Shield originating or receiving end tunnel portal maintenance process

Abstract

The invention belongs to the technical field of subway tunnel engineering, particularly relates to a shield end tunnel portal maintenance process, and provides an economic, safe and quick method. A tunnel portal maintenance structure during originating and receiving a shield can prevent water and play a role in maintaining a soil body and is easy to remove. The process comprises the following steps of: during shield end tunnel portal maintenance wall construction, inserting a steel sheet pile into a tunnel portal position; moving the steel sheet pile up and down before initial setting of maintenance wall concrete; and when the shield is originated or received and the front end of the shield is jacked to the steel sheet pile, pulling up the steel sheet pile, and impelling the shield to finish originating or receiving. The process is simple and easy to operate, and has low manufacturing cost; and the steel sheet pile can be reused, so the process has particularly predominant economic benefit and social benefit, significance and extremely high popularization value at modern stage of vigorously building subway traffic engineering.

Description

technical field [0001] The invention belongs to the technical field of starting or receiving shield tunneling in subway tunnel engineering, and in particular relates to a maintenance process for a portal at the starting or receiving end of a shield tunnel. Background technique [0002] The superiority of underground railway transportation in solving urban traffic problems is very obvious. In recent years, subway construction has been spread across the country on a large scale. In subway construction projects, shield tunneling is widely used as an intelligent construction machine for tunnel construction. The construction process of shield tunneling projects Among them, the launching and receiving of shield tunneling is generally regarded as a difficult and key project today, and it is also one of the important risk sources in shield tunneling engineering. The maintenance measures of the soil behind the door and the portal are very important. [0003] At present, there are ...

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Problems solved by technology

[0004] 1. Simple grouting reinforcement, that is, grouting reinforcement in a certain range of soil behind the cave, so that after the cave is broken, the soil can resist the pressure of the rear soil and prevent groundwater from gushing. This method is widely used due to its simple process , but this method has great disadvantages when the shield is received. After the portal is broken, the reinforced soil is very likely to collapse towards the portal under the strong thrust of the rear shield, and the inner reinforcement of the portal should not be removed too early.

Before the shield is about to arrive, the reinforced soil is broken due to the thrust of the shield, and groundwater gushing accidents are very likely to occur. At this time, because the reinforcement bars of the portal are not broken and the shield cannot be pushed out by force, catastrophic accidents are very likely to occur

[0005] 2. Maintenance of pile-type portal reinforcement measures, that is, pouring piles and other piles behind the portal circle to maintain the stability of the portal soil. This reinforcement method is the time to break the pile during the process of shield tunneling and receiving. It is difficult to grasp, and this pile-type reinforcement method is extremely unfavorable to waterproofing, so it is generally used in anhydrous formations with low water levels, and its scope of application is extremely limited

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