DYNAMIC PORE WATER PRESSURE N SATURATED SAND

ONE OF THE DYNAMIC PROBLEMS IN SOIL MECHANICS IS THAT OF LIQUEDFACTION IN SATURATED SAND. THE MECHANISM OF LIQUEFACTION IN SAND HAS BEEN EXPLAINED AS FOLLOWS: THE SKELETON OF THE SAND IS SUCCESSIVELY BROKEN DOWN BY THE EFFECT OF DILATANCY WHEN SATURATED SAND IS SUBJECTED TO VIBRATION, IF DRAINAGE IS NOT POSSIBLE. THE TENDENCY TO DECREASE IN VOLUME PRODUCES AN INCREASE IN PORE WATER PRESSURE AND THE EFFECTIVE STRESS TENDS TO BECOME ZERO; THE SAND LOSES ITS STRENGTH COMPLETELY, AND GOES INTO A LIQUIFIED STATE. THIS STUDY PRESENTS A QUANTITATIVE EVALUATION OF THE PORE WATER PRESSURE GENERATED IN SATURATED SAND UNDER A VIBRATING LOAD. THE DYNAMIC WATER PRESSURE IN LIQUEFIED SAND WAS MEASURED AT SEVERAL OBSERVATION POINTS IN A TANK WHICH WAS EXCITED BY A VIBRATION TABLE. THE DATA OBTAINED AGREE WITH THOSE OF ANALYTICAL SOLUTIONS IN WHICH THE LIQUEFIED SAND WAS TREATED AS WATER HAVING THE DENSITY OF THE SUBMERGED WEIGHT OF SAND. THE EFFECT OF WEIGHT FLUCTUATION ON THE LIQUEFACTION OF SATURATED SAND DURING EARTHQUAKES IS ALSO DISCUSSED. THIS WEIGHT FLUCTUATION IS PROPORTIONAL TO THE VERTICAL GRADIENT OF DYNAMIC PORE WATER PRESSURE. THEREFORE THE WEIGHT FLUTCTUATION IS MOST NOTABLE AT THE SURFACE OF THE SATURATED SAND IN A TANK WITH REAGRD TO THE VERTICAL DIRECTION AND AT THE BOUNDARIES WITH REGARD TO THE HORIZONTAL DIRECTION. IF THE WEIGHT FLUCTUATION IS CLOSELY RELATED TO THE INCREASE IN LIQUEFACTION IN SATURATED SAND, IT MAY BE SAID THAT THE LIQUEFACTIN IS GREATER WHERE THE WEIGHT FLUCTUATION IS GREATER. /RRL/

  • Supplemental Notes:
    • Vol 19, P 78
  • Authors:
    • Toki, K
    • ISHIGURO, Y
  • Publication Date: 1970-8

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Filing Info

  • Accession Number: 00235204
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: TRIS
  • Created Date: Feb 24 1972 12:00AM