Grouting Rock Fractures with Cement Grout

Abstract

The radial flow rate of a cement grout in a rock fracture is obtained from Bingham's relation and the fact that the power expended by the injection mechanism is the energy dissipated by viscous effects. The energy balance reveals that the advance ratio is of fundamental importance in the grouting process and is inherently related to the rest and advance phases of a cement grout. This allows giving a precise definition of the zero flow path that divides the energy diagram into two distinct domains for advancing and non-advancing grout. The advance ratio and the zero flow path are used to explore the grouting of one or more fractures, analyze the GIN model in the context of the SL dispute, draw a terminal sequence considering the energy interval alternative, and reformulate the refusal criterion of the North American grouting method. Secondary grouting effects are also investigated. Keywords Cement grout Á Bingham material Á ZFP Á Refusal criterion Abbreviations List of Symbols a Borehole radius b Front radial coordinate b 0 Front radial coordinate for n = 1 on the zero path flow c Cohesion or yield shear E Extent or length E m Lower bound of the energy interval E M Upper bound of the energy interval G Energy value or GIN number H Fracture half thickness H c Core half thickness L d Flow rate limit P Excess pressure p Absolute pressure p a Injection pressure p b Front pressure, in situ pressure (P 0 , V 0 ) Zero flow path parameterization (P 0 , V 0 ) Intersection of the ZFP with G (P m , V m ) Intersection of the ZFP with E m (P M , V M ) Intersection of the ZFP with E M Q Flow rate r Radial coordinate R Radial dimension Re Reynolds number S Span t Time t 0 Starting time v Velocity V Grout volume w Width z Transverse coordinate Greek Symbols b Core ratio d Relative difference of the grout advance to the span d Relative change in the front position / Diameter g Viscosity s Shear stress r r Radial normal component of the deviatoric stress tensor r t Tangent normal component of the deviatoric stress tensor

Experimental investigation on sealing efficiency of chemical grouting in rock fracture with flowing water

“…Stille (2009, 2010) studied fracture dilation, and fracture-fracture interaction during grouting. Similar flow rate equations were obtained for the flow of Binghamian fluid in fractures (Dai and Bird, 1981;Lombardi, 1985;Hassler et al, 1992;Amadei and Savage, 2001;Tani, 2012) on the basis of the work by Wallner (1976) or the principle of energy dissipation.…”

Experimental Study on Sulfoaluminate Cement-Based Grout

“…In geotechnical and underground engineering, grouting technology is widely employed to strengthen the fracture, to ensure the safety of the engineering structure and to achieve the objective of effective reinforcement [1][2][3][4]. Compared with chemical grouts, cement-based grouts are inexpensive, environmentally friendly and more durable [5][6][7].…”

“…The hydration products of ordinary SAC are different from those of OPC. In the initial period, the C 4 A 3 S hydrates to form AFt (ettringite) in the absence of CS or CS H 2 (1). The continuous hydration of C 2 S can provide the strength development in the later period, and the CH generated (2) can promote the formation of AFt (4)(5).…”

Comparative Study of Soil Grouting with Cement Slurry and Cement‐Sodium Silicate Slurry

“…e viscosity change of cement slurry during grouting period is not large enough to affect other parameters obviously such as grouting pressure and grout slurry space distribution, so the viscosity of cement slurry is assumed to be time independent [11]. It will be supposed that viscosity of cement slurry maintains constants throughout the grouting process.…”