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In this study,field surveys were carried out at the damaged area of slope stabilization works,where the main cause was presumed to be the frost heaving of the rock mass.Field measurements of the freezing depth and the amount of frost heave were also conducted.In addition, the effectiveness of the slope stabilization work with the frost heave measures was verified based on the investigation results.The findings are summarized as follows. (1) From the results of the field survey and the field measurements,it was found that even if frost heaving occurred in the extreme surface layer, the rock mass would be degraded and the slope stabilization work would be affected.(2)From the results of the frost heaving tests, it is clear that the frost susceptibility of the damaged rock slope is extremely high, and there was wide agreement between the results of the frost heaving tests and the results of determining the frost susceptibility of the damaged rock slope using a simple strength test method. Therefore, the validity of the simple method proposed by Nakamura et al. for determining the frost susceptibility of rocks by using the strength test was also verified. (3)It was confirmed that both the gabion and the continuous fiber reinforced soil work were effective in preventing the freezing front from advancing into the rock mass.The method of covering the rock slope with non-frost susceptible material to prevent the penetration of the freezing front was found to be effective as a countermeasure against frost heaving.

Background: Diffuse idiopathic skeletal hyperostosis (DISH) is a pathology characterized by enthesis ossification, but there have been few reports on epidemiological surveys. This report presents a cross-sectional survey of DISH from thoracic to sacral spine in patients at the tertiary emergency medical center. Methods: The patients were divided into DISH (+) group and DISH (−) group for a retrospective comparative study. The primary outcome measures were the frequency of DISH and the patient demographic data, the secondary outcome measures were the previous medical history (diabetes mellitus, cardiovascular disease), the extent of aortic calcification, the frequency of hyperostosis around the costovertebral joint and the mortality rate within 3 months of the initial examination. Results: This survey examined a total of 1519 patients. There were 265 cases (17.4%) in the DISH (+) group and 1254 cases in DISH (−) group. The prevalence of DISH was concentrated at the thoracolumbar junction, particularly at T9. The mean age, ratio of male and hyperostosis around the costovertebral joint were significantly higher in the DISH (+) group (p < 0.001), but there was no significant difference in other variables. Conclusions: The pathology of DISH might involve the effects of age-related changes or biomechanical effects.

Recently it has been found that frost heave phenomena can be seen not also in soil but also in rock. It is obvious, however, that the number of researches on frost heaving in rock is much less than that of researches on frost heaving in soil. In the present research, we newly developed test equipment in which a pressure transducer is incorporated into a device for testing frost heave in rock. Frost heaving tests were performed using three types of rocks (Ohya tuff, which is soft rock with high frost susceptibility; Kimachi sandstone, which is medium-hard rock with low frost susceptibility; and Sapporo soft rock, which is non-frost-heaving soft rock) to measure the suction pressure generated in the process of frost heaving. In these tests, we obtained fairly large negative pressures for Ohya tuff and Kimachi sandstone. In mediumhard Kimachi sandstone, negative pressure was generated before frost heaving displacement started. On the other hand, negative pressure was not generated in non-frost-heaving Sapporo soft rock. Therefore we considered that frost heaving in rock might be caused by negative pressure generated in the process of frost heaving.

In this study, we conducted a follow-up survey of brick cracking on a brick wall in the parking space of JR Kitami Station and installed temperature sensors on the surface of the brick wall in order to measure changes in the brick wall temperature during late winter. In addition, we attempted to reproduce the brick cracking observed on the brick wall by conducting an indoor freeze-thaw experiment. The field investigation confirmed that the brick cracking on the brick wall occurred on the south-facing wall in the period from the coldest season to late winter. It was also confirmed from the records of the measured surface temperatures of the brick wall that, even in winter, the bricks could thaw in daytime and re-freeze at night, depending on the weather, solar radiation, and depth of snow coverage. Furthermore, we were successful in reproducing the brick cracking observed on the brick wall in the parking space of JR Kitami Station in the indoor freeze-thaw experiment. Our experience outlined above has demonstrated that frost damage can occur on the brick wall at JR Kitami station by a mechanism caused by the phenomenon of closed-system freeze-thaw, which the authors propose.

In recent years, earthquakes have caused several types of damage to residential embankments. To assess the integrity of residential embankments and ascertain necessary countermeasures following ground disasters, it is crucial to accurately define the boundary of cutting and filling. Although surface wave methods nondestructively unveil the S-wave velocity VS across a broad spectrum, there are currently no methods available to predict the boundary of cutting and filling based on VS. In this investigation, surface wave measurements were conducted in an area thought to be an embankment, according to aerial topographic interpretation. The acquired VS data were used to ascertain the soil characteristics of the unaffected residential embankment. Furthermore, the applicability of a method for predicting the boundary of cutting and fillings was examined. When the mode value of VS within the embankment was selected as the threshold for the boundary of cutting and filling, some agreement was confirmed with the outcomes calculated through aerial topographic interpretation. In addition, a straightforward technique for calculating ground subsidence based on VS was considered. It was found that it may be feasible to determine the estimated seismic settlement of residential levees swiftly and nondestructively throughout a sizable region. These results indicate that the use of the surface wave method has the potential to advance residential embankment health assessment systems. [ABSTRACT FROM AUTHOR]

In snowy cold regions such as Hokkaido, slopes can collapse owing to the frost heave phenomenon, freeze-thaw actions in winter, or snowmelt in spring. Kitami City in Hokkaido recently suffered from such slope failures when the extremely shallow layer eroded and slid after snowmelt in the early spring of 2020. The depth of this slope failure was about 0.20 to 0.25 m, which was very shallow compared with general surface failures. In this research, we conducted a site investigation of the road slope and collected undisturbed soil samples from a non-collapsed area near the slope failure to conduct a constant pressure direct shear test. For the direct shear tests, specimens with natural water content at the time of sampling and forcibly saturated specimens were used. The results of the slope stability analysis with the strength parameters obtained from the direct shear test showed that the slope failure was caused by snowmelt penetration, mainly due to a decrease in cohesion. [ABSTRACT FROM AUTHOR]