Urban underground tunnels are motor vehicle roads below the surface of the city. At present, with the rapid development of China’s economic construction and the continuous acceleration of urbanization, the number of motor vehicles is increasing.
1. Design principles and standards for urban underground tunnel lighting
(1) Design principles
1. The lighting design of urban underground tunnels should comprehensively consider the engineering environment, engineering conditions, traffic conditions, ventilation methods, power supply conditions, operation management and other factors of underground roads to ensure the normal operation of underground roads and lighting requirements under accident conditions to improve tunnel lighting. Security performance.
‘ 2. Tunnel lighting should select energy-efficient light sources and luminaires that do not exceed the specified lighting power density values.
3. According to the plane and cross section of the underground tunnel and the installation of the equipment, the best lighting lighting mode, reasonable lighting cable tray and pipeline laying method should be determined by the calculation of brightness or illuminance.
(2) Design standards
1. Architectural Lighting Design Standard GB 50034-2013.
2. “Design Rules for Highway Tunnel Lighting” JTG/T D70/2-01-2014.
3. JTG D70/2-2014, “Traffic Design and Auxiliary Facilities for Highway Tunnel Design”.
4. Urban Road Lighting Design Standards CJJ 45-2015.
5. “Code for Design of Road Tunnels” DG/TJ 08-2033-2008.
6. “Technical Specifications for Tunnelled Lighting Applications” DG/TJ 08-2141-2014.
(2) Contents of urban underground tunnel lighting design
- The middle section of the tunnel can be divided into general lighting and power saving lighting.
- The entrance section of the tunnel is illuminated.
- Tunnel transition section lighting.
- Lighting at the exit section of the tunnel.
- The tunnel section is illuminated outside the tunnel.
- The emergency lighting of the tunnel can be used as general lighting.
(3) The relationship between illumination brightness and length and illumination
In Figure 1, P is the hole (or shed), S is the starting point of the segment, A is the adaptation point, d is the adaptation distance: L20 (S) is the brightness outside the hole; Lthl, Lth2 is the brightness of the entrance section: L20 (A) In order to adapt to the brightness of the point; Lch is the brightness of the entrance segment; Ltrl, Ltr2, Ltr3 are the brightness of the transition segment; 1in is the brightness of the middle segment; Lexl and Lex2 are the brightness of the exit segment; Dthl and Dth2 are the segment length of the entry segment THI, TH2; Dtrl, Dtr2 and Dtr3 are the segment lengths of the transition segments TRI, TR2 and TR3; Din is the length of the intermediate segment; Dexl and Dex2 are the segment lengths of the exit segments EEI and EX2.
In the tunnel lighting design, the illuminance parameters are usually used for calculation. This requires conversion between average brightness and average illuminance. Black asphalt pavement can take 15lx/(cd/m2): cement concrete pavement can take lOlx/(cd/m2).
(4) Calculation conditions
1. Roads with mixed traffic of people and vehicles (including non-motorized roads), the brightness of the middle section is less than 20cd/m2; the brightness of horizontal passages (including non-motorized roads) should not be lower than 1.0cd/m2; the left and right sides of the road The average brightness in the 2m high range should not be less than 60% of the average brightness of the road surface.
2. In the range of 2m above the wall surface of the underground tunnel, it is advisable to lay the wall material with a reflectivity of ≥0.7.
3. The curing factor of the luminaire is generally 0.6 – 0.7.
4. Photometric data such as light intensity distribution table, utilization coefficient curve, equal light intensity curve, and brightness generation curve of the selected luminaire.
5. The driving speed adopted should not be greater than l00km/h. If it is greater than l00km/h, it should be specially designed.
(5) Lighting layout requirements of tunnel lighting
1. The luminaire should be arranged to meet the flicker frequency below 2.5 Hz or above 15 Hz; if there is difficulty, the flicker frequency should be below 4 Hz or above 11 Hz.
2. The two-lane middle section of the luminaire should be arranged in the middle line, staggered on both sides or symmetrically arranged on both sides. Under the premise of facilitating road closure and maintenance, the luminaires can be arranged in a single row at the top of the tunnel.
3. The three-lane shield method underground road, the middle section lighting fixtures should be staggered on both sides of the road or symmetrically arranged on both sides.
4. For the three-lane immersed tube method or the open-cut tunnel, the middle section lighting fixtures should be staggered or symmetrically arranged above the centerline of the lanes on both sides of the road.
5. For the four-lane immersed tube method or the open-cut tunnel, the middle section lighting fixtures should be staggered or symmetrically arranged at a position wider than the wall at the top of the tunnel.
6. The lighting fixture layout should consider the installation height, spacing and elevation of the luminaire.
7. Under the premise of meeting glare requirements and being safe and reliable, try to reduce the installation height of the lamps:
(6) Lighting calculation
1. The specific calculation of tunnel lighting needs to select energy-saving light sources, lamps and layout schemes according to the road surface brightness and illumination requirements required by the building conditions and specifications. Illumination calculations are based on different calculation methods and conditions of use to calculate the illuminance or brightness and uniformity of the road surface. The comparison of the calculated values should not exceed ±10% of the standard value: if the deviation is too large, the lighting scheme should be re-adjusted and then calculated until the requirements are met. The calculation can be done with the lighting design software DIALux or other lighting design software for simulation aided design.
2. Middle section lighting. The total uniformity and longitudinal uniformity of brightness and road surface brightness are generally selected according to the tables listed in the specification and should not be lower than those in Tables 12.2.1 and 12.2.2 of DG/TJ 08-2033-2008 “Road Tunnel Design Code”. value. In the design calculation, special attention should be paid to the indicator of the longitudinal uniformity of the road surface brightness. Continuous channel illumination should be greater than 2 cd/m2. It must be stated. DG/TJ 08-2033-2008 in the middle section and the inlet section of the table JTG/T D70/2-01-2014 comprehensive, adding three lanes of brightness, total uniformity, longitudinal uniformity value.
3, the entrance section lighting. It should be divided into two segments: one segment of brightness Lthl-kL20(S), and the brightness of two segments of Lth2 is half of it, where k is the brightness reduction factor of the inlet segment and L20(S) is the brightness outside the hole. The brightness of the short track with length <500m must also be reduced: length Dthl=Dth2-1/2[ 1.154Ds -(h- 1.5Vtanloo], where Ds is the illumination parking line of sight and h is the clearance height in the hole. The basic lighting and the reinforced lighting are composed of two parts. The former lighting arrangement should be considered according to the middle section lighting, and the latter can be reinforced by the higher power luminaire. The reinforced lighting fixture can be arranged from the inside of the hole at 10m.
4. Transition section lighting. The brightness is calculated according to the formula of the TRI, TR2, and TR3 segments divided by the JTG factory TD70/2-01-2014; the length must also be calculated according to the formula of the TRI, TR2, and TR3 segments divided by the standard and the table in the description of the reference article. 5-1 Calculate the table to select.
5. Exit section lighting. It should be divided into two sections, each section should take 30m; the brightness of the second section should be 3 and 5 times of the brightness of the middle section respectively; the length is ≤300m, and there is no exit section illumination: only the enhanced illumination is provided between 300-500m in length. .
6. The tunnel section shall be provided with a light transition section for the illumination of the approach section of the tunnel, through artificial light transition, natural light transition or mixed light transition, such as the construction of a light-shielding shed or a planting evergreen, and the use of cold tones on both sides of the approach section. Measures such as low-reflection material decoration to achieve sequential changes in illumination brightness and achieve a good dimming effect.
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