A 400km / h high-speed railway bridge transition structure and construction method

Abstract

A 400km / h high-speed railway bridge-road transition structure is used to effectively control the differential settlement of the 400km / h high-speed railway bridge-road transition section, while ensuring convenient, safe and efficient construction. It includes a pile-sheet transition structure and a stiffness transition structure; the pile-sheet transition structure is arranged behind the abutment, and includes a pile-sheet structure composed of a bearing plate and piles, and a common filling body filled between the bearing plate and the foundation. The piles are arranged at intervals along the horizontal direction, the lower part penetrates the foundation bearing layer, and the upper end is consolidated with the bearing plate. The longitudinal section of the common filling body is trapezoidal; the stiffness transition structure is composed of a roadbed body, a stepped base bed bottom layer and a stepped base bed surface layer constructed in sequence from the foundation upwards, and the thickness of the stepped base bed surface layer gradually decreases from the end of the bearing plate along the extension direction of the line.

Description

Technical Field

[0001] The invention belongs to the field of roadbed engineering and relates to a 400km / h high-speed railway road-bridge transition structure and a construction method. Background Art

[0002] High-speed is the main development direction of today's high-speed railways. China currently has the world's largest and fastest high-speed railway network, with a maximum operating speed of 350km / h. With the further increase in the operating speed of high-speed railways, mastering the key technologies for building 400km / h high-speed railways has become the most important and urgent task on the road to my country's high-speed railway development at this stage.

[0003] High-speed railways require track structures to have high smoothness. The transition section between the roadbed and the bridge is an important part of the high-speed railway and has a significant impact on the line smoothness. Differential settlement is the main control factor for whether the train runs smoothly and comfortably in the transition section. Excessive differential settlement in the transition section will pose a threat to the safety and comfort of high-speed railway operations. The existing high-speed railway ballastless track has extremely strict control over the differential settlement of the road-bridge transition section. The misalignment caused by the settlement difference shall not exceed 5mm, and the angle caused by uneven settlement shall not exceed 1 / 1000.

[0004] When the train speed is increased to 400km / h, the dynamic effect caused by the longitudinal unevenness of the transition section is further amplified. The increased dynamic effect will affect the fatigue damage of the track structure components, the accumulation of line deformation, and aggravate the deterioration of the track geometry. Therefore, when the train speed is increased to 400km / h, the smoothness of the transition section is required to be higher. In addition, large-scale mechanical rolling construction cannot be carried out near the back of the abutment of the existing bridge-road transition structure, and it is difficult to meet the compaction standard by using small-scale mechanical compaction, which can easily lead to excessive settlement control indicators. For this reason, it is urgent to design a 400km / h high-speed railway bridge-road transition structure to solve the above problems. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a 400km / h high-speed railway road-bridge transition structure to effectively control the differential settlement of the 400km / h high-speed railway road-bridge transition section while ensuring convenient, safe and efficient construction.

[0006] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0007] The present invention discloses a road-bridge transition structure for a high-speed railway with a speed of 400 km / h, which is characterized by comprising a pile-sheet transition structure and a stiffness transition structure; the pile-sheet transition structure is arranged behind the abutment, and comprises a pile-sheet structure composed of a bearing plate and piles, and a common filling body filled between the bearing plate and the foundation, the piles are arranged at intervals along the horizontal direction, the lower part of the piles penetrates into the foundation bearing layer, and the upper end is consolidated with the bearing plate, and the longitudinal section of the common filling body is trapezoidal; the stiffness transition structure is composed of a roadbed body, a stepped base bed bottom layer and a stepped base bed surface layer sequentially constructed from the foundation upwards, and the thickness of the stepped base bed surface layer gradually decreases from the end of the bearing plate along the extension direction of the line.

[0008] The length of the pile-plate transition structure is the sum of the lengths of the two track plate structures, i.e. 9.872m, 10.05m or 11.34m; the slope of the ordinary fill body should be 1:1, and the length of its bottom along the line direction should not be less than 2.0m.

[0009] The thickest part of the stepped base bed surface is not less than 1.1m, the width of each step is 5-7m, the height of the step is 0.3-0.5m, the filling length to the pile-sheet transition structure area is not less than 1.0m, and the length of the stiffness transition structure is not less than 20m.

[0010] Another technical problem to be solved by the present invention is to provide a construction method for the above-mentioned 400km / h high-speed railway bridge transition structure. The construction method comprises the following steps:

[0011] ① Construction of abutments;

[0012] ② Level the base, and simultaneously fill the common filling body, roadbed body, stepped base bottom layer and stepped base surface layer in layers. Except for the area within 2m of the abutment end, which uses small-scale mechanical rolling and tamping, the rest of the locations are all compacted by large-scale mechanical rolling;

[0013] ③Construct the pile-board structure, accurately locate the position of each pile, use the rotary drilling rig to drill holes, lower the steel cage, and then pour concrete;

[0014] ④ Cut the surface layer of the subgrade where the bearing plate is located, dig out the ordinary filling body where the bearing plate is located, place the bearing plate steel cage, weld the bearing plate and the main reinforcement of the pile together, and then pour concrete;

[0015] ⑤ Use high-performance asphalt to fill the gap between the bearing plate and the base surface.

[0016] The beneficial effect of the present invention is that a pile-slab transition structure is set at the boundary between the road and the bridge, and the change point of the offline engineering stiffness is moved from the boundary between the road and the bridge to the roadbed direction for a distance, thereby avoiding the differential settlement of the roadbed filler near the boundary between the road and the bridge due to insufficient rolling; the stiffness transition structure adopts a stepped base bed surface filling to control the gradual change of the stiffness of the transition structure and reduce its impact on the smoothness of the transition section. This structure can not only effectively solve the problem of differential settlement of the road-bridge transition section under the condition of a speed of 400 km per hour, but also is convenient to construct, safe and efficient, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] This specification includes the following three drawings:

[0018] Figure 1 It is a longitudinal section of a 400km / h high-speed railway bridge transition structure of the present invention;

[0019] Figure 2 It is a cross-sectional view along the line Ⅰ-Ⅰ in the figure;

[0020] Figure 3 It is a cross-sectional view along the line Ⅱ-Ⅱ in the figure.

[0021] The figure shows the components, part names and corresponding marks: abutment 1, bearing plate 2, pile 3, ordinary fill body 4, stepped base bed surface layer 5, stepped base bed bottom layer 6, road base body 7. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0023] Reference Figure 1 , Figure 2 and Figure 3The present invention discloses a 400km / h high-speed railway road-bridge transition structure, which includes a pile-sheet transition structure and a stiffness transition structure. The pile-sheet transition structure is arranged behind the abutment 1, and includes a pile-sheet structure composed of a bearing plate 2 and piles 3, and a common filling body 4 filled between the bearing plate 2 and the foundation. The piles 3 are arranged along the horizontal intervals, the lower part penetrates into the foundation bearing layer, and the upper end is consolidated with the bearing plate 2. The longitudinal section of the common filling body 4 is trapezoidal; the stiffness transition structure is composed of a roadbed body 7, a stepped base bed bottom layer 6, and a stepped base bed surface layer 5 constructed in sequence from the foundation upwards. The thickness of the stepped base bed surface layer 5 gradually decreases from the end of the bearing plate 2 along the extension direction of the line. The pile-sheet transition structure is arranged at the boundary between the road and the bridge, and the stiffness change point of the offline engineering is moved a distance from the boundary between the road and the bridge to the roadbed direction, thereby avoiding the differential settlement of the roadbed filler near the boundary between the road and the bridge due to insufficient rolling. The upper layer of the stiffness transition structure is filled into a stepped base surface layer 5 to control the gradual change of the stiffness of the transition structure and reduce its impact on the smoothness of the transition section. This structure can not only effectively solve the problem of differential settlement of the road-bridge transition section under the condition of a speed of 400 km / h, but also has convenient construction, safety and efficiency, and broad application prospects.

[0024] Reference Figure 1 As a preferred parameter, the length L of the pile-sheet transition structure 1 The sum of the lengths of the two track slab structures is 9.872m, 10.05m or 11.34m. The slope of the ordinary fill body 4 is preferably 1:1, and the length of its bottom along the line direction is a 2 The thickness of the stepped subgrade surface layer 5 is not less than 1.1 m at its thickest point, the width b of each step is 5 to 7 m, the height h of each step is 0.3 to 0.5 m, and the filling length a to the transitional structure area of ​​the pile board is 1 Not less than 1.0m, and the length L of the stiffness transition structure 2 Not less than 20m.

[0025] As a preferred embodiment, the ordinary filling body 4 is filled with fillers of groups A, B, and C, and the compaction standard should meet the compaction coefficient K ≥ 0.93 and the foundation coefficient K 30 ≥130MPa / m, compacted by small machinery. The road base body 7 is filled with A, B, C1, C2 group filling materials, and the compaction standard should meet the compaction coefficient K≥0.92, foundation coefficient K 30 ≥90MPa / m; the step-shaped base bed bottom layer 6 is filled with coarse gravel and crushed stone soil in group A and B fillers, and the compaction standard should meet the compaction coefficient K≥0.95 and foundation coefficient K 30 ≥150MPa / m, dynamic deformation modulus E vd≥40MPa; the stepped subgrade surface layer 5 is filled with graded crushed stone mixed with 5% cement, and the compaction standard should meet the compaction coefficient K≥0.97 and the foundation coefficient K 30 ≥190MPa / m, dynamic deformation modulus E vd ≥55MPa; the roadbed body 7, the stepped base layer 6 and the stepped base surface layer 5 are all compacted by large-scale machinery.

[0026] Reference Figure 1 The present invention provides a construction method for a 400 km / h high-speed railway bridge transition structure, comprising the following steps:

[0027] ① Construction of abutment 1;

[0028] ② Level the base, and simultaneously fill the common filling body 4, the roadbed body 7, the stepped base bed bottom layer 6 and the stepped base bed surface layer 5 in layers. Except for the area within 2m from the end of the abutment 1, which is compacted by a small machine, the rest of the areas are compacted by a large machine.

[0029] ③Construct the pile-board structure, accurately locate the position of each pile 3, use a rotary drilling rig to drill holes, lower the steel cage, and then pour concrete;

[0030] ④ Cut the surface layer 5 of the subgrade where the bearing plate 2 is located, dig out the common filling body (4) where the bearing plate 2 is located, place the steel cage of the bearing plate 2, weld the main reinforcement of the bearing plate 2 and the pile 3 together, and then pour concrete;

[0031] ⑤ Use high-performance asphalt to fill the gap between the bearing plate 2 and the base bed surface layer 5.

[0032] The filling and rolling thickness of the common filling body 4, the roadbed body 7, the stepped subgrade bottom layer 6 and the stepped subgrade surface layer 5 is 15 to 30 cm.

[0033] The above description is only to illustrate some principles of the present invention, and is not intended to limit the present invention to the specific structure and applicable scope shown and described. Therefore, all corresponding modifications and equivalents that may be used belong to the patent scope applied for by the present invention.

Claims

1. A 400km / h high-speed railway road-bridge transition structure, characterized by: The invention comprises a pile-sheet transition structure and a stiffness transition structure; the pile-sheet transition structure is arranged behind the abutment (1), and comprises a pile-sheet structure composed of a bearing plate (2), piles (3), and a common filling body (4) filled between the bearing plate (2) and the foundation, wherein the piles (3) are arranged along the horizontal intervals, the lower part of which penetrates into the bearing layer of the foundation, and the upper end is fixed to the bearing plate (2), and the longitudinal section of the common filling body (4) is trapezoidal; the stiffness transition structure is composed of a roadbed body (7), a stepped foundation bottom layer (6), and a stepped foundation surface layer (5) constructed in sequence from the foundation upwards, and the thickness of the stepped foundation surface layer (5) gradually decreases from the end of the bearing plate (2) along the extension direction of the line.

2. The 400 km / h high-speed railway road-bridge transition structure as claimed in claim 1, characterized in that: The length (L1) of the pile-plate transition structure is the sum of the lengths of the two track plate structures, i.e., 9.872m, 10.05m or 11.34m; the filling slope of the ordinary filling body (4) is preferably 1:1, and the length (a2) of its bottom along the line direction is not less than 2.0m.

3. The 400 km / h high-speed railway road-bridge transition structure as claimed in claim 1 is characterized by: The thickest part of the stepped base bed surface layer (5) is not less than 1.1m, the width (b) of each step is 5-7m, the height (h) of each step is 0.3-0.5m, the filling length (a1) to the pile-sheet transition structure area is not less than 1.0m, and the length (L2) of the stiffness transition structure is not less than 20m.

4. The 400 km / h high-speed railway road-bridge transition structure as claimed in claim 1, characterized in that: The ordinary filling body (4) is filled with fillers of groups A, B and C, and the compaction standard should meet the compaction coefficient K ≥ 0.93 and the foundation coefficient K 30 ≥130MPa / m, compacted by small machinery.

5. The 400 km / h high-speed railway road-bridge transition structure as claimed in claim 1 is characterized by: The road base body (7) is filled with fillers of groups A, B, C1 and C2, and the compaction standard should meet the compaction coefficient K ≥ 0.92 and the foundation coefficient K 30 ≥90MPa / m; the step-shaped base bed bottom layer (6) is filled with coarse gravel and crushed stone soil in group A and group B fillers, and the compaction standard should meet the compaction coefficient K≥0.95 and the foundation coefficient K 30 ≥150MPa / m, dynamic deformation modulus E vd ≥40MPa; the stepped subgrade surface layer (5) is filled with graded crushed stone mixed with 5% cement, and the compaction standard should meet the compaction coefficient K≥0.97 and the foundation coefficient K 30 ≥190MPa / m, dynamic deformation modulus E vd ≥55MPa; the roadbed body (7), the stepped subgrade bottom layer (6) and the stepped subgrade surface layer (5) are all compacted by large-scale machinery.

6. A construction method for a 400 km / h high-speed railway road-bridge transition structure according to any one of claims 1 to 5, comprising the following steps: ① Construction of abutment (1); ② Level the base, and simultaneously fill the ordinary filling body (4), the roadbed body (7), the stepped base bed bottom layer (6) and the stepped base bed surface layer (5) in layers. Except for the area within 2m of the end of the abutment (1), which is compacted by a small machine, the rest of the areas are compacted by a large machine. ③ Construct the pile-board structure, accurately locate the position of each pile (3), use a rotary drilling rig to drill holes, lower the steel cage, and then pour concrete; ④ cutting the surface layer (5) of the base bed where the bearing plate (2) is located, digging out the common filling body (4) where the bearing plate (2) is located, placing the bearing plate (2) steel cage, welding the bearing plate (2) and the main reinforcement of the pile (3) together, and then pouring concrete; ⑤ Using high-performance asphalt to fill the gap between the bearing plate (2) and the base bed surface layer (5).

7. The construction method of a 400 km / h high-speed railway road-bridge transition structure as claimed in claim 6, characterized in that: The filling and rolling thickness of the common filling body (4), the roadbed body (7), the stepped base bed bottom layer (6) and the stepped base bed surface layer (5) is 15 to 30 cm.

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