Title page for ETD etd-11012000-08130056


Type of Document Dissertation
Author Bonita, John Anthony
Author's Email Address jbonita@schnabel-eng.com
URN etd-11012000-08130056
Title The Effects of Vibration on the Penetration Resistance and Pore Water Pressure in Sands
Degree PhD
Department Civil Engineering
Advisory Committee
Advisor Name Title
Brandon, Thomas L. Committee Co-Chair
Mitchell, James K. Committee Co-Chair
Haycocks, Christopher Committee Member
Martin, James R. II Committee Member
Mayne, Paul W. Committee Member
Keywords
  • Pore Water Pressure
  • Soil Dynamics
  • Liquefaction
  • Cone Penetration Testing
  • Vibration
Date of Defense 2000-07-28
Availability unrestricted
Abstract
The current approach for using cone penetration test data to estimate soil behavior during seismic loading involves the comparison of the seismic stresses imparted into a soil mass during an earthquake to the penetration resistance measured during an in-situ test. The approach involves an indirect empirical correlation of soil density and other soil related parameters to the behavior of the soil during the loading and does not involve a direct measurement of the dynamic behavior of the soil in-situ. The objective of this research was to develop an approach for evaluating the in-situ behavior of soil during dynamic loading directly through the use of a vibrating piezocone penetrometer.

Cone penetration tests were performed in a large calibration chamber in saturated sand samples prepared at different densities and stress levels. A total of 118 tests were performed as part of the study. The piezocone penetrometer used in the investigation was subjected to a vibratory load during the penetration test. The vibratory units used in the investigations were mounted on top of a 1m section of drill rod that was attached at the lower end to the cone penetrometer. Pneumatic impact, rotary turbine, and counter rotating mass vibrators were used in the investigation. The vibration properties generated by the vibratory unit and imparted into the soil were measured during the penetration test by a series of load cells and accelerometers mounted below the vibrator and above the cone penetrometer, respectively. The tip resistance, sleeve friction and pore water pressure were also measured during the test by load cells and transducers in the cone itself.

The vibration and cone data were compiled and compared to evaluate the effect of the vibration on the penetration resistance and pore water pressure in the soil mass. The results of the testing revealed that the influence of the vibration on the penetration resistance value decreased as the density and the mean effective stress in the soil increased, mainly because the pore water pressure was not significantly elevated throughout the entire zone of influence of the cone penetometer at the elevated stress and density conditions. An analysis of the soil response during the testing resulted in the generation of a family of curves that relates the soil response during the vibratory and static penetration to the vertical effective stress and density of the soil. The data used to generate the curves seem to agree with the proposed values estimated through the empirical relationship. An evaluation of the effects of the frequency of vibration was also performed as part of the study. The largest reduction in penetration resistance occurred when the input vibration approximated the natural frequency of the soil deposit, suggesting that resonance conditions existed between the input motion and the soil. An energy-based approach was developed to compare the energy imparted into the soil by the vibrator to the energy capacity of the soil. The input energy introduced into the soil mass prior to the reduction in penetration resistance agrees well with the energy capacity of the soil, especially in tests at the low effective stress level where a high excess pore water pressure was observed.

Files
  Filename       Size       Approximate Download Time (Hours:Minutes:Seconds) 
 
 28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access 
  01Introduction.pdf 44.20 Kb 00:00:12 00:00:06 00:00:05 00:00:02 < 00:00:01
  02Chapter_1.pdf 24.02 Kb 00:00:06 00:00:03 00:00:03 00:00:01 < 00:00:01
  03Chapter_1_Figures.pdf 13.99 Kb 00:00:03 00:00:01 00:00:01 < 00:00:01 < 00:00:01
  04Chapter_2.pdf 141.90 Kb 00:00:39 00:00:20 00:00:17 00:00:08 < 00:00:01
  05Chapter_2_Figures.pdf 236.54 Kb 00:01:05 00:00:33 00:00:29 00:00:14 00:00:01
  06Chapter_3.pdf 80.65 Kb 00:00:22 00:00:11 00:00:10 00:00:05 < 00:00:01
  07Chapter_3_Figures.pdf 821.86 Kb 00:03:48 00:01:57 00:01:42 00:00:51 00:00:04
  08Chapter_3_Tables.pdf 16.03 Kb 00:00:04 00:00:02 00:00:02 00:00:01 < 00:00:01
  09Chapter_4.pdf 37.50 Kb 00:00:10 00:00:05 00:00:04 00:00:02 < 00:00:01
  10Chapter_4_Figures.pdf 1.52 Mb 00:07:00 00:03:36 00:03:09 00:01:34 00:00:08
  11Chapter_5.pdf 169.13 Kb 00:00:46 00:00:24 00:00:21 00:00:10 < 00:00:01
  12Chapter_5_Figures.pdf 1.79 Mb 00:08:17 00:04:15 00:03:43 00:01:51 00:00:09
  13Chapter_5_Tables.pdf 76.17 Kb 00:00:21 00:00:10 00:00:09 00:00:04 < 00:00:01
  14Chapter_6.pdf 78.30 Kb 00:00:21 00:00:11 00:00:09 00:00:04 < 00:00:01
  15Chapter_6_Figures.pdf 402.22 Kb 00:01:51 00:00:57 00:00:50 00:00:25 00:00:02
  16Chapter_7.pdf 27.08 Kb 00:00:07 00:00:03 00:00:03 00:00:01 < 00:00:01
  17References.pdf 38.06 Kb 00:00:10 00:00:05 00:00:04 00:00:02 < 00:00:01
  18Appendix_A.pdf 102.71 Kb 00:00:28 00:00:14 00:00:12 00:00:06 < 00:00:01
  19Appendix_B.pdf 21.35 Kb 00:00:05 00:00:03 00:00:02 00:00:01 < 00:00:01
  20Appendix_C.pdf 81.80 Kb 00:00:22 00:00:11 00:00:10 00:00:05 < 00:00:01
  21Vita.pdf 4.51 Kb 00:00:01 < 00:00:01 < 00:00:01 < 00:00:01 < 00:00:01

Browse All Available ETDs by ( Author | Department )

dla home
etds imagebase journals news ereserve special collections
virgnia tech home contact dla university libraries

If you have questions or technical problems, please Contact DLA.