Post-Earthquake Investigation of Several Geosynthetic Reinforced Soil Retaining Walls and Slopes During Ji-Ji Earthquake of Taiwan - Reinforced Soil Engineering: Advances in Research and Practice - page 289

1 REINFORCED SOIL APPLICATIONS IN TAIWAN

Taiwan is an island country of 360,000 km 2 with over 21.9 million people
(ROC, 2000). The main island is densely populated (606 persons/km 2 ), ranked
second in the world. More than 70% of the island is composed of slopes and
mountains. Reinforced soil retaining walls and reinforced slopes have gained
wide popularity in Taiwan over recent years because of the many large-scale
housing and industrial development projects located at the slopes and

hillsides.
Chou (2000) gave an overview of the recent development of geosynthetic
reinforced soil structures (GRSS) in Taiwan. There are several unique features
for GRSS constructed in Taiwan compared to the technology that has been
developed and established in North America, Europe and Japan:

1. The topography and geotechnical conditions of Taiwan are quite
different from the rest of the world. Many recent constructions are
located along the slopes and mountains. While GRSS constructed in the
United States, Europe, and Japan are mostly near vertical and for a
height of less than 10m, some of the reinforced slopes in Taiwan are
over 30 to 40m, usually with a series of walls stacking over each other
(multiple walls).
2. The on-site soil is usually used as backfill material. The cost of granular
sand is relatively high at its scarcity. Disposal of on-site soils and
transportation of granular soils to the construction site, typically in the
mountains, are difficult and costly.
3. A wraparound facing structure is commonly used for reinforcing
slopes. The wall face is usually finished with a vegetated facing.
4. For reinforced soil retaining walls, the modular block facing structure is
most popular. The height is typically between 2 and 10 m.
5. Geogrids comprise more than 95% of the applications in reinforced soil
structures for economic reasons. There are several local geogrid
manufacturers in Taiwan. The geotextiles and metallic reinforcements
are not popular.
6. The designs of GRSS are typically provided by the manufacturers.
There is a lack of geotechnical consideration for certain specific
applications.

The reinforced soil technology has not been adopted widely by the
public sectors compared to the private developers, such as for residential and
industrial facilities. So far, three sets of design manuals are available by the
highway and railway authorities, and the Society of Civil Engineers. The
design manual for the highway (Chen et al., 1990) is an adopted version of
the FHWA and AASHTO documentation. The version for the railway