Construction method of water-rich sand layer shield interval contact channel

Abstract

The invention discloses a construction method of a water-rich sand layer shield interval contact channel. The construction method comprises the steps that 1, a segment temporary supporting structure is erected; 2, stratum pre-reinforcement is conducted; 3, precipitation construction is conducted; 4, cutting and dismantling are conducted on a segment; 5, a channel opening section is excavated, andprimary support construction is conducted; 6, a front side tunnel section is excavated, and primary support construction is conducted. The method is simple in step, reasonable in design, easy and convenient to construct and safe and reliable in construction process, and the segment temporary supporting structure is erected at the joint of the shield tunnel and the contact channel before stratum pre-reinforcement. Then stratum advanced small guide pipe grouting reinforcement at the end of the channel and overall grouting reinforcement of a sleeve valve pipe of the stratum where the channel is located are combined for stratum pre-reinforcement, the stratum is further reinforced through rainfall after the stratum pre-reinforcement, the construction process of the water-rich sand layer shieldinterval contact channel can be easily and conveniently completed, and the construction process is safe and reliable.

Description

technical field [0001] The invention belongs to the technical field of construction of communication passages in shield tunneling intervals, and in particular relates to a construction method for communication passages in shield tunneling intervals in water-rich sand layers. Background technique [0002] In the subway tunnel construction project, in order to meet the needs of emergency evacuation and drainage, it is necessary to set up communication channels in the shield section. The construction risk of the communication channel is relatively high, and it has always been the accident-prone part of the subway construction. Communication channel accidents can easily lead to damage to ground cables and buildings, and even endanger the entire subway line. Therefore, the communication channel construction plays a pivotal role in shield tunneling construction. However, for water-rich sand layer areas, due to the loose sandstone structure, large porosity, poor ground self-stabi...

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 water-rich sand layer shield tunnel construction method to reduce the occurrence of accidents

Images