Case studies of Advanced Construction and Demolition waste(CDW)
Recycling initiatives and technologies In JAPANAffiliation
Location
Position:
Name/Surname

Japan Industrial Waste Management Foundation,e-mailyamawaki@sanpainet.or.jp

Title

Slope stability and bearing capacity of landfills and simple on-sitetest methods
Prevention
Re-useTheme
classification

Technology
development stage

6-1 Kajicho 2-chome, Chiyoda-ku, Tokyo 101-0044, Japan.
Waste Resources Management Division
ATSUSHI YAMAWAKI〇〇Recycle
Reduce Co2Legacy
Business to overseas
Etc.
Practical use
Scheduled to be put into practical use by 2020Scheduled to be put into practical use after 2020

Specific content- According to the past study, it was grasped that the waste landfills mixed
with plastics, etc. had tensile resistance exerted by fibrous materials such as
plastics, etc. and large frictional resistance caused by engagement of large
and small wastes, etc., and the slope stability was extremely high.
-However, many construction companies believe that such waste landfills
cannot used as be soft. Therefore, It is almost impossible to use it as aground for installing a heavy structure at the disposal site.
- In addition, since the individual size of waste is much larger than that ofsoil, it is difficult to apply the conventional indoor soil test method to thestrength test.
- Against this background, in FY2013-FY2015,with the support of theministry of environment's Subsidy for Promotion of Comprehensive
Environmental Research, We studied the strength characteristics such as thesupporting capacity of waste landfill sites contaminated with plastics etc.
and the mechanical test method etc and clarified basic ground strengthcharacteristics and proposed on site test method.
- In addition, this on site test method was applied to a large-scale waste
slope collapse site in Sri Lanka, and the usefulness was confirmed even inwaste landfills outside Japan.
Appeal point- In August 2017,We participated in "Field Survey for Safety
Assessment of Slope Safety of Waste Disposal Site Meethotamulla SriLanka Country" by the Japan International Cooperation Agency(JICA), and provided technical support by this on site test method atthis large scale collapse site.
- We provided the strength data of the waste layer to Sri Lanka ·National Institute for Building Research and provided technology on aseries of strength testing methods.
- Large-scale slope collapse occurs frequently at waste disposal sites
in heavy rain areas such as Southeast Asian countries, and technology
transfer of this on site test method can be expected.

-94-

Slope stability and bearing capacity of landfills and simple on-site test
methods
Atsushi Yamawaki 1 ,Waste Resources Management Division, Japan Industrial Waste Management Foundation, Tokyo,
Japan (Email: yamawaki@sanpainet.or.jp)

This study discusses strength characteristics (slope stability, bearing capacity, etc.) of waste
landfills through on-site tests that were carried out at 29 locations in 19 sites in Japan andthree other countries, and proposes simple methods to test and assess the mechanicalstrength of landfills on site. Also, the possibility of using a landfill site was investigated by afull-scale eccentric loading test. As a result of this, landfills containing more than about 10cm long plastics or other fibrous materials were found to be resilient and hard to yield. An
on-site full scale test proved that no differential settlement occurs.The repose angle test
proposed as a simple on-site test method has been confirmed to be a good indicator forslope stability assessment. The repose angle test suggested that landfills which have high,near-saturation water content have considerably poorer slope stability. The results of ourrepose angle test and the impact acceleration test were related to the internal friction angle
and the cohesion, respectively. In addition to this, it was found that the air pore volume ratio
measured by an on-site air pore volume ratio test is likely to be related to various strengthparameters.

References
Atsushi Yamawaki, Yoichi Doi and Kiyoshi Omine; Slope stability and bearing capacity oflandfills and simple on-site test methods; Waste Management & Research, vol. 35, Issue 7,
pp.730-738, (2017)-95-