Gravimetric detection of mining subsidence

Gravimetric detection of mining subsidence

165A 864298 Use of a Bouygues tunnelling machine in the Basin du Nord et du Pas-de-Calais coalfield. France Blanc. A In: Tunnelling '85 (paper to the...

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165A

864298 Use of a Bouygues tunnelling machine in the Basin du Nord et du Pas-de-Calais coalfield. France Blanc. A In: Tunnelling '85 (paper to the conference, Brighton, 10-15 March 1985) P209-212. Publ London." IMM, 1985

8643O2 Development of mechanized pipe jacking in the United Kingdom Washbourne, J In: Tunnelling '85 (paper to the conference, Brighton, 10-15 March 1985) P243-249. Publ London. IMM. 1985

This machine has a rotary boring head with four oscillating arms, each carrying one disc cutter and boring in a spiral pattern within a spherical domed face. These areas are concentric. This allows a lower total thrust, and, consequently, a lower weight and smaller size, and a lower compressive stress on side walls. Its use on a contract to drive a mine roadway, 6km long and 5m diameter, is described.

The history of the adoption of mechanised pipe jacking in the UK is described. The techniques and equipment for installing jacked linings behind back-acter machines, full-face tunnel boring machines, slurry shield machines, and boom cutter and disc cutter tunnelling machines are briefly considered with references to specific projects. The advantages and limitations of the technique are examined.

864299 Tunnel mechanization at two underground mines in the People's Republic of China Gao Zidong; Chang Dehe: Hei Shuguang In: Tunnelling '85 (paper to the conference, Brighton, 10-15 March 1985) P221-225. Publ London." IMM, 1985 The excavation of two drifts by drill and blast is described. The first was 1150m long and rock varied from stable dolomite, through fractured dolomite and limestone, to crushed limestone. The second was 350m long in hard dense granite and skarns. The planning, preparation, equipment for and execution of the two projects are considered. To improve efficiency it was necessary to modify the hole pattern, depth, charging and blasting to match rock characteristics and geology.

864300 Construction of a 3.16m diameter tunnel by extruding shield in Chicago, lfinois, U.S.A Gill. S A In: Tunnelling '85 (paper to the conference, Brighton, 10-15 March 1985) P229-234. Publ London. IMM, 1985 A 122m long connecting tunnel was excavated in saturated very soft clayey silt and soft clay, 10-11.5m below street level, by use of a specially constructed closed-face hand-mine tunnel shield. The reasons for choosing this method instead of compressed air tunnelling, ground freezing, soil grouting or open cut are given. The means of controlling settlement and heaving, the tunnelling procedures and the forces on the shield are described, and its performance is compared with that of the larger shields used to construct subway tunnels in Chicago in the 1940s.

864301 Research studies for slurry shield tunnelling Mohkam, M; Bouyat, C In: Tunnelling '85 (paper to the conference, Brighton, 10-15 March 1985) P235-241. Publ London." IMM, 1985 Construction of the Lyon Metro, France, requires driving a tunnel under the beds of the rivers Rhone and Saone, through highly permeable alluvium containing coarse gravel. It is to be constructed by the slurry shield method. A research program has been instigated to optimise the properties of the stabilising slurry, utilising a tunnelling simulation apparatus with reconstituted ground and slurry chambers. Evolution of the mud cake and pressure gradient can be studied and the stability of the ground under slurry or air pressure can be examined. The pressure gradient within the mud cake is seen to be non-linear. It was concluded that the apparatus could to a large extent, simulate in situ ground characteristics and the state of the tunnelling process under slurry pressure.

Groundwater problems 864303 Mine inundations Nicholson, D E In: Research and Engineering Applications in Rock Masses (paper to the 26th US Symposium on Rock Mechanics, Rapid City, 26-28 June 1985) V1. P297-303. Puhl Rotterdam. A. A. Balkema, 1985 Inundation from, for example, saturated strata or mine tailings can be disasterous, as is demonstrated by case histories. Subsidence or failure of the crown strata above the mine is a precursor of inundation. The present US method of calculating crown pillar dimensions, based on the dimensionless values of span, seam thickness and depth, or on measured subsidence profiles, is discussed. Alternative design methods are proposed based on modern soil and rock mechanics theory. The possible roles of hydrostatic uplift and pore pressure phenomena in inducing crown pillar failures are examined.

Surface subsidence, caving and rockbursts 8643O4 Gravimetric detection of mining subsidence Lyness, D Geophys Prospect V33, N4. June 1985. P567-576 A small scale study demonstrates the suitability of gravimetric surveying to the problem of mining subsidence. Results are sensitive to small scale elevation changes and can be directly related to altitude. Results of two dimensional modelling are used to estimate the gravitational effect of the extracted material. This controlled experiment demonstrates the possibility of using high precision gravity measurements as a substitute for levelling.

8643O5 Rockburst prevention by infusion (In German and English) Reiss, R; Kasimir, F; Klammer, G Gluckauf V122, NI, 9 Jan 1986. P42-47 (german), P19-22 (english) Preventative infusion requires small amounts of water to be fed into the coalface at low pressure over long periods. Increased moisture content modifies the mechanical properties of the coal and prevents dangerous stresses building up. The geological and operational conditions, infusion preparation and hole drilling, equipment requirements and results of monitoring its effects are described for a face in the NordsternVollverein colliery in Germany.

~_~ 1986 Pergamon Journals Ltd. Reproduction not permitted