Brief Introduction of Tunnel Lining Trolley

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.