铁路隧道断层带复杂地层冻结工程中注浆对冻结的影响

Grouting Affected to Ground Freezing of Railway Tunnel Ground Freezing Project in Complicated Strata of Fault Zone

程儿山隧道F2断层破碎带冻结工程采用地面垂直群孔方式冻结,冻结段水平长度56.44m,冻结深度234m,布置5排共128个冻结孔。其中有29个冻结孔施工中进行了注浆,主要注入水泥-水玻璃双液浆,以确保顺利成孔。由于水泥-水玻璃双液浆结石体凝固过程中,释放出大量的热量;加之水玻璃属弱酸盐类,冰点较低,不易结冰,冻结时温度降到0℃后,需持续很长时间,最长达37d,才能降到-0.5℃以下。受注浆影响的区域,温度降到-0.5℃以下后,迅速下降,不再受注浆影响。表明冻结受注浆影响只是暂时性的,可用延长冻结时间的方法来加以解决。

A ground freezing method with vertical boreholes at the surface ground was applied to the ground freezing project of Chengershan Tunnel in broken zone of F2 fault.The horizontal length of the freezing section was 56.44 m,the freezing depth was 234 mand there were totally 128 freezing boreholes in five rows applied.Among the boreholes,the grouting operations were made in the constructions of the 29 boreholes and the cement-sodium silicate double grouts were mainly injected in order to ensure the successful borehole completed.Due to the consolidated process of the rock with the cement-sodium silicate double grouts,great heats were released.Thus the sodium silicate was a weak acid salt,the freezing point of the sodium silicate would be low and the sodium silicate would not be easy to be frozen.When the ground was frozen and the temperature was 0 ℃,a long time would be sustained,a longest period would be 37 days and the ground temperature would be reduced below-0.5℃.In the area affected by the grouting,when the ground temperature was reduced below-0.5℃,would rapidly reduced and then would not be affected by the grouting.The freezing affected by the grouting was temporary only and a method to expand the freezing time would be applied to solve the problem.