The Delivery Tunnel North, Lesotho Highlands Water Project

被引：0

作者：

De Graaf P.J.H. ^{[1
]}

Bell F.G. ^{[1
]}

机构：

[1] Dept. of Geology and Applied Geology, University of Natal, Dalbridge

来源：

Geotechnical & Geological Engineering | 1997年 / 15卷 / 2期

关键词：

Boreability; Lining; Overbreak; Rock mass classification; Tunnel boring machine;

D O I：

10.1007/BF00880752

中图分类号：

学科分类号：

摘要：

The Delivery Tunnel North starts in Lesotho and continues into South Africa. It is divided into two sections by the Caledon and Little Caledon rivers. It runs through the mudrocks and sandstones of the Tarkastad Subgroup, and the Elliot and Molteno Formations. The tunnel was excavated by a double-shield tunnel boring machine, except for the sections beneath the two rivers, which were constructed by drill and blast methods. The tunnel boring machine was selected to bore through the anticipated changing ground conditions and also was capable of installing the segmental lining of the tunnel. Boreability tests showed that the sandstones and siltstones had good boreability, but that it was very low in the dolerite dykes. At depth, the weaker mudstones presented the worst tunnelling conditions, giving rise to squeezing ground and to shear failure with accompanying overbreak. Initially a small amount of cracking occurred in the tunnel lining but this was reduced significantly as experience was gained. Cracking was observed predominantly in the weaker rock types, and this was probably associated with overbreak.

引用

页码：95 / 120

页数：25

共 12 条

[1]

Barton N., Rock mass classifications and tunnel reinforcement selection using the Q-system, Proceedings of the Symposium on Rock Classification for Engineering Purposes, pp. 59-88, (1988)

[2]

Barton N., Lien R., Lunde J., Engineering Classification of Rock Masses for the Design of Tunnel Support, (1974)

[3]

Bieniawski Z.T., Geomechanics classification of rock masses and its application to tunnelling, Proceedings of the 3rd International Congress of the International Society of Rock Mechanics, 1, pp. 27-32, (1974)

[4]

Bieniawski Z.T., Engineering Rock Mass Classifications, (1989)

[5]

Chen J.F., Vogler U.W., Rock cuttability/boreability assessment research at CSIR, Proceedings of Tuncon '92, Design and Construction of Tunnels, pp. 91-97, (1992)

[6]

Lesotho Highlands Water Project, Delivery Tunnel North, Caledon Tunnel and Ash Tunnel Tender Document, (1990)

[7]

McBean R.J., Harries D.A., The development of high-speed soft ground tunnelling using pre-cast concrete segments and tunnelling machines, Proceedings South African Tunnelling Conference, Tuncon '70. The Technology and Potential of Tunnelling, 1, pp. 129-134, (1970)

[8]

Parkes D.B., The Performance of Tunnel Boring Machines in Rock, (1988)

[9]

Richards J.A., Remmer F., Sharp J.C., Design and construction of a segmented lining for a machine bored tunnel - Delivery Tunnel North, Lesotho Highlands Water Project, Proceedings of Tuncon '92, Design and Construction of Tunnels, pp. 147-156, (1992)

[10]

Sharp J.C., Lesotho Highlands Water Project - Delivery Tunnel North, (1992)

← 1 2 →