ABSTRACT
The preparation of a quality borehole is the single most important step in obtaining a satisfactory pressuremeter test. Two conditions are required to obtain a quality borehole: the diameter of the borehole must be within certain tolerances, the equipment and the method used to prepare the borehole should cause the least possible disturbance to the soil and the wall of the borehole. The rotary drilling method with axial injection of drilling mud is by far the most versatile and most common method used. A videotape has been prepared to demonstrate this method. For the proper preparation of a pressuremeter borehole with this method the following is recommended. The borehole should be prepared in one downward passage of the bit followed by an immediate retrieval of the bit. Never should the borehole be cleaned by ramming the bit up and down the hole while circulating the mud at high flow; this leads to oversized boreholes.
