含水量对先注浆后冻结粉细砂剪切强度的影响

Effects of Water Content on Shear Strength of Silty Sands Reinforced by Grouting First and Freezing Subsequently

研究目的:含水粉细砂地层具有压缩性小、渗透系数大、易液化、无粘聚力、自稳能力差的特点,在该地层中开挖隧道极易发生涌水、涌砂、塌方等工程灾害。本文探究先注浆后冻结联合加固含水粉细砂等软弱地层,进而改善土体强度的方法,针对含水粉细砂,通过试验方法对注浆、冻结不同条件下含水粉细砂试样的剪切应力-剪切位移关系曲线进行研究,并分析不同含水量条件下对含水粉细砂试样剪切应力-剪切位移关系曲线的影响。研究结论:(1)先注浆后冻结的联合方法可以有效加固含水粉细砂地层;(2)试验得出含水粉细砂剪切应力-剪切位移关系曲线随含水量的变化有两种走势;(3)在一定条件下,适当增加含水量,先注浆后冻结粉细砂试样的剪切强度明显提高;(4)该研究成果可为含水粉细砂及软弱地层中土体的加固提供参考。

Research purposes： Water - beating silty sands ground is characteristic of small compressibility, large permeating coefficient, none cohesion and poor self - stability, in which there are often accidents of water inflow, sands inflow and collapse. This paper presented a combined method to reinforce the silty sands ground by grouting first and freezing subsequently. Then an experiment was performed, in which the relationship between shear stress and shear displacement of the samples of the silty sands was analyzed under different grouting and freezing conditions and different water context conditions.Research conclusions： （ 1 ） The combined method of grouting first and freezing subsequently can effectively reinforce the silty sands ground. （2） The trends of change in the relationship between shear stress and shear displacement of samples with different water context conditions were obtained by the experiment. （3） Under a certain condition, increasing the water context can improve the shear strength of silty sands ground when applying the combined method. （4） The research results can be applied to the reinforcement of water- bearing silty sands ground and soft ground.