Construction safety technology of the hottest wate

2022-08-26
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The main procedures of dam construction are: construction cofferdam filling, foundation pit drainage, dam foundation overburden excavation, rock excavation, dam abutment excavation on both banks, high slope treatment, dam concrete pouring, metal structure installation, etc

1. Cofferdam construction safety technology

cofferdam is an auxiliary project built for dam or plant construction. The standard of cofferdam is determined by the grade and service life of the main building. During the cofferdam construction, especially when the closure dragon mouth is closed, due to the gradual narrowing of the riverbed and the acceleration of water flow in the river, it is necessary to throw large stones or polyhedral concrete blocks to prevent the filling from being washed away by the torrent. During the construction of the cofferdam, due to the narrow site, many people and vehicles, the site should be under unified command and coordinate actions to prevent accidents. After the cofferdam is closed, loess shall be filled on the water side of the cofferdam to improve the seepage prevention effect of the cofferdam. In addition to wearing labor protection articles as required, personnel working on the cofferdam filling face must also wear life jackets and prepare lifebuoys to prevent drowning accidents

2. Dam excavation safety technology

(1) earth rock excavation should be carried out in layers from top to bottom, and the thickness of the layers should be determined according to the comprehensive study of geological conditions, slag Road, construction site, excavation scale, performance of drilling rig, characteristics of excavation section, blasting mode, capacity of transportation equipment, etc

(2) the excavation blasting technology should be advanced, reliable, economical and reasonable, and the blasting will not damage the foundation and endanger the safety of nearby buildings. The selection of blasting parameters is reasonable, and the slope is stable after blasting. Cavern blasting is not allowed at the dam foundation

(3) secondary slope cutting shall be avoided in the excavation of high slope, so as to prevent casualties caused by the increase of construction difficulty in the secondary slope cutting. In the high slope with bolt, anchor cable or shotcrete support, shotcrete and anchor support shall be carried out immediately after the excavation of each layer to ensure the stability and safety of the slope. A drainage ditch must be set at the top of the high slope to ensure that the construction will not be affected. Operators working on high slopes must wear safety belts and helmets. In the construction of "you can no longer use ordinary trees, all plastics have limited grease or polymers", add a certain number of observation equipment to measure the stability of the slope at any time. If there are signs of landslide, measures must be taken in time to ensure construction safety.

(4) Safety precautions for high slope construction:

① ensure slope stability and avoid landslides

② pry and remove pumice stones in time to prevent falling stones from injuring people, and do a good job of shotcrete and anchor support, so that the rock mass is no longer weathered due to exposure. A slag retaining wall shall be set at the top of the high slope to prevent the pumice on the top of the mountain from rolling and hurting people

③ prevent the construction personnel from falling from the high slope

3. Grouting engineering construction safety technology

(1) each section of grouting must be continuously grouted without stopping halfway. Before grouting, in addition to the careful inspection of the machinery and pipeline system, the pressure test of the maximum grouting pressure of the grouting section for 10 ~ 20min must also be carried out. Protective facilities shall be provided for the high-pressure regulating valve

II. Safety technology for Headrace Tunnel Construction

(1) the excavation of headrace tunnel is generally constructed by drilling and blasting method. Blasting the world's first kiloton, then right click my computer graphene production line is put into operation in Dalang Town, Dongguan. Smooth blasting and presplitting blasting should be given priority, and the footage value of excavation cycle operation should be reasonable and moderate

(2) the excavation and construction of the headrace tunnel should be supported by shotcrete bolts in time, and the unstable rock mass of the tunnel top arch, high side wall and portal slope with large span must be reinforced by anchor bolts or prestressed anchor cables; The rock mass between adjacent caverns is reinforced with opposite through anchor cables

(3) blasting safety regulations of Headrace Tunnel: blasting materials should meet the construction conditions and national technical standards. Before each batch of blasting materials is used, relevant performance tests must be carried out; During blasting, personnel shall withdraw to the safety zone and excavate the tunnel in one direction. The distance from the safety zone to the blasting surface shall not be less than 200m; Several working faces of the cavern group shall be shot at the same time, and a special person shall be assigned for unified command to ensure the safety of blasting operators; When the two working faces of opposite excavation are shot at a distance of 30m or 5 times the tunnel diameter, the personnel of both sides need to evacuate the working face. When the distance is 15m, one party's operation should be stopped and one-way excavation should be completed

(4) ventilation and dust removal facilities must be installed in the construction of headrace tunnel to ensure that the air in the tunnel meets the national health standards. Wet drilling method shall be adopted for construction

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