Secondary Grouting Method for Shield Construction

Abstract

The invention provides a secondary grouting method for shield construction, which adopts the method of substantially equal pressure with the high-pressure liquid in the space outside the segment, and replaces the high-pressure liquid in the space outside the segment with grout under the state of dynamic pressure balance , to achieve the second grouting. Compared with the prior art, the present invention can easily and effectively inject the grout into the gap between the segment and the surrounding rock, effectively guarantee a sufficient amount of grouting, and will not damage the safety of the shield tail brush and the segment sealing strip , avoiding the safety and quality accidents caused by conventional overpressure grouting, and reducing the risk of shield tunneling construction.

Description

technical field [0001] The invention belongs to the technical field of shield tunnel construction in civil engineering, and more specifically relates to a secondary grouting method for shield construction. Background technique [0002] In tunnel shield excavation construction, the construction gap between segment and surrounding rock must be filled with grouting slurry, that is, grouting. The purpose of grouting is: (1) to fill the gaps in the shield tail building in time, support the rock mass around the segment, and effectively control the surface settlement; (2) the condensed grout will be used as the first waterproof barrier of the shield construction tunnel to enhance the tunnel’s durability. Waterproof ability; (3) Provide early stability for the segment and integrate the segment with the surrounding rock mass, which is conducive to the control of the shield tunneling direction and can ensure the final stability of the shield tunnel. There are two types of grouting: s...

AI Technical Summary

Problems solved by technology

[0003] However, in the water-rich section of hard rock, problems such as "insufficient grouting volume" and "segment floating" often occur, and the quality of the tunnel is difficult to guarantee, and it is easy to cause quality and safety accidents

The main reason for "insufficient grouting amount" is that in the water-rich section of hard rock, the building gap between the segment and the surrounding rock is filled with high-pressure liquid (actually a liquid mixture of circulating mud and groundwater, etc., for the convenience of description, Hereinafter referred to as high-pressure liquid), since the surrounding rock is densely packed, it is basically a relatively sealed space, and it is difficult for the high-pressure liquid in it to enter the surrounding rock for circulation and exchange. Difficult to inject

[0004] In similar tunnel shield construction, in order to increase the amount of grouting, the method of overpressure grouting (that is, increasing the grouting pressure) is generally adopted, but overpressure grouting will pose a threat to the shield tail brush and segment sealing strip, and it is very easy to Cause cracks in the segment, water leakage at the joint, and even "breakdown" the shield tail brush in severe cases, thus causing safety and quality accidents

It can be seen that the "overpressure grouting" method commonly used in shield tunneling construction has great quality and safety risks

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