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FAULTS IN CLAYS : THEIR DETECTION AND PROPERTIES.

Objective

THE CONTRACT HAS TO BE COORDINATED WITH A COMPANION CONTRACT TO BGS TO PERFORM SIMILAR WORK IN UK CLAYS.

FAULTS AND FRACTURES ARE KNOWN TO INTERSECT ARGILLACEOUS FORMATIONS THAT MIGHT BE CONSIDERED SUITABLE AS HOST ROCKS FOR A RADIOACTIVE WASTE REPOSITORY. IN SOME CASES THESE STRUCTURAL DISCONTINUITIES HAVE BEEN OBSERVED TO ENHANCE THE HYDRAULIC CONDUCTIVITY OF MUDROCKS. CONSEQUENTLY ANY ARGILLACEOUS FORMATION CONSIDERED FOR THE LOCATION OF A WASTE REPOSITORY SHOULS BE CHARACTERIZED THOROUGHLY FROM THE POINTS OF VIEW OF OCCURENCE OF FRACTURES AND THEIR HYDRAULIC SIGNIFICANCE.

AVAILABLE GEOPHYSICAL TECHNIQUES WITH THE CAPABILITY OF REVEALING THE EXISTENCE OF STRUCTURAL DISCONTINUITIES IN MUDROCKS, PARTICULARLY WATER-BEARING ONES, COULD BE DEVELOPED, THEN SITE INVESTIGATION STUDIES WOULD RELY MORE ON GEOPHYSICS AND LESS ON DRILLING WITH SIGNIFICANT ADVANTAGES FROM DIFFERENT POINTS OF VIEW.

THE OBJECTIVES OF THE CONTRACT ARE:
- TO DEVELOP SUITABLE GEOPHYSICAL TECHNIQUES TO DETECT WATER-BEARING FAULTS IN MUDROCKS. THE MAIN INTENDED APPLICATION IS FOR SURFACE INVESTIGATIONS, BUT POSSIBLE APPLICATION IN TUNNELS AND BOREHOLES SHOULD BE CONSIDERED;
- TO CARRY OUT HYDRAULIC TESTING ACROSS DEEP FAULTS TO DETERMINE THEIR HYDRAULIC CONDUCTIVITY AND THE HYDRAULIC CONDITIONS OF ANY MEASURABLE WATER FLOW;
- TO DEFINE SUITABLE TECHNIQUES FOR USE IN SITE INVESTIGATION CAMPAIGNS.

THE PROJECT CONSISTS OF THE FOLLOWING ACTIVITIES:

1. A SURVEY WITHIN THE COUNTRY TO IDENTIFY SITES WHERE FAULTS INTERSECT MUDROCKS;
2. CHOSING THE MOST SUITABLE SITES FOR CARRYING OUT FIELD WORK;
3. DRILLING AT LEAST TWO BOREHOLES IN SUCH A WAY THAT THE FAULT PLANE WILL BE INTERSECTED AT A SUITABLE DEPTH;
4. PERFORMING GEOPHYSICAL INVESTIGATIONS OF THE FAULT ZONE BOTH FROM THE SURFACE AND DOWN HOLE;
5. HYDRAULIC TESTING OF THE FAULT ZONE (RESPONSABILITY OF BGS);
6. GEOPHYSICAL LOGGING OF THE BOREHOLES;
7. GEOTECHNICAL MEASUREMENTS OF SAMPLES OBTAINED FROM THE CORES;
8. HYDRAULIC MODELLING OF GROUNDWATER FLOW IN THE FAULT ZONE.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

ENEL.HYDRO SPA
Address
Via Pastrengo 9
24068 Seriate
Italy

Participants (1)

NERC British Geological Survey
United Kingdom
Address

EX4 6BX Exeter