Discussion on the necessity of ventilation of tunnel construction(2)
3.1 Calculation basis
The ventilation of the cave uses a duct ventilation. The feet in the circulation are 3.3m, and the amount of explosives is 1.6kg/m3 on average. In the first stage, the ventilation time is considered by 30min. The second phase of the hybrid ventilation time is considered by 35 minutes. The air volume required for the palm of the face is calculated according to the minimum wind speed in the hole, the person in the cave requires the air volume, and 30 minutes after a blasting.
3.2 The first stage of construction ventilation calculation
Dig out the ventilation of 1400m from the intersection of the horizontal cave and the positive cave to the main attack direction.
3.2.1 Air volume calculation
3.2.2 Calculation of wind pressure
In order to ensure that sufficient air volume to the working surface and maintain a certain wind speed at the air outlet, the ventilator requires a certain air pressure to overcome all the resistance along the way. The wind pressure that the ventilation machine should have is: H machine> H total resistance.
H total resistance = h dynamic pressure+h static pressure .h static pressure = h motor+h in the huddy.
3.4 The technical approach to improve construction ventilation
3.4.1 Reasonable layout
1) In order to avoid the recycling of the recycling of the exhaustion, the air outlet is located at 30m from the cave: 2) In order to prevent the operation of other parallel processes in the water operation, the ventilation pipe is hung on the wall of the cave wall: 3) to as a waist: 3) as to as to be as a waist: 3) as to as as 3). To ensure the ventilation effect, the distance from the air duct to the palm surface is within the effective range, but it also avoids the comprehensive dust removal technique of enjoying the dust curtain dust reduction and dust collector dust collector's dust removal, and the dust collector dust collector's dust removal technology is avoided. Ventilation workload.
3.4.4 Strengthen the maintenance management of the ventilation system
To maintain a good working condition of the ventilation system, it is necessary to strengthen the maintenance management of the system, especially the long hose, and it is necessary to regularly check, repair, adjust, and replace it. During the construction of tunnel construction, the construction staff often carried out ventilation and safety knowledge publicity and education, and firmly established a sense of safety. At the same time, a special ventilation team was established.
In short, in the construction of highway tunnels, combined with the actual situation of on -site construction, the construction ventilation system has achieved good results through the reasonable optimization and configuration of the construction ventilation system. Through the improvement of construction ventilation, the ventilation costs are reduced. Save expenditures: After the blasting ventilation 30min ~ 40min, the indicators of the air in the cave basically reached the control standards, ensuring the efficiency of the construction machinery in the cave, and ensuring the cave. The health of the internal construction operators has also shortened the time of blasting ventilation smoke and operation cycle, and accelerated the progress of the project.