Simulation tests on fracture-compaction grouting process in sand layer

The fracture-compaction mode is the main diffusion mode of grouting process in sand layer. In order to study the diffusion process of fracture-compaction grouting mode in sand layer, a visible grouting simulation test system composed of test frame, stress loading module, dynamic monitoring module and grouting module is designed and developed. As the typical grouted medium, the clayey sand in Qingdao is used in the fracture-compaction grouting simulation tests. The characteristics of the dynamic evolution of the stress and displacement fields of sand layer and the propagation of fracture channel are derived. The influence scope of fracture-compaction grouting in sand layer is obtained. The results show that the initiation and propagation of fracture channel direction are consistent with those of the major principal stress in sand layer. The width of grouting vein decreases remarkably along the propagation direction. Under the influences of grouting, the vertical stress increases from the minor principal stress and decays spatially along the propagation direction. However, the horizontal stress has no obvious changes in the grouting process. The influence scope of fracture-compaction grouting in sand layer is very limited (20~40 cm). Finally, improvement suggestions for fracture-compaction grouting in sand layer are put forward from two aspects (grouting amount of single hole and arrangement of injection hole).