ENGINEERING GEOLOGY IN URBAN PLANNING WITH AN EXAMPLE FROM THE NEW CITY OF MILTON KEYNES

Abstract

THE NEW CITY OF MILTON KEYNES WILL HAVE A POPULATION OF ABOUT 250 THOUSAND BY THE END OF THE CENTURY. SITUATED SOME 50 MILES NORTH OF LONDON IT AIMS TO PROVIDE EMPLOYMENT AND RECREATIONAL AND EDUCATIONAL FACILITIES FOR A RAPIDLY EXPANDING POPULATION IN THE HEART OF ENGLAND. THE LOCALITY FOR THE NEW CITY WAS CHOSEN ON ECONOMIC, POLITICAL AND SOCIAL GROUNDS. THE ROLE OF THE ENGINEERING GEOLOGIST WAS THEREFORE TO CLASSIFY THE NATURAL MATERIALS WITHIN THE CITY BOUNDARIES AND TO DRAW ATTENTION TO POSSIBLE HAZARDS. A NEW GEOLOGICAL SURVEY OF THE AREA WAS MADE AT 6 INCHES TO 1 MILE SCALE AND A MAP IN TERMS OF STRATIGRAPHICAL UNITS WAS PRODUCED AT 1.25,000 SCALE BY THE FIELD STAFF OF THE INSTITUTE OF GEOLOGICAL SCIENCES (IGS). A GEOTECHNICAL SURVEY WAS THEN CARRIED OUT BY THE ENGINEERING GEOLOGY UNIT. FROM THE LITHOLOGIES, VISUAL CHARACTERISTICS AND INDEX PROPERTIES OF THE NATURAL MATERIALS AS SEEN IN BORE SAMPLES, THE STRATIGRAPHICAL UNITS WERE REGROUPED INTO ENGINEERING GEOLOGY UNITS, AND A MAP AND TABLE OF PROPERTIES, ENGINEERING CHARACTERISTICS, ETC. PREPARED IN TERMS OF THESE UNITS. IN ADDITION, ADVICE WAS GIVEN ON THE PRESENCE OF RUNNING SANDS, LAMINATED LAKE SEDIMENTS AND THEIR PROBABLE EFFECT ON EXCAVATION OF THE MAIN DRAINAGE CHANNEL, ON CONDITIONS ALONG ALTERNATIVE TRUNK SEWER ROUTES, AND ON PROBLEMS OF DIFFERENTIAL SETTLEMENT ON GLACIAL TILL. IT IS SUGGESTED THAT THIS APPROACH SHOULD BE MADE AT AN EARLIER STAGE IN THE PLANNING PROCESS, BEFORE NEW CITY AREAS HAVE BEEN DELIMITED WITHIN REGIONS OF URBAN GROWTH. A COMBINED GEOLOGICAL-GEOTECHNICAL APPRAISAL OF SUCH A REGION WOULD POINT OUT PROBABLE HAZARDS AND ENABLE PLANNERS TO TAKE THEM INTO ACCOUNT AT THE OUTSET OF PLANNING. /AUTHOR/