CN215593509U - Cutting structure of ballastless track of strong expansion rock section - Google Patents

Abstract

The utility model relates to a ballastless track cutting structure of a strong expansive rock-soil section, which comprises a backfill layer arranged below the surface layer of a foundation bed, a water seepage blind ditch arranged at the center of a roadbed below the backfill layer, a water prevention and drainage layer arranged at a position outside the water seepage blind ditch arranged at the center below the backfill layer, lateral ditches and platforms arranged at two sides of the roadbed of the backfill layer respectively, slope protection arranged on slopes at two sides of the roadbed, and anchoring piles arranged on the bottom slope toe of the slope protection at least at one side. The method is suitable for mechanical construction, can quickly seal and reduce the exposure time of the expansive rock soil, and has the characteristics of safety, reliability, high construction efficiency and low construction cost.

Description

Cutting structure of ballastless track of strong expansion rock section

Technical Field

The utility model belongs to the field of ballastless track high-speed railways, and particularly relates to a cutting structure of a ballastless track of a strong expansion rock section.

Background

The expansive rock soil is a special rock soil with the characteristics of repeated expansion and contraction, lower strength, more cracks and the like, has poor engineering properties, has extremely large change of mechanical properties after meeting water, and is very easy to cause disasters such as collapse, landslide and the like. According to the design specification of railway subgrade, the design of the expansive soil cutting slope follows the principle of combining the slope slowing rate, the wide platform, the reinforced slope toe and the proper slope protection.

The general structure form of the ballastless track subgrade of the strongly expansive rock-soil section is shown in figure 1. The foundation bed is characterized in that a replacement filling layer 2 is arranged below a foundation bed surface layer 1, side ditches and platforms 4 are arranged on two sides of a roadbed of the replacement filling layer 2 respectively, water seepage blind ditches 5 are arranged below the side ditches and the platforms 4, slope protection 7 is arranged on slope surfaces on two sides of the roadbed, and anchoring piles 6 are arranged on bottom slope feet of the slope protection 7 on at least one side.

The ballastless track has extremely strict requirements on roadbed deformation, and particularly the upward arch deformation value is only 4mm in terms of the adjustable amount of the track. The method mainly comprises a replacement filling method, a drainage water retention method and a pile plate structure method, wherein the replacement filling and drainage water retention method is mainly adopted as measures for controlling the upward arching deformation of the expansive rock soil, the bottom surface of a water seepage blind ditch of a general section is 0.2m lower than the bottom surface of a replacement filling layer, the replacement filling or drainage depth needs to be increased for the strong expansive rock soil, and the increase of the water seepage blind ditch depth is relatively economical.

But strong expansion rocks such as shale still have the characteristic of low strength usually, because drainage french drain 5 sets up in roadbed face both sides, the height of face sky has been showing to increase during the excavation, under the requirement that strong expansion rock soil increases infiltration french drain degree of depth, need further strengthen temporary support engineering (anchor pile 6) in the work progress in order to guarantee that the slope is stable, the height of supporting engineering design with infiltration french drain 5 bottom surface to supporting construction (anchor pile 6) top surface is as the cantilever segment length, anchor length generally is according to 1 in the engineering: 1, the design is considered, so that the length of the supporting structure is greatly increased, and the engineering investment is large.

Meanwhile, the traditional drainage-preventing layer adopts medium-coarse sand sandwiched with two pieces of membrane geotextile, is arranged below the replacement and filling layer 2, and if the drainage-preventing layer and the foundation bed filling (the replacement and filling layer 2 and the foundation bed surface layer 1) are constructed after the water seepage blind ditch construction is finished, the exposure time of the expansive rock soil is longer; if the drainage layer and the foundation bed are constructed and filled firstly, and then the blind ditches 5 with water seepage on two sides are excavated, secondary excavation is needed.

Disclosure of Invention

The utility model aims to solve the problem of providing a cutting structure form of a ballastless track of a strong expansive rock-soil section, which is particularly suitable for mechanical construction, can quickly seal and reduce the exposure time of expansive rock-soil and has the characteristics of safety, reliability, high construction efficiency and low construction cost.

The technical scheme adopted by the utility model for solving the technical problems is as follows:

the utility model provides a strong inflation ground section ballastless track cutting structure, includes that bed top layer below is for changing the filling layer, and the roadbed center of changing the filling layer below sets up the infiltration french drain, and it sets up the drainage layer to change the position outside the filling layer below center sets up the infiltration french drain, and the roadbed both sides of changing the filling layer are provided with side ditch and platform respectively, are equipped with domatic protection on the domatic of roadbed both sides.

And the surface layer of the foundation bed is filled with graded broken stones. The filling layer is filled with the bed bottom filler; the top surface of the filling layer is convex, the bottom surface of the filling layer is concave, and the transverse drainage gradient is not less than 4 percent, preferably 4 to 5 percent. The water-proof and drainage layer is of a reinforced concrete structure and has the whole thickness of 20 cm; and a reinforcing steel bar net piece is arranged in the middle of the waterproof and drainage layer, the diameter of the reinforcing steel bar is 6mm, and the size of the grid is 10cm multiplied by 10 cm. A sand-free concrete cover plate is arranged at the top of the water seepage blind ditch; the bottom surface of the water seepage blind ditch is lower than the bottom surface of the filling layer by more than 0.2m, and is preferably lower than the bottom surface of the filling layer by more than 2 m. The bottom slope toe of the slope surface protection on at least one side is provided with an anchor pile, the anchor pile can adopt a circular or rectangular reinforced concrete structure, a mechanical drilling construction mode is suitable to be adopted, and the instability risk is favorably reduced under the condition that the cutting slope is high, bedding or unfavorable structural surfaces and the like are easy to destabilize.

Compared with the prior art, the utility model has the beneficial effects that: by adopting the technical scheme, a user can use large machinery to carry out rapid construction, the blind ditch is deepened, the instability risk of the temporary side slope and the foundation pit can be reduced, the supporting engineering cost is reduced, and the method has the characteristics of safety, reliability, high construction efficiency, low construction risk and high economy and has popularization and application values.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the utility model and, together with the description, serve to explain the utility model and not to limit the utility model. In the drawings:

FIG. 1 is a schematic cross-sectional view of a ballastless track roadbed structure of a strong expansive rock-soil section in the prior art;

FIG. 2 is a schematic cross-sectional view of a cutting structure of a ballastless track of a strongly expansive rock-soil zone in the utility model;

FIGS. 3-4 are shale topography maps of the construction sites of the present invention.

Wherein:

1. bed surface layer 2, replacement and filling layer 3 and drainage prevention layer

4. Side ditches and platforms 5, water seepage blind ditches 6 and anchoring piles

7. Slope surface protection

Detailed Description

For a better understanding of the present invention, reference is made to the following detailed description taken in conjunction with the accompanying drawings. Technical terms used in the following description have the same meanings as commonly understood by one of ordinary skill in the art to which the present invention belongs.

As shown in figure 2, the cutting structure of the ballastless track of the strong expansive rock-soil section comprises a replacement and filling layer 2 below a foundation bed surface layer 1, a water seepage blind ditch 5 is arranged at the center of a roadbed below the replacement and filling layer 2, a water prevention and drainage layer 3 is arranged at a position other than the water seepage blind ditch 5 at the center below the replacement and filling layer 2, side ditches and platforms 4 are respectively arranged on two sides of the roadbed of the replacement and filling layer 2, and slope protection 7 is arranged on slopes on two sides of the roadbed.

The bottom toe of the slope protection 7 on at least one side can be provided with an anchoring pile 6 according to the requirement. When the side slope is high or bedding condition exists, the anchor piles 6 need to be arranged, and the following conditions are specifically included: (1) if slope protection 7 on both sides is all higher then both sides all set up anchor pile 6, (2) if slope protection 7 on both sides is all lower, also do not have the problem of following the layer, can not set up, (3) if there is one side to have the following the layer, then regardless of slope protection 7 height all set up anchor pile 6. The situation is illustrated in fig. 2 where the anchor piles 6 are provided on one side only.

The surface layer 1 of the foundation bed is filled with graded broken stones. The replacement and filling layer 2 is filled by adopting foundation bed bottom layer fillers, such as A, B groups of gravel and sand soil fillers; the top surface of the filling layer 2 is convex, the bottom surface is concave, and the transverse drainage gradient is not less than 4%, preferably 4-5%. The waterproof and drainage layer 3 is of a reinforced concrete structure and has the whole thickness of 20 cm; and a reinforcing steel bar net piece is arranged in the middle of the waterproof and drainage layer 3, the diameter of the reinforcing steel bar is 6mm, and the size of the grid is 10cm multiplied by 10 cm. The top of the water seepage blind ditch 5 is provided with a sand-free concrete cover plate, which is convenient for the construction of the reinforced concrete water-proof and drainage layer 3; the bottom surface of the water seepage blind ditch 5 is more than 0.2m lower than the bottom surface of the backfill layer 2, and preferably more than 2m lower than the bottom surface of the backfill layer 2. The anchor pile 6 can adopt a circular or rectangular reinforced concrete structure, a mechanical drilling construction mode is suitable to be adopted, and the instability risk is favorably reduced under the condition that the cutting side slope is high, and the bedding or unfavorable structural surface and the like are easy to destabilize.

The construction of the ballastless track cutting structure of the strong expansive rock-soil section adopts the following method: firstly, cutting excavation and slope protection 7 and anchor pile 6 construction are carried out. Excavating a foundation pit of the filling layer 2 after the anchoring pile 6 reaches the design strength, immediately paving a prefabricated reinforcing mesh after the excavation is in place, spraying C25 concrete, completing the construction of the side wall outside the center position of the foundation pit and the waterproof and drainage layer 3 near the slope toe, reducing the disturbance to the strong expansive rock-soil foundation as much as possible, and ensuring the safety of the temporary side slope and the foundation pit; then constructing a water seepage blind ditch 5, wherein the bottom surface of the water seepage blind ditch 5 is 2m lower than the bottom surface of the replacement and filling layer 2; after the construction of the water seepage blind ditch 5 is finished, the construction of the residual water-proof and drainage layer 3 nearby is finished, the water-proof and drainage layer 3 can be constructed mechanically, and the construction speed is high; after the concrete of the water-proof and drainage layer 3 is finally set, the filling layer 2 can be replaced by large-scale mechanical layered filling, so that the construction speed is high; then constructing a side ditch and a platform 4, and finally constructing a foundation bed surface layer 1.

According to the structural scheme, the water seepage blind ditch 5 is arranged in the center of the roadbed surface, so that the depth of the water seepage blind ditch 5 can be increased to be more than 2m lower than the bottom surface of the filling layer 2, the risk of upwarp deformation is relieved, meanwhile, the water seepage blind ditch 5 is far away from the cutting slope toe, and the instability risk of a temporary slope during construction is reduced. The height from the bottom surface of the filling layer 2 to the top surface of the anchor pile 6 can be used as the length of the cantilever when the anchor pile 6 is designed, so that the length of the anchor pile 6 is greatly reduced, and the number of supporting projects is reduced. The convex-concave design of the backfill layer 2 increases the thickness of the backfill layer 2 and enhances the capability of the foundation bed to resist the deformation of the upper arch. The water-proof and drainage layer 3 is made of reinforced concrete, so that the aims of following excavation and protection and quick sealing are fulfilled.

The main structure of the utility model has been practically applied in the high-speed rail engineering construction:

a high-speed railway of a certain ballastless track passes through a mud shale stratum hilly area in the form of a roadbed and a bridge, and the accumulated line length is about 23 km. The mud shale with light gray, dark gray and brown gray is of a layered structure (shown in figures 3-4), has strong expansibility and is easy to weather and disintegrate, cracks develop extremely after the fully weathered and strongly weathered layer is excavated, the strength of a rock mass is extremely low, and the strength of the rock mass is reduced rapidly when the rock mass meets water.

In order to ensure that the slope stability and the foundation bed deformation of the ballastless track strong-expansion rock-soil cutting meet the requirements, a embankment type cutting structure is designed, as shown in figure 2. The surface layer 1 of the foundation bed is higher than the side ditch and the platform 4, and is filled with graded broken stones, and the thickness of the foundation bed is 0.4 m; the whole replacement is carried out within the thickness range of the foundation bed, and the replacement and filling layer 2 adopts A, B groups of fillers and has the thickness of 2.1 m; the bottom surface of the filling layer is provided with a waterproof and drainage layer 3 with the thickness of 0.2 m; the slope feet at two sides are provided with ground drainage side ditches and platforms 4 which are made of reinforced concrete, the section size is not less than 0.6m multiplied by 0.6m, and the wall thickness is 0.2 m; the water seepage blind ditch 5 is arranged in the center of the roadbed surface, and the bottom surface is 2m lower than the bottom surface of the filling layer 2. The bedding side slope and the slope foot of the high side slope are reinforced by anchor piles 6, the anchor piles are circular cast-in-situ bored piles, the pile diameter is 1.2m, the pile spacing is 1.5-3 m, the pile top is 3-4 m higher than the side ditch and the platform 4, and the pile length is 10-12 m.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the utility model, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims (9)

1. The utility model provides a strong inflation ground section ballastless track cutting structure, includes that bed top layer (1) below is for filling layer (2), and the roadbed center of filling layer (2) below sets up infiltration french drain (5), and the position that fills layer (2) below center set up outside infiltration french drain (5) sets up prevents drainage blanket (3), and the roadbed both sides of filling layer (2) are provided with side ditch and platform (4) respectively, are equipped with domatic protection (7) on the domatic of roadbed both sides.

2. The cutting structure of the ballastless track of the strongly expansive rock-soil section according to claim 1, wherein the bed surface layer (1) is filled with graded crushed stones.

3. The cutting structure of the ballastless track of the strongly expansive rock-soil section according to claim 1, wherein the backfill layer (2) is filled with bedding underfill; the top surface of the filling layer (2) is convex, the bottom surface is concave, and the transverse drainage gradient is not less than 4%.

4. The cutting structure of the ballastless track of the strongly expansive rock-soil section according to claim 3, wherein the transverse drainage gradient of the backfill layer (2) is 4-5%.

5. The cutting structure of the ballastless track of the strongly expansive rock-soil section according to claim 1, wherein the water-proof and drainage layer (3) is of a reinforced concrete structure and has a thickness of 20 cm; and a reinforcing steel bar net piece is arranged in the middle of the waterproof and drainage layer (3), the diameter of the reinforcing steel bar is 6mm, and the size of the grid is 10cm multiplied by 10 cm.

6. The cutting structure of the ballastless track of the strongly expansive rock-soil section according to claim 1, wherein a non-sand concrete cover plate is arranged on the top of the water seepage blind ditch (5); the bottom surface of the water seepage blind ditch (5) is lower than the bottom surface of the filling layer (2) by more than 0.2 m.

7. The cutting structure of the ballastless track of the strongly expansive rock-soil section according to claim 6, wherein the bottom surface of the water seepage blind ditch (5) is lower than the bottom surface of the backfill layer (2) by more than 2 m.

8. The cutting structure of ballastless tracks of strongly expansive geotechnical zone according to claim 1, characterized in that the bottom toe of the slope protection (7) on at least one side is provided with an anchor pile (6).

9. The cutting structure of the ballastless track of the strongly expansive rock-soil section according to claim 8, wherein the anchor piles (6) are of a circular or rectangular reinforced concrete structure.

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