The Nippon Screw Weight System (NSWS) is an on-site
ground survey machine that examines the
geotechnical engineering
Geotechnical engineering is the branch of civil engineering concerned with the engineering behavior of earth materials. It uses the principles of soil mechanics and rock mechanics for the solution of its respective engineering problems. It als ...
properties of
soil. The NSWS was developed to encounter weather abnormalities and natural hazards, saving human lives.
Introduced in 2012 by the
National Agriculture and Food Research Organization
The is a Japanese research facility headquartered in Tsukuba Science City, Ibaraki, and the workforce is located in Tsukuba and in several cities and towns throughout Japan. The organization is dedicated to scientific research related to Agric ...
(NARO), the NSWS was designed to overcome problems with the
Method for standard penetration test (SPT).
NSWS was created by 耕三 大北, was the member of
311 earthquake 311 may refer to:
* 311 (number), a natural number
* AD 311, a year of the Julian calendar, in the fourth century AD
* 311 BC, a year of the pre-Julian Roman calendar
* 311 (band), an American band
** ''311'' (album), band 311's self-titled album
...
disaster committee
of the
Japanese Geotechnical Society The Japanese Geotechnical Society was established in 1949 and had a total of 122 members. Its purpose was to promote technical advances and research activities in the field of geotechnical engineering. From the very outset, its role has been expandi ...
. The society released a report in June, 2012 proposing to the Japanese government a use of NSWS to investigate the aftermath of the
2011 Tōhoku earthquake and tsunami
The occurred at 14:46 JST (05:46 UTC) on 11 March. The magnitude 9.0–9.1 (M) undersea megathrust earthquake had an epicenter in the Pacific Ocean, east of the Oshika Peninsula of the Tōhoku region, and lasted approximately six minutes ...
.
Features
The NSWS is compact, weighs 120 kg, and has wheels, making it suitable for ground measurement in crowded
residential areas. It costs much less than the conventional SPT test and
triaxial compression test.
NSWS can measure very soft zones, converted N-value of zero in the ground that had been considered difficult. It has 1.08 cm interval.SPT conducts the test every 50 cm, and 30 cm interval out of 50 cm is tested so the rest, 20 cm, is not measured; that means 40% of an entire hole is unknown. NSWS does not suffer from such a limitation.
NSWS can penetrate the ground diagonally and can cut through soft
gravel
Gravel is a loose aggregation of rock fragments. Gravel occurs naturally throughout the world as a result of sedimentary and erosive geologic processes; it is also produced in large quantities commercially as crushed stone.
Gravel is classifi ...
s. NSWS has in-situ shear test capability, the result of the joint research with NARO and Okita-Ko Co., Ltd
NSWS can prepare converted N-value,
density, in-situ shear data for Stability Analysis. NSWS enables multi-point surveying due to its diagonal penetration capability and high-mobility. The multiple spots on the weak layers can be analyzed.
See also
*
Boring (earth)
*
Cone penetration test
*
Geotechnical investigation
*
Soil mechanics
References
{{reflist
External links
National Agriculture and Food Research Organization of JapanIndependent Administrative Agency of Japan specialized in research and development of agriculture and food.
Japanese Geotechnical Society
In situ geotechnical investigations
Articles containing video clips
Geotechnical engineering
Land surveying systems