The aqueous morphology and slope processes in a fjord delta, Bella Coola, British Columbia

The aqueous morphology and slope processes in a fjord delta, Bella Coola, British Columbia

255A 876315 Subaqneous morphoio~" and slope processes in a qord delta, Bella Coola, British Columbia Kostaschuk, R A: McCann, S B Can J Earth Sci V24,...

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255A 876315 Subaqneous morphoio~" and slope processes in a qord delta, Bella Coola, British Columbia Kostaschuk, R A: McCann, S B Can J Earth Sci V24, N1, Jan 1987. P52-59 Site investigation of the Bella Coola delta delineated a proximal sandy delta front, up to 3km offshore, depths to 275m, slope 2.2-15 deg, and a distal silt-clay delta, 3-15km offshore. depths to 550m, slope 0.5-2.2 deg. Large chutes, succeeded downstream by depositional zones, characterise the delta front. Deep seated rotational slides occur in the proximal part of the prodelta, indicating that the delta front and prodelta are separate, but related, mass movement systems. 876316 Ratio of factors of safety in slope stability analyses. Technical note

Cavoundis, S Geotechnique V37. N2, June 1987, P207-210 The ratios of safety factors obtained in two- and three dimensional slope stability analyses are examined. It is demonstrated mathematically that, for limit equilibrium analysis, the ratio of minimum value of three dimensional safety factor to two dimensional safety factor must always be equal to or greater than unity. 876317 Kinematic modelling machine for rock slope studies. Short contribution Teme, S C Int J i~tin Geol Engng V5, N1, March 1987. P75-81 The base-friction table is a simple, inexpensive apparatus which can be used to demonstrate and simulate the behaviour patterns in blocky rock slopes during excavation. The inclinable base-friction apparatus described can, in addition, be used to represent the various dip angles at prototype sites. 876318 Rheologic properties and kinematics of emplacement of the Chaos Jumbles rockfall avalanche, Lassen Volcanic National Park, California Eppler, D B; Fink, J; Fletcher, R J Geophys Res V92, NB5, 10 April 1987, P3623-3633 Potential hazards due to future movements from the Chaos Crags have been investigated. The deposit distribution, morpholo~, and fabric from previous events were examined, and a model of the behaviour of moving debris and an estimate of travel distance for future movements are derived. Results suggest that the rheologic properties of these mass movements during the final stages of emplacement resemble those of a psuedoplastic material with a finite yield strength. 876319 Viscous analysis of submarine flows Edgers, L; Karlsrud, K Norw Geotech Inst Publ N166, Dec 1986, 9P A theoretical viscous flow model is applied to rapidly moving submarine slides for which velocity measurements are available. The possibility that viscous flow may account for large runout distances and high flow velocities observed is examined. Limited data on soil parameters for engineering analysis of viscous flows are also obtained. Viscous flow analysis of some surface quick clay slides is also presented, to widen the database from which viscosity of soil flows can be estimated.

876320 Computer aided analysis of rock slope stability Leung, C F; Kheok, S C Rock Mech Rock Engng V20. N2. April-June 1987, Pl11-122 A computer program, which will run on microcomputers, is presented for the kinematic analysis of rock slope stability. It can handle wedge and plane sliding and toppling failures. Examples of its application to open pit mine excavations and highway cuts are shown. Computer output is in the form of tables and diagrams for ease of application. The accuracy of the output was confirmed by the use of stereographic plots.

876321 Accelerating creep of the slopes of a coal mine Cruden, D M; Masoumzadeh, S Rock Mech Rock Engng V20, N2, April-June I9~'7, P123-135 Four creep laws were tested by linear regression analysis of the 249 day long record of accelerating creep of a slope at an open pit coal mine. The Saito and Zavodni and Broadbent laws were unsatisfactory. The generalised Saito law gave an upper limit of time to failure of 168 days after actual failure. Using two new models employing power and exponential laws, a critical slide velocity as an indication of impending failure was predicted. Three acceleration stages were identified and threshold values to mark the initiation of the second and third stages calculated.

876322 Field investigations on seasonal variations of the groundwater level and pore water pressure in landslide areas Ogawa, S; Ikeda, T; Kamei, T; Wada, T Soils Found V27, N1, March 1987, P50-60 Five years of field data from a landslide area in Japan have been analysed. Seasonal changes in groundwater level and pore pressures are related to climatic events, with a time lag of about two weeks. Pore pressures at landslide slip surfaces do not always coincide with those calculated from groundwater level, and, when considering slope stability, measurements made at the slip surface should be used. Stability analyses should use shear strengths allowing for the effects of increased pore pressure.

876323 Use of probabilistic stability analysis and cautious blast design for an urban excavation McCracken, A; Jones, G A In: Rock Engineering and Excavation in an Urban Environment (papers to the conference, Hong Kong, 24-27 February 1986) P231-240. Publ London: IMM, 1986 The case of a large city hospital, sited in a disused quartzite quarry, with the quarry wall retained as a natural feature, is described. Rock mass geology, strength, jointing and joint properties were surveyed. Probabilistic stability analysis was used to quantify the risk of failure,and showed it to be favourable in terms of the function of the excavation. The BLASTS program designed an acceptable cautious blast to minimise rock mass damage and maintain stability. The overall program ensured a high level of confidence regarding successful implementation of the project.

© 1987 Pergamon Journals Ltd. Reproduction not permitted