Various drilling or boring machines are developed, modified, and applied in the field of mining and tunneling. However, the principle for design of drill and decision of their technical specifications is not established, and they are based substantially on the experiences in the field operation.
Firstly, the author refers to several test results on the process of bit penetration into the sample rock as well as results of the field test. Then, some fundamental equations between the force and depth of penetration of each bit wedge are given ,taking the effect of rock strength into account, on the basis of theoretical analysis and/or experimental results in the laboratory as well as field. The equation is written in the form of the complete equation in dimension.
Secondly, the author gives several mathematical equations to estimate and control the drilling rate of drill bit, as the function of various operational parameters of drilling machine. The equation of drilling rate includes the proportional constant which is affected by such technical factors as drillability of the rock mass, interference between each bit wedge, effect of flushing fluid, length of drill rod, etc.. These constants could be estimated from results of test drilling and/or field experiences.

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Uniaxial and triaxial compression tests were conducted for five rocks with the strain rate alternately switching between C1 and C2 at every predetermined strain interval. It was found that the strain interval had to be appropriately selected according to the confining pressure and the ratio, C2 / C1, in order to obtain the loading rate dependency precisely. Two stress-strain curves corresponding to the strain rates C1 and C2 were obtained applying the spline interpolation to the experimental data for just one specimen.
Concerning Tage tuff, Sanjome andesite and Akiyoshi marble, the loading rate dependency of peak strength estimated by the proposed method was reasonably well coincided with the published data. So it can be said that the proposed method is useful to evaluate the loading rate dependency of peak strength.
Loading rate dependency of residual strength was discussed for Tage tuff, Kimachi sandstone and Horonobe mudstone. Under the confining pressure, the ratio, (stress at the strain rate C2) / (stress at C1), was almost constant in the post-failure region. It is the most important finding of this study.
Time-dependent properties of the rock are indispensable to estimate the long-term stability of underground structures. In this study, the accurate and easy method was proposed to obtain the loading rate dependency. The advantage of the method is that a few rock specimens are enough for testing.

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We have developed the geo-environmental risk assessment model for organic compounds, which are considered both soil properties and exposure factors specific to Japanese situations. The exposure rates, the distribution of exposure paths and the risk level of soil content to the human have been evaluated by using this model.
Since the Japanese soil have the specific properties, i.e. high fraction of organic carbon content, it is difficult to transport into the groundwater and the air in comparison with other kinds of soil. The exposure rates of children are higher than those of adults. Especially, infants aged 0 to 2 are much more exposed to the organic compounds. The major exposure paths to the human are different due to the kind of organic compounds. The human are mainly exposed to dichloromethane and 1,4-dioxane from groundwater intake, whereas they are mainly exposed 1,2-dichloroethane and 1,1,2-trichloroethane from inhalation of indoor air. The leaching concentrations of exposure limit are estimated at 0.06mg/dm3 for dichloromethane, 2mg/dm3 for 1,1,1-trichloroethane, 0.002mg/dm3 for tetrachloromethane, 0.05mg/dm3 for tetrachloroethene, 0.1mg/dm3 for trichloroethene, 0.03mg/dm3 for cis-1,2-dichloroethene, 0.02mg/dm3 for 1,1-dichloroethene, 0.02mg/dm3 for benzene and 0.2mg/dm3 for 1,4-dioxane.

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This paper describes a new liberation model considering preferential breakage at phase boundaries to make a predicted degree of liberation to be feasible. This model is a modification of the Wiegel model, which is one of the most popular and widely acceptable models, introducing an index of "Preferential Breakage Probability, e" at phase boundaries. Concept, structure, simulation results, and validation of the model were shown in this paper, including the results of applicability for various kinds of natural and synthetic composite materials. This index of "Preferential Breakage Probability, e" is considered useful to quantify the facility with liberation for various comminution methods, and this index could also become a good measure to evaluate product design for materials recycling when applying disassembly and solid/solid separation technologies. One of the problems of these kinds of models was the determination of a reasonable unit grain size for materials which have grain size distribution. This paper also describes a solution for such cases.

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