Strength and filtration stability of cement grouts in porous media

The diffusion of cement-based grouts in porous media is an important issue in soil sealing and grouting effects. To better understand the effects of grouting parameters, including grouting temperature, water-cement ratios and mass fractal dimensions, on the retention of slurry particles, the permeability of injected media, and the strength of cementation under a constant pressure condition, several types of tests, including filtration, permeability and uniaxial compressive strength tests, were performed. The experimental results indicate the following: (1) The retention rate of cement particles decreases sharply with an increase in the distance from the grouting source in the porous media with a higher mass fractal dimension, whereas the retention rate of cement particles decreases slowly with increasing diffusion distance in the porous media with a lower mass fractal dimension. (2) Within a certain distance, the retention of cement particles at a lower temperature is slightly higher than that at a higher temperature. Beyond this critical distance, the retention of cement particles at a lower temperature is generally lower than that at a higher temperature. (3) Regardless of the cement slurry, the damage is not uniform in the injected porous media. (4) The compressive strength of the porous media with a higher fractal dimension at the test point near the grouting source is higher than that of the media with a lower fractal dimension. However, at the test point far from the grouting source, the compressive strength of the porous media with a lower fractal dimension is greater than that of the media with a higher fractal dimension.