Real Time Measurement of Flow Properties and the Design of Cement Grouting

Despite of the significant development of grouting theories and technologies, very little have been implemented in field. The recent theoretical development leads to the estimation of the propagation of grout inside one dimensional and two dimensional geometries, which implies that the unnecessary spread of grout can be reduced. The yield stress and viscosity is required to estimate the spread of grout. Due to thixotropic nature; the yield stress depends on the shear history and shear rate, generated during propagation. Therefore, during the design of grouting, the estimation of grout spread should be designed considering a definite shear rate at the grout front for required spread. This implies that, the yield stress and viscosity of grout needs to be continuously measured in-line during grouting. In addition, the shear rate needs to be estimated to choose the design value of yield stress. In this work, the ultrasound based flow-viz industrial rheometer was successfully used to perform in-line measurement of the rheological properties and visualize the flow profiles of cement grout. In addition, a non-dimensional nomogram was developed based on a ‘semi-analytical’ approach to estimate the shear rate at the grout front. The relevant design parameters can be obtained from the nomogram for the corresponding relative spread of the grout, and it can therefore be used as a simple design tool for cement grouting.