Construction method for reinforcement of open cut tunnel portal

Abstract

The invention belongs to the technical field of tunnel portal reinforcement, and discloses a construction method for reinforcement of an open cut tunnel portal. The method comprises the steps of anchor cables; frame beam construction; anti-slide pile construction; biased retaining wall construction; lining formwork, wherein trolley positioning, lining steel bar, concrete construction, disassemblyand maintenance are carried out; tunnel structure waterproofing drainage, wherein tunnel waterproofing drainage, water-stop band construction, water-stop strip construction, construction joint construction and deformation joint construction are carried out; and ditch and cable groove construction, wherein a ditch groove adopts ejecting set-shaped steel formworks, concrete is manually poured, tamping compaction is carried out by a plug-in vibrator, and a water ditch, a cable groove and a side ditch are constructed by using a whole mobile formwork. The construction method for reinforcement of the open cut tunnel portal is small in portal excavation amount, good in reinforcing effect and low in cost, and can ensure the safety stability of tunnel portal construction; and the problem of tunnelportal entrance is effectively solved, economy, rationality, safety and efficiency are achieved as best possible, and the scientific basis is provided for the design of the method for reinforcement ofthe open cut tunnel portal.

Description

technical field [0001] The invention belongs to the technical field of tunnel opening reinforcement, and in particular relates to a construction method for reinforcing an open hole at a tunnel entrance. Background technique [0002] At present, in the tunnel construction process, the opening construction is particularly important. The erosion of rainwater on the entrance of the cave may easily lead to rockfall, instability and collapse of the slope. With the weathering of the slope at the entrance of the cave, it is easy to cause soil erosion. At the same time, when the tunnel entrance encounters slippery strata and mountains, the construction of the tunnel entrance is more difficult. It is necessary to ensure the stability of the slippery stratum and the safety and stability of the tunnel entrance construction. According to the current research, when joints and fissures are developed at the entrance of the cave, advance anchor rods or pipe sheds shall be installed outside...

AI Technical Summary

Problems solved by technology

However, the traditional hole reinforcement construction method has a large amount of hole excavation, increases construction investment, and at the same time seriously damages the environment, and cannot effectively ensure the stability of the slippery ground, the cost is high, and the reinforcement effect is not obvious

[0003] Through the above analysis, the existing problems and defects of the existing technology are: the traditional method of opening reinforcement construction requires a large amount of excavation, increases construction investment, and seriously damages the environment, and cannot effectively ensure the stability of slippery ground, and the cost is relatively high High, the reinforcement effect is not obvious

[0004] Difficulty in solving the above problems and defects: Most of the tunnel entrances are V-level surrounding rocks, with complex mechanical properties, and due to the influence of bias pressure, the distribution of ground stress is uneven, which makes the stability analysis of shallow tunnels very difficult. It is difficult to achieve construction quality and safety control during construction

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