Application of Freezing Method in Shield Originating and Arriving in Water-rich Silt and Fine Sand Layer
The water and soil outside the portal influx into the starting shaft or the receiving shaft along the gap between the cement-soil reinforcement and the enclosure structure,causing ground subsidence or even collapse outside the well,which is one of the main risks in the process of breaking the outer retaining structure of the portal during the launching and receiving stages of the shield project in the water-rich silt and fine sand layer.The freezing method is an effective measure to avoid the above risks.Taking a shield project in the water-rich silt and fine sand layer of the Yangtze River floodplain as an example,the successful application of the freezing method in the removal of the outer retaining structure of the portal during the shield launching and receiving stage is introduced in detail,including design scheme,construction technology,temperature monitoring,effect acceptance,freezing pipe removal,etc.Practice has proven that the freezing method can control the interface temperature between the reinforced body and the enclosure structure below-5℃,and avoid the risk of fine sand flowing along the gap between the reinforced body and the retaining structure.
shieldsfreezing methodwater-rich silt and fine sand layerretaining structureconstructionmonitoring
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