126A 912503 Ground vibration caused by construction works New, B N Tunnlg Underground Space Technol V5, N3. 1990, P179-190 Construction related vibration is temporary but nevertheless a problem. Current damage and nuisance criteria are reviewed. Geotechnical factors affecting input and propagation of ground vibration are described. Prediction of vibration from blasting and non-blasting vibration sources is examined. Measurement procedures and equipment for blasting trials, general and site specific scaling factors, and contractual specifications and vibration control are discussed. 912504 Blast loading of buried structures Shin, C J; Hon-Yim Ko; Sture, S
Proc 3rd International Symposium on Numerical Models in Geomechanics (NUMOG !!!), Niagara Falls, 8-11 May 1989 P340-348. Publ London: Elsevier Applied Science, 1989 The dynamic finite element program SAMSON-2 was used to model free field stress wave propagation through soils and the resulting response of a shallow buried pipe. Various constitutive models were used to represent the soil and the concrete pipe. Results are compared to those from scale model tests using the University of Colorado geotechnical centrifuge, with a specially developed impact generator and dynamic strain gauges. Accuracy of the numerical solution is discussed.
Subjects Peripheral Geomechanics
912505 Elasto-plastic constitutive modeling of plain concrete and an optimization procedure for parameter evaluation Najjar, Y M; Zaman, M M; Faruque, M O
Comput Geotech V9. N3. 1990, P185-208 The model presented uses a single yield surface to describe both yielding and failure behaviour. Transition between contraction and dilatancy is identified by the point on the yield surface where the gradient tensor becomes deviatoric. The model effectively describes hardening, stress path dependency, and variation of shear stress with orientation of the stress path on the octohedral plane. An optimisation procedure is developed to evaluate the model constants. Predictions from the model are in good agreement with experimental data.
9 ! 2507 Discussion of recent work to develop a more realistic pressurearea model for ice Winkler, M M: Dorris, J F Proc 9th International Conference on Offshore Mechanics and Arctic Engineering, Houston, 18-23 February 1990 V4. P231235. Publ New York. ASME. 1990 Development of a realistic constitutive model for ice is needed to provide better understanding of previously obtained laboratory and field test results and to allow the efficient design of future arctic offshore structures. Recently developed arguments showing the feasibility of using the finite element approach to evaluate such tests are summarized. An overview is presented on the development of a crushing model for ice, which is expected to provide an accurate solution for small areas and an upper bound for large areas, ~here other modes of failure may occur. 912508 Confined compressive test on multi-layer sea-ice Yue, Q J; Li, H S; Shen, W; Zhang, T Proc 9th International Conference on Offshore Mechanics and
Arctic Engineering, Houston, 18-23 February 1990 V4. P237240. Publ New York: ASME, 1990 The formation process and the structure of multi-layer ice observed during the ice survey are presented. A series of confined compression tests was performed under the same temperature and loading rate but different initial confining pressures. This allows wider distribution of test points along the yield envelope and more reasonable describtion of yield function using the least squares curve fit method. The results show that the multi-layer ice behaves differently to columnar ice. 912509 Pressuremeter creep tests in spray ice Shields, D H; Domschuk, L; Funegard, E G; Azizi, F Proc 12th International Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, 13-18 August 1989
VI. P313-317. Publ Rotterdam." A A Balkema. 1989 Spray ice, formed by pumping seawater into the Arctic air, can be used to construct artificial islands for use in petroleum exploration. In situ tests have been carried out for the Mars island off Alaska. Application of the results of pressuremeter tests lasting only a few hours to prediction of subsequent island creep settlement is examined. An empirical relation between pressuremeter creep rate and island settlement appears to work well, suggesting steady state creep of spray ice can be predicted by the pressuremeter test.
Snow and ice mechanics 912506 Failure stress and failure modulus of natural ice island ice under uniaxial compression at constant strain rates Jeffries. M O; Sinha, N K; Sackinger, W M Proc 9th International Conference on Offshore Mechanics and Arctic Engineering, Houston, 18-23 February 1990 114, P223-
229. Publ New York: ASME. 1990 The most massive ice features in the Arctic Ocean are the natural ice islands or icebergs which occasionally break off the ice shelves. The first results and initial data analysis of uniaxial compression tests on natural island ice at constant strain rates are presented. The time and strain rate dependence of the failure stress and failure modulus are qualitatively similar to those of other ice types. The failure stress and failure modulus display only weak dependence on physical properties.
912510 Relationship between petrographic image analysis data and fracture toughness Ferm, J B: Ehrlich, R; Kranz, R L; Park, W C
Bull Assoc Engng Geol V27. N3. Aug 1990. P327-339 Quantitative image analysis procedures were applied to 14 thin sections of sandstones from 5 sources, for which fracture toughnesses were known. The samples were subdivided into 2 groups by petrographic classification. For group I (quartzarenites with point grain contacts) a strong relation was seen between fracture toughness and optical porosity, a better one using the parameter perimeter area of interstitial material (Non Grain Area). For group II, where porosity does not contribute significantly to NGA, a strong relation was seen with measurements of the perimeter of the interstitial material.
~ 1991 Pergamon Press plc. Reproduction not permitted