Funatsu, Takahiro (National Institute of Advanced Industrial Science and Technology) | Takashi, Takehara (National Institute of Advanced Industrial Science and Technology) | Kuruppu, Mahinda (Curtin University of Technology)
The deformation and strength properties of rocks are often affected by internal structures of rock, such as bedding planes, microcracks, etc. These structures may cuase the mechanical anistorpy, and crack growth may be also affected the internal structures. In this study, we use the sedimentary rock sample having the bedding planes. There are two main aims in this study. The purposes of this research are:
1) To investigate relationship between fracture toughness and loading axis with respect to bedding planes.
2) To investigate relationship between fracture toughness and other mechanical properties of rock.
The mechanical properties investigated other than fracture toughness are uniaxial compressive strength, Young’s modulus, Poisson’s ratio and P-wave velocity. The experimental results indicate that Kimachi sandstone shows anisotropic properties of Young’s modulus, tensile strength and mode I fracture toughness, but little anisotropy of uniaxial compressive strength, Poisson’s ratio and P-wave velocity.
Upper Gotvand Dam in Khuzestan province, 30 km. north-west Shushtar city and 12 km. Gotvand city is Located and the last dam on the Karun River will be constructed.
The dam has 180 meters height, with clay core type. One of the executive activities of this dam is excavating and supporting surge shaft system. The aim of these excavations is balance between power plant and waterway system and also acts to prevent of water hammer. These shafts are located in the Bakhtiari Formation (Conglomerate rocks) and the Lhbary formation (conglomerate- silt Stone and clay stone with the thin sandstone layer and filling some kind of gypsum and clay). Project consists of four shafts with a diameter about 18 meters and about 60 meters height.
Because synchronization explosion (as blasting) and concreting, effect of waves and vibrations is inevitable on the necessity of concrete monitoring by seismograph systems. In this paper, data from seismograph machines around surge shaft and using existing standards, in relation to controlled explosions adjacent concrete structures based on the distance from center of blasting and charge per delay is derived.
Some laboratory tests such as absorption, porosity, P-wave velocity and uniaxial compressive strength (UCS) were performed to examine the physical property changes of ilmenite by microorganism. Physical properteis was quantitavely compared according to culture period in the condition of abiotic oxidation without microorganism and biooxidation with microorganism. The average pH values by biooxidation was smaller than that by abiotic oxidation. Physical properties of absorption and porosity by biooxidation showed higher values than that by abiotic oxidation. The P-wave velocities were decreased with culture period comparing with the initial average P-wave velocity. Change range of P-wave velocity showed that the case of biooxidation was larger than the case of abiotic oxidation. The UCS was obviously decreased as a whole, reduction of about 38% of its initial value in the case of abiotic oxidation and reduction of about 65 % in the case of biooxidation. In conclusion, it is indicated that physical property changes of ilmenite is highly dependent on culture period and microorganism.
Nara, Yoshitaka (Kyoto University) | Meredith, Philip G. (University College London) | Nakabayashi, Ryo (Hokkaido University) | Yoneda, Tetsuro (Hokkaido University) | Kaneko, Katsuhiko (Hokkaido University)
It is essential to know how fluid flow in pores and fracture networks in rock and elastic wave velocities respond to the elevated pressures found at depth for better understandeing of seismology, volcanology and rock engineering. In this study, we investigate the changes in fluid permeability and associated changes in P-wave and S-wave velocities at elevated effective pressure for both intact and fractured rock samples of two sandstones and two igneous rocks. It was shown that the wave velocities increased with increasing pressure for all cases. The permeability of igneous rock decreased with increasing pressure. On the other hand, the permeability of a porous sandstone remained essentially constant over the whole pressure range. For sandstone samples, it was also shown that the difference in permeability between intact and fractured samples was little. By contrast, the fluid permeability in fractured igneous rock samples was higher than that in intact rock sample. From our experimental results, it is concluded that the networks of pores control the permeability in sandstone, and that the networks of fractures have significant influence on permeability in igneous rock.
Wanxiang, Chen (South China University of Technology, PLA University of Science and Technology) | Junhuab, Ye (PLA University of Science and Technology) | Zhikun, Guo (PLA University of Science and Technology) | Qihu, Qihu (PLA University of Science and Technology)
Bursting layer with irregular barriers on surface was a new composite bursting layer that had already caused people’s attentions about protective engineerings all over the world. A simplified computation formula of penetration depth for yaw-inducing bursting layer with irregular barriers on surface impacted projectile with probability was presented on the basis of computation method of penetration depth for normal impact or oblique impact. The influencing factors such as the attack angle, angular velocity, impact attitude of projectile and the uncontrolled free surface of target were synthetically considered for the computation formula by introducing the influencing coefficient of oblique impact and the influencing coefficient of yaw-inducing layer with normal impact. It was shown that the value of influencing coefficient of oblique impact was decreased with both impact angle and initial attacking angle increased, and also increased with impact velocity increased. The value of influencing coefficient of yaw-inducing layer was decreased with impact velocity increased. Computation results of the simplified formula were in good agreement with the test datum, it was indicated that the simplified computation formula could be used to accurately estimate the penetration depth for yaw-inducing bursting layer with irregular barriers on surface impacted by projectile.