STUDIES OF FILL CONSTRUCTION OVER MUD FLATS INCLUDING A DESCRIPTION OF EXPERIMENTAL CONSTRUCTION USING VERTICAL SAND DRAINS TO HASTEN STABILIZATION

STUDIES WERE CONDUCTED OF FILL CONSTRUCTION OVER MARSH LANDS IN CALIFORNIA TO DETERMINE: (1) METHOD OF CONSTRUCTING THE FILL WITH MINIMUM SLIPPAGE, (2) REQUIRED YARDAGE OF FILL MATERIAL, INCLUDING YARDAGE NECESSARY TO COMPENSATE FOR UNAVOIDABLE LATERAL DISPLACEMENT AND LOSS BETWEEN DREDGER CUT AND FILL, AND (3) PROBABLE RATE OF SUBSIDENCE AND TOTAL SETTLEMENT SUBSEQUENT TO INITIAL CONSTRUCTION DUE TO SLOW DEHYDRATION AND CONSOLIDATION OF THE MUD STRATA. THE DATA FROM DEEP BORINGS, STUDIES OF THE FOUNDATION PRESSURE, AND LABORATORY ANALYSES OF FOUNDATION MATERIAL, INCLUDING THE DETERMINATION OF UNIT WEIGHT, DENSITY, MOISTURE CONTENT, GRAIN SIZE, CONSOLIDATION, COHESIVE STRENGTH, AND ANGLE OF INTERNAL FRICTION, WERE USED IN THE FILL DESIGN AND CONSTRUCTION TO DETERMINE THE PROBABLE SETTLEMENT AND EMBANKMENT QUANTITIES. A STANDPIPE TEST DEVELOPED BY THE AUTHOR, WAS USED TO CHECK THE ASSUMPTIONS AND THEORETICAL ANALYSES OF FOUNDATION PRESSURES. A HEAVY SIX-IN. DIAMETER CASING WAS DRIVEN THROUGH THE FILL INTO AN IMPERMEABLE CLAY MUD STRATUM, THUS PREVENTING WATER FROM FLOWING READILY UP ALONG THE OUTSIDE OF THE PIPE. THE CASING WAS CLEANED TO THE BOTTOM AND CONTINUOUS UNDISTURBED CORE SAMPLES OBTAINED FROM THE BOTTOM OF THE CASING TO ELEVATION. A TWO- IN. DIAMETER PERFORATED SAND FILLED PIPE WAS PLACED BETWEEN CERTAIN ELEVATIONS TO SERVE AS A FILLER, THUS ALLOWING THE WATER BELOW THE ELEVATION TO PASS UPWARDS THROUGH THE STANDPIPE. THE BOTTOM 2 FT. OF THE 6-IN. CASING WAS ALSO FILLED WITH SAND TO PREVENT MUD FROM ENTERING. THE TEST WAS FOUND SUFFICIENTLY SENSITIVE TO REFLECT THE INCREASED WEIGHT OF THE FILL DURING WET SEASON AND THE LOAD RESULTING FROM PLACEMENT OF SUBGRADE MATERIAL, BASE, AND PAVEMENT. THE HYDRODYNAMIC EXCESS PRESSURE AGREES CLOSELY WITH THE THEORETICAL ANALYSIS MADE PRIOR TO CONSTRUCTION. THE TEST PROMISES TO BE USEFUL FOR MEASURING THE RATE OF CORE SOLIDIFICATION AND THE HORIZONTAL COMPONENT IN HYDRAULIC- FILL DAMS. VERTICAL SAND DRAINS WERE INSTALLED IN THE MARSH FOR TESTING UNDER FIELD CONDITIONS. THREE TEST SECTIONS WERE USED TO MAKE BORINGS AND OBTAIN SOIL PROFILES AND THEORETICAL PRESSURE CONTOURS. SUBSTRATA DRAINAGE WAS FOUND NECESSARY TO RELIEVE HYDRODYNAMIC PRESSURE AND STABILIZE IMPERMEABLE SATURATED GROUND. THEORETICAL ADVANTAGES OF VERTICAL DRAINS IN CONNECTION WITH FILL CONSTRUCTION OVER DEEP MARSH LANDS HAVE BEEN CONFIRMED BY THE EXPERIMENTAL CONSTRUCTION DESCRIBED. IT IS POSSIBLE, WITH PROPER SPACING OF THE DRAINS, TO OBTAIN PRACTICALLY ALL OF THE SETTLEMENT DURING THE 6 MONTHS TO ONE YEAR'S TIME FOLLOWING CONSTRUCTION. WATER USUALLY TRAVELS THROUGH SOIL DEPOSITS MORE READILY HORIZONTALLY (WITH THE BEDDING) THAN VERTICALLY. THE DRAINS MAY ACCELERATE THE RATE OF SETTLEMENT BY PROVIDING AN OUTLET FOR HORIZONTAL MOVEMENT OF EXCESS MOISTURE. DRAINS, WITH A SPACING CONSISTENT WITH THE TYPE OF MATERIAL AND THE DESIRED RATE OF LOADING, READILY RELEASE THE EXCESS WATER, RELIEVE THE HYDRODYNAMIC PRESSURE, AND THUS PREVENT LATERAL DISPLACEMENT DURING FILL CONSTRUCTION.

  • Supplemental Notes:
    • Vol 18, ParT 2, PP 129-141, 15 FIG, 1 TAB
  • Authors:
    • Porter, O J
  • Publication Date: 1939

Media Info

  • Monograph Title: Proceedings of the Eighteenth Annual Meeting of the Highway Research Board Held at Washington, D.C. November 28-December 2, 1938. Part II: Soil Mechanics and Soil Stabilization
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00231417
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Aug 15 2004 2:41AM