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914410 Studies of failure mechanisms and design methods for geotextile reinforced soil walls Krieger, J; Thamm, B R Geotext Geomem VIO, NI, 1991, P53-63 The Federal Highway Research Institute of Germany has carried out a series of tensile and shear box tests on reinforced earth using a range of geotextiles. Wrapped wall structures reinforced with woven geotextiles were erected for pre-test and calibration purpose of instruments and for measuring the strains in the reinforcement during construction and as the wall was loaded to failure. Limit equilibrium analysis based on wedges allows reasonable description of failure observed.
914414 Limehouse Link: two cut-and-cover techniques Darling, P Tunn Tunnlg V23, NI, Jan 1991, P16-18 The 1.8km Limehouse Link in London's Docklands development area will use two construction techniques. Across the water filled Limehouse Basin in the central section, conventional bottom-up construction between sheet pile cofferdams is specified. The remaining sections will use top-down excavation, chosen to allow 24 hour working without violating noise restrictions once the top slab is installed. Dewatering of the Woolwich, Reading, and Thanet beds will be necessary once excavation below the top slab has started. Advantages and disadvantages of the two methods are compared.
Groundwater problems 914411 Finite element modelling of a strutted excavation Lee, F H; Yong, K Y; Lee, S L: Toh, C T Proc 3rd International Symposium on Numerical Models in Geomechanics (NUz~IOG 1II), Niagara Falls, 8-11 May 1989 P577-584. Publ London: Elsevier Applied Science. 1989 The finite element code CRISP is used to model the construction of a deep strutted excavation in marine clay. Output is compared to measurements from a strutted sheet pile excavation. Predicted lateral wall displacement profile is similar in trend to that observed. The analyses underpredict maximum wall displacement and strut loads and overpredict toe movement and base heave. Influence of soil. strut, and sheet pile properties on computed results is examined.
914412 Excavation in cohesive soils: modelling the effects of creep on long-term performance Borja, R J; Lee, S R; Seed, R B Proc 3rd International Symposium on Numerical Models in Geomechanics (NUMOG 111), Niagara Fails, 8-11 May 1989 P585-592. Puhl London: Elsevier Applied Science, 1989 A numerical procedure for modelling excavation in cohesive soils is presented. It uses the excavation algorithm of Borja, Lee, and Seed (1988) and an extended three dimensional Cam Clay constitutive model. It enables accurate simulation of the construction sequence and time dependent behaviour of the soil, and is theoretically correct and analytically efficient. It is demonstrated using the case of a deep strutted excavation in Boston Blue Clay.
Construction methods 914413 Luxury liner Ground Engng V23. NIO. Dec 1990. P14-16 Construction of a natural/synthetic liner for a sand extraction pit to be used for landfill is described, lm of compacted London Clay forms the liner base. Leachate collection is in HDPE drains. This is followed by a HDPE membrane, which is extended upwards on the pit wall as waste disposal continues. Care was taken in ensuring uniformity of the clay, which was sourced from one site and characterised before placement and compaction. Leachate and gas monitoring systems are specified.
See also: 914153 914415 Utilization of clogging in geotextiles for sealing of earthworks Ruckert, H; Uhlig, T; Kruse, G; Zschernitz, P Geotext Geomem VIO, NI, 1991, P103-113 Clogging may be undesirable in well filters, but is advantageous where geotextiles are used to seal earthworks. Using the analysis of clogging of slack rock as a basis, conditions necessary to achieve clogging of a geotextile were evaluated in the laboratory. Different constructions and soil-water mixtures were used. Where clogging occurs, cost savings are possible when compared to sealed geomembranes. Other applications for the self-sealing membrane include cases where periodic or only partial sealing are necessary. A large scale application of the self-sealing geotextile to river bed grouting is planned.
Influence of dynamic loads See a~o: 914017, 914225 914416
Numerical simulation of pile driving: the BRUTUS computer code (In French) Lepert, P; Meignen, D Bull Liaison Labs Ponts Chaussees N169, Sept-Oct 1990, P512 A dynamic analysis of pile driving, using the method of characteristics for numerical integration of the equations of motion, forms the basis of the program BRUTUS. It can be used to process dynamic measurements made during pile driving, either to check bearing capacity predictions or assess driveability. The mathematical and numerical background are discussed, and a flowchart of the program illustrated. Its application to interpret measurements made during driving of a precast concrete pile is presented. 914417 Dynamic pile-soU-pile interaction. Part I: analysis of axial vibration Gazetas, G; Makris, N Earthq Engng Struct Dynam V20, N2, Feb 1991,-P115-132 Simple methods for analysis of dynamic steady state axial response of floating pile groups are developed. Physically motivated approximations are introduced to account for the interaction between individual piles. This interaction arises largely from interference of wave fields originating along the shafts of the piles. In homogeneous deposits, the wave fronts are essentially cylindrical and interaction is independent of pile
O 1991 Pergamon Press plc. Reproduction not permitted RMMS 21 4.--K