Grouting reinforcement experiment for water-rich broken rock mass
LI Zhaofeng1，2，LI Shucai1，LIU Rentai1，JIANG Yujing2，3，SHA Fei1
(1. Geotechnical and Structural Engineering Research Center，Shandong University，Jinan，Shandong 250061，China；
2. Geoenvironmental Laboratory，Graduate School of Engineering，Nagasaki University，Nagasaki 8528521，Japan；
3. State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of
Science and Technology，Shandong University of Science and Technology，Qingdao，Shandong 266510，China)
Abstract：In this research，the simulation of grouting for water rich and broken sandstones was performed. The ordinary Portland cement #42.5(PO.42.5)，the Sulphatealuminium cement #42.5(SAC.42.5) and the self-developed cement-based composite grouting material(CGM) were applied. Comparison of the uniaxial strengths of samples of broken limestone and sandstone after grouting shows that when the broken degree of rock is higher，the strength improving effect is more obvious，and that the larger the porosity，the better the strengthen improvement. The toughness enhancement of grouted stone is significant. The strengths of CGM strengthened stones are significantly higher than those of PO and SAC materials. The performance improvement of CGM on the porous sandstone is the best. The slippage probability on the surface of CGM and rock is the least. The effect of SAC grouts is better than PO grouts. Scanning electron microscopy was applied to analyze the mineral species and distribution patterns in the interface transition zone of rocks and grouts，which reveals the essence of different grouting effects. The bonding types of the interface between grouts and rocks are mainly determined by the types of rocks. The high-density limestone rocks belong to the Ollivier-Grandet model，and the porous sandstone rocks belong to the Zimbelinan model. The results of X-ray diffraction and scanning elemental analysis show that the grouting can not only improve the mechanical properties of rocks，but also change the chemical composition of rocks. The generated minerals by grouts in the interface zones can improve the bonding strength between the interface of rocks and grouts.
2017, Vol. 36 
