IWM 2000 Turku, Finland

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