近接隧道冻结对运营车站冻胀变形控制研究

为了研究不同冻胀控制方法下土体冻胀的发展规律，以上海某近接穿越既有车站的隧道冻结加固工程为原型，根据相似准则建立了冻土与车站结构相互作用的模型试验台，对隧道水平冻结过程进行模拟研究，探究调整冻结盐水温度以及泄压等方法下隧道冻结冻胀变化规律。研究结果表明，将冻结盐水温度从-28℃提升至-18℃后，隧道的积极冻结时间增长91%，但车站底板冻胀力减小了16.7%；三角区泄压后车站底板冻胀力减小了26.3%。根据相似模拟试验得到的不同冻胀控制措施下车站结构的冻胀变化规律，提出在施工工程中采取三角区泄压及调整冻结参数等措施来控制冻胀对车站结构的影响。同时根据工程施工监测数据，对不同冻胀控制措施的应用效果展开了研究，研究结果表明，三角区泄压孔泄压后10d内车站底板位移量减少了65.5%；冻结盐水温度为-28℃、-20℃、-10℃时车站底板竖向位移增长速率分别为0.35mm/d、0.14mm/d和0.01mm/d，随着冻结盐水温度的提高，车站结构竖向变形速率明显减缓，调整冻结盐水温度对冻胀控制效果十分显著。

The fros theave deformation controlling method of an #br# operation station caused by freezing adjacent tunnel

To study the development law of soil frost heave under different frost heave control methods, a tunnel of Shanghai metro line passing down the existing station was taken as the research object, and a model test bench for the interaction between frozen soil and station structure was established according to the similarity criteria. The horizontal freezing process of the tunnel construction was simulated, and the changing law of frost heave was discussed by adjusting the freezing brine temperature and pressure relief measures. The results show that, after increasing the freezing brine temperature from -28°C to -18°C, the active freezing time increases by 91%, and the frost heave force of the station base slab decreases by 16. 7%. The frost heave force of the station base slab was reduced by 26. 3% after using the pressure relief measures in triangular area. Some measures such as pressure relief in the triangle area and adjustment of freezing parameters were proposed to control the safety of station structure according to the experiment results. The application effects of different frost heave control measures were studied according to the construction monitoring data of the engineering. It is shown that, the displacement of the station base slab was reduced by 65.5% within 10 days after use pressure relief measures in the triangle area. When the freezing brine temperature was -28℃, -20℃, -10℃, the vertical displacement growth rate of the station base slab was 0.35mm/d, 0.14mm/d and 0.01mm/d, respectively. The vertical deformation rate of the station structure is significantly slowed down with the increase of the temperature of the frozen brine, which has a significant effect on the frost heave control.