The paper discusses the results of in-situ rock shear tests that were examined at 11 sites in Hokkaido. The failure processes and displacement patterns resulting from these were related to the geological conditions. These are summarized as follows: 1) There aro four types of displacement patterns, defined N type, J type, R type and S type. Each content in total test is 53.1 %, 18.8 %, 17.2 % and 10.9 %, respectively. 2) N-type occoured at the geological conditions which were soft and non clear joint-ie, pyroclastic rocks, Tertiary sedimentary rocks, etc. The basic friction angles are from 25° to 45°. 3) J-type occoured at the geological conditions which were clear joint-ie. Volcanic rockes, Pre-tertiary sedimentary rocks, etc. The basic friction angles are from 30° to 40°. 4) R-type occured at the special geological conditions which were very hard and nearly intact rocks. 5) S-type occured also at the special geological conditions which were crashed, or very soft, rock, often by faulting.
Recently a new Geotechnical Instrument “Inclinometer of servo-accelerometer” has been developed and introduced. This new Inclinometer is characterized by the high resolution mainly depending on the unique sensing mechanism of closed loop servo accelerometer. In this report, many laboratory and field calibration or correlation test results for this type inclinometers, which have been carried by author, are presented. Tests on two inclinometers, the OYO-TTC Mini-Probe, and the SINCO Digitilt show a similar performance under laboratory and field conditions with an accuracy which is acceptable engineering purposes. Vertical profiles of Horizontal Movements and Horizontal Profiles of Vertical Movements may be measured with this type inclinometer very satisfactory.
Measurement of the vertical water velocities flowing through a bore-hole when the water is pumped out or injected will indicate the position of inlets or outlets in the hole. Lowered into a bore-hole or into a suitable piezometric installation, Microflowmeter makes it possible to measure natural rates of flow and rates following pumping in and pumping out of water, and hence to deduce the petmeability of the strata which the bore-hole crosses. The instrument we have used consists of a propellor and a photo cell detection system, and is particularly suitable for bore-hole measurements. Some examples of the test show that the measurement of the vertical water velocities flowing through a bore-hole is useful not only to determine the permeability of strata, but also to estimate the behavior of ground water through the basement rock of dames and around tunnels.
The Digital Stacking System has been developed to improve the signal to noise ratio in seismic prospecting by the refraction method. This has been accomplished by stacking the recorded data created by repeated impacts to the seismic source. The benefits of this system have been to eliminate the need for dangerous explosives and to make possible the use of seismic prospecting in areas previonsly closed to its use. This paper will detail the results of actual field use over the past several years and, addition, will discuss the conditions under which the Digital Stacking System can be utilized.
Seismic prospecting is apt to increasing yearly and utilizing effectively for many geological surveys in civil engineering as one of the most popularized survey method. Recently, the measurement of S-wave velocities are taking in effect as a necessary to make a basic data of the dynamic properties of soil ground in predicting the behavior of the ground at the time of an earthquake. However, as though the seismic prospecting in the field of civil engineering become generalized, there are many problems unsolved on actual survey. Especially, the seismic prospectingare limited by the problems on the preservation of safety by using an explosive. On the other hand, it is impossible to carry on seismic prospecting in the urban area by high noise level and also unable to use any explosive compound. As one of the method to solve this problems, the data processing method called Enhancement and Stacking become the object of public attention in recent year. The existing several equipments were so large scale and expensive so far, but recently the inexpensive, easy handling, light weighted and small equipment is developed using a low-cost semiconductor memories and IC, which are produced by the most advanced electronics technology. In this paper, it is described a special features, utilization and prospecting samples of signal enhancement equipment called “McSeis”, which is newly developed by OYO CORPORATION and Nimbus Instruments in U.S.A. Furthermore, refering an expansion of application in seismic prospecting by utilizing “McSeis” and present problems on “McSeis”, it is introduced as an aid to contemplate developement of geophysical prospecting in Civil Engineering in the future.