Earth pressure balanced _EPB_ full face tunneling machines have experienced a remarkable increase in the number of applications throughout the world due to both mechanical developments and a more effective use of additives to condition the ground. Conditioning modifies the mechanical and hydraulic properties of a soil by making it suitable for the pressure control in the bulk chamber and extraction with the screw conveyor. The extraction system plays a fundamental role during the EPB operations particularly for a correct application of the face pressure. Despite the extensive use of the EPB technique, little knowledge exists concerning the understanding of the behavior of conditioned soil, particularly for noncohesive ground _sand and gravel_. This paper presents and describes a prototype laboratory device, which simulates the extraction of the ground from a pressurized tank with a screw conveyor. The results of a preliminary test program carried out on a medium sized sand show that the prototype device is efficient in verifying the effects of foam for an optimal use in EPB conditioning.

Screw Conveyor Device for Laboratory Tests on Conditioned Soil for EPB Tunneling Operations / Peila, Daniele; Oggeri, Claudio; Vinai, R.. - In: JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING. - ISSN 1090-0241. - STAMPA. - 133:12(2007), pp. 1622-1625. [10.1061/ASCE1090-02412007133:121622]

Screw Conveyor Device for Laboratory Tests on Conditioned Soil for EPB Tunneling Operations

PEILA, Daniele;OGGERI, CLAUDIO;
2007

Abstract

Earth pressure balanced _EPB_ full face tunneling machines have experienced a remarkable increase in the number of applications throughout the world due to both mechanical developments and a more effective use of additives to condition the ground. Conditioning modifies the mechanical and hydraulic properties of a soil by making it suitable for the pressure control in the bulk chamber and extraction with the screw conveyor. The extraction system plays a fundamental role during the EPB operations particularly for a correct application of the face pressure. Despite the extensive use of the EPB technique, little knowledge exists concerning the understanding of the behavior of conditioned soil, particularly for noncohesive ground _sand and gravel_. This paper presents and describes a prototype laboratory device, which simulates the extraction of the ground from a pressurized tank with a screw conveyor. The results of a preliminary test program carried out on a medium sized sand show that the prototype device is efficient in verifying the effects of foam for an optimal use in EPB conditioning.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/1663936
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