كليدواژه :
زيرساختهاي شهري , برنامه ريزي شهري , بررسي آثار زيست محيطي , ماتريس تلفيقي (ليو پلد - ساراتوگا) , تونل مشترك تأسيسات شهري
چكيده لاتين :
Urban facilities are the essential components of cities. In all the well expanded and developed cities of the world, there are intricate networks of facilities such as electric grids, water sewage drainage, water and gas piping. However in many cases, they have not been installed in proper depth underground and are not suitable for the growing population and consumption demand. Often, they need to be replaced by excavating the street pavements, which creates traffic and some environmental problems.
Current urban facilities distribution system in Tehran has considerable leakage. The main cause is the construction of the system without the necessary calculations on the performance of the networks. Use of utility tunnels started from few decades ago in most European (France, UK, and Switzerland) and American countries. In Iran, some preliminary works on utility tunnel construction started from few years ago, like the urban utility tunnel construction in district 22 of Tehran. In this research, the environmental conditions of study area were analyzed and according to the aim of the research, study area location, wind speed (3.7 m/s ), wind direction ( East to West), height of sampling , suitable distance from devices during activity and around green space, six monitoring stations were selected. Table (1) shows the locations of the stations.
Table 1: Location of the stations
Location Station Location Station Number
Number
End of utility tunnel 4 Around Green Space 1
Adjacent streets Residential area
5 2
Operation phase 6 Head of utility tunnel 3
Measurements of concentration of air pollutants such as ( CO, N02, S02, and PM10) and sound levels in six
monitoring stations in construction and operational phases have been done. Table (2) shows the results.
Pollutant Station 1 Station 2 Station 3 Station 4 Station 5 Station 6 Standard Level
CO (ppm) 1.94 2.21 1.73 8 6.6 4.5 9 ppm
(8h)
S02(ppb) 2.21 24.4 23.8 8.75 8.2 7.35 140 ppb
(24h)
N02(ppb) 68 53 40 57 51 46 210 ppb
(lh)
PM10(^ig/ 11.09 84.5 164.4 177.3 102.1 80 150 jiig/m3
m3) (24h)
Then with the aid of integrated matrix (Leopold - Saratoga), impacts of utility tunnel constructions on the environmental parameters were studied. The findings indicated that in construction phase, the most negative effect was imposed on the physiochemical environment (such as noise, and air pollutions, soil erosion and solid waste). The negative effects can be reduced by applying proper management and corrective actions. Meanwhile, the positive effects are on the socioeconomic environment like (welfare facilities, urban transportation systems quality of life and landscape). Figure (1) shows the impacts of different activities during the construction phase on the environmental parameters.
40 20 0 -20 40
do chemical environment
Stan economic Biologiral environment
environment
Fig.l: Impacts of different activities in construction phase on environmental parameters
In operational phase, the most positive effects are related to the socioeconomic environment without negative effects on the other environments. Figure (2) presents the impacts of different activities in the operational phase on the environmental parameters.
Urban utilities are overcrowding underground space. Therefore, future sustainable underground strategies will consist of the ability to reduce the use of traditional trenching. During the last century, there was an increasing interest in utility tunnels for urban areas as a problem-solving technique to avoid congestion of the street subsurface. Utility tunnels are joint-use underground facilities that may contain multiple utilities such as water, sewerage, gas, electrical power, telephone, and central heating in various combinations or in some cases all together. The key advantage of utility tunnels is their substantially lower environmental impact when compared with trenching alternatives. Results indicated that the urban utility tunnel is a proper choice for urban area which can fully comply with policy and philosophy of urban design and sustainable development.
