So far, a measured seepage through a rockfill dam with a central core and its foundation has not been quantitatively analyzed. In order to quantitatively evaluate a measured seepage through a central core and its foundation, a simplified model based on a potential theory was proposed, and quantitative characteristics of seepage were discussed using the model. In addition, concerning the foundation, the concept of coefficient of the permeability efficiency was also proposed. The seepage measured at several existing dams could be explained well by use of the proposed model. This result proved that the analysis with the proposed model was useful to quantitatively evaluate a measured seepage through a central core and its foundation.

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It is well known that a self-excited vibration of a fixed wheel gate occurs when a gate has a small opening in the water flow. Although many reports on the phenomena have been published so far, no research on the vibration control has been reported. This paper describes that a study on the control for the self-excited vibration was carried out using active mass damper (AMD) applying the direct velocity feedback control (DVFB) which is one of several control methods for vibration. The formula which expresses three values, equivalent damping value, mass ratio and amplitude ratio between the gate and AMD was determined, and the relation among three values was expressed by the graph. And added mass weight for the gate vibration was examined. Results of numerical simulations for control and stability of the gate vibration proved that the self-excited vibration of the gate can be controlled by DVFB with AMD. Furthermore, control force on the gate was examined while vibration control is in operation.

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Seismic waves observed at dam site rock are not only necessary for seismic design of dams but are also important to research on the characteristics of seismic waves on hard bedrock. Many seismic wave measurements have been recorded at the base of embankment dams. The observed waves suffer the effects of dynamic interaction between the embankment dam and the foundation, and include the waves reflected through the dam body. In this paper, the effect of characteristics of frequency spectra of input waves and impedance ratio between dams and foundations on the response and dynamic interaction at the dam base was evaluated using FEM analyses. The observed seismic waves and microtremor measurements at dam sites verified the results of the FEM analyses. Next, an incident seismic wave on the basement layer was estimated analytically by excluding dynamic interaction from the observation at a dam base. The estimation was performed using the acceleration wave measured at the base of a rockfill dam during the Kobe Earthquake. The dam was located near the earthquake fault. The incident wave on the basement layer during the Kobe Earthquake was estimated by the proposed method.

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Since a dam lake of hydraulic power station repeats to change its water level, a slope part which is influenced by water level change tends to be poor in vegetation leading to occurrence of banded bared slopes at a low water level. This bared should be problems in terms of landscape, water quality of damlake and soil erosion. The Kansai Electric Power Company, Inc. has been developing greenery techniques at the slope of this kind influenced by water level change. This report explains mainly results of field planting experiment on the slope at pumping-up power plant.

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A series of permeability tests under confining pressure using the triaxial cell on undisturbed samples taken from fill dam core zone under construction was performed to investigate the influence of overburden pressure increase with stage-constructed embankment on the permeability of the core zone. It is clear from test results that the confining pressure has a significant influence on the permeability of core material (kv=α⋅(σc)β).

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Many small earthen structures were damaged by the Hanshin-Awaji Earthquake, while large-scale dams did not suffer serious damage. As dams near an epicenter must be inspected immediately after an earthquake, it is necessary to construct a dam information database in order to maintain a large number of dams efficiently to mitigate damage resulting from earthquakes. In this paper, I will discuss database system for irrigation dams of at least 15m in height.

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