CN219604048U

CN219604048U - Existing railway high-filling roadbed widening structure

Info

Publication number: CN219604048U
Application number: CN202320825894.2U
Authority: CN
Inventors: 聂文峰; 刘欢; 王识; 芶文锦; 尹述遥; 孙希望; 邱绍富; 李能; 王卫斌; 任庆慧; 杨子龙; 谢湘焱; 程泽瑞
Original assignee: CREEC Kunming Survey Design and Research Co Ltd
Current assignee: CREEC Kunming Survey Design and Research Co Ltd
Priority date: 2023-04-14
Filing date: 2023-04-14
Publication date: 2023-08-29
Anticipated expiration: 2033-04-14

Abstract

The utility model discloses an existing railway high-fill roadbed widening structure, which comprises a counter weight retaining wall, a reinforced concrete foundation, a miniature cast-in-place pile, a bidirectional geogrid, a bagged sand gravel reverse filtering layer and a PVC drain pipe, wherein the counter weight retaining wall is arranged on the foundation; a reinforced concrete foundation is arranged below the counter weight retaining wall, and the upper load is transmitted into the lower soil body through the micro bored pile; the two-way geogrid is paved in the filling soil behind the counter weight retaining wall, the integrity and the stability of the filling soil are enhanced, the bagged sand gravel reverse filtering layer is paved along the wall height direction and clinging to the wall back, so that accumulated water behind the wall can be timely discharged through the PVC drain pipe buried in the wall. The utility model sets the balance weight type retaining wall on the existing high-road embankment side slope in a manner of setting the reinforced concrete foundation and the miniature bored pile, thereby ensuring the bearing capacity requirement of the retaining wall base, meeting the widening of the existing roadbed, avoiding newly added land, reducing the risk of instability of the side slope and having certain supporting and reinforcing effects on the existing side slope.

Description

Existing railway high-filling roadbed widening structure

Technical Field

The utility model relates to the field of reconstruction and extension of existing railway roadbeds, in particular to an existing railway high-fill roadbed widening structure.

Background

The railway is an important component of land traffic in China, and along with the development of social economy, the transportation capability of the existing old railway cannot meet the increasing railway transportation requirement, and the need for energy expansion transformation of some existing railways is urgent. In the existing railway engineering reconstruction and expansion design, the widening of the roadbed at a high filling level is unavoidable. In the prior art, when the filled roadbed is widened, the existing filled side slope is generally dug to have steps, then the widened roadbed width is used for filling, and the new and old side slope interfaces are reinforced, so that the roadbed widening method has certain applicability when the filled side slope is lower, but when the filled side slope is higher, the problem of unstable connection is inevitably encountered due to the longer new and old side slope interfaces, and the newly-filled roadbed side slope is likely to slip and collapse along the new and old side slope interfaces to affect the operation safety of railways in serious cases; meanwhile, the railway land is inevitably increased when the high-fill roadbed is widened according to the conventional method, and the land is saved and protected as much as possible in the existing railway reconstruction and extension process; in addition, if a retaining structure such as a retaining wall is arranged on an existing high embankment slope, the retaining wall base has insufficient bearing capacity, and the existing slope stability is adversely affected.

Disclosure of Invention

Aiming at the defects in the prior art, the utility model provides the high-fill subgrade widening structure of the existing railway, so as to solve the problem of widening the high-fill subgrade in the reconstruction and the extension process of the existing railway.

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

the existing railway high-fill roadbed widening structure is characterized by comprising a counter weight type retaining wall, a reinforced concrete foundation, a miniature filling pile, a two-way geogrid, a bagged sand gravel reverse filtering layer and a PVC drain pipe, wherein the reinforced concrete foundation is arranged below the counter weight type retaining wall, and the miniature filling pile is connected below the reinforced concrete foundation to transfer an upper load into a lower soil; a two-way geogrid is paved in the back filling soil of the counter weight type retaining wall, a bagged sand gravel reverse filtering layer is paved along the wall height direction and clinging to the back of the wall, and a PVC drain pipe is buried in the counter weight type retaining wall; the miniature bored concrete pile is connected with the reinforced concrete foundation through the reinforcing steel bars extending from the top.

Furthermore, the counter weight type retaining wall is poured by adopting concrete with the number not lower than C30.

Further, the reinforced concrete foundation: the strength grade of the concrete is not less than C30, the stressed main reinforcement adopts low alloy twisted steel, the standard value of tensile strength is not less than 400Mpa, the thickness of a reinforcing steel protection layer is not less than 35mm, the thickness of the reinforced concrete is 0.5m, and the width is 0.5m respectively along two sides on the basis of the width of the balance weight type retaining wall substrate.

Further, the miniature bored concrete pile: the diameter of the drilling hole is 150mm, and the depth is more than or equal to 15cm of the pile length; the plane error of the drilling position is not more than 5cm, and the inclination angle error is not more than 1 degree; pile steel bar bundles are formed by welding 3 HRB400 phi 32mm steel bars, and the pile steel bars extend into the reinforced concrete foundation and are bound with main bars on the upper layer of the reinforced concrete foundation; the pile is poured by M35 cement mortar, and the grouting pressure is 0.6-1.0 MPa.

Further, the miniature bored concrete pile: the distance between piles is more than or equal to 3d, d is the diameter of the piles, and the distance from the outer edges of the piles to the edge of the reinforced concrete foundation is not less than 75mm; each micro cast-in-place pile unit is arranged at a spacing of 4m according to transverse x longitudinal = 4 x 3, wherein the transverse direction is perpendicular to the line direction, and the longitudinal direction is along the line direction.

Furthermore, the bidirectional geogrid is welded in a bidirectional manner by adopting polyester engineering plastics, the longitudinal and transverse corresponding elongation is not more than 8%, the longitudinal and transverse tensile strength is not less than 25kN/m, the strength is not less than 10kN/m at 2% elongation, the strength is not less than 18kN/m at 5% elongation, and the mesh diameter of the geogrid is 50-80 mm.

Furthermore, the interval between the two-way geogrid laying layers is 0.6m, the position close to the back of the wall is subjected to reverse packing treatment through the bagged sand gravel, and the reverse packing length is not less than 2m.

Further, the thickness of the packed sand gravel reverse filtering layer is not less than 0.3m, and gaps among bags are filled by sand-sandwiched gravel; the normal permeability coefficient of the bag is not less than 0.3cm/s.

The utility model has the following beneficial effects:

compared with the traditional high embankment filling widening mode, on one hand, the existing railway high filling roadbed widening structure reduces the length of the new and old slope interfaces through the balance weight type retaining wall support, and strengthens the shearing strength of filling soil in the wall back range through the bidirectional geogrid, so that the risk of sliding instability of the slope along the weak structural surface is reduced; on the other hand, as the roadbed filling and widening only occurs at the upper part of the side slope, the existing side slope bottom is not influenced, so that the new railway land is not needed, the cost of land reclamation is saved, the precious land resource is also protected, the influence on the surrounding environment is reduced, and certain social and economic benefits are realized; in addition, the miniature bored concrete pile is arranged on the existing side slope, so that enough bearing capacity can be provided for the counter-balanced retaining wall and foundation, the damage to the existing side slope caused by the retaining wall load is prevented, meanwhile, the miniature bored concrete pile penetrates into the existing earth-filled embankment, a certain supporting and reinforcing effect can be generated on the miniature bored concrete pile, and the overall stability of the existing high-fill roadbed is improved. The existing railway high-fill roadbed widening structure is simple and reliable, is simple to construct and install, is easy to implement, and can obtain good roadbed widening and retaining effects.

In addition to the objects, features and advantages described above, the present utility model has other objects, features and advantages. The present utility model will be described in further detail with reference to the drawings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the utility model and are incorporated in and constitute a part of this specification, illustrate embodiments of the utility model and together with the description serve to explain the utility model. In the drawings:

FIG. 1 is a general schematic view of an existing railway high-fill subgrade widening structure;

FIG. 2 is a schematic cross-sectional view of an existing railway high-fill subgrade widening structure;

FIG. 3 is a plan view of a miniature bored pile;

in the figure: 1-balancing retaining wall; 2-a reinforced concrete foundation; 3-miniature filling piles; 4-a bi-directional geogrid; 5-a packed sand gravel reverse filtering layer; 6-PVC drain pipe; l-widening the width of the existing railway roadbed; h-balance weight retaining wall height.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without any inventive effort, are intended to be within the scope of the utility model.

Referring to fig. 1 to 3, a preferred embodiment of the present utility model provides a widening structure of a high-fill subgrade of an existing railway, which mainly includes: the soil retaining wall comprises a counter weight type retaining wall 1, a reinforced concrete foundation 2, a miniature cast-in-place pile 3, a bidirectional geogrid 4, a bagged sand gravel reverse filtering layer 5 and a PVC drain pipe 6; wherein, the counter weight type retaining wall 1 is a main upper retaining structure, the lower part is a reinforced concrete foundation 2, and upper load is transmitted into the lower soil body through the micro filling pile 3; a bidirectional geogrid 4 is paved in the back filling soil of the counter weight retaining wall 1, the integrity and the stability of the filling soil are enhanced, a bagged sand gravel 5 reverse filtering layer is required to be paved along the height direction of the wall and clinging to the back of the wall, so that accumulated water behind the wall can be timely discharged through a PVC drain pipe 6 buried in the wall; the miniature bored concrete pile 3 is arranged below the reinforced concrete foundation 2, and is connected with the reinforced concrete foundation 2 through the reinforced steel bars extending out of the top of the miniature bored concrete pile, so that the bearing capacity of the filling soil below the reinforced concrete foundation 2 is ensured.

The working principle of the existing railway high-fill roadbed widening structure is as follows:

the existing railway high-fill subgrade widening structure is supported and blocked by the counter weight retaining wall 1, so that the length of an interface between a new slope and an old slope is reduced, the shear strength of filling soil in the wall back range is enhanced by the bidirectional geogrid 4, and the risk of sliding instability of the slope along a weak structural surface is reduced; meanwhile, the miniature filling pile 3 is arranged on the existing side slope, so that enough bearing capacity can be provided for the counter-weight retaining wall 1 and the reinforced concrete foundation 2, the damage to the existing side slope caused by the retaining wall load is prevented, and as the bored miniature filling pile 3 penetrates into the existing filled embankment, a certain supporting and reinforcing effect can be generated on the bored miniature filling pile 3, and the overall stability of the existing high-fill roadbed is improved; the PVC drain pipe 6 buried in the wall body can timely drain accumulated water in the filled soil in front of the wall.

The construction and installation steps of the existing railway high-fill roadbed widening structure are as follows: (1) after the position of the balance weight type retaining wall 1 is determined on site, the existing side slope excavation operation is firstly carried out, and the construction temporary excavation slope rate is not more than 1:0.5, forming a construction operation platform of the drilling miniature bored concrete pile 3 after excavation is completed; (2) the drilling and excavating operation of the pile body can be carried out after the position of the pile top of the miniature filling pile 3 is determined, the drilling depth is generally designed pile length +0.15m, 3 welded HRB400 phi 32mm steel bars are put after drilling to the designed bottom elevation, the top of the pile steel bars need to be stretched into the reinforced concrete foundation 2 and bound with the main steel bars on the upper layer, M35 cement mortar is adopted for filling within 24 hours after drilling is completed, and the grouting pressure is 0.6-1.0 MPa; (3) and after the construction of the miniature cast-in-place pile 3 is completed, the construction of the balance weight type retaining wall 1 and the reinforced concrete foundation 2 can be carried out, and short steel bars are arranged between the balance weight type retaining wall 1 and the reinforced concrete foundation 2 to ensure the tight connection between the balance weight type retaining wall 1 and the reinforced concrete foundation 2, so that the interface anti-slip capability is improved. The balance weight type retaining wall 1 is subjected to field sectional formwork erection casting, concrete casting is performed continuously, horizontal through seams cannot be formed, and the PVC drain pipe 6 is embedded during casting. If casting cannot be performed once, tenons are required to be arranged or reinforced by short steel bars, and the area of the tenons should not be less than 20% of the cross-sectional area. The strength of the joint is not less than that of the whole wall body; (4) and after the concrete strength reaches 75% of the design strength, carrying out layered filling of wall back filler in time, and paving a bidirectional geogrid 4 and a bagged sand gravel reverse filtering layer 5.

The foregoing description of the preferred embodiments of the utility model is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the utility model.

Claims

1. The existing railway high-fill roadbed widening structure is characterized by comprising a counter weight type retaining wall, a reinforced concrete foundation, a miniature filling pile, a two-way geogrid, a bagged sand gravel reverse filtering layer and a PVC drain pipe, wherein the reinforced concrete foundation is arranged below the counter weight type retaining wall, and the miniature filling pile is connected below the reinforced concrete foundation to transfer an upper load into a lower soil; a two-way geogrid is paved in the back filling soil of the counter weight type retaining wall, a bagged sand gravel reverse filtering layer is paved along the wall height direction and clinging to the back of the wall, and a PVC drain pipe is buried in the counter weight type retaining wall; the miniature bored concrete pile is connected with the reinforced concrete foundation through the reinforcing steel bars extending from the top.

2. The widening structure for the high-fill subgrade of the existing railway as set forth in claim 1, wherein said counter-balanced retaining wall is poured with concrete with a number not lower than C30.

3. The existing railway high-fill subgrade widening structure as set forth in claim 1, wherein said reinforced concrete foundation: the strength grade of the concrete is not less than C30, the stressed main reinforcement adopts low alloy twisted steel, the standard value of tensile strength is not less than 400Mpa, the thickness of a reinforcing steel protection layer is not less than 35mm, the thickness of the reinforced concrete is 0.5m, and the width is 0.5m respectively along two sides on the basis of the width of the balance weight type retaining wall substrate.

4. The widening structure for the roadbed of the existing railway high-fill according to claim 1, wherein the micro cast-in-place pile comprises: the diameter of the drilling hole is 150mm, and the depth is more than or equal to 15cm of the pile length; the plane error of the drilling position is not more than 5cm, and the inclination angle error is not more than 1 degree; pile steel bar bundles are formed by welding 3 HRB400 phi 32mm steel bars, and the pile steel bars extend into the reinforced concrete foundation and are bound with main bars on the upper layer of the reinforced concrete foundation; the pile is poured by M35 cement mortar, and the grouting pressure is 0.6-1.0 MPa.

5. The widening structure for the existing railway high-fill roadbed according to claim 1, wherein the micro cast-in-place pile comprises: the distance between piles is more than or equal to 3d, d is the diameter of the piles, and the distance from the outer edges of the piles to the edge of the reinforced concrete foundation is not less than 75mm; each micro cast-in-place pile unit is arranged at a spacing of 4m according to transverse x longitudinal = 4 x 3, wherein the transverse direction is perpendicular to the line direction, and the longitudinal direction is along the line direction.

6. The widening structure of the existing railway high-fill roadbed according to claim 1, wherein the bidirectional geogrid is formed by adopting polyester engineering plastics for bidirectional welding, the longitudinal and transverse corresponding elongations are not more than 8%, the longitudinal and transverse tensile strength is not less than 25kN/m, the strength at 2% elongation is not less than 10kN/m, the strength at 5% elongation is not less than 18kN/m, and the mesh diameter of the geogrid is 50-80 mm.

7. The widening structure for the roadbed of the high-filling railway of claim 1, wherein the interval between the laying layers of the two-way geogrid is 0.6m, the position close to the back of the wall is subjected to reverse-packing treatment through packed sand gravel, and the reverse-packing length is not less than 2m.

8. The widening structure for the existing railway high-fill roadbed according to claim 1, wherein the thickness of the packed sand gravel reverse filtering layer is not less than 0.3m, and gaps between bags are filled by sand-sandwiched gravel; the normal permeability coefficient of the bag is not less than 0.3cm/s.