This paper contains a discussion concerning to the jack m anod and the result of rock deformation test.
In Yuda Dam, two kinds of jack method were performed at the concrete gallery wall which was regarded as an elastic body, by using a diaghragm aiming at uniformly distributed loading and a rigid disc aiming at equally displaced loading. In the case of uniformly distribruted loading, those results obtained from the surface displacement, strain meters embedded in the concrete and concrete test pieces, were approximately similar values. In the case of equally displaced loading, those results were various, and Youngs modulus calculated from surface displacement was about 1/3 to that by uniformly displaced loading method.
In Koshibu Dam-site, the bedrock of test place consists of sound granodiorite, which is called Ikuta granite, the series of rock deformation test were peformed by jack method, water chamber method and seismic method. The relation between those results from water chamber method, jack method and seismic method was 1: 1.4: 2.2, and the difference of the modulus of deformatin by those three methods was than that which had been before.