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Showing 1-5 of 44 Abstracts search results

Document: 

SP54-34

Date: 

January 1, 1977

Author(s):

Hans Treichl

Publication:

Symposium Papers

Volume:

54

Abstract:

During the recent years, the Tyrol has become more and more important as a cross road center in the Alps, due to the construction of important north-south road links. The Brenner and Reschenpass are the lowest, and during the winter, safest crossings in the Alps.

DOI:

10.14359/18047


Document: 

SP54-25

Date: 

January 1, 1977

Author(s):

W. Mayrhauser

Publication:

Symposium Papers

Volume:

54

Abstract:

The NATM is a double shell building mehtod consisting of the shotcrete outer arch (reinforced by welded wire fabric and steel rib sections) and the systematically anchored rock carrying ring. The rock carrying ring is the primary supporting element and thus of the greatest importance. These two shells - the shotcrete outer arch and the rock carrying ring - have to be dimensioned in such a manner that the gound reaches a permanent equilibrium. To ascertain this, extensive measuring is required. These measurements are a fundamental criterion of the NATM and consist of: a) Roof conolidation bolts b) Convergency measurements c) Extensometer measurements d) Measuring anchors. These measurements are taken continuously in the course of the advance on site.

DOI:

10.14359/18038


Document: 

SP54-30

Date: 

January 1, 1977

Author(s):

Gaberial Fernandez-Delgado

Publication:

Symposium Papers

Volume:

54

Abstract:

This report presents the results of model tests on thin shotcrete layers similar to those potentially used as initial tunnel support. The structural behavior and maximum carrying capacity of these layers were determined in this testing program. The large-scale test facility used was versatile enough to accommodate different geometrical configuration. Four principal modes of failure were observed: diagonal tension in the shotcrete, separation of the layer from the wall, thrust-moment interaction in the separated portion of the layer and bending failure of shotcrete layers loaded by sharp-edged blocks.

DOI:

10.14359/18043


Document: 

SP54-29

Date: 

January 1, 1977

Author(s):

R. Cordel

Publication:

Symposium Papers

Volume:

54

Abstract:

Since EDF was founded in 1946, it has achieved a great number of hydroelectric plants, leading it to dig several million cubic meters of underground excavations for the intakes, the power stations and auxiliaries, plus hundreds of kilometers of head race tunnels. Rather often, these underground structures, standing in poor ground, had to receive a support. Let us note that since 1950 there have been a few applications of gunite. In fact, it was not exactly a support but rather a rock protection against weathering due to air and water.

DOI:

10.14359/18042


Document: 

SP54-12

Date: 

January 1, 1977

Author(s):

Harvey W. Parker, Gabriel Fernandez-Delgado, and Loren J. Lorig

Publication:

Symposium Papers

Volume:

54

Abstract:

Some rebound is an inevitable consequence of a shotcrete operation. The many various factors leading to excessive rebound were identified and appreciated by those familiar with shotcrete long ago. Studebaker (1939) was only one of the early researchers. However, the relative significance of many of these factors is not yet well understood. The magnitude of rebound is difficult to determine and "eyeball estimates" cannot always be relied upon to base conclusions about the various factors of rebound.

DOI:

10.14359/18025


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