Ulf Håkansson

COMPUTER-SIMULATED FLOW OF GROUTS IN JOINTED ROCK

Abstract This article presents a model for simulating grout propagation in jointed rock. The joint planes are described as channel networks initially filled with water. The grouth can be either a Bingham or a Newtonian fluid, with time-dependent properties. The presentation includes the mathematical base for the model and some practical examples. The practical examples include testing of a grouting method based on manipulations of the groundwater level, a comparison of results when using grouts having different rheological properties, and a comparison of pre- and post-grouting.

Rheological properties of microfine cement grouts

Abstract This paper describes a measuring technique, based on rotational viscometry, that can be used to evaluate the flow properties of grouts. The technique has been used on cement grouts, assuming the Bingham model. The paper discusses field equipment that can be used easily to estimate the flow properties on site. The results shown indicate the effect on the flow properties by different admixtures and additives. It is concluded that an increase in specific surface and addition of bentonite will increase both the yield stress and the plastic viscosity. Plasticizing admixtures reduce the yield stress and the plastic viscosity. By combining bentonite and plasticizers in the grout, improved flow properties (i.e., low yield stress, low plastic viscosity) can be achieved.

CLASSIFICATION OF JOINTED ROCK WITH EMPHASIS ON GROUTING

Abstract This article includes the mathematical foundations of a proposed geometrical model describing the rock, and shows how the geometrical properties of the rock mass can be evaluated. The base for evaluating the parameters describing the rock mass can be a continuous recording of the flow and pressure for a grout hole during a grouting session. Recorded data are then fitted to a mathematical function that describes the flow in the geometrical model. A rough estimation of the geometrical properties can also be done from the volume of injected grout, combined with ordinary water pressure tests. The evaluated geometry can be used to classify the rock.

In-line Measurements of Rheological Properties of Cement-Based Grouts -Introducing the UVP+PD Method

In-line measurements of rheological properties of cement-based grouts : Introducing the UVP-PD method