Tunnel Lining Formwork Safety Operation Procedures Tunnel lining formwork is a special equipment that must be used in the secondary lining of tunnel construction process. It is used for lining construction of the inner wall of the tunnel. There are mainly simple lining trolleys, full hydraulic automatic walking lining trolleys and grid-type lining trolleys. Tunnel lining formwork should follow the corresponding safety procedures during the construction process. First, The Operator`S Job Requirements 1. The operator should do a good job in the inspection and maintenance of the daily use of the tunnel lining trolley, and make necessary records. 2. It is strictly forbidden to operate according to the safety technology and the corresponding operating procedures. Second, The Job Conditions 1. The operator should have received good safety and technical training. Hold the certificate and work. Third, Pre-Job Preparation 1. After the lining trolley is assembled, each connecting screw should be inspected and tightened one by one, and can be put into use after being inspected and accepted by all parties. 2. Wear belts on the lining trolley. The operating parts should be covered with 5cm planks to prevent the workers from falling from high places. The trolleys are equipped with eye-catching reflective strips. Fourth, The Safety Procedures 1. The base surface of the lining trolley track should be solid and flat. It is strictly forbidden to be soft on the side and the top surface of the track should be on the same plane. The track pitch is consistent with the wheel edge of the platform. 2. The top surface of the lining trolley track is basically parallel with the longitudinal excavation surface of the tunnel. When the slope is large, the railing device should be installed at a position of not less than 3m at the track head to prevent the lining trolley from derailing during operation. 3. When the lining trolley moves in position, when there is automatic downward sliding, the operator should select an experienced person to operate, and send people on both sides of the forward direction to check the operation. When an abnormal situation occurs, the operator is notified at any time. Immediately brake the lining trolley. When the external force (loader, excavator) moves, it is necessary to use a qualified wire rope to drag along the uphill direction of the tunnel, slowly slide and move, let it move under the action of gravity, and it is strictly prohibited to lining the trolley in the direction of the slope. 4. The trolley should be slow and stable during the movement. When the movement is difficult, it should be carefully checked whether there are hard objects stuck on the two sides or the bottom of the trolley. Check whether there are steel intrusion restrictions on both sides and the top surface to hinder the running of the trolley. The trolley should be stopped, and the collapse of the steel skeleton will occur. 5. After the trolley is positioned, the operator should first wedge the wheel with a wooden wedge and then adjust the trolley under the command of the surveying personnel. When the offset of the trolley is large, the cylinder should be adjusted symmetrically. Make the trolley position reach the balance requirement. When the positioning of the trolley meets the requirements, the screw jacks on the bottom of the trolley should be tightened first, and then the jacks on both sides of the trolley should be screwed tightly. When the tops of the trolleys are tightened in place, the hydraulic cylinders are loosened. Open to protect the cylinder. 6. Before pouring concrete, the operators should check the jacks one by one to ensure that each screw jack is tightened and the top of each hydraulic jack is relieved. In the process of concrete pouring, it should be strictly symmetrically poured. The height difference between the concrete on both sides should not exceed 1 m, 0.5-0.8 m is appropriate, and the jack should be sent to check. When the concrete structure is thick and the square is large, the pouring speed should be slowed down in a timely manner, and the frequency of the mold should be tightened to prevent accidents such as running, rising and falling. 7. The power supply control box of the trolley should be placed on the base surface of the tunnel. It is strictly forbidden to install the control electric box on the trolley. All the power cords must pass through the leakage protector. The action current should not exceed 30MA, and the action time should not exceed 0.1S. The cable must be made of rubber flexible cable, and there must be no joints or damage in the middle. The frame body must have a reliable protection and zero connection. 8. The lighting on the trolley should use an electric voltage or a flashlight. Five, Other Matters Needing Attention 1. When a vehicle passes under the clearance of a trolley during construction, it shall be assigned to conduct traffic command and management to prevent vehicle from colliding with the trolley. 2. Strictly control the center line of the rail to avoid excessive deviation between the center of the backstage vehicle and the center of the tunnel. 3. During the laying process of the rails, the rails and rails must be firmly connected to avoid the rails being crushed or the trolleys derailed during the running. 4. Remove the imaginary underneath the sleeper to avoid sinking due to the weight of the raft and the trolley. 5, the head plate is stressed, the reinforcement must be reinforced in the process of standing, in the process of pouring, there are people to see, strengthen at any time. 6. The second lining is poured for a long time. In order to facilitate the simultaneous construction of the second lining and the shovel, the pump is placed away from the lining trolley. 7. The conveying pipe is fixed firmly on the gantry. The pipe should not be in contact with the stencil, so as to avoid strong vibration at the nozzle when the squeezing is pressed out, so that the stencil can be deformed and run. The joint pipe clamps should be connected firmly to avoid explosion. The pipe squares are raised above the ground. When passing through the trolley, the pipe clamps are not in direct contact with the trolley components.

The Use And Structure of Tunnel Lining Trolley First of all you should know the structure of the trolley Hydraulic and mechanical can be selected. After analysis and comparison, the hydraulic type has low requirements for rigidity of the trolley frame, sensitive structure, light weight, low processing requirements and low elevation requirements of the laying track during construction, and is convenient to use, but it has high requirements for the self-locking of the hydraulic cylinder. The hydraulic cylinder in the lining does not Allow retraction. The mechanical type is the opposite. Because one motor needs to drive several screw drives, the coaxiality of each drive shaft is required to be high, and the trolley frame must have greater rigidity, and the structure and size must be accurate. Due to the heavy structure and high processing requirements, And because the lead screw is synchronized action (unlike hydraulic transmission, each hydraulic cylinder can be synchronized or independently), when the track elevation error (each point is not at the same elevation) is large, it will directly affect the template orientation and then affect the lining quality . After analysis and comparison, the hydraulic transmission plan is selected, and measures such as hydraulic lock and balance valve are adopted for the hydraulic cylinder to make the hydraulic cylinder self-locking; together, the screw organization is selected for mechanical determination, and the support of the template is strengthened to ensure that the template does not return during lining. Shrink without deformation. Practice has proved that it is reasonable to choose hydraulic type for lining trolley, which is the development direction. Trolley frame structure optimization The trolley adopts hydraulic transmission, which simplifies the structure of the trolley frame and reduces the weight. At the same time, it also improves the sensitivity and diversity of the structure. After analysis and comparison of various trolley frame structure plans, strength calculations, and optimization, the 9m four-door frame 12m is selected The main mast structure plan reduces the structure weight by more than 40% compared with the mechanical type, and reduces the manufacturing cost by more than 25%. Steel mold steel mold is the operating equipment of the trolley. Its surface quality and external dimension accuracy directly determine the quality of the concrete lining. Together, it is the most difficult part to process. Reasonable processing and welding technology have been formulated, and special assembly welded tires have been planned and processed. Die to ensure the accuracy of the overall dimensions, minimize welding distortion, ensure lubrication of the surface, and no defects such as height. In order to control the misalignment of adjacent templates, the stabilizing pins of interference cooperation are used to fix the connecting plates of adjacent templates as a whole, which effectively controls the misalignment of adjacent templates caused by the gap of the bolt holes. After successfully solving the above-mentioned problems, the quality of concrete lining is ensured. Determination of bearing position The entire mass of the lining concrete is transmitted to the supporting organization through the steel mold of the trolley, and then to the portal frame. The lining concrete is in a solid-liquid state. Large vertical pressure and lateral pressure are generated on the top and side, and a large buoyancy occurs together. When the buoyancy exceeds the straight pressure and the weight of the trolley, the trolley will float up. Will not work normally. In order to deal with this technical problem, after careful calculation, optimized planning, and reasonable selection of each supporting position. That is, the lower longitudinal beams inside the mast are supported on the ground to prevent the side pressure from causing the mast columns to retract, and there are several horizontal supports on the outer side of the mast and the longitudinal beams of the side form, at the upper beam and the upper longitudinal beam of the mast Several straight supports are selected (the top hydraulic cylinders are arranged on the horizontal part of the gantry at both ends, and the middle is a straight supporting screw), which is uniformly distributed in the longitudinal direction of the trolley. The hydraulic cylinder is determined by hydraulic lock, and the supporting screw is used for mechanical determination, which ensures that the hydraulic cylinder does not retract and the template does not deform during the lining construction. Tunnel lining trolley: The lining formwork trolley (referred to as the trolley) is the construction equipment for pouring the secondary lining concrete of the tunnel. Cooperating with other auxiliary machinery, it can greatly reduce the labor force, improve the mechanization efficiency of the tunnel second lining construction, and improve the construction progress. It has investment It has the advantages of low cost, reliable structure, convenient operation, and good tunnel forming surface. Therefore, it is widely used in the construction of highways, railways, water conservancy and hydropower, municipal, national defense and military engineering. According to the different tunnel engineering, the lining trolley is divided into side-top arch type, straight wall variable cross-section side-top arch type, abrupt surface type, full circle needle beam type, full circle travel type, etc. According to the actual needs of the user, the fully hydraulic self-propelled, fully hydraulic dragged, mechanical steel formwork, simple combined formwork and other types can be selected. The length of the trolley can be selected according to the length of the tunnel and the construction period of 6 meters, 7.5 meters, 9 Meters, 10.5 meters, 12 meters, etc. In addition, everyone knows that if we just use anything without paying attention to maintenance, it will affect its performance and even its service life. How should the tunnel trolley be maintained in daily life? 1. After the tunnel trolley works for 15 working cycles, replace the hydraulic oil and reduce the oil. 2. Grease the screw jacks in each working cycle to remove the concrete on the surface of the portal frame, jacks and formwork. 3. Mold release agent must be applied to the template during each working cycle. 4. The piston rod of each cylinder must be covered when pouring concrete to prevent concrete from falling on the surface of the piston rod. 5. After each demolding, check whether the connecting bolts are loose, and tighten them if they are loose. It is best to pay attention to prevent the oxide pickup from getting stuck in the furnace wire to cause a short circuit. At the same time, check whether the over-temperature alarm and temperature measurement system are normal. Don't forget to maintain it after the work is completed to extend the utilization rate.

Brief Introduction of Tunnel Lining Trolley The tunnel lining trolley is a special equipment that must be used in the secondary lining of the tunnel construction process, and is used for the concrete lining construction of the inner wall of the tunnel. Concrete lining trolley is an indispensable non-standard product for secondary lining during tunnel construction. It mainly includes simple lining trolley, fully hydraulic automatic walking lining trolley and grid-frame lining trolley. Full hydraulic lining trolley can be divided into side-top arch type, full circle needle beam type, bottom mold needle beam type, full circle travel type, etc. In the construction of hydraulic tunnels and bridges, lifting slipforms, jacking slipforms and overturning forms are also commonly used. Product Usage The full-circle lining jumbo is often used in hydraulic tunnel construction. The tunnel is not allowed to have longitudinal joints for concrete construction. It is generally used when the hydraulic tunnel has a large span Use full-circle travel type; side-top arch lining trolley is the most common application, often used in the construction of concrete secondary lining of highway, railway tunnel and underground cavern. Product Classification Introduction Simple The trolley is generally designed as a steel arch type, using a standard combined steel template, without automatic walking, using external power to drag, and the detachment template is all manually operated, which is labor-intensive. This type of lining trolley is generally used for short tunnel construction, especially for tunnel concrete lining construction with complex plane and space geometry, frequent process conversion, and strict process requirements. Its advantages are more obvious. The second tunnel reinforced concrete lining adopts a simple arch frame design, which solves these problems well, and at the same time, the engineering cost is low. Most of the simple trolleys use artificial concrete pouring, and the simple lining trolley is filled with concrete conveying pump trucks, so the rigidity of the trolley should be particularly strengthened. Some simple lining trolleys also use integral steel formwork, but they still use threaded rods and do not move automatically. This type of trolley is generally filled with concrete delivery pump trucks. Simple lining trolleys generally use combined steel formwork. Combined steel formwork is generally made of thin plates. The rigidity of the steel formwork should be considered in the design process, so the spacing between steel arches should not be too large. If the length of the steel formwork is 1.5m, the average spacing between the steel arches should not be greater than 0.75m, and the longitudinal joint of the steel formwork should be set between the push and the push to facilitate the installation of formwork fasteners and formwork hooks. If the pump is used for infusion, the infusion speed should not be too fast, otherwise it will cause deformation of the composite steel formwork, especially when the lining thickness is greater than 500mm, the infusion speed should be slowed down. Be careful when capping and pouring. Pay attention to the pouring of concrete at all times to prevent the concrete pouring after filling, otherwise it will cause mold explosion or deformation of the trolley. Full hydraulic It is mainly used in the construction of medium and long tunnels, with high requirements for construction progress and concrete surface quality. This type of lining trolley is designed as an integral steel formwork, hydraulic cylinders to be released from the vertical mold, and supported by screw rods during construction, electric reducer automatic walking or cylinder stepping automatic walking, all are filled with concrete conveying pump trucks. Most lining trolleys are of this type. When designing this type of lining trolley, in the case of meeting the clearance requirements, the installation position of the lower part of the oblique support inside the mast should be considered, as close as possible to the lower part of the column, so that it can bear the best force. The portal beam should be high enough, not less than 400mm for conventional railway tunnels, and not less than 5500mm for highway tunnels. The minimum adjustment distance between the end face of the formwork and the door frame is not less than 250mm, otherwise it will cause difficulty in overlapping the front and rear lining sections. When using this type of lining trolley, it should be noted that the laying height difference of the running rails on both sides is not more than 1%, otherwise it will cause the deformation of the screw jack and the jacking cylinder. When lining a tunnel with a ramp, in order to adjust the lining elevation, the height difference between the front and rear ends of the trolley will be caused, and the end face of the formwork and the end face of the gantry will not be parallel, which will cause a large horizontal force to be formed between the formwork and the gantry. The supporting screw rod between the template and the mast is misplaced, causing damage to the jack and the cylinder. Therefore, in the design, full consideration should be given to the restraint structure or adjustment system of the horizontal component caused by the height difference between the front and rear. When positioning the vertical mold, a rail clamp must be installed, and the foundation screw jack, the gantry jack and the template jack must be tightened. If necessary, other measures can be used to reinforce the position of the arch foot of the lower mold so that the gantry is fully stressed. May be small to prevent mold running and mast deformation. Grid Compared with the traditional lining trolley, the structure of the grid-frame lining trolley has been greatly changed. In the construction of the traditional lining trolley, the trolley's mast is a stress-bearing part, and it is subject to greater lateral pressure, which produces unequal deformations with the rigidity of the mast, and it is not suitable for direct work in tunnels with large transverse and longitudinal slopes , It has high requirements on the working environment, otherwise it will cause the overall deformation and damage of the trolley. The main frame of the grid-type lining trolley is a non-stressed part during construction. The support of the formwork is the ground screw jack of the side mold arch foot. The main frame is only stressed during the process of removing the standing form and walking. The force is vertically downward, there is no side pressure, and the mast is designed with sufficient rigidity according to the weight of the trolley to prevent deformation. When constructing or walking in a tunnel with a ramp, whether it is a horizontal slope or a longitudinal slope, the height can be adjusted by the jacking cylinder at the lower part of the mast, so that the entire trolley is in a horizontal state, and the entire trolley does not have forward tilting force. And the roll force ensures the overall stability of the trolley. Because the trolley completely eliminates the screw jacks used for support, the trolley is simple to locate and can be adjusted to the lining geometric position very quickly, saving a lot of manpower and material resources, improving work efficiency, shortening the work cycle period, and correspondingly saving engineering cost. In order to ensure the rigidity and strength of the top arch formwork, the upper frame is designed as a grid-type rod structure to make it bear the best force and the formwork will not be deformed and displaced during the lining process. The weakest link in the entire trolley is the lower template and the lower die supporting diagonal rod. Therefore, when designing the lower template, the force of the lower die should be fully calculated, and the width and thickness of the arc plate should be widened as much as possible. The supporting diagonal rod must pass The stable calculation of the pressure rod ensures that the inclined rod has sufficient rigidity and strength, so that it will not deform and bend during use and cause mold running. In the calculation process, the influence of concrete lining thickness, slump, pouring speed, aggregate size and whether it is reinforced concrete should be fully considered. The screw jack at the top of the arch foot of the lower mold is the main force-bearing part. When the entire template is below the center line of the lining circle, it is completely supported by it. Therefore, its structure and rigidity should be considered in the design. In use, the jack must be firmly pressed against the ground, and no looseness is allowed. If necessary, it can be reinforced with other parts as an auxiliary support to prevent the mold from running and the trolley from shifting downward. It should be noted that, as the longitudinal positioning of the trolley, the rail clamp and the foundation screw jack must be tightened, clamped and secured to the rail, especially when lining the ramp. This type of lining trolley is mainly used for the construction of large-span tunnels and underground caverns. If the traditional full hydraulic lining trolley is adopted, the design of the mast is difficult to meet the requirements of use, and the mast is deformed and damaged. First of all, the mast beam is twisted and deformed, which eventually leads to mold running. If the beam is heightened, the vertical beam, the lower longitudinal beam, and the oblique support section of the end face are enlarged, unnecessary waste will be caused. However, the use of a grid-type lining trolley can overcome the above difficulties. Since this type of lining trolley is for large-span construction, its operability should be considered when designing, and its working ladder and working walkway should be able to easily reach every working position.

How to strengthen the steel structure? The structural reinforcement design can use the linear elastic analysis method to calculate the effect of the structure, and should comply with the relevant regulations of the current standards. The reinforcement design of the structure should be closely integrated with the actual construction method, and effective measures should be taken to ensure that the new components and components are reliably connected to the original structure, and the new section and the original section are firmly combined to form an overall joint work. The unreinforced part should not be dealt with. And related structures, components and foundations cause adverse effects. The reinforcement of steel structure can be divided into two types: direct reinforcement and indirect reinforcement. When designing, suitable reinforcement methods and technologies can be selected according to actual conditions and use requirements. Direct reinforcement should be selected according to the actual situation of the project to increase the section reinforcement method, stick steel plate reinforcement method and combined reinforcement method. Indirect reinforcement should be adopted to change the structural system reinforcement method and prestressed reinforcement method according to the actual situation of the project. The connection method of structural reinforcement should adopt welding seam connection, friction-type high-strength bolt connection, or mixed connection of welding seam and friction-type high-strength bolt. Steel structure reinforcement materials (1) Material strength of original structure and component materials When the structural reliability appraisal considers that the original design documents are valid, and there is no obvious deterioration in the performance of structural members or connections, the original design values can be used. When the structural reliability appraisal considers that the on-site inspection should be carried out again, the inferred yield strength or the conditional yield point of the test results shall be used for determination. When the inferred value fy of the on-site yield strength is determined, the tensile strength design value f shall be taken as The ratio of fy to γR, and the resistance partial coefficient γR should be taken as 1.2. For the original steel structure subject to vapor phase corrosion, when the cross-sectional area loss is greater than 25% or the remaining thickness of the plate is less than 5mm, the steel strength design value at the time of the check calculation should be multiplied by the 0.8~1.0 strength reduction factor according to the corrosion level . (2) Steel and welding materials for reinforcement The steel grade of the reinforcement should be the same or equivalent to the steel grade of the original component, and the toughness, plasticity and welding performance should match the steel grade of the original component. The types of steel bars for structural reinforcement should be HRB400 or HPB300 steel bars, and their quality and performance should meet the relevant national standards. The quality and performance of welding materials used for structural reinforcement should comply with relevant national standards (3) Structural adhesive Structural adhesives for steel structure reinforcement should be structural adhesives with steel as the base material, and adhesives with unsaturated polyester or alkyd resin as the main component are strictly prohibited. When the use environment is normal temperature, the I type AAA or AA normal temperature structural adhesive should be used; when the use environment is high, the II or III temperature resistant structural adhesive should be used.

Steel Structure Brings More Possibilities to Future Cities. Steel structures are widely used in our lives, but it is inevitable that they will have some problems. In order to reduce the occurrence of problems, it is necessary to strengthen steel structures. The following is a comprehensive introduction to the reinforcement of steel structures. Reinforcement of steel structure. Before reinforcement, inspection or appraisal shall be carried out according to the types of buildings (structures) according to the current standards. When combined with seismic reinforcement, the seismic capability evaluation should still be carried out. A test and appraisal report for the project will be issued based on the test and appraisal results. The service life after the structure is strengthened shall be jointly negotiated by the property owner and the design unit. When structural adhesives or other polymer components are used in structural reinforcement materials, the service life after structural reinforcement should be considered as 30 years. If the service life after structural reinforcement is 50 years, the glue and polymer used The bonding performance of the product should pass the test of the ability to withstand long-term stress. Common reinforcement methods (1) Increase section method The method of increasing the cross-section can be reinforced by welding connection, bolt connection, rivet connection and pasting steel plate. Under load, the welding reinforcement of steel components should be checked according to the original component's service conditions, and its maximum nominal stress σ0max should not exceed the limit of stress ratio, otherwise, other methods of increasing the section should be adopted for reinforcement. (2) Sticking steel plate reinforcement method The sticking steel plate reinforcement method can be used for the reinforcement of steel structures under bending, tension, and shearing solid web members and the reinforcement of compression members. For steel structures reinforced by this method, the environmental temperature for long-term use should not be higher than 60℃; steel structures in special environments such as high temperature, high humidity, medium corrosion, radiation, etc., when reinforced by this method, except that they should be in accordance with the current national standards In addition to adopting corresponding protective measures in accordance with the regulations, adhesives resistant to environmental factors should be used, and adhesives should be adhered according to special process requirements. After the flexural member is strengthened with bonded steel, the increase in the flexural capacity and the shear capacity should not exceed 30%.