The safety requirements for cavern excavation and blasting engineering are very high. Today, let's learn about the safety technical regulations for cavern excavation and blasting operation.

1. The excavation of cavern shall comply with the following provisions:

1.1 There shall be no pumice, dangerous stones and hanging stones on the slope of the cavern excavation.

1.2 when the working environment and conditions are relatively poor, all-round safety technical measures should be formulated before construction, and the operators should be disclosed.

1.3 slope cutting at the mouth of the cave shall be carried out according to the requirements of lighting excavation. Do not work at the same time from top to bottom, and do a good job in slope reinforcement and drainage.

1.4 before entering the cave, the rock mass on the face of the cave should be inspected, and the hole can be excavated only after the stability is confirmed or reliable measures are taken.

1.5 the hole should be provided with a protective shed. The length along the axis of the tunnel can be selected according to the actual topography, geology and tunnel section, and generally should not be less than 5m.

1.6 from the beginning of the hole, when the digging length is less than 15m～2m, the permanent or temporary support of the hole should be done in time according to the geological conditions and section size. The supporting length shall generally not be less than 1m. When the geological conditions are bad and all the tunnels should be supported, the tunnel section should be permanently supported.

1.7 in the process of underground excavation, in case of unexpected events such as unfavorable geological structure or landslide-prone areas, escape of harmful gas and underground water gushing, the work should be stopped immediately, and the workers should be evacuated to a safe place.

1.8 the pipeline lines of wind, water and electricity set for underground excavation shall comply with relevant safety regulations.

1.9 after each shooting, all-round safety inspection shall be conducted immediately, and dangerous stones and pumice shall be removed. If any danger that cannot be eliminated by digging is found, other measures shall be taken to deal with it. When the safety treatment is carried out in the cave, there should be someone to monitor it.

1.1 when dealing with the phenomenon of roof caving or side wall slippage:

1) find out the reasons, formulate specific construction plans and safety precautions, and deal with them quickly.

2) In the area where the groundwater is very active, the water should be treated first and then the collapse should be treated.

3) Prepare an unobstructed evacuation passage and sufficient construction equipment.

4) Before the treatment, the undamaged support or rock mass at both ends of the landslide section should be reinforced.

5) When dealing with collapse, it is generally appropriate to deal with the side walls on both sides first, and then deal with the top arch step by step.

6) Construction personnel should work under a reliable cover, and the whole process of operation should be supervised by special personnel on site.

7) Observe the change of dangerous situation at any time, and modify or supplement the original measure plan in time.

8) The distance between excavation and lining during parallel operation should be controlled according to the design requirements, but generally it should not be less than 3m.

2. The following provisions shall be observed in the excavation of unfavorable geological sections:

2.1 Work out the construction technical measures and safety technical measures according to the design engineering geological data, and make disclosure to the operators. There should be full-time security personnel on the job site for monitoring.

2.2 the support in bad geological areas should be carried out in strict accordance with the construction plan, and the next working procedure can be carried out only after the support is stable and qualified.

2.3 in case of unstable surrounding rock, water gushing and landslide, all operators should immediately evacuate to safety.

2.4 during construction, the rock is not only the object of excavation, but also the medium of hole formation. Therefore, the construction personnel need to fully understand the nature of surrounding rock and rationally use the shape characteristics of the cavern to ensure the construction safety.

2.5 shallow drilling, weak blasting and multi-cycle shall be adopted during construction to minimize the disturbance to surrounding rock. Take the division excavation, support in time. Each cycle of excavation is controlled at about .5m～1.m.

2.6 when the first excavation cycle is completed, the dangerous stones should be completely removed and supported in time to prevent falling rocks.

2.7 in the construction of unfavorable geological areas, the engineering geology, groundwater type and water inflow should be well predicted, and drainage ditches, water accumulation pits and adequate pumping and drainage equipment should be set up.

2.8 in the soft and loose broken zone, the next construction operation can be carried out only after the support is stable.

2.9 construction in unfavorable geological areas shall be carried out according to the temporary safe electricity utilization scheme, with leakage protectors and emergency measures for power failure.

3. Mechanical excavation and transportation of stonework shall comply with the following provisions:

It is forbidden to use the stonework excavation and transportation equipment powered by gasoline engines in the p>3.1-hole. Mechanical excavation and transportation equipment should have tail gas purification measures.

3.2 operators of mechanical equipment must obtain training and examination before taking up their posts. Operators are not allowed to leave their posts, operate machinery that does not conform to the operation certificate, or hand over mechanical equipment to other personnel for operation.

3.3 the operator shall strictly implement the inspection system before work, the observation during work and the inspection and maintenance system after work according to the specifications of this machine.

3.4 other personnel are not allowed to get on the bus during mechanical operation, and the driver should be informed to stop when they have to get on and off.

3.5 Dangerous stones must be cleared before excavation and transportation, and excavation and transportation can be carried out under the condition of ensuring safety.

3.6 there should be sufficient lighting at the excavation site.

3.7 when excavating the tunnel face, the tunnel face should be excavated from top to bottom, from left to right or from left to right, so as to keep the tunnel face stable.

3.8 the slag road should be kept smooth and unobstructed, and a drainage ditch should be set up.

3.9 The slag discharge location should be clearly marked and commanded by designated personnel.

3.1 when the loader is used to dig and install, the loader should shovel and cut at a low speed, and it is not allowed to use the way of increasing the throttle and rushing at a high speed.

3.11 according to the conditions of the tunnel face, different shoveling methods should be adopted, and uneven load or unilateral stress on the bucket is strictly prohibited. When shoveling, the bucket should not be cut too deeply.

3.12 it is strictly forbidden to load the loader in a biased way, and the slag should be discharged slowly.

3.13 it is forbidden to stay around the working place of the loader, and the loader should continuously sound the horn when retreating.

3.14 during manual shipment, operators must wear labor protection articles as required. It is forbidden to put your hand into the car or put it on the bucket gang to avoid hurting your hand. Stones weighing more than 5kg shall not be filled by manpower.

4. Ventilation and drainage shall comply with the following provisions:

During the construction of p>4.1 tunnel, 3m3 of fresh air per person per minute shall be supplied to the working face in time.

4.2 when the depth and length of the hole are more than 3 ~ 5 times of the hole diameter, forced ventilation measures should be taken, otherwise the construction shall not be continued.

4.3 natural ventilation is adopted, and the pilot tunnel should be opened as soon as possible. Temporary ventilation measures should be taken before the pilot tunnel is opened; The wind speed of the working face shall not be less than .15m/s, and the maximum wind speed: 4m/s for the inclined shaft of the tunnel, 6m/s for the ventilated place of the transportation tunnel, and 8m/s for the shaft of the lifting personnel and equipment.

4.4 the fan suction port shall be provided with lead wire protection net.

4.5 when compressed air ventilation is used, it is advisable that the distance between the air duct end and the excavation face is 1m～15m; If air suction is adopted, the distance between the end of the air duct and the excavation face should be 2m.

4.6 the pipeline should be lifted by the rock wall, and the passage of pedestrians and vehicles should not be blocked. when it is installed overhead, the fulcrum or hanging should be firm and reliable.

4.7 it is forbidden to place or hang anything on the ventilation pipe.

4.8 before construction, the water used for construction and the seepage quantity influenced by external factors should be fully considered, and the drainage facilities should be properly arranged to facilitate the construction of construction machinery and equipment and staff under normal conditions.

5, construction safety monitoring, should comply with the following provisions:

5.1 The purpose of construction safety monitoring is to grasp the surrounding rock dynamics, judge the stability of surrounding rock, verify the construction method and supporting effect, guide the design and construction, and find the dangerous situation in time, so as to provide prediction for construction safety.

5.2 according to the engineering geological and hydrogeological data, design documents, combined with engineering practice, determine the specific safety construction monitoring scheme.

5.3 key parts of construction safety monitoring arrangement:

1) within the tunnel: ⅲ ~ ⅴ surrounding rock sections, sections rich in groundwater, fault fracture zones, openings and forks, sections with shallow buried depth, sections greatly affected by excavation in adjacent areas and high ground stress sections. 2) Outside the tunnel: soft rock or soft soil section with shallow burial depth.

5.4 Main contents of construction safety monitoring:

1) Inside the tunnel: convergence and displacement of surrounding rock, stress and strain of surrounding rock, top arch sinking, bottom arch lifting, stress and deformation of supporting structure, blasting vibration, harmful gas and dust, etc.

2) Outside the tunnel: ground subsidence, building inclination and cracking, underground pipeline rupture and damage, etc.

5.5 Key points of safety monitoring for large cavern:

1) Typical cavern section perpendicular to the longitudinal axis.

2) The small tunnel mouth and the inner section of the mouth of the tunnel run through the high side wall.

3) The rock platform of the rock wall beam (especially the part with small holes below).

4) Thin rock wall between adjacent caverns.

5) unstable bodies which are not conducive to the combined cutting of geological structural planes.

5.6 blasting operation in the near area is not allowed within 2h after drilling and grouting by monitoring instrument. Before re-blasting, the protective measures of instruments should be taken to avoid the damage of flying stones.

5.7 Key inspection sites for monitoring:

1) Surrounding rock and front support status of tunnel face after blasting.

2) Intersection section, entrance section, cavern rock wall and arch support section of large and small cavern groups.

3) weak surrounding rock section and supporting structure state.

4) Slope and unstable mountain at the outer entrance, ground above the entrance and affected buildings, flood control facilities at the entrance, etc.

5.8 Preliminary safety judgment of stability in monitoring: Under normal circumstances, when the surrounding rock and supporting structure have the following change characteristics, they will tend to be stable:

1) With the distance from the excavation face, the change rate of measured values tends to slow down gradually.

2) The total measured value has reached more than 8% of the maximum regression value.

3) the displacement growth rate is less than .1 mm/d ~ .3 mm/d (soft rock takes the largest value).

5.9 when any of the following situations is found during monitoring, it should be treated as a dangerous situation, followed up and monitored, and early warning and forecast should be made in time.

1) The excavation face is gradually away from or stopped, but the change rate of measured values does not slow down or has an accelerated growth trend.

2) intermittent rockfall occurs in surrounding rock.

3) The deformation of the supporting structure is too large and too fast, and there are stress cracks developing constantly.

I believe that after the above introduction, everyone has a certain understanding of the safety technical regulations for cavern excavation and blasting operation. Welcome to visit Zhongda Consulting for more information.

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