Calculation and Analysis of Track Bed Floating Characteristics of Karst Tunnel Considering Water Basin Effect
Focusing on the problem of floating floor heave on the track bed of water-rich tunnel,this paper explores the introduction of water basin effect into the study of floating floor heave disease on the ballastless track bed of tunnels.Firstly,based on the strain energy and energy theory,combined with the contact mechanical conditions between structural layers,the stress and deformation of tunnel track bed are deduced to verify the rationality of the correlation between water basin effect and track bed floating.Secondly,the deformation deflection curve equation of track bed and the formula of stress and maximum deformation are constructed.It is obtained that the floating floor heave of track bed can cause bonding failure at the height of 0.5m water head,and the floating stage is divided into three stages by setting the critical water head value of floating:1)initial infiltration catchment stage;2)local ponding stage;3)basin floating stage.Finally,the calculation formulas of horizontal and vertical floating amount of track bed under different drainage conditions are established,the curves of relationship between base water flow difference,pressure rate,floating rate and floating amount are formed,and the calculation method of minimum head height of tunnel track bed floating is constructed,so as to help the research of track bed floating control and the improvement of treatment measures.
water-rich tunnelballast bed floatingbasin effectmechanical characteristics
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