Cement grouting design: a nomogram for velocity, plug thickness and shear rate
(English)Manuscript (preprint) (Other academic)
In recent decades, there has been a substantial increase in knowledge of the propagation of cement grout inside rock fractures, assuming the Bingham model. Yield stress is used as an important design parameter in estimating grout penetration and maximum penetration length. Due to the thixotropic nature of cement grouts, the yield stress depends on the shear history and shear rate present during propagation. Although analytical solutions for velocity, plug thickness and shear rate are available for one-dimensional geometries, a different approach must be used for two-dimensional radial Bingham fluid flow. This is due to the non-linear pressure and velocity distribution leading to a change of the plug thickness along the radial distance. In this work, an analytical approach is provided for the determination of the velocity, plug thickness and shear rate for a two-dimensional (2D) radial Bingham flow between parallel disks. The results were compared with rectilinear flow in a one-dimensional (1D) circular pipe and rectangular channel. In addition, numerical calculations and experimental tests were used to validate the results. A non-dimensional nomogram was also developed in order to facilitate the design of the grouting time with respect to velocity, plug thickness and shear rate. 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.
grouting, grouting design, cement grout, Bingham number, shear rate, plug flow, thixotropy, yield stress
Research subject Civil and Architectural Engineering
IdentifiersURN: urn:nbn:se:kth:diva-176887OAI: oai:DiVA.org:kth-176887DiVA: diva2:868712
The authors wish to acknowledge the financial support from the Swedish Rock Engineering Research Foundation (BeFo) and the Swedish Construction Industry Development Fund (SBUF). The experimental test using the fracture replica was performed at the Division of Geo Engineering, Chalmers University of Technology and gratefully acknowledged. QS 20152015-11-112015-11-112015-11-12Bibliographically approved