On the Stress Dependent Contact Erosion in Vibro Stone Columns

J. Wehr,C. Boley,Y. Zou

doi:10.1061/41147(392)23

Abstract

In order to investigate the hydraulic contact erosion during and after the installation of a stone column, model tests were carried out in the laboratory. Under a critical hydraulic gradient, some fine soil particles in the subsoil around the stone column may be brought into the pore space of the stone column under certain conditions. The critical hydraulic gradient not only depends on the type of stone columns and the fine grained soils around the stone columns, but also on the stress state in the subsoil. Terzaghiχs filter criteria (Terzaghi 1948) do not apply to determine the critical hydraulic gradient. For the stone columns with a suitable grain size distribution the hydraulic contact erosion will not occur, and a geotextile cover around the stone column hardly influences the critical hydraulic gradient. The critical hydraulic gradient can be estimated by using present theoretical models.

Highlights

Vibro replacement stone columns are commonly used to .improve saturated soft subsoil which consists mainly of fine grained soils (Kirsch 1979)
If under the pressure p = pcr for a constant pressure cry a hydraulic fracture occurs, i.e. a continuous flow canal has been formed in the fine grained soil, the discharge q increases and a large amount of fine soil particles are brought into the void space of the model stone column, and the corresponding hydraulic gradient is defined as critical hydraulic gradient icr
Observations When the pressure p in the water tank 5 which corresponds to the hydraulic gradient, was relatively low, seepage occurred in the fme grained soil, but none or only a few of fme soil particles have been brought into the pore space of the stone column

Summary

On the Stress Dependent Contact Erosion in Vibro Stone Columns

Verfügbar unter/Available at: https://hdl.handle.net/20.500.11970/100248 Vorgeschlagene Zitierweise/Suggested citation: Zou, Y.; Boley, C.; Wehr, J. (2010): On the Stress Dependent Contact Erosion in Vibro Stone Columns. Verfügbar unter/Available at: https://hdl.handle.net/20.500.11970/100248 Vorgeschlagene Zitierweise/Suggested citation: Zou, Y.; Boley, C.; Wehr, J. (2010): On the Stress Dependent Contact Erosion in Vibro Stone Columns. (Hg.): Proceedings 5th International Conference on Scour and Erosion (ICSE-5), November 7-10, 2010, San Francisco, USA. Standardnutzungsbedingungen/Terms of Use: Die Dokumente in HENRY stehen unter der Creative Commons Lizenz CC BY 4.0, sofern keine abweichenden Nutzungsbedingungen getroffen wurden. Das Verwenden und das Bearbeiten stehen unter der Bedingung der Namensnennung. Im Einzelfall kann eine restriktivere Lizenz gelten; dann gelten abweichend von den obigen Nutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte. Documents in HENRY are made available under the Creative Commons License CC BY 4.0, if no other license is applicable. In some cases a different, more restrictive license may apply; if applicable the terms of the restrictive license will be binding

INTRODUCTION

EXPERIMENTS

IJ I

OBSERVATIONS AND EXPERIMENTAL RESULTS

CONCLUSIONS