45. Foundation design and construction in coal measures

The design of piled foundations in Coal Measures can be particularly challenging, especially where coal seams have been worked and mudstones of variable strength and weathering together with seat earths are involved. The paper describes the investigation, design, ground treatment and construction of piled foundations for a Retail Development in Oldham, UK. On this site there are several significant coal seams, some of which have been worked in earlier time. The rocks are faulted and dip at up to 25°. In some areas the mudstones are very weak and weathered whilst in others they are sandy and competent. An observational approach has been adopted throughout construction and all data gathered has been used to improve the geological and structural plans of the site. Design procedures have been evolved to ensure that the additional stresses applied to coals or infilled grouted seams does not exceed 150 kpa although this criterion is questioned by the authors.

• INTRODUCTION

• GEOLOGY OF THE SITE

• PILE DESIGN

• PRELIMINARY TEST PILES

• WORKING PILE TESTS

• INVESTIGATION DURING CONSTRUCTION

• DISCUSSION

• CONCLUSIONS

• ACKNOWLEDGEMENTS

• REFERENCES