XN000022-1991-03-24 — Page 2

SUNDAY, MARCH 24, 1991

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PUBLICATION ON FOUNDATION PROPERTIES OF ROCKS PUBLISHED

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A TECHNICAL PUBLICATION ENTITLED

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"FOUNDATION PROPERTIES OF TUEN MUN

MARBLE AND OTHER ROCKS IN THE YUEN LONG

AREA" HAS BEEN PUBLISHED BY THE GEOTECHNICAL CONTROL OFFICE OF THE CIVIL ENGINEERING SERVICES DEPARTMENT.

THE DOCUMENT PRESENTS THE RESULTS OF A LABORATORY AND FIELD STUDY ON THE ENGINEERING PROPERTIES OF MARBLE AND OTHER ROCKS UNDERLYING THE YUEN LONG TURN MUN AREA, PARTICULARLY WITH RESPECT TO DEEP FOUNDATIONS.

THE HEAD OF THE GEOTECHNICAL CONTROL OFFICE, DR ANDREW MALONE, SAID FOUNDATION CONDITIONS IN THE NORTHWEST NEW TERRITORIES WERE GENERALLY MORE VARIED AND COMPLEX THAN IN OTHER URBAN AREAS OF HONG KONG WHERE ONLY GRANITIC AND VOLCANIC ROCKS WERE ENCOUNTERED.

HE SAID THE COMPLEX GEOLOGICAL CONDITIONS GAVE RISE TO VARIOUS CONCERNS REGARDING THE DESIGN OF DEEP FOUNDATIONS, NOT THE LEAST BEING THE OCCURRENCE OF BURIED MARBLE CONTAINING CAVITIES.

"THE DISCOVERY OF MARBLE WITH KARSTIC FEATURES CAVITIES LED TO SPECIAL INSTRUCTIONS BEING ISSUED FOR WORKS WITHIN A DESIGNATED AREA BETWEEN TUEN MUN AND AFFECTED BY MARBLE BEDROCK, DR MALONE ADDED.

INCLUDING FOUNDATION

YUEN 1.ONG

THE BUILDINGS ORDINANCE AND REGULATIONS WERE AMENDED LAST YEAR TO INTRODUCE NEW CONTROL PROVISIONS FOR THE AREA WITHIN WHICH MARBLE MAY BE FOUND, REFERRED TO AS AREA NUMBER 2 OF THE SCHEDULED AREAS.

THE GEOTECHNICAL CONTROL OFFICE HAS RECENTLY PUBLISHED A NUMBER OF DETAILED 1:5,000 SCALE GEOLOGICAL MAPS OF THE AREA.

THE ACCOMPANYING GEOLOGICAL MEMOIR FOR THESE MAPS IS IN PREPARATION AND WELL BE PUBLISHED THIS YEAR.

MARBLE WAS ALSO DISCOVERED UNDER THE RECLAIMED LAND AT MA ON SHAN LAST YEAR.

DR MALONE SAID THE HIGHWAYS DEPARTMENT HAD BEGUN CONSTRUCTION OF THE YURN LONG TUEN MUN EASTERN CORRIDOR, A SEVEN KILOMETRE-LONG DUAL TWO-LANE TRUNK ROAD IN THIS AREA OF COMPLEX GEOLOGY.

THE GEOTECHNICAL CONTROL OFFICE HAS BREN ASSISTING THE HIGHWAYS DEPARTMENT WITH THE GROTECHNICAL ASPECTS OF THE FOUNDATION AND SLOPE DESIGN IN THIS PROJECT.

IN VIEW OF THE LACK OF PUBLISHED LOCAL DATA ON THE ENGINEERING PROPERTIES OF THE ROCK TYPES, INCLUDING MARBLE, IN THIS AREA, THE OFFICE DECIDED TO PUBLISH THE DATA OBTAINED IN THIS PROJECT ALONG WITH AN OUTLINE OF THE APPROACH TO THE DESIGN OF BORED PILES.

/THE DOCUMENT