INSTRUMENTATION METHODS AND RESULTS FOR THE JOHN DAY DAM RELOCATION

A TOTAL OF ONE HUNDRED FIVE MILLION CUBIC YARDS OF EXCAVATION, SEVENTY-SEVEN MILLION CUBIC YARDS OF EMBANKMENT, AND ONE MILLION FOUR HUNDRED THOUSAND CUBIC YARDS OF RIPRAP WERE REQUIRED FOR THE RELOCATION OF THE JOHN DAY DAM ON THE COLUMBIA RIVER APPROXIMATELY 115 MILES UPSTREAM FROM PORTLAND, OREGON. THE GEOLOGIC FEATURES OF THE REGION INCLUDE THE COLUMBIA RIVER FAULT AND THE KLONDIKE AND ALDER RIDGE ANTICLINES. SOIL TESTS SHOWED THE MAJOR CONSTITUENTS OF THE UPPER AND LOWER INTERBEDS TO BE MONTMORILLONOID SILT DERIVED FROM METAMORPHOSED VOLCANIC ASH OR TUFF, HOWEVER, THE MATERIALS HAD MANY CLAY CHARACTERISTICS AND WERE COMMONLY CALLED CLAY OR CLAYSTONE. ON EITHER END OF THE LANDSLIDE REACHES, THE PREDOMINANT SOILS CONSISTED OF SANDY SILTS OR BLOWSANDS. IN SOME LANDSLIDE AREAS, MASSES OF DEBRIS WERE SO DEEP THAT UNLOADING BACKSLOPES WHICH ARE REINFORCING THE BASE OF SLOPES WAS PHYSICALLY IMPOSSIBLE. THE THREE TYPES OF MEASUREMENTS REQUIRED WERE FOR VERTICAL MOVEMENT, HORIZONTAL MOVEMENT AND GROUND-WATER ELEVATIONS. VERTICAL MEASUREMENTS WERE MONITORED BY THESE INSTRUMENTS: (1) THE SLOPE INDICATOR, (2) THE U.S. BUREAU OF RECLAMATION CROSS ARMS, AND (3) SETTLEMENT PINS WHICH WERE ALSO INSTALLED IN BRIDGE ABUTMENTS RESTING ON FILLS. HORIZONTAL MEASUREMENT WAS MONITORED BY THESE INSTRUMENTS: (1) THE SLOPE INDICATOR, (2) SLIDE PLANE INDICATORS, (3) THE LONG GAGE MULTI-POSITION EXTENSOMETER, AND (4) KELLY WIRES WHICH CONSISTED OF AN OIL-TEMPERED STEEL WIRE STRETCHED ABOVE GROUND BETWEEN AN ANCHOR POINT INSIDE THE ACTUAL OR SUSPECTED SLIDING MASS AND A SPRING ATTACHED TO AN ANCHOR WELL OUTSIDE THE SLIDING AREA. GROUND-WATER MEASUREMENTS WERE OBTAINED WITH: (1) SLOPE INDICATOR CASING, (2) WELL- POINTS ATTACHED TO INSIDE DIAMETER PIPES, AND (3) PLASTIC CASING INSTALLED AS SLIDE PLANE INDICATORS. THE INSTRUMENTATION PROGRAM PROVIDED EXCELLENT INFORMATION ON THE DESIRED MEASUREMENTS. MOVEMENT DIAGRAMS WERE PROVIDED FOR CRITICAL AREAS SO THAT RATES OF MOVEMENT CAN BE MONITORED PRECISELY. STUDY CAN BE MADE OF MOVEMENT GRAPHS TO DETECT ANY RAPID ACCELERATION SO THAT PREVENTIVE WORK CAN BE ACCOMPLISHED BEFORE FAILURE OCCURS.

• Authors:
  • Kelly, W L
• Conference:
  • Engineering Geology and Soils Engineering Symposium, Proceedings of the 6th Annual
  • Location: Boise ID, United States
  • Date: 1968-4-17 to 1968-4-19
• Publication Date: 1969-4

Subject/Index Terms

• TRT Terms: Clay; Dams; Groundwater; Indicators (Instruments); Landslides; Measuring instruments; Motion; Relocation (Facilities); Silts; Slopes; Soil tests; Subsurface drainage; Water table
• Uncontrolled Terms: Relocation
• Old TRIS Terms: Groundwater level; Slope indicators
• Subject Areas: Geotechnology; Highways; Hydraulics and Hydrology;

Filing Info

• Accession Number: 00229738
• Record Type: Publication
• Report/Paper Numbers: pp 144-158
• Files: TRIS
• Created Date: Mar 9 1970 12:00AM