Freezing consolidation and soil-accumulating watering shield arrival method

Abstract

The invention discloses a tunnel freezing consolidation and soil-accumulating watering shield arrival method, which comprises the following steps of: (1) consolidating a stratum of a tunnel arrival section by using a jet pile or a mixing pile; (2) stopping water for a stratum close to an opening of a receiving well by using a freezing method; (3) removing a retaining wall of a tunnel portal, and filling in the receiving well to obtain a mound; (4) injecting water into the receiving well to reach the designed height; and (5) making a shield machine tunnel to enter the receiving well structure to finish the whole receiving work. By the method, when tunnel portal concrete is removed, the integral stability of soil mass can be ensured, seepage damage caused by a fine sand stratum is prevented, muddy water pressure during tunneling of the shield machine can be balanced, and is prevented from breaking through the peripheral soil mass of the tunnel portal, and the shield arrival is carried out safely and smoothly.

Description

technical field [0001] The invention relates to the field of tunnel construction, in particular to a shield tunnel arrival and reception method of freezing reinforcement + soil irrigation, which is particularly suitable for shield tunnel reception in soft and permeable strata. Background technique [0002] In recent years, domestic shield tunnels have developed rapidly, and many shield tunnels have been built in industries such as subways, highways, urban roads, railways, water transmission, and gas transmission. Shield reception is one of the key processes in the construction of tunnels by the shield method. At present, a single method of ground reinforcement is generally used. This method has great risks in the application of silt fine sand strata or super large diameter shields. It has appeared in China in recent years. Many tunnel collapse accidents during the receiving of the shield indicate that the technology needs to be further improved. At present, there are mainly...

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Problems solved by technology

[0003] 1. It cannot be applied to the silt fine sand formation with strong water permeability

Since the current shield receiving only adopts a single method of stratum reinforcement, and the stratum reinforcement mainly adopts jet grouting piles or stirring piles, for the silt fine sand stratum, due to the unevenness of the reinforcement itself and the gap between the soil and the surrounding structure of the receiving well There will be detachment phenomenon, which will easily cause the silt fine sand to produce piping phenomenon, and then cause ground subsidence, and in severe cases, it will cause soil collapse and tunnel structure collapse

For super-large-diameter shield tunneling, due to the large diameter of the tunnel, there may be multiple strata with greatly different properties (such as interbedded clay and silt-fine sand) in the same excavation face, and the safety cannot be guaranteed only by soil reinforcement.

[0004] 2. It is impossible to guarantee the safety of super-large diameter shield receiving

The super-large-diameter shield has a large thrust during the excavation process. When the shield approaches the receiving shaft, the soil between the shield cutter head and the receiving shaft becomes thinner and thinner, and the ability to withstand the thrust becomes smaller and smaller. It is likely that The muddy water pressure of the shield will break through the soil, resulting in soil collapse accidents, which will affect the safety of the tunnel

[0005] At present, there is no example of a comprehensive method of freezing reinforcement + soil irrigation, which is a technical gap in the industry

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