Location

Arlington, Virginia

Session Start Date

8-11-2008

Session End Date

8-16-2008

Abstract

This case history presents an application of Dynamic Compaction of the soil layers susceptible to liquefaction behind the main container quay wall of Shahid Rajaee Port Complex Development (SRPCD), situated on shores of Persian Golf near Bandar-Abbas. The liquefaction of such layers during earthquake results in the great lateral earth pressure as well as the settlement and large horizontal deformation of the main wall and anchor wall. Regarding the extension and the depth of the identified liquefiable layers, the improvement method of dynamic compaction was employed to mitigate the liquefaction destructive effect. Generally, the subsoil liquefiable layers of the SRPCD site consisted of reclaimed layers of silty sand with the maximum depths of 7 to 12 meters and the fine content of 20% – 40%. The preliminary compaction patterns were obtained using the energy-based method and the available empirical relationships based on the depth of influence and the required improving energy. Considering the previously conducted researches, the effectiveness of dynamic compaction and the applied energy to subsoil collapsible layers deteriorates due to the presence of fine content. Therefore, the effective influence depth of soil that is affected by this method of improvement is reduced. The effectiveness of the employed dynamic compaction patterns for different parts behind the main quay wall and anchor wall is evaluated comparing the results of pre and post-CPT tests (cone penetration tests performed before and after the compaction) with the criterion. Such criterion is defined as the liquefaction threshold resistance of the soil layers that is obtained using the most recent and distinguished CPT based liquefaction evaluation method. In case the criterion is not satisfied using CPT test results, the pattern (weight and drop height of the tamper, spacing and the passes of compaction) is modified in order to apply the greater amount of energy. Comparing the obtained values for influence depth resulted from empirical formula and the Pre/Post-CPT results, the validity of the preliminary used relationships and empirical constants are studied. In addition, back calculating the constants using the obtained improved depths from pre/post-CPT, the achieved constants for the available relationships are suggested.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Sixth Conference

Publisher

Missouri University of Science and Technology

Publication Date

8-11-2008

Document Version

Final Version

Rights

© 2008 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

Share

 
COinS
 
Aug 11th, 12:00 AM Aug 16th, 12:00 AM

Evaluation of Empirical Relationships for Dynamic Compaction in Liquefiable Reclaimed Silty Sand Layers Using Pre/Post Cone Penetration Tests

Arlington, Virginia

This case history presents an application of Dynamic Compaction of the soil layers susceptible to liquefaction behind the main container quay wall of Shahid Rajaee Port Complex Development (SRPCD), situated on shores of Persian Golf near Bandar-Abbas. The liquefaction of such layers during earthquake results in the great lateral earth pressure as well as the settlement and large horizontal deformation of the main wall and anchor wall. Regarding the extension and the depth of the identified liquefiable layers, the improvement method of dynamic compaction was employed to mitigate the liquefaction destructive effect. Generally, the subsoil liquefiable layers of the SRPCD site consisted of reclaimed layers of silty sand with the maximum depths of 7 to 12 meters and the fine content of 20% – 40%. The preliminary compaction patterns were obtained using the energy-based method and the available empirical relationships based on the depth of influence and the required improving energy. Considering the previously conducted researches, the effectiveness of dynamic compaction and the applied energy to subsoil collapsible layers deteriorates due to the presence of fine content. Therefore, the effective influence depth of soil that is affected by this method of improvement is reduced. The effectiveness of the employed dynamic compaction patterns for different parts behind the main quay wall and anchor wall is evaluated comparing the results of pre and post-CPT tests (cone penetration tests performed before and after the compaction) with the criterion. Such criterion is defined as the liquefaction threshold resistance of the soil layers that is obtained using the most recent and distinguished CPT based liquefaction evaluation method. In case the criterion is not satisfied using CPT test results, the pattern (weight and drop height of the tamper, spacing and the passes of compaction) is modified in order to apply the greater amount of energy. Comparing the obtained values for influence depth resulted from empirical formula and the Pre/Post-CPT results, the validity of the preliminary used relationships and empirical constants are studied. In addition, back calculating the constants using the obtained improved depths from pre/post-CPT, the achieved constants for the available relationships are suggested.