Abstract of Special Research Report (SRR-No.14)
National Institute of Occupational Safety and Health, Japan
Prevention of Trench Failure Accidents in Exacavation Works
Introduction
SRR-No.14-1 |
Katsunori OGAWA |
: The accident associated with earth failures (e.g. trench failures and slope failures) is one of the three major accidents in construction work. These accidents occasionally involve serious accident in which more than 3 workers are injured. The numbers of accident in construction work have been gradually decreasing, yet they still account more than 1000 accidents in every year. Among them, trench failures and slope failures are major causes of accidents that account for 6-8% of accidents in construction work.
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Analysis of the Fatal Accident Caused by Trench Failure
SRR-No.14-2 |
Yasuo TOYOSAWA, Noriyuki HORII and Satoshi TAMATE |
: Trench failures cause a considerable number of deaths and injuries in Japan. For the purpose of establishing countermeasures, it is necessary to understand the basic information about fatal accidents due to trench failure. Little attention has been given to the fatal accidents due to earth failure, especially on the relations between the failure patterns and cause of death.
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Field Tests to Measure the Ground Vibration and Earth Pressure Induced by Trench Excavation Work
SRR-No.14-3 |
Satoshi TAMATE, Noriyuki HORII and Yasuo TOYOSAWA |
: A lot of slope failure accidents have been occurring in every year during the carrying out of trench excavation work. Some of these accidents were caused by vibration induced by the movement of construction machinery such as bulldozers and backhoes. These vibration may have been the cause of the decrease in ground foundation strength. Generally, slope stability in trench excavation is calculated using the static state conditions. To estimate foundation strength during excavation, it is necessary to make sure the influence of vibration caused by the movement of construction machinery and pile driving work and the earth pressure change acting on sheet pile with excavation. Therefore, field tests were carried out to investigate all these factors at the RIIS testing field.
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Effects of Cyclic Loadings Due to the Construction Machinery
on Geotechnical Characteristics of Soils
SRR-No.14-4 |
Noriyuki HORII, Yasuo TOYOSAWA and Satoshi TAMATE |
: When clay layers are subjected to transient loadings such as induced by an earthquake or traffic, excess pore water pressure are generated. Due to the generally low permeability of clays, such pore water pressures persist for some time after the cyclic events. An understanding of the behaviour of soils subjected to subsequent undrained loading is necessary not only for the safety design of structures but also for the safety of the working environment of construction workers under such conditions.
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Deformation and Failure Characteristics of Trench Excavation in Centrifuge Tests
SRR-No.14-5 |
Yasuo TOYOSAWA, Noriyuki HORII and Satoshi TAMATE |
: Accidents due to trench failure frequently occur on construction sites. Statistical analysis shows that more than 90% of fatal accidents during trench excavation in Japan, occurred as a result of collapse of un-supported or insufficiently supported trench walls.
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