What is common trench construction technology?

... slightly ...

Second, the construction principle

Before construction, we should carefully survey the weak surrounding rock, deeply understand the design intention, and work out feasible construction schemes according to different geological conditions. In the construction, the principles of "emphasizing geology, guiding water pipes, strict grouting, short footage, strong support, diligent survey and early closure" are strictly followed, and the relevant regulations of tunnel construction are strictly implemented.

Third, the construction technology and construction scheme

Full-face method is used for the construction of Class III surrounding rock of tunnel, and bench method is used for the excavation of Class IV and V surrounding rock. Anchor, mesh and shotcrete are used for initial support, inverted arch is advanced, arch wall is lined once, arch wall full-ring grid steel frame and double-layer φ42 small conduit are used for seismic fortification lining section of active fault zone, and lining trolley is used for tunnel lining.

In the process of construction, advance geological prediction, deepening blasting hole detection, infrared detection method and advance geological confirmation are carried out for the tunnel to see if there are design differences. Advanced horizontal drilling should be used in the key geological dangerous areas mentioned in the drawings, and the settlement observation should be carefully measured and analyzed.

Four, the hole excavation and support

The new Austrian tunneling method is adopted for the excavation of the cave body.

The V-class surrounding rock section is excavated with three steps and seven steps. The shallow buried section of Grade V surrounding rock is located at the entrance of tunnel, with advanced geological prediction, short footage, weak blasting, early closure and frequent measurement to ensure construction safety.

Construction technology: advanced conduit support → excavation of upper steps → initial spraying → installation of grid or steel frame → combined hollow anchor rod at arch → hanging net → re-spraying → excavation of middle steps → initial spraying → grid steel frame at side wall → hanging net → radial anchor rod at side wall → re-spraying → excavation of lower steps → initial spraying → grid steel frame at side wall → re-spraying.

Ⅳ class surrounding rock section is excavated by arc heading method.

Advance conduit support → upper step excavation → initial spraying → grid or steel frame installation → arch combined hollow anchor rod → hanging net → re-spraying → lower step excavation → initial spraying → straight wall grid steel frame → lateral wall radial anchor rod → re-spraying.

Bench excavation in the third-grade surrounding rock section.

Construction technology: upper step excavation → initial spraying → combined hollow anchor rod at arch → hanging net → re-spraying → lower step excavation → initial spraying → radial anchor rod at side wall → re-spraying.

Construction of Grade Ⅴ, Ⅳ and Ⅴ Surrounding Rock by Step Method

The surrounding rocks of Grade ⅳ and ⅴ are excavated by step method, the distance between upper and lower steps is not more than 1.5 times the excavation width, and the reserved settlement of vault is 5 ~ 10 cm (adjusted appropriately according to the measurement). The upper and lower steps are drilled by YT-28 manual rock drill jumbo, smooth blasting and non-electric millisecond detonator network initiation. Excavators are used to cooperate with manual excavation in soft surrounding rock. The lower steps are excavated and ballasted by excavators and loaders. During construction, the left and right steps are staggered by three meters.

Before drilling, measure the top surface line and center line of the inner rail, draw the excavation outline, and mark the hole position according to the design (when the geological conditions change, adjust the drilling position appropriately). The diameter of drilling hole is φ42mm, the depth of upper bench cut and bottom hole is 1.4- 1.6m, and the depth of other holes is1.3m.: ; The depth of the lower step hole is 3.1m.

After drilling, check and make records according to the hole arrangement, and re-drill holes that do not meet the requirements. Before charging, blow the mud and stone powder in the hole with high-pressure wind, check the hole, and then charge after confirming that it meets the design requirements. The fees shall be charged in strict accordance with the design fees. After charging, all the blastholes are blocked with stemming. Peripheral eyes are connected by interval charge and detonating cord, cut eyes are charged intensively, the bottom is reinforced by 30% of the length, and the rest eyes are charged intensively.

The blasting network is initiated by millisecond detonator. Non-electric millisecond detonator is inserted into the cartridge and reversely loaded into the eye hole. The lead connection of nonel tube adopts grab type.

Six, mortar anchor construction

The anchor rod adopts 22mm threaded steel bar. Check whether the model, specification, quality and performance of anchor rod meet the design before construction. According to the anchor type, specifications and surrounding rock conditions, prepare drilling tools.

Pneumatic drill is used for drilling, and the spacing, depth and arrangement of holes meet the requirements of design parameters, and its direction is perpendicular to the rock stratum. The anchor rod is driven by a pneumatic stirrer to rotate rapidly, and the anchor rod is slowly advanced while rotating.

In order to test the installation quality of the anchorage, the pull-out test of the anchorage is carried out as required, and the installation tension is timed. The line of action is concentric with the anchor and fixed firmly. Load evenly and slowly, and stop drawing after reaching the design tonnage, without destructive test.

Seven, advance small catheter construction

The small catheter is made of steel pipe, and its front end is closed and sharp, so that it can be inserted into the borehole smoothly. Plum blossom grouting holes are arranged on the pipe wall, the length of the tail grouting section is not less than 30 cm, and the extrapolation angle is10-15.

First, drill a hole with a pneumatic drill. The diameter of the opening is 50 mm, and the sand and gravel are blown out with a blowpipe. Then push the small catheter into the hole with an impact pneumatic drill, or directly insert the steel pipe with a hammer. Finally, the periphery and orifice of the conduit are blocked with plastic mud, and the cracks on the working face are blocked at the same time. Grouting pressure is controlled at 0.5- 1.0mpa. ..

Eight, steel production, installation and construction

Steel frame processing is carried out in the steel bar processing plant according to different surrounding rock reserves.

After processing each unit steel frame according to the design, organize trial assembly, check whether the size and shape of the steel frame are qualified, and carry out structural tests on it.

The specific detection method is as follows: assemble the steel frame into a ring on the workbench, use oil caps and instruments on the outside, pressurize according to the design load, and detect the internal force and deformation of the steel frame by using the steel bar stress meter and convergence instrument. Strictly control the drilling size of the joint plate.

The steel frame should be installed after the initial shotcrete according to the design requirements, and the thickness of the shotcrete covered steel frame should not be less than 4 cm.

Nine, shotcrete construction

After the tunnel section is formed, shotcrete protection should be carried out in time. The spraying sequence is symmetrical from bottom to top. The gap between the steel frame and the surrounding rock is sprayed first, then around the steel frame, and then between the steel frames. Sprayed concrete covers all lattice steel frames, and the thickness of protective layer is ≥2cm. Sprayed concrete is wet sprayed in wet spraying machine, with an initial thickness of 3cm, and then sprayed to the design thickness. The concrete is sprayed from both side walls by two wet spraying machine machines at the same time, which speeds up the construction progress, makes the grid steel frame and sprayed concrete become an organic whole in time, and plays a supporting role.

Check the dimensions of excavation section before spraying. Remove pumice on the excavation surface and stone slag and deposits in corners. Treat the rock surface, remove obstacles, repair and chisel out the under-excavated part, and set up a working platform when necessary. Clean the sprayed surface with high-pressure air. A conduit is buried in the dripping part of the jet surface for drainage, a blind ditch can be set in the aquifer with poor water guiding effect, and a drain can be set in the dripping part for drainage. Bury signs to control the thickness of concrete. There is good ventilation and adequate lighting. Before spraying operation, mechanical equipment, air, water pipelines and circuits shall be thoroughly inspected and put into trial operation.

According to the mix proportion of wet sprayed concrete provided by the central laboratory, the mixing is completed at one time in the mixing station, and the slump is checked to keep it at 5 ~ 8 cm. Before the concrete tanker transports the mixture to wet spraying machine, the liquid accelerator is added from the nozzle through wet spraying machine and sprayed on the sprayed surface.

The spraying operation is carried out in stages, and the spraying order is from bottom to top; It shall be repainted after the final setting of the previous layer of concrete. At the beginning of spraying operation, air is first supplied, then the machine is turned on, then the material is fed, and finally the material feeding is stopped, and then the air supply is stopped. The material supply of the jet is continuous and uniform. When the machine is running normally, keep enough materials in the hopper, and control the working air pressure of the ejector at 0.45 ~ 0.7 MPa. When the spraying operation is finished or interrupted for some reason, the accumulated materials in the spraying machine and the conveying pipeline should be cleaned.

The spray hand always keeps the nozzle perpendicular to the sprayed surface with a distance of 0.6 ~ 1.0m, and at the same time controls the smoothness of the concrete surface. Two hours after the final setting of sprayed concrete, water shall be sprayed for curing, and the curing time shall not be less than 7 days.

X. Inverted arch and filling construction

During construction, the inverted arch should be closed as soon as possible to facilitate the overall stress of the lining structure.

Inverted arch shall be poured in sections, and the excavation of inverted arch shall be controlled at 3m per section, and the length of each section shall be 5~ 10m. Before concrete pouring, the empty ballast and accumulated water at the bottom of the inverted arch should be cleaned up, and the concrete can be poured only after the steel bar binding is inspected by the supervision engineer. When pouring inverted arch concrete, it shall be carried out symmetrically from the center of inverted arch to both sides. Concrete pouring shall be transported by tank car, the radian of inverted arch shall be strictly controlled, and inverted arch and inverted arch shall be poured separately.

After the inverted arch concrete reaches the design strength, it will be filled with concrete. Before pouring concrete, remove sundries, dust and water on the surface of inverted arch.

In inverted arch construction, in order to realize parallel operation with excavation and lining, a trestle is built on the inverted arch working face to ensure the normal running of all kinds of working vehicles without damaging the newly poured inverted arch concrete.

XI。 Waterproof and drainage construction of structure

A composite waterproof board is arranged on the arch wall between sprayed concrete and molded lining concrete of tunnel lining. A blind ditch is set every 8m, and a φ50mm soft permeable pipe is set around it. During construction, the setting of circumferential blind pipes can be adjusted according to the water outlet situation of the tunnel, and centralized water outlet points should be set. φ 100 longitudinal permeable blind pipes are arranged at the lower parts of the side walls on both sides, and the drainage pipes are wrapped with perforated corrugated pipes.

Before waterproof board construction, the tunnel clearance should be measured and checked, and the clearance requirements should meet the excavation contour line of tunnel design. It is required that the base surface should be smooth, without obvious bumps and bumps, and without sharp protrusions such as steel bars and protruding pipe fittings, otherwise it will be cut off, and the cut-off parts should be rounded with mortar to avoid the waterproof layer from being punctured.

When laying waterproof board, the longitudinal center line of the tunnel should be correctly marked at the top of the sprayed concrete tunnel, and then the center line of the cut non-woven fabric should coincide with the center line mark on the sprayed concrete and be laid from the vault to both sides.

The waterproof board is laid without nails. First, correctly mark the longitudinal center line of the tunnel on the non-woven fabric at the top of the tunnel arch, and then the center of the waterproof board coincides with this mark. Like non-woven fabrics, they are hung and laid from the arch to both sides, and welded with gaskets when laid.

The connection of waterproof board is welded by thermal bonding machine, the lap length is 15cm, and the seam is welded on both sides, leaving a cavity in the middle for inspection.

After the waterproof layer is completed, concrete should be poured in time for protection.

XII. Tunnel Lining Construction

Tunnel lining adopts combined steel formwork lining trolley. The workbench is made of I-beam, and the counterpart support is made of steel pipe. Template adopts special composite steel template.

After the tunnel excavation and support is completed, the displacement rate shown by various test items after construction monitoring obviously slows down and basically tends to be stable; The generated displacement has reached 80% ~ 90% of the predicted displacement; When the horizontal convergence rate (near the arch foot) is less than 0.2 mm/day or the vault subsidence rate is less than 0. 15 mm/day, the side wall and arch lining construction will be carried out. When the supporting deformation is large, it is difficult to strengthen the supporting capacity, and the deformation has no obvious convergence trend, the secondary lining construction should be carried out in advance after being reported to the supervision engineer for approval.

Concrete shall be poured symmetrically on both sides at the same time, and the uniformity of pumping concrete on both sides shall be controlled, and the elevation difference of pouring concrete on both sides shall not exceed 50 cm.

Before each round of lining, the concrete at the joints of the previous group of lining should be chiseled and cleaned, and a layer of cement slurry should be brushed to make the new and old concrete combine well.

After a continuous concrete pouring, the pouring surface should be leveled and vibrated to prevent power failure and other accidents that must be stopped. Stop working for more than 2 hours and wait for 24 hours before receiving irrigation.

After the arch is capped, it must be filled and compacted without gaps.

According to the humidity in the cave, water spraying or natural curing is adopted. Demolition should be carried out after the concrete in the arch reaches the design strength, and attention should be paid to the protection of the angle and surface of the concrete formwork during formwork removal.

Thirteen. Construction survey, monitoring survey and geological advance prediction

Tunnel survey shall be managed at different levels, and a precision survey group and a construction survey group headed by a full-time survey engineer shall be established to be responsible for their respective functions and powers. Strictly abide by the provisions of the railway engineering survey specification to ensure the measurement accuracy. The construction survey grade and accuracy standard of this bid section shall be implemented according to the specified requirements.

Before construction, the ground control piles delivered by the design unit shall be retested and handed over; Joint survey between adjacent blocks; Joint survey of tunnel entrance and exit, layout of traverse control network, control of tunnel centerline and elevation.

Control survey outside the cave: Total station is used for control survey outside the cave. Strengthen the contact and coordination with the line in the process of measurement to ensure that the through measurement is correct.

In-tunnel control survey: Total station is used for precise control survey in tunnel centerline survey, and the in-tunnel control network and centerline adjustment are carried out in time.

The precision survey team of the project management department is responsible for the control survey, phased control survey, review and inspection of the tunnel, review and guide the construction survey team of the tunnel construction team to complete the construction survey task, and provide the construction survey team with on-site intersection, pile delivery and survey data and results. Responsible for controlling pile protection survey and protecting all triangle points, leveling points and control points within the scope of the project.

The construction survey team of the tunnel team is responsible for the daily construction survey, construction lofting and control of the embedding and protection of pile points on the project site.

During engineering construction, the center line and elevation should be measured according to the design drawings to ensure the accuracy of the center line and elevation. After the completion of the project, the whole line shall be measured, overlapped and closed in time, and the measurement data shall be submitted to the supervision engineer. The original measurement records, data, calculations and charts shall be true and complete, and shall be properly kept by special personnel.

Seriously implement the measurement recheck system, the field measurement data must be rechecked by a second person, and the indoor measurement results must be independently calculated by two people and verified by each other before delivery. It is strictly forbidden to use data that has not been checked and confirmed by a second person.

Fourteen Monitoring and measurement

Field monitoring is one of the core technologies in the design and construction of NATM composite lining. During the construction, a detailed monitoring and measurement plan shall be formulated, and a full-time measurement team shall be set up to be responsible for the daily work of measuring point embedding, monitoring and measurement, data processing and analysis, instrument maintenance, etc., so as to ensure the reliability of measurement data, provide accurate basis for construction and design, and ensure construction safety, quality and investment.

A. Purpose of measurement

A. 1 master the surrounding rock dynamics and control the surrounding rock deformation during construction.

A.2 Understand the function of supporting structure, and take timely measures to ensure safe construction.

A.3 Provide a basis for optimizing the design and ensure that the tunnel is stable and economical.

B. Monitoring and measurement projects

Deformation measurement, stress and strain measurement, surrounding rock stability and supporting effect analysis of tunnel surrounding rock.

C. observation of engineering geology and supporting conditions

C1observation content: after the tunnel excavation, check the stability, geology and rock quality of the excavation surface and its surrounding areas, check the classification of surrounding rocks, draw a geological sketch, and check whether the structural conditions of the initial support (anchor rod, shotcrete and steel support) are damaged.

The observation of excavation surface should be carried out after each blasting, especially under the condition of weak surrounding rock. Geological survey should be carried out immediately after excavation. In case of special instability, a special person shall be assigned for uninterrupted observation. Make records after observation, and organize and save them.

D. Tunnel clearance convergence measurement

Clearance change measurement and vault subsidence measurement are carried out on the same section in principle. The measured section spacing is related to many factors such as tunnel length, surrounding rock conditions and excavation methods.

There are two horizontal baselines in the general section of clearance change measurement, and four baselines in the section with buried depth less than 2 times the excavation width and the section with expansion or eccentric pressure.

Key points of measurement: fix the short rod of the gap displacement meter in the rock mass of two points to be measured; Determine the measuring distance according to the surrounding rock conditions; Measurement accuracy: generally 0. 1mm in the case of small changes, and 1mm in the case of large changes.

E. vault subsidence measurement

The measuring points of vault subsidence are generally arranged in the arch and on both sides of the arch waist, and three measuring points are arranged on each section. When affected by ventilation pipes or other obstacles, the position can be moved appropriately.

F. Measurement of surrounding rock displacement and anchor strength

According to the surrounding rock conditions and engineering importance, 2 ~ 5 measuring points are set for each section.

G. stress and strain measurement of tunnel steel arch frame

The stress and strain measurement of tunnel steel arch adopts a stress box which can support the yield strength and is placed under the bottom plate supported by steel arch. In the stratum with extrusion force or expansion force, when using the inverted arch cross brace, the stress box is placed on the special arch frame.

Measure the stress in the lining concrete, arrange several pairs of stress boxes (one radial and one tangential) on the measuring section, and then read the measuring pipeline centrally.

The stress-strain measurement is carried out on the anchor rod, and the pressure box is placed on the anchor rod to form an enlarged washer, which can directly measure the stress value imposed on the rock mass.

H. The measuring frequency mainly depends on the displacement rate and the distance between the measuring point and the excavation face, and is generally selected according to the following table, that is, the measuring frequency in the initial embedding stage should be 1 ~ 3 times a day. As the surrounding rock becomes more stable, the measurement frequency can be reduced, and when there are signs of instability, the measurement frequency should be increased.

When the surrounding rock is basically stable, the measurement shall be carried out at the frequency of 1 time /3 days for 2 weeks. If there is no obvious deformation, the measurement can be ended.

Fourteen Geological advance prediction

Geological advance prediction is one of the important means to determine the change of surrounding rock, especially in tunnel construction, especially in bad geological sections. In the construction, a comprehensive advanced geological prediction system combining advanced geological prediction and advanced drilling exploration was established. TSP203 geological advanced predictor, HY303 infrared water detector, horizontal geological drilling rig and other instruments and equipment were used to accurately predict the geological conditions ahead and provide reliable technical parameters for the construction.

Regularly predict the engineering geology, hydrogeology and surrounding rock types in front of the tunnel excavation face, and formulate feasible construction methods and construction precautions according to the prediction results. After excavation, the prediction results are analyzed and compared, and the accuracy of advanced geological prediction is gradually improved.

Fifteen, quality assurance measures

In strict accordance with the smooth blasting design, the hole arrangement and charge are determined, the excavation section is determined, the blasting effect is checked, the blasting design is revised, the smooth blasting quality is improved, and the excavation section is effectively controlled.

Establish a monitoring and measuring team, equipped with special measuring instruments, measure regularly according to regulations, collect data accurately and completely, analyze and master the convergence of surrounding rock, and feed back information in time, so as to provide scientific basis for design and construction.

Strive to improve the quality of bolting and shotcreting support, check the pullout force of anchor rod and the thickness of bolting and shotcreting layer according to regulations to ensure that the section size meets the design and the supporting structure is stable and reliable.

The tunnel should be equipped with soft permeable blind ditches in the circumferential direction and longitudinal direction according to the design requirements to ensure the performance of waterproof materials and meet the design standards in the construction process. When laying, it must be closely attached to the sprayed concrete surface to ensure the lap length. The tunnel lining is assembled with fixed steel formwork. First, the design, and then the trial before lining. In the construction process, after accurate measurement, ensure that the formwork joints have the neat appearance effect of longitudinal lines and circumferential surfaces.

The overbreak part of the tunnel shall be backfilled and compacted with concrete of the same grade in strict accordance with the specification requirements.

Construction quality assurance measures in rainy season:

Before the rainy season construction, do a good job in rainy season protection measures, establish flood control organizations, prepare sufficient flood control materials, and make all preparations for flood fighting and emergency rescue.

During the rainy season construction, a special person will be responsible for the weather forecast and timely deliver the rain. According to the weather trend forecast, arrange the working procedure reasonably and do the protection work well in advance.

Technical measures to ensure tunnel impermeability, seepage prevention and crack prevention;

Do a good job in tunnel waterproof and drainage. Ensure the smooth drainage behind the tunnel lining, and the waterproof isolation layer can prevent water seepage and leakage, improve the stress conditions of the secondary lining and reduce the cracks in the secondary lining. During the tunnel construction and operation, the quantity and direction of groundwater may change. There is no guarantee that there will be no water accumulation or less water accumulation during construction, and the waterproof board itself has good waterproof performance, but it is often destroyed by pouring the secondary lining during construction, thus affecting the waterproof effect. Therefore, we must not despise the application of waterproof layer or ignore the construction quality because of temporary water shortage.

The back of primary support and secondary lining must be backfilled and compacted. Foreign bodies or cavities shall not be backfilled behind the initial support. If necessary, grouting should be carried out several times until it is dense. In order to prevent the secondary lining from being stressed too much, we should strengthen monitoring and measurement, adjust the construction support parameters according to the measurement results, and determine the construction time of the secondary lining.

Make expansion joints according to design requirements. Expansion joints must be vertical and straight, and there can be no dislocation or occlusion. The water stop at the expansion joint is set as required. In order to reduce the construction joints of secondary lining, continuous grouting must be carried out during secondary lining. When it is necessary to stop, the water stop must be set according to the design requirements. For unfavorable geological conditions, such as when the tunnel passes through faults and broken zones, the tunnel lining structure should be strengthened according to the design.

In order to prevent the secondary lining from cracking due to the sinking of the basement, the foundation of the side wall must be cleaned before the formwork can be placed before the secondary lining construction. In order to prevent the lining from cracking, additives and admixtures, low water-cement ratio and high content fly ash concrete are also used. Choosing cement type, concrete coarse and fine aggregate and construction water in concrete construction are also the main technical measures to solve the tunnel cracking problem. Do a good job in the maintenance of secondary lining concrete to ensure the quality of concrete.

Cement is piled up in the canopy, wooden pillows or square towels are laid on the bottom, and waterproof ponchos are laid to avoid being affected with damp. All materials and machinery should be placed in higher places, and tarpaulins should be supported to prevent rain when necessary, and water retaining and drainage facilities should be set on the ground.

Improve the standard of construction access road to prevent the access road from blocking the entry of materials and the passage of construction machinery in rainy season.

XVI. Safety measures

Workers participating in tunnel construction must receive safety technical education, be familiar with and abide by the technical specifications for tunnel construction safety, take safety examinations, and work at their posts only after passing the examinations, and wear safety protection articles as required. All kinds of mechanical operators must hold relevant certificates, and all kinds of machines and tools should be inspected and tested regularly to ensure that they are in good condition. Full-time safety inspectors often supervise and inspect construction safety. Those who seriously violate the construction safety regulations have the right to order them to stop work for rectification until they pass the re-examination. Once an accident occurs, it should be handled in strict accordance with the "three-no-pass" method.

A. Construction safety measures

A. 1 Adhere to the principle of geological orientation, keep abreast of the previous geological conditions, and adopt special advance support and initial support measures for abnormal geology.

A.2 Adhere to the principle of roof protection first and then excavation, and organize construction: adopt pre-grouting reinforcement measures with advanced small pipes. Through experiments, the grouting pressure and consolidation range are determined, so that the grouting bodies can be bonded to each other and the stability of surrounding rock itself can be improved.

A.3 Strictly control the footage of each cycle, carry out initial support in time after excavation and molding, ensure the process connection, and construct inverted arch into ring as soon as possible, so as to improve the stress situation, narrow the space between grid steel frames in special areas, and encrypt the leading small pipes to strengthen the initial support.

A.4 Strengthen the measurement of excavation surface: After the initial support of excavation, systematically analyze the vault subsidence, the convergence between the arch foot and the wall, the tunnel uplift measurement and the internal force measurement of the grid, and take reinforcement measures immediately if any abnormality is found.

B. Safety measures for electricity consumption at the construction site

Temporary power consumption on the construction site shall be strictly implemented in accordance with relevant regulations.

B. 1 Temporary power lines shall be installed, maintained and dismantled by trained electricians who have obtained the work license, and electricians are not allowed to carry out electrician operations.

B.2 Cable lines shall be connected in tn-s mode, and electrical equipment and lines must be well insulated. The hanging height and line spacing of power lines erected in the field should meet the safety requirements and should be installed on special poles.

B.3 The transformer shall be equipped with grounding protection device, and its grounding resistance shall not be greater than 4Ω. The transformer shall be fenced, the door shall be locked and managed by a special person, and a warning sign "Keep away from high voltage" shall be hung.

B.4 Insulating pads should be set in front of indoor power distribution cabinets and distribution boxes, and leakage protection devices should be installed.

B.5 The metal shell of various electrical switches and equipment shall be protected by grounding or zero connection. It is forbidden to use other wires instead of fuses.

B.6 There shall be no sundries in the fire-proof and electricity-proof distribution box, and the door of the box shall be locked and managed by special personnel.

B.7 rubber cables shall be used for the power cord of mobile electrical equipment. When crossing the driveway of the stadium, it should be laid underground through pipelines. Do not use damaged cables.

B.8 When overhauling electrical equipment, the power supply must be cut off, and a warning sign "No switching on" should be hung on the power box or switch handle, or someone should be assigned to take care of it. Live working must be approved by relevant departments.

B.9 bare wires shall not be used for power lines erected on site, and temporary power lines shall not be hung on steel formwork and scaffolding, and insulating supports must be installed.

B. 10 safe voltage 36V is used for hand-held lighting in the construction site, and 12V is used for lighting in wet foundation pit and cavern excavation.

Seventeen, environmental protection and water and soil protection measures

According to the requirements of environmental management system standards, a construction environmental protection organization was established, with the project captain as the team leader, the deputy team leader and the chief engineer as the deputy team leader, and the heads of relevant departments as members. The engineering team is equipped with full-time environmental protection engineers and part-time environmental protection personnel.

Before construction, formulate specific arrangements and corresponding measures for construction environmental protection and soil and water conservation to ensure the environmental protection objectives of construction.

During the construction process, the production and living quarters will be arranged centrally, and corresponding preventive measures will be formulated for possible pollution types, and the production and living garbage will be stored and treated centrally, so as to achieve the purpose of centralized control and reduce the pollution range.

Strengthen inspection and monitoring, strengthen the monitoring, monitoring and inspection management of dust, noise, vibration, waste gas and strong light on the construction site, and organize relevant personnel to regularly evaluate environmental protection work.

After the completion of the project construction, the construction site should be cleaned up in time, the abandoned temporary facilities should be dismantled, and the remaining materials and construction waste should be transported away from the site, so that the site can be cleaned up after work.

The material comes from the network, edited and arranged: Luqiao network.

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