杯型冻结壁不同杯身长度的数值分析

以某过江隧道东端头盾构始发工程为依托,在封门拆除这个最不利工况下对冻土帷幕及端头地层进行数值分析,对不同杯身长度冻土帷幕的位移场和应力场分布情况进行研究。主要得出:杯身基本不发生位移;地表离掌子面越近沉降量越大;纵向位移最大值均发生在暴露掌子面中心处;应力值均在设计强度范围之内,且有较多富余;杯身和杯底厚度均为2 m时,该工程杯身长度取3 m就可在强度和变形上满足要求,但为了止水,杯身长度宜为18 m。

Numerical Analysis on Cup Length of Cup-shaped Freezing Wall

Depending on the shield lanuching project at the east end of a underwater tunnel, numerical analysis was carried out on the frozen curtain and end strata when removing the diaphragm, the most adverse conditions, and the distribution of displacement and stress fields in such frozen curtains in different cup length was studied. It is found mainly that the cup body almost has no displacement;the closer of the ground surface to the tunnel face, the larger of the settlement;the maximum values of longitudinal displacement arise at the exposed tunnel face;the stress values are within the design strength with large margin;when the thickness values of cup body and bottom are 2 m, the length of cup body reaching 3m in this project may meet the strength and deformation requirements, however, it is good to be 18m for the purpose of water stop.