) is provided with a fixed end (9), and the fixed end ( 9) Buried in the original roadbed (1) or the hard roadbed (13).

3. The anti-floating structure of a light-weight soil widening embankment containing a geotextile according to claim 2, characterized in that: the diameter of the fixed end (9) is equal to the outer diameter of the anchor pile (8). 3 to 5 times; the anchor piles (8) are pre-buried in the lightweight soil filling material.

4. A light-weight soil widening embankment anti-floating structure containing a geotextile according to claim 1, characterized in that: the cell sheets of the geocell (7) are distributed in a square shape, and the edges of the square hole are distributed in a square shape. The length is 5cm, forming a mesh structure; a local hardening zone (5) is provided at the intersection of the geocell (7) and the anchor pile (8), and an abandoned scaffolding buckle is set directly above the local hardening zone (5). (4) to prevent floating.

5. The light-weight soil widening embankment anti-floating structure containing geotextile according to claim 1, characterized in that: a sand bed (10) is laid on the road bed (13), and the sand bed (10) There are multi-layer geocells (7) above, each layer of geocells is filled with foam light soil, the bottom geocell is laid on the cushion sand layer, and one end of the other geocells is fixed to the to-be-expanded geocell. On the stepped structure opened by the wide embankment, the other end is fixed on the foam light soil under the geocell. The foam light soil is located on the opposite side of the embankment to be widened. The top surface of the soil is flush with the top surface of the embankment to be widened, and a geotechnical anti-seepage membrane (3) is laid.

6 . The anti-floating structure of a light soil widening embankment containing a geotextile according to claim 1 , wherein the stepped surface of the stepped structure adopts an inclination stepped surface, and the inclination gradient is 3% to 5%. 7 .

7 . The anti-floating structure of a light-weight soil widening embankment containing a geotextile according to claim 1 , wherein a drainage groove ( 11 ) is provided on the cushion sand layer outside the clay edging ( 6 ). 8 .

8 . The anti-floating structure of a light soil widening embankment containing a geotextile according to claim 1 and a construction method thereof, characterized in that: the waterproof layer (2) is located on the vertical side of the stepped steps. 9 . surface and fixed between the widened roadbed and the old roadbed (1).

9. the construction method of a kind of light soil widening embankment anti-floating structure containing geotextile as claimed in claim 1, is characterized in that: comprise the steps:

Step 1: The embankment to be widened is excavated into stepped steps; the inclination gradient of the step surface is 3% to 5%, the width of the step surface is 1.0m to 2.0m, and the height is 0.5m to 1.0m, and the surface of the step is chiseled. deal with;

Step 2: Reinforce the roadbed on the widened side of the embankment to be widened, so that the bearing capacity of the roadbed to be widened is not less than 8OkPa, and carry out surface leveling, so that the lateral slope of the embankment to be widened is 3% to 5%. %;

Step 3: Use the high-pressure rotary jet drilling machine to drill on the roadbed to form the enlarged head hole, wherein when the drilling depth reaches the design depth, the high-pressure rotary jet drilling machine stops and withdraws the drill bit and the drill pipe from the hole; then expand A certain length of waste steel pipe is fixed at the center of the head hole, and its outer diameter is 48mm; then grouting is poured into the enlarged head hole, and vibrated by a vibrator, so that the water slurry, medium sand and gravel are evenly mixed to form a fixed end ;

Step 4: When the concrete slurry solidifies and reaches 75% of the design strength, lay a sand cushion layer with a thickness of about 15cm on the surface of the roadbed, and carry out compaction and leveling. The maximum particle size does not exceed 5cm, and the compaction degree is not below 91%;

Step 5: Lay a waterproof layer on the vertical surface of each step, then directly lay the bottommost geocell on the sand cushion layer, and then fill the foam light soil above the geocell, and pour it in the same way as the first step. After reaching a certain strength, lay the geocell;

Step 6: Fix the reinforcement in the predetermined position at the junction with the anchor rod, and pour concrete. After reaching a certain strength, a local hardening area is formed, and the discarded scaffolding fasteners are fixed directly above it to prevent floating;

Step 7: Repeat steps 5 and 6 for the rest of the steps. One end of the geocell is fixed on the stepped structure of the embankment to be widened, and the other end is fixed on the foam light soil under the geocell. The end on the opposite side of the embankment to be widened is filled with clay edging, the top surface of the top foam light soil is flush with the top surface of the embankment to be widened, and a geotechnical anti-seepage membrane is laid.