| In the planning and design of urban subway interval tunnel,it is usually necessary to set up cross-section channel between up-and-down tunnels.In the construction of urban subway stations and tunnels,the excavation and construction of connecting channels have also become an indispensable link in the construction of subway.In the event of fire,water inrush,collapse and other sudden events in a tunnel during the operation of the subway,passengers can move through the cross-section of the tunnel to another tunnel and then evacuate to the ground rapidly.Artificial freezing method is widely used in subway connection channel engineering as one of the main ground reinforcement methods for excavation of connecting channel under soft soil geological conditions.This paper takes the design and construction of No.1 connection channel and pumping station structure of Changer Road-Wuchang Station of Hangzhou Metro Line 5 as the research content,combined with the engineering geology and hydrogeology conditions in this area,the freezing curtain design of the connecting channel with gathering water well has been carried out.A series of studies are carried out on the construction scheme of the freezing method of connecting transverse channels,the layout of freezing holes,the refrigeration design,the layout of freezing stations,excavation and construction,monitoring design and parameters,freezing heaving and thawing control techniques,and so on.In this paper,some hypotheses and corresponding control measures are put forward to solve the possible risks in actual construction.The third chapter of the paper is the parameter design of the freezing method of the contact channel,including the structural size of the contact channel and the minimum effective thickness of the frozen curtain.The strength and deformation of the frozen wall of the channel meet the design requirements by ansys finite element calculation.The refrigerating capacity and the related parameters of freezing hole are designed.Chapter 4 is the construction scheme and measures of freezing method,from preparation work to freezing hole construction,freezing refrigeration system installation,actively freezing and maintaining freezing,and finally excavation and construction.The corresponding measures are put forward for the phenomenon of frost heave and thaw settlement,so that the quality of frozen soil curtain can be guaranteed in the process of construction.Chapter 5 is freezing method analysis of monitoring data,including brine removal,loop temperature change monitoring,temperature change of temperature measuring hole and pressure change trend of pressure relief hole.The data of temperature measuring hole and pressure relief hole are used to judge the time required for intersection and the development speed and thickness of frozen curtain.The practice proves that the horizontal freezing method is very effective,safe and reliable for strengthening the soil layer around the connecting passage construction of Hangzhou Metro Line 5.Figure [32] Table [12] Reference [51]... |
