ABSTRACT:The chemical grouting is one type of ground-improvement methods. It injects liquid consolidation material into the gaps of a soft sandy ground. It is mainly used for improving a stable ground, such as by preventing liquefaction and increasing the strength of the ground. Chemical grouting has been successfully applied at many construction sites; however, the behavior of the chemical solution being injected into the ground is unclear. Furthermore, because the ground involves uncertainty, it is difficult to determine the penetration range of the chemicals (grouting materials). In this study, the authors carry out a seepage flow analysis of a chemical solution for a ground requiring improvement due to uncertainty. They then compare the difference in the behavior of the chemical solution between the case in which the ground is assumed to be heterogeneous and that in which it is assumed to be homogeneous.

In 2011, a number of radioactive substances were released as a result of the accident at the Fukushima Daiichi Nuclear Power Plant, Japan, which was caused by the Tohoku region Pacific coast earthquake. The radioactive substances that were released fell onto the surrounding ground and into the sea. Therefore, decontamination measures for the ground have been conducted at the field site. However, the safety and validity of modern decontamination measures were uncertain because no analytical verification had been performed that considered the various properties of the ground. Moreover, selection of the site where storage containers for radioactive materials could be constructed was a critical issue that required a solution. Therefore, it was necessary to evaluate quantitatively the behaviour of radioactive substances in soils to prepare new decontamination methods for the ground. In this study, the advection–dispersion equation was added to the radioactive half-life to evaluate the transportation of radioactive substances. As the results of this study show, this analytical method could recreate the on-site situation through comparison of the analysis results with the measurement results. Furthermore, modern decontamination techniques were effective for the section under analysis for ground with a silt or a clay layer. However, these techniques were not effective for sand layers.

In late years, quantity of construction by-products tends to increase in our country. Therefore, dumping restraint of construction by-products and promote those recycling are the most critical issue from a viewpoint of establishing the recycling society. In the other hand, soils generated from construction generally show strong alkalinity because cements are mixed. Thus, the cost at the time of the disposal of soils generated from construction becomes expensive, and it is thought that it has a great influence on environment when the soils is disposed by no improvement. However, it is the present conditions that technique in consideration of the influence on environment with non-appropriate processing is not established. Therefore, a vegetation is applied for an index indicating a recycling potential of soils generated from construction. This paper is inspected experimentally to the potential of soils generated from construction as a planting base by mixing neutralizing agents. It was realized that the soils generated from construction had vegetation by mixing neutralizing agents.

ABSTRACT:In contrast to the mechanical stirring method in which the ground soil and the modifying material are mixed and stirred by stirring blades and the improved body is formed in the ground, the high pressure injection stirring method is a method in which the improved diameter is changed due to soil condition and so on. There is a possibility that it can be changed with, and a method for easily confirming the shape, particularly the improved diameter, is highly desired. In this research, the authors propose and propose a method that can make "visualization" of this improvement situation and confirm the improved diameter in real time. Confirmation was made by measuring water quality in multiple items. From the results, it was confirmed that pH and the values of the other 5 items changed at the same time. And the change was due to the arrival of the cement slurry. Therefore, it can be said that real-time measurement is possible by visualization of improved diameter by water quality measurement conducted this time.

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