326A

Ground freezing

896299 Use of NATM in combination with compressed air and ground freezing during Vienna subway construction Deix, F; Braun, B Proc 1987 Rapid Excavation and Tunnelling Conference, New Orleans, 14-17 June 1987 V1, P488-506. Publ Littleton." Society of Mining Engineers, 1987

One section of the metro in clayey soils and sandy gravel passed close to a telecommunications building. Because of minimal ground movement tolerance and cover as low as 1.5m in places, the NATM with compressed air and partial dewater- ing was supplemented by ground freezing. Laboratory and in situ tests were used to collect frozen soil data such that the freezing scheme ensured a small heave magnitude.

896300 Extensometer investigations of frozen shaft lining Bielecka-Przygodzka, B; Boleslaw, G; Matlawski, A; Szczepaniak, S Proc Conference on Shaft Engineering, Harrogate, 5-7 June 1989 P61-72. Publ London: IMM, 1989

Sinking of deep shafts in the weathered and saturated rock masses of the Legnica-Glogow Copper Basin has been studied for 25 years, in particular variable loading on the rock mass and shaft lining. The ground is frozen for shaft sinking. The influence of the frozen mantle on the lining and characteristics of the shaft lining are described. Results from damaged linings in shafts sunk in frozen ground are presented, along with data obtained from strain gauges and other instruments in the lin- ing and rock mass of one shaft. Timing of loading change is outlined and rock mass pressure on the shaft lining calculated.

896301 Utilisation of a reinforced concrete permanent shaft tower for shaft sinking with the application of ground freezing Brzozka, J; Gasior, S; Paszcza, H Proc Conference on Shaft Engineering, Harrogate, 5-7 June 1989 P73-81. Publ London: [MM, 1989

In Poland, reinforced concrete shaft towers are often con- structed prior to shaft sinking. A shaft at Czeczott mine had unfavourable hydrogeological conditions so ground freezing was used. A reinforced concrete shaft tower was constructed with foundations outside the freeze zone to avoid problems with heave. The freezing process is outlined. To study the influence of freezing on the foundation, bench marks were installed in the shaft walls. The structure settled 5-gram during construction, and, despite being founded away from the freeze zone, upheaval of 3-5mm occurred as a result of freezing.

Surface Structures

Geological factors of importance in surface structures

896302 Criteria for quarry development in Southeastern Ontario Verschuren, C P; Kingston, P W; Caley, W F CIM Bulletin V82, N922, Feb 1989, P55-60

There is increasing demand for natural stone for construction in North America. Criteria for determination of a new quarry site include quarry block size, colour and texture, uniformity,

physical requirements, mineralogy, and location and access. Geological criteria for commercial granite and marble are discussed.

896303 Crucial issues in geotechnical engineering of water resource projects Madhavan, M R Indian Geotech J V18, N1, Jan 1988, P1-30

One of the main factors identified as contributing to cost esca- lation in hydropower projects in India is inadequate site inves- tigation. Three cases are cited: Solal, Loktat and Srisailam projects. Evolution of design during construction, slope stabil- ity and support, tunnels and underground structures, and dam foundations are discussed with reference to geological influ- ences. The need to employ personnel with specialised knowl- edge of potential geological hazards for such projects is emphasised.

896304 Engineering geology of the Kidder Dam Anderson, J G C; McNicol, R Q J Engng Geol 1/22, N2. 1989. Pl11-130

Engineering geology was important in the planning, design, construction and performance of the Kielder dam. Pre-con- struction site investigation identified distribution, volume and quality of the major construction materials, boulder clay, sandstone and dolerite, and allowed planning of groundwater monitoring using piezometers and relief wells. The influence of geology and groundwater distribution on the south abutment, central dam area, diaphragm cut-off wall and river channel valve tower and culvert, north abutment, overflow channel, stilling basin and reservoir impounding is discussed.

896305 Formation of pockmarks and their potential influence on offshore construction Hovland, M Q J Engng Geol V22, N2, 1989, P131-138

Pockmarks are craters in the soft sea-bed formed by gas erup- tion and seepage. A tentative formation theory is given: pres- sure build up phase, eruption phase and post-eruption phase, which may be dormant or continuous gas seepage. Triggering for pockmarks may be earthquakes, sea bed pressure per- turbations caused by tidal or gravity waves, or, in deep water, by a combination of tidal waves and low atmospheric pressure and storm waves. Implications for the construction of offshore structures are discussed. 25 refs.

Base courses and pavements

See also." 896088

896306 New approach to the design of unpaved roads - Part I Milligan, G W E; Jewell, R A; Houlsby, G T; Burd, H T Ground Engng V22, N3, April 1989, P25-29

The design of reinforced and unreinforced unpaved roads on soft clay soils is investigated. The design concept is that verti- cal loads applied to the granular layer cause horizontal stresses to be developed within the layer, and these are held in equilib- rium by shear stresses at the surface of the subgrade. In unreinforced roads, these stresses have a detrimental effect on bearing capacity. This theory can account for improvements due to reinforcement at small deflections, which previous anal- ysis based on membrane theory is unable to do. Analysis using the new method is compared with results of model tests.

© 1989 Pergamon Press plc. Reproduction not permitted