Shanxi Building talks about the ventilation and lighting project of the expressway tunnel. Xu Zhiyuan Guo Taishan lighting fixture installation requirements and process are elaborated, and the equipment control method is proposed.
The expressway has a fast speed and a large traffic flow. The tunnel must have complete ventilation facilities and lighting facilities to ensure the driving environment and driving safety.
1 Tunnel power supply and distribution system Tunnel ventilation and lighting projects must be implemented with reliable power supply. Power should be considered for one type of load.
1 The distribution equipment should be equipped with a substation at each end of the tunnel. The power supply is taken from the different 10kV grid loops at the two ends of the tunnel. The two power supplies are reserved for each other.
Ventilation and lighting power supply shall be provided with dry transformers at both ends of the tunnel.
In order to ensure the lighting power supply in the tunnel, a self-starting generator should be installed on the low voltage side of the two substations. When the two 10kV power supplies are powered off at the same time, the generator will start by itself and maintain the full daylighting power in the tunnel. When the utility power is restored, the generator is stopped and the two power supplies are switched. A set of UPS uninterruptible power supply is provided in each power distribution station as a tunnel emergency lighting power supply during the two power switching processes.
1.2 Power supply line laying General highway tunnels are divided into two holes according to the direction of driving, and the ventilation and lighting facilities of the two holes are basically the same. One-way single-hole driving, two cement cable trenches on both sides of the hole, one cable trench for the power supply line, and the other signal cable for the highway communication system and monitoring system.
Each group (two units) ventilator adopts a special cable to be led from the cable outlet pipe outside the hole of the power distribution station and the cable trench in the hole to the distribution box inside the hole, and the power supply line from the distribution box to the fan should be flame retardant. The power cable and the gold layer casing are hidden in the cave wall and the vault. The lighting circuit is led to the distribution box inside the hole by the transformer substation and the cable trench inside the hole. After the power distribution, the distribution box is led to the lighting equipment, and the BV copper core plastic wire is placed through the gold layer casing in the cave wall and the vault.
The distribution box in the hole generally determines the installation location according to the position of the fan, and the distribution box can be used for ventilation engineering and lighting engineering.
2 Fan installation tunnel ventilation is mainly for the dilution of carbon monoxide (CO), smoke and odor.
The selection, power and installation interval of the tunnel ventilator are considered based on the traffic volume and the expressway design speed. In general, the highway tunnel selects a special jet ventilator (referred to as a jet fan) with a silencer and a reversible road tunnel.
For the general requirements of the jet fan, the reversing reverse air volume of the jet fan reaches 95% of the forward positive air volume. When a fire occurs in the tunnel, the jet fan should be able to operate normally for 60 minutes at an ambient temperature of 250 * C. At the exit of the fan from the fan outlet 10m and 45), the noise of the test jet fan should be no less than IP55. The installed jet fan of the jet fan is located at the top of the tunnel, and the two fans are arranged side by side. After the ventilation capacity of the fan is determined, the interval between the group and the group is mainly related to the traffic flow. According to the traffic flow of the newly built expressway, the general planning interval is 150m. The jet fan should be installed 15cm~20cm away from the building limit. The axis is parallel to the tunnel axis. The installation method should be fixed or suspended. The structural strength of the supporting fan should be more than 15 times of the actual static load. The load test of the supporting structure should be done before the fan is installed.
3 Tunnel lighting installation tunnel lighting system is designed according to people's visual characteristics and highway traffic conditions.
The tunnel lighting system consists of tunnel lighting, section lighting, transition section (which can be divided into several sections), basic section (also called middle section) lighting and exit section lighting. The daytime illumination is gradually reduced from the hole to the basic section. The lamps in the cave are divided into white daylights, dusk daylights, all-day lights and emergency lights. The emergency light is used as a full-day light in the normal city network power supply; the full-day light works 24h; the white light only works when the brightness of the hole is large during the day; the dusk daylight works in the early morning or dusk. The full-day lamp loop voltage is appropriately lowered in the middle of the night (the illumination is also reduced accordingly).
2 For lighting fixtures, the illumination source should be a high pressure sodium lamp. The light box protection level is not less than IP65. The electronic ballast lamp power factor is not less than 0.95; the inductive ballast lamp power factor is not less than 0.85. There are anti-shock protection devices and anti-glare devices.
3.3 Installation of lighting fixtures The lighting fixtures are installed on both sides of the center line of the top of the tunnel, and two rows of lamps are symmetrically installed side by side. The interval of the lamps in the driving direction is about 7 m in the basic section, and the lamps are gradually densified toward the introduction section. According to different lighting sections, the luminaires are generally divided into 70W, 150W\250W\400W, the lead-in and transition-section luminaires have relatively large power, and the other sections use low-power luminaires. The luminaire is fixed on the top of the tunnel by the base of the luminaire, and the light illumination angle of the luminaire can be adjusted on the base.
4 Equipment operation control The control fan of the fan can be controlled manually or automatically. The manual control device is located in the power distribution station. The automatic control is controlled by an automatic operating system according to the detection data of the carbon monoxide concentration detector provided by the highway monitoring system in the tunnel.
2 The lighting status of the lighting fixtures is set by the miniature computer placed in the power distribution panel of the tunnel substation. Female, graduated from Taiyuan University of Technology in 1985, majoring in power system automation, engineer, Shanxi Building Materials Industry Design and Research Institute. Guo Taishan (1961), male, graduated from Communication Engineering, Northern Jiaotong University in 1983, senior engineer, Jiangsu Maosheng Engineering Consulting Supervision Co., Ltd., Nanjing 210004, Jiangsu, China. Method for determining the maximum dry density of two-ash stabilized gravel. The experience to improve work efficiency and ensure construction quality.
With the massive construction of highways in China and the increase of vehicle load, higher requirements are imposed on the overall strength and flatness of the road surface. The strength and quality of the base layer are good for the entire road surface, especially the asphalt pavement. Both quality and service life have a very important impact. Combined with the design of the proportion of the semi-rigid base of lime fly ash stabilized gravel in the northern section of the Shizhong Expressway in Ningxia, there is no limitation on the selection of material quality (the selection of the material yard) and the determination of the dry density (using the calculation method and the compaction method). The change of compressive strength, the method of determining the maximum dry density of lime fly ash stabilized gravel by application calculation method.
The following is an analysis of the construction of the Shizhong Expressway in the Ningxia Hui Autonomous Region.
1 The introduction of the problem The northern section of the Shizhong Expressway is one of the sections of the national highway main line No. 25 Ningxia. In May 1999, the construction drawing design was completed. The design of the pavement base and the basement are lime fly ash stabilized gravel. The design mix ratio is 5:1580 (lime: fly ash: gravel), 1% cement is added to the base layer to improve the early strength of the semi-rigid base. In August 2000, the headquarters organized the bidding for the pavement, and prepared the hall from September to October. According to the planned data, the construction unit organized the 240m sub-base test section and the 640m base test section as soon as possible according to the intention of the headquarters, and reflected the indoor and outdoor sampling data from the construction unit and the supervision unit's sub-base and basic test sections.
1 The raw material lime material yard is sampled as first-grade lime, and the mixed field is sampled as three-grade lime after digestion; the specific surface area of ​​fly ash of Dawukou Power Plant is 1700cm2/g, the particles are coarser and the specific surface area is less; the grade of red fruit sand gravel yard The stone is good, and the fine material is too much.
The ratio of 5:15:80 is verified by the self-inspection and supervision center laboratory of the test section. The unconfined compressive strength is 0.28MPa~0.58MPa, which does not meet the requirements of the specification.
1.3 Compaction 1) Substrate lamination is generally more than 100%, the average compaction is 105.8%, the standard deviation is 2.95%, and the coefficient of variation is 2.79%. 2) The information obtained from the test section shows that the base compactness The average value is 97.27%, the standard deviation is 3.5%, and the coefficient of variation is 3.6%. 2 Determination method of maximum dry density and optimum water content There are two methods for determining the maximum dry density. The conventional method is to apply such materials to heavy-duty compaction standards. Get the actual method. When the aggregate content exceeds 50%, the conventional method cannot give a true maximum dry density. Key research project of the Ministry of Communications “Study on semi-rigid base asphalt pavementâ€, Professor Lin Xiuxian from Tongji University proposed a theoretical 2.1 method to calculate the maximum dry density of the mixture. From the basic principle of material composition design, when the aggregate is at its maximum Within the allowable content, the maximum dry density of the mixture will consist of the weight of the aggregate in the unit volume and the binder at the maximum dry density filled in the voids of the aggregate. Thus, as with the material composition design, as long as the measurement is combined indoors The maximum dry density Pi is calculated, and then the weight ratio of the combined binder to the aggregate is converted into a real volume ratio V2 according to the average relative density A of the aggregate, and the maximum dry density Pa of the mixture is calculated by the following formula: p0 =VixPi+V2XA, calculated from the test section of the basement of the northern section of the Shizhong Expressway. According to the mix ratio provided by the design, lime: fly ash: aggregate = 5: 1580, the mixture binder (two ash) and The ratio of aggregate is 20:80, the maximum dry density of the two ash (1:3) is 1.08g/cm3, and the relative density of the gravel is 2.67g/cm3, the volume ratio of binder to aggregate. :V/V2= 2.06g/cm3, the maximum dry density obtained by conventional compaction method is 1.98g/cm3, which is equivalent to 96% of the calculation method. This is the reason why the compaction degree of the test section is more than 100%. .
2.2 Optimum water content calculation method The conventional heavy-duty compaction method can measure the optimum water content of semi-rigid base material, but it takes time and labor. After a large number of tests and comparisons, the optimal water content of such mixture is called The optimum moisture content % of the binder portion and the saturated water-filled street lamp timing control of the aggregate portion can also be controlled by the light intensity detector of the monitoring system opening. ), female, graduated from Taiyuan University of Technology in 1993, assistant engineer, Shanxi Yuncheng Road and Bridge Co., Ltd., Yuncheng, Shanxi 044000, China
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