Tunnel foot locking steel pipe having freezing function and partial freezing construction method

Abstract

The invention discloses a tunnel foot locking steel pipe having a freezing function and a partial freezing construction method. The tunnel foot locking steel pipe having the freezing function comprises a common foot locking steel pipe and a freezing cavity arranged in the common foot locking steel pipe, and the freezing cavity is connected with a refrigerant circulating system. The partial freezing construction method comprises the steps that a tunnel is excavated in water-rich soft surrounding rock through a benching tunneling method, after upper benching and preliminary supporting, the tunnel foot locking steel pipe is driven from an arch foot supported in the upper benching preliminary stage, the tunnel foot locking steel pipe is connected with the refrigerant circulating system so thatthe surrounding rod around the foot locking steel pipe is partially frozen, then, lower benching is conducted, lower step preliminary supporting is conducted, cyclic construction is conducted in sequence till the whole tunnel is sealed and cyclic, and freezing is stopped. According to the tunnel foot locking steel pipe having the freezing function and the partial freezing construction method, materials are saved, the freezing pipe material consumption and construction cost are reduced, the surrounding rock is partially frozen through the foot locking steel pipe, thus, the surrounding rock freezing range is greatly reduced, the bearing capacity of the foot locking steel pipe is effectively improved, and the construction economical efficiency and flexibility are improved.

Description

technical field [0001] The invention relates to the field of tunnels and underground engineering, in particular to a tunnel locking foot steel pipe with a freezing function and a local freezing construction method. Background technique [0002] Locking foot steel pipe is an important method for controlling the settlement of the primary support structure of the tunnel. Locking foot steel pipes are usually seamless steel pipes with a diameter of 42mm to 108mm. The outer end is welded to the I-beam for primary support, and the inner end is inserted into the rock and soil mass. When the initial support I-beam settles downward, the outer end of the steel pipe inserted into the rock and soil mass also moves downward synchronously, causing the steel pipe to bend to provide upward supporting force. The size of the supporting force of the locking foot steel pipe depends not only on the parameters and deformation of the steel pipe, but also on the properties of the rock and soil mass...

AI Technical Summary

Problems solved by technology

[0005] The invention aims at the problem that the locking foot steel pipe does not work or the effect is not good during the construction of the tunnel with rich water and weak surrounding rock, and it is difficult to suppress the large settlement of the tunnel. Tunnel lock foot steel pipe with freezing function and partial freezing construction method for safety protection

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