LANDSLIDE STABILIZATION USING HORIZONTAL DRAINS

ONE OF THE MAJOR PROBLEMS FACED BY THE TRANSPORTATION ENGINEER IS LANDSLIDES. RELIABLE COSTS ARE NOT AVAILABLE, HOWEVER, IT IS ESTIMATED THAT IN BRITISH COLUMBIA, THE DIRECT COSTS OF INVESTIGATION, STABILIZATION AND PREVENTION AND INDIRECT COSTS OF DELAYS, CLAIMS AND LIABILITY TOTAL IN EXCESS OF $10,000,000 ANNUALLY. WHEN THE TOPOGRAPHIC, GEOLOGIC AND CLIMATIC CONDITIONS COMMON TO THIS AREA ARE CONSIDERED, MAJOR EARTH MOVEMENTS ARE NOT UNEXPECTED. LANDSLIDES IN BRITISH COLUMBIA HAVE RANGED IN SIZE FROM SEVERAL CUBIC YARDS TO MILLIONS OF CUBIC YARDS. TYPES OF MOVEMENT HAVE COMPRISED CREEP, SLUMP, BLOCK SLIDES, FALLS AND FLOWS, OCCURRING SEPARATELY OR IN COMBINATION. FACTORS WHICH HAVE CONTRIBUTED TO INSTABILITY HAVE INCLUDED GRAVITY (WHICH ACTS ON ALL LANDSLIDES), EXCESSIVE POREWATER PRESSURES, REDUCTION IN SOIL STRENGTH, STEEPENING OF SLOPES, REMOVAL OF NATURAL VEGETATION, VIBRATION, ETC. STABILIZATION PROCEDURES HAVE UTILIZED RELOCATION, COUNTERBALANCING BY UNLOADING THE TOP OR LOADING THE TOE, SURFACE AND SUBSURFACE DRAINAGE, RETAINING DEVICES, ETC. THE GREAT TOPOGRAPHIC RELIEF AND HIGH ANNUAL OR SEASONAL RAINFALL AND SNOWFALL WHICH OCCURS IN MANY AREAS OF THE PROVINCE IS CONDUCTIVE TO THE DEVELOPMENT OF EXCESS POREWATER PRESSURES WHICH CAN CAUSE SERIOUS REDUCTION IN STABILITY. IN MANY OF THESE AREAS THE INSTALLATION OF HORIZONTAL DRAINS HAS PROVEN AN EFFECTIVE AND ECONOMICAL MEANS OF IMPROVING STABILITY. THESE DRAINS COMPRISE SMALL DIAMETER PERFORATED PIPE INSTALLED ON A SHALLOW GRADE IN PREDRILLED HOLES FOR DISTANCES OF 60 TO 300 FEET INTO THE ACTIVE OR POTENTIALLY ACTIVE SLIDE AREA. THIS PAPER BRIEFLY SUMMARIZES THE PURPOSE, HISTORY, EQUIPMENT PRELIMINARY INVESTIGATIONS, INSTALLATION DETAILS, COSTS, MAINTENANCE PROCEDURES AND SOME CASE HISTORIES OF HORIZONTAL DRAIN INSTALLATIONS. /CGRA/

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  • Supplemental Notes:
    • Vol 17, No 10, PP 8-11, 1 TAB, 2 PHOT, 3 REF
  • Authors:
    • Brawner, C O
  • Publication Date: 1966-10

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  • Accession Number: 00214633
  • Record Type: Publication
  • Source Agency: CANADIAN GOOD ROADS ASSOCIATION
  • Files: TRIS
  • Created Date: Oct 7 1994 12:00AM