Line worker: Junior

Author: Chief Editor: Wang Jing'an
Publisher:
Publish Date: 2004-09-01
Features:
Section:
Roadbed Protection and Reinforcement Equipment are divided into four categories based on their usage performance:
(1) Slope Protection For slopes with vegetation, grass, sod, or trees can be planted for protection. For weathered or easily eroded slopes, methods such as grouting, plastering, shotcrete, sprayed concrete, dry-stone masonry, or rubble masonry can be used.
(2) Erosion Protection To prevent scouring by water and waves, methods such as planting sod, establishing water-resistant forests, dry-stone masonry or rubble masonry, dumping stones or stone cages, or constructing submerged retaining walls can be adopted.
(3) Support and Reinforcement Various types of retaining walls, support walls, and anti-slide piles (anchored piles) are used to support roadbed slopes and prevent slope failure or rockfall.
(4) Sand and Snow Protection Various types of fences and protective forests are used to prevent sand or snow from burying the track.
Section 7: Bridge and Tunnel Structures
When a railway passes through natural obstacles such as rivers, valleys, and mountains, or crosses highways and other railway lines, various bridge and tunnel structures need to be constructed. These structures include bridges, culverts, and tunnels.
1. Bridges
There are many types of railway bridges, and different classification methods include:
- By bridge length
- By construction material
- By structural type
- By bridge deck location
- By obstacles crossed
(1) By Bridge Length
Classification by bridge length is the primary method for categorizing railway bridges, directly indicating their size.
Bridge Length:
- Beam Bridge: The distance between the abutment's ballast wall and the other abutment's ballast wall.
- Arch Bridge: The distance between the outer ends of two expansion joints on the upper side wall of the arch and the side wall of the abutment.
- Rigid Frame Bridge: The length between the outer sides of the rigid frame along the span direction.
- Extra-long Bridges: Lengths exceeding 500m.
- Large Bridges: Lengths between 100m and 500m.
- Medium Bridges: Lengths between 20m and 100m.
- Small Bridges: Lengths of 20m or less.
(2) By Construction Material
1. Steel Bridges
The main structure of a steel bridge is a steel beam, which is assembled from steel sections. Common types include steel trusses and steel plate girders.
2. Reinforced Concrete Bridges
Reinforced concrete or prestressed reinforced concrete beams or rigid frame structures are used in these bridges. They are cost-effective, durable, and easy to maintain, making them widely adopted.
3. Stone Bridges
Stone bridges are constructed using stone materials. Stone can be sourced locally, making them cost-effective and long-lasting.
(3) By Structural Type
1. Beam Bridges
The main structure of a beam bridge is a beam supported by bearings on piers and abutments. Beam bridges can be classified by their structural form into simply supported beam bridges, continuous beam bridges, and cantilever beam bridges.
2. Arch Bridges
The main structure of an arch bridge is an arch. Arch bridges can be divided into solid-arch bridges and hollow-arch bridges based on their superstructure.
3. Rigid Frame Bridges
The beam structure of a rigid frame bridge is integrated with the pier (abutment). They can be classified into portal rigid frame bridges and skewed-leg rigid frame bridges based on the form of the pier (abutment) and span.