Development and application of a new comprehensive grouting reinforcement test system

Existing grouting test devices have difficulty providing sufficient sealing effect and experimental space in multifunctional tests. Due to the limitations of current devices, this paper developed a new comprehensive grouting reinforcement test system. The major advantages of this system include:(1) its moderate size and reasonable structure that offer a large experimental space and good sealing property; (2) its ability to simulate the different groundwater environments and grouting conditions of rock soil media; (3) its ability to obtain a variety of physical information for researching the space-time response law of reinforcement parameters; and (4) its ability to simultaneously test the compressive and shear strengths of the solid and microscopic grouting coupling mechanisms of the slurry-rock interface. An orthogonal grouting reinforcement test was designed for fault breccia using the new device. The study then investigated the grouting reinforcement mechanism of fault breccia with respect to the stress response-transfer characteristics, the growth law of solid strength, and the reinforcement mode. The test results show fault breccia to be mainly reinforced by permeation grouting and the grouting reinforcement model can be divided into three types-substrate, micro-splitting, and significant splitting. The study achieved an increase in the strength of grouting reinforcement bodies by changing the medium connection mode and fitted the empirical formula for the increased strength of solid grouting. It also determined the distribution and transfer mechanism of grouting pressure.