Control of Ground Uplift Based on Flow-Field Regularity during Grouting in Fracture with Flowing Groundwater

Abstract

Controlling rock mass uplifting is of great importance when grouting in large opening fracture with flowing groundwater. This paper investigated the basic mechanism of overburden stratum uplift. The ideal fluid assumption was used to analyze the flowing regularity of the grout spreading against flowing groundwater and fluid pressure distribution in a single flat fracture grouting work. The calculated fluid pressure was modified according to the results of single flat fracture grouting simulation test in a prior work to estimate the actual uplift force acting on fracture walls induced by grout pressure. Results showed that the deviation from the actual value induced by ideal fluid assumption can be omitted in the calculation of grout velocity and spreading distance. On the other hand, the deviation for pressure distribution is rather large, and should be modified according to the real-time monitoring of the injection pressure in the actual grouting project. According to the requirement for sealing groundwater, the maximum grouting pressure is determined, and a criterion for risk assessment on overburden stratum uplifting is established.