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Vibroflotation method at sea bottom
293A modified vibroflotation equipment. Plate bearing tests indicated the seabed bearing capacity was increased from 50kPa to 130kPa.
Soil stabilisation See also: 905121 905309 Reinforcement of soil slopes by electrochemical methods Perera, A K S A Proc International Geotecimical Symposium on Theory and Practice of Earth Reinforcement, Fukuoka Kyushu, 5-7 October 1988 P341-345. Publ Rotterdam: A A Balkema, 1988 An electrochemical method of soil reinforcement is described. A hexagonal arrangement of anodes with cathodes in the centre of the hexagons is used. Electrosilication using solutions injected through the tubular anodes is used in conjunction with electrochemical reinforcement because of the inhomogeneity of the soil. Large volumes of soil in a slope of clayey soil over a pre-existing slip surface of an ancient river bed have been stabilised. Strength increases of 1.5-2 times have been achieved. Water contents at anode and cathode were reduced by 7% and 4% respectively.
Soil compaction
Ground freezing 905313 Frozen collar protects tunnel drive beneath rail tracks Semprich, S; Losch, M Tunn Tunnig V22, N4, April 1990, P27-29 Construction of the Fahrlach Tunnel, Mannheim, is described. A 184m long tunnelled section joins-cut and cover sections. The ground was layered gravel, sand and silt, with high water table. The cut and cover sections were excavated between sheet pile and diaphragm walls, using dredgers for excavation under water. The tunnelled section was excavated by roadheader after ground freezing, and used a two stage in situ concrete lining. Settlement of railway tracks was within permissable limits.
Surface Structures
905310 Soil peculiarities of marshlund reclaimed for a housing project: New Flnima, Nigeria
Owuama, C O Engng Geol 1/28, N1/2, Feb 1990, P95-104 New Fenima on the Nigerian coast is built largely over reclaimed mangrove swamp and creeklets. Sand from the adjacent salt-water Monglobie Greek was placed hydraulically. The immediate marsh soil is high plasticity, dark brown organic silty clay. Adequate strength is mobilised in this soil on consolidation, but if it is overstressed, damage to surface structures is possible. Because of the relative impermeability of the clay, regional waterlogging after rainfall becomes a problem. Loss of nutrients during emplacement of the sand also reduces its ability to support vegetation. Requirements for planning and execution of reclamation projects are discussed.
905311 Unified approach to ground improvement by heavy tamping Lo, K W; Ooi, P L; Lee, S L J Geotech Engng Di~ ASCE Vl16, N3, March 1990, P514527 Mechanisms of ground improvement by heavy tamping are described: dynamic compaction (DC); dynamic replacement (DR); and dynamic replacement and mixing (DRM), whcrc the sand columns produced by DR are dispersed by claquage to form a subsurface sand blanket. On the basis of field trials on soils from granular to organic cohesive, a rational basis for procedure is proposed, incorporating initial conditions and operational parameters. Energy per blow, point spacing, and number of blows per point for a required degree of ground improvement can be specified.
905312 Vibroflotation method at sea bottom Qian, Z; Suen, W H; Suen, S B; Yuan, D J; Li, R K; Chang, S F Proc International Conference on Engineering Problems of Regional Soils, Bcijiug, 11-15 August 1988 P444-447. Publ Beijing: International Academic Publishers, 1989
Vibroflotation has been used onshore for many years, but its application to the sea bed is rare. Its use to improve a sea floor of sand over muddy loam and loam is described. Stone columns were installed from a ship in up to 29m of water using
Geological factors of importance in surface structures 905314 Urban geology: case study of Kuala Lumpur, Malaysia Tan, B K; Komoo, I Engng Geoi V28, NI/2, Feb 1990, P71-94 The Kuala Lumpur area is characterised by residual soils over limestone, granitic, quartzite and phyllite, and schist rocks. Geological maps are discussed. Mine tailings, municipal fills and the collapsed soil zone above limestone bedrock all show very poor engineering properties. Solution features in karstic limestone over pinnacled bedrock give rise to problems for deep foundations. Landslides are frequent in hilly areas and are related to geology and weathering of the rocks and soils. These influences are discussed with reference to case histories.
905315 Turkwel Hydropower Project near the Kenyan Rift Valley (East Africa) Antoine, P; Giraud, A; Huber, R; Lavedan, G; Moullard, P Y Engng Geol V28, NI/2, Feb 1990, P133-147 This scheme with a thin arch dam 155m high, 150m crest length is sited in the vicinity of the collapse zone of the great East Africa Rift. Geology of the site varies from metamorphic series to intrusive granite of Precambrian age. The geology and its development, lithology, and physical and mechanical properties are described. Major features of relevance to the project and its excavations are discussed.
905316 Typical landforms and slope stability of the Zngros Mountains along the Shiraz-Bonshire road in Southwestern Iran Rantucci, G Proc Symposium on Envirommental Geoteclmics and Problematic Soils a~! Rocks, Bangkok, December 1985 P321332. Pubi Rotterdam: d A Baikema, 1988 Optimisation of route and costs was made on the basis of aerial photo investigation, geology and tectonics, plus more detailed examination by seismic and drilling investigations.
© 1990 Pergamon Press plc. Reproduction not permitted
Soil stabilisation See also: 905121 905309 Reinforcement of soil slopes by electrochemical methods Perera, A K S A Proc International Geotecimical Symposium on Theory and Practice of Earth Reinforcement, Fukuoka Kyushu, 5-7 October 1988 P341-345. Publ Rotterdam: A A Balkema, 1988 An electrochemical method of soil reinforcement is described. A hexagonal arrangement of anodes with cathodes in the centre of the hexagons is used. Electrosilication using solutions injected through the tubular anodes is used in conjunction with electrochemical reinforcement because of the inhomogeneity of the soil. Large volumes of soil in a slope of clayey soil over a pre-existing slip surface of an ancient river bed have been stabilised. Strength increases of 1.5-2 times have been achieved. Water contents at anode and cathode were reduced by 7% and 4% respectively.
Soil compaction
Ground freezing 905313 Frozen collar protects tunnel drive beneath rail tracks Semprich, S; Losch, M Tunn Tunnig V22, N4, April 1990, P27-29 Construction of the Fahrlach Tunnel, Mannheim, is described. A 184m long tunnelled section joins-cut and cover sections. The ground was layered gravel, sand and silt, with high water table. The cut and cover sections were excavated between sheet pile and diaphragm walls, using dredgers for excavation under water. The tunnelled section was excavated by roadheader after ground freezing, and used a two stage in situ concrete lining. Settlement of railway tracks was within permissable limits.
Surface Structures
905310 Soil peculiarities of marshlund reclaimed for a housing project: New Flnima, Nigeria
Owuama, C O Engng Geol 1/28, N1/2, Feb 1990, P95-104 New Fenima on the Nigerian coast is built largely over reclaimed mangrove swamp and creeklets. Sand from the adjacent salt-water Monglobie Greek was placed hydraulically. The immediate marsh soil is high plasticity, dark brown organic silty clay. Adequate strength is mobilised in this soil on consolidation, but if it is overstressed, damage to surface structures is possible. Because of the relative impermeability of the clay, regional waterlogging after rainfall becomes a problem. Loss of nutrients during emplacement of the sand also reduces its ability to support vegetation. Requirements for planning and execution of reclamation projects are discussed.
905311 Unified approach to ground improvement by heavy tamping Lo, K W; Ooi, P L; Lee, S L J Geotech Engng Di~ ASCE Vl16, N3, March 1990, P514527 Mechanisms of ground improvement by heavy tamping are described: dynamic compaction (DC); dynamic replacement (DR); and dynamic replacement and mixing (DRM), whcrc the sand columns produced by DR are dispersed by claquage to form a subsurface sand blanket. On the basis of field trials on soils from granular to organic cohesive, a rational basis for procedure is proposed, incorporating initial conditions and operational parameters. Energy per blow, point spacing, and number of blows per point for a required degree of ground improvement can be specified.
905312 Vibroflotation method at sea bottom Qian, Z; Suen, W H; Suen, S B; Yuan, D J; Li, R K; Chang, S F Proc International Conference on Engineering Problems of Regional Soils, Bcijiug, 11-15 August 1988 P444-447. Publ Beijing: International Academic Publishers, 1989
Vibroflotation has been used onshore for many years, but its application to the sea bed is rare. Its use to improve a sea floor of sand over muddy loam and loam is described. Stone columns were installed from a ship in up to 29m of water using
Geological factors of importance in surface structures 905314 Urban geology: case study of Kuala Lumpur, Malaysia Tan, B K; Komoo, I Engng Geoi V28, NI/2, Feb 1990, P71-94 The Kuala Lumpur area is characterised by residual soils over limestone, granitic, quartzite and phyllite, and schist rocks. Geological maps are discussed. Mine tailings, municipal fills and the collapsed soil zone above limestone bedrock all show very poor engineering properties. Solution features in karstic limestone over pinnacled bedrock give rise to problems for deep foundations. Landslides are frequent in hilly areas and are related to geology and weathering of the rocks and soils. These influences are discussed with reference to case histories.
905315 Turkwel Hydropower Project near the Kenyan Rift Valley (East Africa) Antoine, P; Giraud, A; Huber, R; Lavedan, G; Moullard, P Y Engng Geol V28, NI/2, Feb 1990, P133-147 This scheme with a thin arch dam 155m high, 150m crest length is sited in the vicinity of the collapse zone of the great East Africa Rift. Geology of the site varies from metamorphic series to intrusive granite of Precambrian age. The geology and its development, lithology, and physical and mechanical properties are described. Major features of relevance to the project and its excavations are discussed.
905316 Typical landforms and slope stability of the Zngros Mountains along the Shiraz-Bonshire road in Southwestern Iran Rantucci, G Proc Symposium on Envirommental Geoteclmics and Problematic Soils a~! Rocks, Bangkok, December 1985 P321332. Pubi Rotterdam: d A Baikema, 1988 Optimisation of route and costs was made on the basis of aerial photo investigation, geology and tectonics, plus more detailed examination by seismic and drilling investigations.
© 1990 Pergamon Press plc. Reproduction not permitted