Standard for design of immersed tunnel
1 General provisions
1.0.1 This standard is developed in order to make the design of immersed tunnel safe, reliable, technologically advanced, economically reasonable, durable and applicable.
1.0.2 This standard is applicable to the survey and design of immersed tunnel structures with reinforced concrete elements.
1.0.3 In addition to this standard, the survey and design of immersed tunnel structure shall also comply with the requirements of the current relevant standards of the nation.
2 Terms and symbols
2.1 Terms
2.1.1 immersed tunnel
tunnel formed mainly with several prefabricated basic structural units by floating transportation, immersion and underwater connection in water area
2.1.2 element
basic unit prefabricated one time or several times, used to form immersed tube structure by floating transportation, immersion and underwater connection
2.1.3 floating transportation
transportation of prefabricated elements floating on the water surface to the designated location
2.1.4 immersion
sinking of elements to the designated location
2.1.5 connection
pulling and hydraulic connection between elements and elements or connection tunnels
2.1.6 immersed elements assembly
tunnel segment formed by connecting all elements
2.1.7 connection tunnel
tunnel or underground structure connected with both ends of the immersed elements assembly and generally constructed by open-cut and cast-in-place method
2.1.8 dry dock
site used for element prefabrication, which may also be used for outfitting, floating and mooring, usually fixed dry dock; under special circumstances, the large barges used for prefabrication and outfitting of elements referred to as mobile dry dock
2.1.9 closure joint
structure connecting immersed tunnels, also referred to as final joint
2.1.10 shear key
shear member arranged at the element joint to limit the horizontal and vertical displacement between the elements or between the element and the connection tunnel
2.1.11 element joint
connecting structure between the elements or between the element and the connection tunnel
2.1.12 GINA gasket
compression-type waterproof rubber product attached outside of the element joint
2.1.13 OMEGA seal
detachable waterproof rubber product attached inside of the element joint
2.1.14 mooring
pulling and fixing element on the water surface by anchor after it floats out of the water surface or reaches the designated location by floating transportation
2.1.15 freeboard
vertical distance of the top surface of element above the waterline during submersion, mooring and floating transportation
2.1.16 trench
strip-shaped underwater foundation pit for burying tunnels
2.1.17 ballast concrete
concrete placed in elements to provide ballast weight
2.1.18 pulling bearing
pulling device arranged at the top of both ends of the element joint and used for realizing the initial connection of the element
2.1.19 bulkhead
wall structure for temporary closing of elements and buried sections for the purpose of floating transportation, immersion and installation of elements
2.1.20 steel shell of the terminal surface
steel member at the end of element or connection tunnel for the installation or connection of GINA gasket and OMEGA seal
2.1.21 watertight door
waterproof sealing door arranged on the bulkhead and used for temporary passage after the element immersion
2.1.22 bearer
device with temporary supporting and guiding functions used for element immersion and connection
2.1.23 ballast tank
temporary facilities used to adjust the ballast weight during the floating, floating transportation and immersion of elements
2.1.24 outfitting
installation of temporary facilities and equipment required for floating transportation and immersion of elements
2.1.25 man hole
hole pre-set at the top of the element for temporary personnel access
2.1.26 segment
basic unit of immersed tube segment prefabricated one time or several times and connected by joints on land. The longitudinal reinforcement between adjacent segments is not through, and the formed element is called segmental element. On the contrary, it is generally called integral element.
2.1.27 segment joint
connecting structure between the segments
2.1.28 pre-bedding method
construction method of element foundation pad completed before element immersion and connection
2.1.29 post filling method
construction method of element foundation pad completed after element immersion and connection
2.1.30 sand flow method
method of forming foundation pad by filling the gap between the bottom plate of the element and the bottom of the trench by injecting sand (or sand and cement clinker) through a pre-embedded pipe in the structure such as the side wall of the element and the bottom plate of the element
2.1.31 grouting method
method of forming foundation pad by filling the gap between the bottom plate of the element and the bottom of the trench by pouring mortar through a pre-embedded pipe at the bottom plate of the element
2.1.32 locking backfill
backfilling the bottom of the trench within a certain range on both sides of the free end of the element tail, after the elements are connected, in order to limit their horizontal displacement
1 General provisions
2 Terms and symbols
2.1 Terms
2.2 Symbols
3 Basic requirements
4 Investigation and survey
4.1 General requirements
4.2 Engineering investigation
4.3 Engineering survey
5 General design
5.1 General requirements
5.2 Tunnel site arrangement
5.3 Geometric design
5.4 Key technical solutions
6 Materials
7 Loads and combination of loads
7.1 Classification of loads and representative values of loads
7.2 Combination of loads
8 Structural calculation
8.1 General requirements
8.2 Buoyancy calculation
8.3 Calculation of static load of element
8.4 Calculation of outfitting parts
9 Element structure
9.1 General requirements
9.2 Structural types and requirements
9.3 Joint
9.4 Parts pre-set and pre-embedded
10 Element floating transportation and immersion
10.1 General requirements
10.2 Element floating transportation
10.3 Element immersion
11 Trench, foundation pad and backfill
11.1 General requirements
11.2 Trench
11.3 Foundation pad
11.4 Backfill
12 Bank revetment and connection tunnel
12.1 General requirements
12.2 Bank revetment
12.3 Connection tunnel
13 Dry dock
13.1 General requirements
13.2 Fixed dry dock
13.3 Factory dry dock
13.4 Mobile dry dock
14 Structural waterproofing
14.1 General requirements
14.2 Structural waterproofing
14.3 Joint and seam waterproofing
15 Durability
16 Seismic resistance
16.1 General requirements
16.2 Calculation of seismic action
16.3 Seismic checking
Explanation of wording in this standard
List of quoted standards
Standard for design of immersed tunnel
1 General provisions
1.0.1 This standard is developed in order to make the design of immersed tunnel safe, reliable, technologically advanced, economically reasonable, durable and applicable.
1.0.2 This standard is applicable to the survey and design of immersed tunnel structures with reinforced concrete elements.
1.0.3 In addition to this standard, the survey and design of immersed tunnel structure shall also comply with the requirements of the current relevant standards of the nation.
2 Terms and symbols
2.1 Terms
2.1.1 immersed tunnel
tunnel formed mainly with several prefabricated basic structural units by floating transportation, immersion and underwater connection in water area
2.1.2 element
basic unit prefabricated one time or several times, used to form immersed tube structure by floating transportation, immersion and underwater connection
2.1.3 floating transportation
transportation of prefabricated elements floating on the water surface to the designated location
2.1.4 immersion
sinking of elements to the designated location
2.1.5 connection
pulling and hydraulic connection between elements and elements or connection tunnels
2.1.6 immersed elements assembly
tunnel segment formed by connecting all elements
2.1.7 connection tunnel
tunnel or underground structure connected with both ends of the immersed elements assembly and generally constructed by open-cut and cast-in-place method
2.1.8 dry dock
site used for element prefabrication, which may also be used for outfitting, floating and mooring, usually fixed dry dock; under special circumstances, the large barges used for prefabrication and outfitting of elements referred to as mobile dry dock
2.1.9 closure joint
structure connecting immersed tunnels, also referred to as final joint
2.1.10 shear key
shear member arranged at the element joint to limit the horizontal and vertical displacement between the elements or between the element and the connection tunnel
2.1.11 element joint
connecting structure between the elements or between the element and the connection tunnel
2.1.12 GINA gasket
compression-type waterproof rubber product attached outside of the element joint
2.1.13 OMEGA seal
detachable waterproof rubber product attached inside of the element joint
2.1.14 mooring
pulling and fixing element on the water surface by anchor after it floats out of the water surface or reaches the designated location by floating transportation
2.1.15 freeboard
vertical distance of the top surface of element above the waterline during submersion, mooring and floating transportation
2.1.16 trench
strip-shaped underwater foundation pit for burying tunnels
2.1.17 ballast concrete
concrete placed in elements to provide ballast weight
2.1.18 pulling bearing
pulling device arranged at the top of both ends of the element joint and used for realizing the initial connection of the element
2.1.19 bulkhead
wall structure for temporary closing of elements and buried sections for the purpose of floating transportation, immersion and installation of elements
2.1.20 steel shell of the terminal surface
steel member at the end of element or connection tunnel for the installation or connection of GINA gasket and OMEGA seal
2.1.21 watertight door
waterproof sealing door arranged on the bulkhead and used for temporary passage after the element immersion
2.1.22 bearer
device with temporary supporting and guiding functions used for element immersion and connection
2.1.23 ballast tank
temporary facilities used to adjust the ballast weight during the floating, floating transportation and immersion of elements
2.1.24 outfitting
installation of temporary facilities and equipment required for floating transportation and immersion of elements
2.1.25 man hole
hole pre-set at the top of the element for temporary personnel access
2.1.26 segment
basic unit of immersed tube segment prefabricated one time or several times and connected by joints on land. The longitudinal reinforcement between adjacent segments is not through, and the formed element is called segmental element. On the contrary, it is generally called integral element.
2.1.27 segment joint
connecting structure between the segments
2.1.28 pre-bedding method
construction method of element foundation pad completed before element immersion and connection
2.1.29 post filling method
construction method of element foundation pad completed after element immersion and connection
2.1.30 sand flow method
method of forming foundation pad by filling the gap between the bottom plate of the element and the bottom of the trench by injecting sand (or sand and cement clinker) through a pre-embedded pipe in the structure such as the side wall of the element and the bottom plate of the element
2.1.31 grouting method
method of forming foundation pad by filling the gap between the bottom plate of the element and the bottom of the trench by pouring mortar through a pre-embedded pipe at the bottom plate of the element
2.1.32 locking backfill
backfilling the bottom of the trench within a certain range on both sides of the free end of the element tail, after the elements are connected, in order to limit their horizontal displacement
Contents of GB/T 51318-2019
1 General provisions
2 Terms and symbols
2.1 Terms
2.2 Symbols
3 Basic requirements
4 Investigation and survey
4.1 General requirements
4.2 Engineering investigation
4.3 Engineering survey
5 General design
5.1 General requirements
5.2 Tunnel site arrangement
5.3 Geometric design
5.4 Key technical solutions
6 Materials
7 Loads and combination of loads
7.1 Classification of loads and representative values of loads
7.2 Combination of loads
8 Structural calculation
8.1 General requirements
8.2 Buoyancy calculation
8.3 Calculation of static load of element
8.4 Calculation of outfitting parts
9 Element structure
9.1 General requirements
9.2 Structural types and requirements
9.3 Joint
9.4 Parts pre-set and pre-embedded
10 Element floating transportation and immersion
10.1 General requirements
10.2 Element floating transportation
10.3 Element immersion
11 Trench, foundation pad and backfill
11.1 General requirements
11.2 Trench
11.3 Foundation pad
11.4 Backfill
12 Bank revetment and connection tunnel
12.1 General requirements
12.2 Bank revetment
12.3 Connection tunnel
13 Dry dock
13.1 General requirements
13.2 Fixed dry dock
13.3 Factory dry dock
13.4 Mobile dry dock
14 Structural waterproofing
14.1 General requirements
14.2 Structural waterproofing
14.3 Joint and seam waterproofing
15 Durability
16 Seismic resistance
16.1 General requirements
16.2 Calculation of seismic action
16.3 Seismic checking
Explanation of wording in this standard
List of quoted standards
