Energetic research and development have been made to achieve miniaturization and the wide use of the previously developed Multiple Groundwater Level Measuring System (MGL System). Following results have been obtained. 1) Development of the miniaturized MGL System, which can be installed in 66 mm diameter boreholes, has been completed. 2) For an improvement of reliability of measured groundwater pressure, two pressure gauges are installed at one measuring point. 3) In the homogeneous sand foundation with the permeability of approximately 10-2cm/s, the seepage velocity of approximately 10-2cm/s does not have a great effect on the leakage of sealing materials from a borehole. 4) New system has been developed in consideration of the collapse of boreholes and sliding in landslide area. 5) A combination of rubber and fabric packers makes it possible to place the MGL System in confined aquifer. Considering the above-mentioned results, procedure of site planning of the MGL System has been proposed.
This research proposes a new design method for tunnel lining with the ECL (Extruded Concrete Lining) method considering creep displacement based on the results of measurement and analysis of ground displacement. This method clarifies the following points. According to the results of displacement measurement, the amount of elastic displacement reached convergence at a distance of approximately 20 m behind the tunnel face.Afterwards, displacement increasing gradually as elapse of time was observed. The displacement is considered to have been caused by the creep of ground. The findings demonstrate that a load corresponding to the creep displacement is acted on the concrete lining. The creep displacement is simulated with the two-dimensional elastic FEM analysis.In the analysis, a stress-releasing rate is used to quantify the creep displacement.The analyzed values correspond very well to the measured ones.
The liquefactions formed during the Southern Hyogo Prefecture Earthquake on 17th January, 1995, were found at a lot of locations along and near the Nojima Earthquake Fault in the nourthern Awaji island, Japan. The instantaneous-shaking liquefaction found at the Ogura location occurred in the consolidated-week consolidated Osaka formation which is composed of alternating beds of silt-clay-sand layers and gravel layers.The grain size distribution shows that the grain size of the boiled sands is in the range of grain size having a potential possibility to generate liquefaction known as so far. It is shown by the field evidence and seismic data that the instantaneousshaking liquefaction formed mainly by the ground motion generated by P-wave rather than S-wave.