THE USE OF WATERJETS IN CUTTING A MULTIPLE PHASE MATERIAL
The University of Missouri-Rolla is carving a new sculpture. This involves shaping 3 rocks, collectively weighing 100 tons, and cutting figures of a man and a woman from two blocks. The three blocks will then be erected to form a Millennium Arch and the Figures will be polished as a second set. A relatively inexpensive X-Y table and cutting head unit were developed. The cutting waterjet was without abrasive at under 100 MPa. One problem in cutting large blocks (5 m x 2 m by 0.75 m) is that the structure changes. A variety of approaches were taken to solve this problem. The process steps required to cut the rock to shape, and then to carve the rock are described in the paper.
THE EFFECT OF ROCK ANISOTROPY ON THE EXCAVATION RATE IN BARRE GRANITE
The variation in the volume of rock removed when a water jet traverses over a sample of Barre Granite is shown to vary with the angle at which the sample is cut relative to the orientation of the main deposit. For example where the jet impacts perpendicular to a microfissure plane a channel up to 10 times the volume is cut as when the jet is traversed along the microfissure plane. A correlation is shown to exist between the dimensions of the rock volume removed and the angle of impact between the water jet and the two microfissure planes of the Barre Granite.
Studies in rock Fracture
In July 1970, a major effort was directed toward the measurment of the in situ state of strain (stress) at an outcrop of Mesa Verde sandstone (Cretaceous), Site No. 1, on the N. 45/sup 0/W.-plunging nose of the Rangely Anticline, W. Colorado. With exception of a few of the photoelastic determinations, all measurements were made within a circle with a radius of about 2 m and within the same joint-bounded block. In addition, a specimen of the sandstone was studied in the laboratory by materials testing, optical, and X-ray diffraction techniques. Results for the strain-relief measurements are expressed as stresses by using a value of 50,000 bars 800,000 psi for Young's Modulus. Compressive stresses are counted positive.