Excavation construction method for water-rich sand layer shield interval contact channel

Abstract

The invention discloses an excavation construction method for a water-rich sand layer shield interval contact channel. The excavation construction method comprises the steps of 1, erecting a segment temporary supporting structure; 2, carrying out stratum pre-reinforcement; 3, constructing a vertical transportation channel; 4, cutting and dismantling duct pieces; 5, carrying out tunnel entrance construction on the channel opening section; and 6, carrying out excavation construction on the front side tunnel section. The method is simple in step, reasonable in design, easy and convenient to construct and safe and reliable in construction process, the segment temporary supporting structure is erected at the joint of a shield tunnel and the contact channel before stratum pre-reinforcement, thenstratum advanced small guide pipe grouting reinforcement at the end of the channel is combined with overall grouting reinforcement of a sleeve valve pipe of the stratum where the channel is located for stratum pre-reinforcement, after stratum pre-reinforcement, the vertical transportation channel is constructed for earthwork outward transportation and material hoisting, the excavation construction process of the water-rich sand layer shield interval contact channel can be completed easily, conveniently and rapidly, and the construction process is safe and reliable.

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 construction method for excavation of contact channels in shield tunnel sections of 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 exc...

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 the conventional communication channel, in terms of excavation, there is a great risk of collapse when excavating the weak roof support area where the tunnel and the communication channel meet (that is, when the tunnel enters the hole). This part is excavated in two stages. In the first stage, excavation is performed at a slope from the elevation of the portal to the design vault of the connecting passage, forming a transition section. In the second stage, after the initial support is penetrated, the transition section is reversely excavated to meet the design requirements. There is still a great risk of collapse under the condition of water-sand layer. Due to the loose sand-stone 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 connecting passage. Therefore, there is a need for a safer construction method for the excavation of the communication channel between the shield tunnels in the water-rich sand layer to reduce the occurrence of accidents

Images