Calculation of stress distribution around a tunnel by using boundary punition element method and finite element method (in Chinese)

92A

EXCAVATIONS:TUNNELS

Requirements of the standard dynamic certificate for hydraulic structures are discussed. The documents corresponds to the generally accepted method of evaluating dynamic phenomena instructures. The enlarged algorithm for evaluating dynamic phenomena and the admissibility of parameters is summarized. Factors influencing the dynamic characteristics of structures are considered. The appendix to the certification also includes instructions on its completion and record keeping. (P.M.Taylor) 962358 Analysis of postbeckllng behavior of line pipe subjected to combined loads Zhilong Zhou & D. W. Murray, International Journal of Solids & Structures, 32(20), 1995, pp 3015-3036. A method is presented to incorporate the local buckling behavior of line pipe, determined from three-dimensionai large deformational elastic-plastic shell analysis, into an interactive soil-structure beam model of a pipeline. The finite element model for the analysis of the pipe as a shell is described and the influence on the results of the buckling analysis of various load combinations are examined from the point of view of buckling configurations, moment-curvature curves and eross-sectional deformations. A method of extracting the stiffness properties of the pipe from these analyses is then described and a technique for determining stiffness coefficients developed. (Authors) 962359 Steady-state vibrations of offshore structures T. Karna, Hydrotechnical Construction, 28(8), 1994, pp 446453; translated from: Fidrotekhnichestyre Stroitel'stvo, (8), 1994 pp 24-27. This paper addresses the structurai response to forces that arise when the ice floe fractures against a vertical structure. It describes a straightforward design procedure for the dynamic response of narrow structures. The applicability of simple design concepts is discussed in connection with the design problems of wide offshore structures. Reference is made to numerical models of dynamic ice-structure interaction that provide a promising design tool for both quasi-static and dynamic response of wide offshore structures. (Journal summary)

962360 A review of the probabillstie description of Morison wave loading and response of fixed offshore structures G. Najafian, R. Burrows & R. G. Tickell, Journal of Fluids & Structures, 9(6), 1995, pp 585-616. In reality offshore structures are exposed to random waveinduced forces in the ocean environment, and hence it is necessary to account for the randomness of the loading by establishing the probabilistic properties of the loading and the resulting responses. In this paper, progress made to date towards a systematic probabilistic analysis of fixed jackettype offshore structures will be reviewed. (from Authors)

EXCAVATIONS Geological factors 962361 Design against collapse of karat caverns T. M. Tharp, in: Karst geohazards: engineering and environmental problems in karat terrane. Proc. 5th conference, Gatlinburg 1995, ed B.F. Beck, (Balkema), 1995, pp 397-406. Load-displacement behavior for single beams may be modeled to ultimate failure with the cracked beam-column finite element program FEBRF. The modeling suggests that a drop in the water table will not precipitate immediate failure, but will cause failure over tens or hundreds of years. (from Author)

Stresses around openings 962362 Calculation of stress distribution around a tuouel by using boundary poaition element method and finite element method (in Chinese) Wang Yongyan, Journal - China Coal Society, 20(1), 1995, pp 78-82. Boundary punition element was introduced into a finite element equation to solve problems with complicated boundary conditions. In the initial period of tunnel excavation, a boundary spring element was set at the periphery of a tunnel. In the analysis a 2 dimension element is combined with the boundary punition element (spring element) to calculate stress distribution at the periphery of a tunnel. This method is simple. The caiculated data are close to the measured data, and accuracy is also high. (from English summary)

962363 Numerical simulation of the convergence of a boltsupported tunnel through a homogenization method D. Bernaud, P. De Buhan & S. Maghons, International Journal for Numerical & Analytical Methods in Geomechanics, 19(4), 1995, pp 267-288. Describes the numerical implementation of constitutive relationships previously developed for modelling the elastoplastic behaviour of bolted rockmass regarded as a homogenized anisotropic medium on the macroscopic scale. Attention is more particularly focused on the iterative algorithm involved in such a numerical method, which makes use of projection formulas onto the yield surface. (from Authors) 962364 Stress-strain condition around a cylinder expanding in the soft J. Mecsi, Periodica Polytechnica: Civil Engineering, 38(1), 1994, pp 67-84. The problem of expansion of an underground cylindrical cavity emerges in a number of geotechnicai problems, for example when the bearing capacity and load-settlement diagram of deep foundations are determined, pressuremeter tests are interpreted, or the tension-strain diagram of grouted soil anchors is calculated and so on. This paper presents a new method to calculate stress/displacement conditions around an expanding cylinder, and the pulling resistance of an axially loaded cylinder after its expansion. (from Author)

Tunnels 962365 Cork harbour sand ban forces Tarmac Walls ashore for backfill D. Fleming, New Civil Engineer (NCE), 1139, 1995, p8. The Cork Environmental Alliance (CEA) has stopped plans by joint venture contractor Tarmac Wails to use sand from Cork Harbour as backfill for its 67 M River Lee Tunnel. Permission to use the sand had been refused by the Irish governments' Department of the Marine because the area was a fish spawning ground. CEA's objections also included the increased coastal erosion mused by the removal of the sand. Alternative land-based quarry backfill would now be used. (P.M.Taylor)

962366 Late Lining ANON, New Civil Engineer (NCE), 1142, 1995, pp 28-29. Tunnelling work on the Highland water delivery tunnel for the Lesotho Highlands water project is described. Rock quality problems meant that the largest section of the 82 km transfer tunnel needed totally lining in concrete. The in-situ 300 mm thick unreinforced lining had to be completed within