Water-rich sand layer shield interval contact channel stratum pre-reinforcement structure and method

Abstract

The invention discloses a water-rich sand layer shield interval contact channel stratum pre-reinforcement structure and method. The pre-reinforcing structure comprises a channel stratum overall reinforcing structure for reinforcing the stratum of the area where a constructed connection channel is located and two channel end portion stratum reinforcing structures for reinforcing the stratum of thefront end and the stratum of the rear end of the constructed connection channel. The method comprises the following steps of 1, arranging advanced small conduits; 2, grouting and reinforcing the stratum at the end parts of the channel; and 3, integrally grouting and reinforcing the channel stratum. The pre-reinforcing structure is reasonable in design, easy and convenient to construct and good inreinforcing effect, the advanced to-be-reinforced area of the water-rich sand layer contact channel stratum is divided, the grouting reinforcing structure of the corresponding type is adopted for effective reinforcing, the reinforced stratum and a shield segment of the constructed shield tunnel are fixedly connected into a whole, and the structural stability of the shield tunnel can be effectivelyimproved while the stratum reinforcing effect of the constructed connection channel is further improved.

Description

technical field [0001] The invention belongs to the technical field of connection channel construction in shield tunnel sections, and in particular relates to a stratum pre-reinforcement structure and method for a shield tunnel section with a water-rich sand layer. Background technique [0002] In subway tunnel construction, for emergency evacuation and drainage needs, it is necessary to set up a communication channel in the shield tunnel section. The construction risk of the communication channel is relatively high, and it has always been an accident-prone part in subway construction. Accidents in the communication channel can easily lead to the damage of ground cables and buildings, and even endanger the entire subway line. Therefore, the communication channel construction plays a pivotal role in the shield construction. However, for the water-rich sand layer area, due to the loose sand and gravel structure, large void ratio, poor stratum self-stability, and high excavat...

AI Technical Summary

Problems solved by technology

However, for water-rich sand layer areas, due to the loose sand and gravel structure, large porosity, poor self-stability of the ground, and high excavation risks, how to ensure the construction quality and safety of communication channels has become an urgent problem to be solved

At present, the conventional construction scheme adopted for underground excavation of connecting passages in subway intervals in water-rich sand layers not only has a long period, but also has a serious impact on the construction of other processes. The most important thing is that construction safety risks are relatively high, and safety accidents are extremely prone

In terms of ground reinforcement, jet grouting piles are now mainly used for reinforcement. During the reinforcement process of jet grouting piles, not only has a great impact on the ground, but also when the communication channel is buried deep, the construction is difficult and the investment cost is high, and the construction period cannot be effectively guaranteed.

[0003] During the construction of conventional communication channels, in terms of excavation, there is a great risk of collapse when excavating the weak roof support area at the junction of the tunnel and the communication channel. This part is excavated in two stages. Excavate upwards to the design vault of the connecting channel with a slope to form a transition section. In the second stage, after the initial support is penetrated, the transition section is excavated in reverse to meet the design requirements. There is a great risk of collapse. Due to the loose sandstone structure, large void ratio, and poor self-stability of the ground, the risk of collapse is greater when excavating the weak area of ​​advanced support at the top where the tunnel connects with the communication channel. Therefore, a safer method is now needed. , Reliable structure and method of advanced grouting reinforcement for the communication channel of the shield section in the water-rich sand layer, so as to reduce the occurrence of accidents

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