岩石力学の研究における光弾性実験

抄録

The states of stress and deformation of foundations rock and of tunnels as well as the stability of rock slopes have been studied extensively in rock mechanics in these days. The study of rock mechanics includes at present the investigation not only of the mechanical behaviours of rock cores but also of rock masses and of rock structures.
The experimental investigations in rock mechanics require the core tests and the model tests in the laboratory and the rock tests in-situ.
The model tests have until recently been carried out extensively by using various materials and by application of various measuring techniques, and in consequence of improvements so far made both in the line of the material and in the line of the technique the photoelastic methods have come to play an important role in rock mechanics. The main subjects of investigations by the photoelastic method have been the rupture phenomena of rock cores, the stress states in the foundation rock, the elastic and plastic states of stress and the propagation of rupture zone around the tunnel or the adit, and the mechanism of progression of crack.
The photoelastic method has been in practice in-situ in field measurements, and its new applications are under consideration.
The photoelastic method developed in this way makes it possible to know better about the mechanical properties of the foundation rock and the earth pressure phenomena, and it renders greater help to planning wiser design of rock structures. From this point of view, the recent photoelastic investigations in rock mechanics according to the corresponding techniques are summarized here under.
The photoelastic investigations in rock mechanics explained herein are conveniently divided in two, the study in the laboratory and the study in the site.
The techniques in the former contain (1) the two-dimensional method by using transparent models, (2) the stress freezing method, (3) the centrifugal photoelastic method, (4) the method by using soft photoelastic materials, (5) the method for orthotropic models, (6) the photoelastic coating method and (7) the method for pulverulent models. In the latter, the bodies to be measured, such as the concrete linings and the rock of the tunnels or the adits and the steel supports, get the photoelastic pieces embedded in them or glued on their surfaces.