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Many types of deep mixing methods were proposed for cost reduction. However,
in case of the high embankment and rapidly construction, it is difficult
to stop to the lateral flow and compression failure of cement columns,
bearing failure of soft ground. We conducted centrifuge model experiment
to confirm the effectiveness of new method and to select suitable spec.
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| A Study on the improved soil used for earth structure |
Because of the shortage of dump yards, it is required to reduce and recycle the construction surplus soil. From the cost reduction for public works, reasonable design and quality of the earth structure is required as well. If the strength characteristic of improved soil is considered for the earth structure, for example the retaining wall, it is possible to design reasonable and economical earth structure.
However, we have two problems for the use of improved soil. The first problem is to be difficult to know the quality of improved soil at construction field. The second problem is to not be able to use the Coulomb design theory because the target model is difference between improved soil and ordinary soil.
we conducted now verification whether new quality control method of improved soil we propose is effective or not in construction field, and conducted the pulling resistance test of anchor plate in improved soil by centrifuge experiment because of the valuation of strength characteristic for improved soil.
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The purposes of the study were 1) to propose a feasible design method for
drainage system with certain drainage materials, rainfall and construction
conditions, and 2) to develop an appropriate inspection method and effective
functional recovery method for the existing embankments and walls.
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Soil Nailing intends for natural ground. Therefore the maintenance after
construction is important, but there is no standard of pulling test of
reinforcement to evaluate the degree of soundness in Japan. It is necessary
to develop the standard of pulling test.
Standards etc. of the pulling test in Japan and foreign countries were collected and analyzed, it was revealed that the influence of the reaction force of pulling out is large as a result.
The pulling out experiments of reinforcement were conducted to discuss of the influences of reaction force.
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PWRI set afloat "Ground Anchor Mentainance Manual" which shows idea of ground anchor maintenance. However, it is required the further enhancement of one.
In fiscal year 2009, the cases of malfunction of ground anchor for slope stability are investigated.
And FEM analysis was conducted to discuss the inference of increased anchor upon existing anchor.
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When the disaster for examples earth quake and rainstorm was happen, we frequently watched the collapsed embankment in Japan. We think the cause is that the quality control system and compaction method of embankment are not enough. It is required to improve the standard of compaction method and quality control system in considering uniformity and soil characteristics.
In this research, we conducted two sort experiments. One is about the relationship between compacting equipment and soil characteristics. Other is about the development on new quality control considered uniformity and soil characteristics.
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All inquiries to:
Construction Technology Team,
Construction Technology Research Department,
The Public Works Research Institute
1-6 Minamihara, Tsukuba City, Ibaraki Prefecture, 305-8516
TEL 029-879-6759
FAX 029-879-6799 |
| Copyright (C) Public Works Research Institute |
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