1. IWM 2000
Turku, Finland
Pasi Korkeakoski

2. Pasi Korkeakoski

3. Session 1 Application Areas
Findings:
Fields of applications of micropile
underpinning
settlement control
uplift securing
slope and embankment stabilisation
alternating compression and tension loads,
combination of micro pile installation with jet grouting
reinforced soil
new foundations
Use of micropiles is concentrating to projects where use of traditional piling methods are technical very difficult or risky.
Gaps:
Use of micropiles in "normal" piling projects is still too expensive.
Load test standardisation
Pasi Korkeakoski

4. Session 2 Classification and Definition of Micropile Type
Findings:
Definition and classifications can be based on
Installation method
Material
Dimension and cross-sectional shape
Geotechnical bearing properties (base, shaft,…)
"Additional treatment" (grouting
Classification systems of Micropiles
FHWA  drilled and grouted small diameter piles
European CEN-standards  small diameter piles
Typical features of micropile
Small diameter
High bearing capacity compared to cross-section
Minimum soil displacement even with displacement piles
Often low head room and restricted access conditions
Pasi Korkeakoski

5. Session 3 Design Some research results:
Micropile groups and networks under earthquake loading
Micropiles under cyclic loading
Bearing capacity of impact driven micropiles
Behaviour of corrosion protection of micropiles
Precise research issues and challenges:
Full-scale loading test (test standards)
Beneficial network/interlocking effect not established
Effects of raked piles still not clear
The aim is develop DESIGN MANUALS and STANDARDS and get better ANALYTICAL APPROACH-PROGRAMS for Micropiles especially under Earthquake loading and Cyclic loading.
Pasi Korkeakoski

6. Session 4 Execution
Micropile practice in Japan, America and Europe was well presented
Many countries has ready Design and Implementation Manuals or at least they are under construction.
In Europe has tried to harmonise individual national standards to global European standards. Standardisation is very demanding and takes a lot of time, because many things are totally different in each country, such as:
soil condition
used pile types and techniques
design, execution, monitoring culture
Pasi Korkeakoski

7. Session 5 Monitoring and Control
Capacity testing methods for conventional driven large diameter piling appear applicable for micropiles, driven or grouted
The importance of environmental awareness (avoiding pollution due to drilling flush and grouting spillage.
The importance of ground water monitoring
The importance of monitoring and testing was emphasised through the session and future efforts should be done with diligence and full enthusiasm.
THE NEED OF STANDARDISATION OF LOAD TEST PROCEDURES BECAME WELL ESTABLISHED.
Pasi Korkeakoski

8. Session 6 Case Histories
"We have great construction information, but not so great geotechnical information".
It was stated that we need three important things:
(a) a broad and detailed database of different construction technology and equipment, correlated to micropile performance data,
(b) well-documented and well-instrumented load tests to FAILURE!, and
(c) data on performance of different micropiles under various field applications. All of these should be available in an accessible repository!
Pasi Korkeakoski