Date
11 May 1984, 8:00 am - 10:30 am
Abstract
A normally consolidated silty clay deposit, varying in depth from 0 to 15 m, was pretreated by surcharging combined with P.V.C. vertical drains. Representative field values of the vertical coefficients of primary (0.0015 m2/kN) and secondary consolidation (0.01) were calculated from the settlements caused by a preliminary fill placed some six years prior to the detailed geotechnical studies. A conservative representative field value of the horizontal coefficient of primary consolidation was established to be 8 m2/year. Asaoka's method was used to predict future settlements due to both primary and secondary consolidation. The vertical drains were installed at a spacing of 1.8 musing a modified crawler crane. The average daily output was 158 drains over 128 working days with an average cycle time per pair of drains of eight minutes. The total cost was $(A) 0.40 per cubic metre, or $(A) 3.23 per square metre of the area treated. Surcharging decreased the settlements due to primary and secondary consolidation. Calculated values of settlement over a 10 year period were 80 mm for a 15 m deposit with 50 mm being contributed by secondary consolidation.
Department(s)
Civil, Architectural and Environmental Engineering
Meeting Name
1st Conference of the International Conference on Case Histories in Geotechnical Engineering
Publisher
University of Missouri--Rolla
Document Version
Final Version
Rights
© 1984 University of Missouri--Rolla, All rights reserved.
Creative Commons Licensing
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Document Type
Article - Conference proceedings
File Type
text
Language
English
Recommended Citation
Lakner, D.; Lee, I. K.; Armstrong, E.; and Ingles, O. G., "Pretreatment of a Soft Soil by Surcharging - A Case History" (1984). International Conference on Case Histories in Geotechnical Engineering. 38.
https://scholarsmine.mst.edu/icchge/1icchge/1icchge-theme9/38
Pretreatment of a Soft Soil by Surcharging - A Case History
A normally consolidated silty clay deposit, varying in depth from 0 to 15 m, was pretreated by surcharging combined with P.V.C. vertical drains. Representative field values of the vertical coefficients of primary (0.0015 m2/kN) and secondary consolidation (0.01) were calculated from the settlements caused by a preliminary fill placed some six years prior to the detailed geotechnical studies. A conservative representative field value of the horizontal coefficient of primary consolidation was established to be 8 m2/year. Asaoka's method was used to predict future settlements due to both primary and secondary consolidation. The vertical drains were installed at a spacing of 1.8 musing a modified crawler crane. The average daily output was 158 drains over 128 working days with an average cycle time per pair of drains of eight minutes. The total cost was $(A) 0.40 per cubic metre, or $(A) 3.23 per square metre of the area treated. Surcharging decreased the settlements due to primary and secondary consolidation. Calculated values of settlement over a 10 year period were 80 mm for a 15 m deposit with 50 mm being contributed by secondary consolidation.
