rocky path for revelstoke hydro : new civ engr, n507, sept 1982, p30–37

1
50A 8321~I 8321~2 8321;~3 8321Ld~ 8321~5 ROCKY PATH FOR REVELSTOKE HYDRO New Civ Engr, N507, Sept 1982, P30-37 A case study of the construction of a gravity dam and embankment dam as part of the Revelstoke hydroelectric power complex, Canada. Several delays occurred, including 2 rock slides, due to bad rock conditions (folded and warped yotung metamorphic rocks with manY shear planes and heavily fractured in places). MOTOR~AY SLIP REPORT "WARNS 'GO EASY' WITH CLAY EMBAN~2~ENTS Byrd, T New Civ Engr, N516, II Nov 1982, P18-20 A final report on the M25 embankment failure concl~ded that: (i) The existing ground was fissured and, at the time of loading, satiated with rain. High water pressure, induced by loading and non-free drainage, then led to progressive loss of strength. (2) A loss of strength due to softening of the clay fill because of non-free drainage also occurred. (3) The London clay used on the embankment with its low or negative pore pressures would have absorbed water from the drainage blanket. Shear straining during loading would then have resulted in softening of the clay. (4) Cracking, emanating from the embankment base, and pro- gressive failure also contributed to the collapse. GRIMSBY'S WASTING SEWERS ARE REVIVED Beckett, D; Barrett, A; Jarvls, W Consult Engr, V~6, N10, Oct 1982, P14-15 A case study of the construction of 3 circular cofferdams, with sheet pile walls and reinforced concrete walings, for the Grimsby and Cleethca~pe's sewerage system is presented. Borehole investi- gations revealed chalk overlain by layers of glacial till and a soft alluvium. Finite element analysis of the sheet pile walls was used to establish loadings on the walings. After driving of the sheet piles the construction was monitored to assess whether soll pressure vas being fully mobilised. TWO PRACTICAL EXAMPLES OF NUMERICAL APFROACHES FOE SOLVINS DISCONTINUITY FROBL~MS IN DAM DESIGN Souza Lima, V; Abrahao, R A Int J NumAnal Meth Geomech, V6, N~, Oct- Dee 1982, ~61-481 Some basic concepts for use in n12nerieal analy- sis of discontinuity problems are first dis- cussed: safety factors, partial safety factors (a sm~i-probabilistic approach), constitutive laws and finite element modelling of Joints. Two case studies are then presented to illust- rate the use of numerical analyses for dams with discontinuity problems: the Agua Vermelha dam, Brazil, containing a major Joint in its foumdation, and the Itaipu dam, Brazil, with marO~ discontinuities between lava flows, @~eatly reducing the strength and stiffness of the rock mass. CONVENYIONAL AND PROBABILISTIC ~MBA~ DESIGN McGuffey, V; Grivas, D; Ic~i, J J Geotech Engng Div ASCE, VI08, NGT10, Oct 1982, P12~6-1254 The safety of a proposed highway embar~ent is evmluated both conventionally and probabilisti- cally. Results from tests on undisturbed soll samples, are statistically analyzed and presen- ted. The factor of safety is introduced <s ~ random variable whose variability is due exclu- sively to the variability of the shear strength of the foundation material. Failure is defined as the event whereby the factor of s~fety (com- puted at end-of-construction) receives v~lues smaller than or, at most, equal to unity, q~ne probability of failure is defined as the prob- ability of the occurrence of this event. From the three models (normal, bet~, znd lognorm::l) considered for the distribution of the fzctor of safety, the normal always provides the l~nrgest, and ~e lognormal the smallest wolues for the probability of failure of the e:r~ank~ent. This difference in the results decreases zs the hcight or angle of the embankment increases. Results obtained using the beta model ~e presented in a nomograph relating embankment height and slope angle to probability of failure. 832146 PHASE 2 INSPECTION OF LAKE M~AT~ DL$~ Carrier, W D; Keshian, B; Bromwell, L G J GeOtech EngngDiv ASCE, VI08, NGTI0, Oct 1982, P1273-!287 Phase i of an inspection of Lake Manatee Dam, Florida, USA, had revealed 2 potential problems: dam overtopping due to inadequate spillway cap- aclty, and slope instability due to inadequate seepage control. As a result of this, an ex- tensive investigation (Fhase 2) of the dam w~s carried out: seepage analysis, slope stabi- lity analysis of the embankment, and spillway stability analysis. The investigation indicated that the embamkment had a satisfactory safety factor against slope failure and the concrete spillway a satisfactory safety factor against cwerturning. Construction of a new toe drain and an emergency spillway was also recomnended. 8321~? OLD NSW DAM IS STRENGTHENED Arbouw, J J Inst Engr Australia, V~4, hq7, 3 Sept 1982 , P18-19 A case stilly of the strengthening of the Chich- ester Dam, Australia, a concrete gravity dam structure which depends on its own weight for stability. This involves anchoring the dam to the bedrock using grouted steel tendons in a bid to combat uplift pressures. 832148 PORE PRESSURE MEASUREMENTS IN THE CORE OF CHYVOR DAM Amay~, F; Cubillos, A; Sierra, J ~ Proc 10th International Conference on Soil Mechanics and Foundation Engineering, Stockholm, 15-!9 June 1981, V1, P19-29. Publ Rotterdam: A. A. Balkema, 1981 Chivar (Esmeralda) dam, 237m high, located in Colombia, South America, is of the rockfill earth core type. Pne%mmtic piezometers were installed in the core of the dam to record pore pressure fluctuations within the core during the period of construction of the dam, the first filling of the reservoir and subsequent drawdowns and fillings of the reservoir. A description of the dam ard characteristics of the core material is presented as well as data registered in several of the plezometers. Pore pressures are evaluated and a comparison is made between actual pore pressures and those derived from a theoretical flow net. }I~,~mulic grad~er~ts thr*ut~ il.e core have been computed and their values are pre~e~t:6 amd discussed.

Post on 21-Jun-2016

218 views

Category:

Documents


0 download

TRANSCRIPT

Page 1: Rocky path for revelstoke hydro : New Civ Engr, N507, Sept 1982, P30–37

50A

8321~I

8321~2

8321;~3

8321Ld~

8321~5

ROCKY PATH FOR REVELSTOKE HYDRO New Civ Engr, N507, Sept 1982, P30-37

A case study of the construction of a gravity dam and embankment dam as part of the Revelstoke hydroelectric power complex, Canada. Several delays occurred, including 2 rock slides, due to bad rock conditions (folded and warped yotung metamorphic rocks with manY shear planes and heavily fractured in places).

MOTOR~AY SLIP REPORT "WARNS 'GO EASY' WITH CLAY EMBAN~2~ENTS

Byrd, T New Civ Engr, N516, II Nov 1982, P18-20

A final report on the M25 embankment failure concl~ded that: (i) The existing ground was fissured and, at the time of loading, satiated with rain. High water pressure, induced by loading and non-free drainage, then led to progressive loss of strength. (2) A loss of strength due to softening of the clay fill because of non-free drainage also occurred. (3) The London clay used on the embankment with its low or negative pore pressures would have absorbed water from the drainage blanket. Shear straining during loading would then have resulted in softening of the clay. (4) Cracking, emanating from the embankment base, and pro- gressive failure also contributed to the collapse.

GRIMSBY'S WASTING SEWERS ARE REVIVED Beckett, D; Barrett, A; Jarvls, W Consult Engr, V~6, N10, Oct 1982, P14-15

A case study of the construction of 3 circular cofferdams, with sheet pile walls and reinforced concrete walings, for the Grimsby and Cleethca~pe's sewerage system is presented. Borehole investi- gations revealed chalk overlain by layers of glacial till and a soft alluvium. Finite element analysis of the sheet pile walls was used to establish loadings on the walings. After driving of the sheet piles the construction was monitored to assess whether soll pressure vas being fully mobilised.

TWO PRACTICAL EXAMPLES OF NUMERICAL APFROACHES FOE SOLVINS DISCONTINUITY FROBL~MS IN DAM DESIGN

Souza Lima, V; Abrahao, R A Int J NumAnal Meth Geomech, V6, N~, Oct-

Dee 1982, ~61-481

Some basic concepts for use in n12nerieal analy- sis of discontinuity problems are first dis- cussed: safety factors, partial safety factors (a sm~i-probabilistic approach), constitutive laws and finite element modelling of Joints. Two case studies are then presented to illust- rate the use of numerical analyses for dams with discontinuity problems: the Agua Vermelha dam, Brazil, containing a major Joint in its foumdation, and the Itaipu dam, Brazil, with marO ~ discontinuities between lava flows, @~eatly reducing the strength and stiffness of the rock mass.

CONVENYIONAL AND PROBABILISTIC ~MBA~ DESIGN McGuffey, V; Grivas, D; Ic~i, J J Geotech Engng Div ASCE, VI08, NGT10, Oct

1982, P12~6-1254

The safety of a proposed highway embar~ent is evmluated both conventionally and probabilisti- cally. Results from tests on undisturbed soll samples, are statistically analyzed and presen-

ted. The factor of safety is introduced <s ~ random variable whose variability is due exclu- sively to the variability of the shear strength of the foundation material. Failure is defined as the event whereby the factor of s~fety (com- puted at end-of-construction) receives v~lues smaller than or, at most, equal to unity, q~ne probability of failure is defined as the prob- ability of the occurrence of this event. From the three models (normal, bet~, znd lognorm::l) considered for the distribution of the fzctor of safety, the normal always provides the l~nrgest, and ~e lognormal the smallest wolues for the probability of failure of the e:r~ank~ent. This difference in the results decreases zs the hcight or angle of the embankment increases. Results obtained using the beta model ~e presented in a nomograph relating embankment height and slope angle to probability of failure.

832146 PHASE 2 INSPECTION OF LAKE M~AT~ DL$~ Carrier, W D; Keshian, B; Bromwell, L G J GeOtech EngngDiv ASCE, VI08, NGTI0, Oct

1982, P1273-!287

Phase i of an inspection of Lake Manatee Dam, Florida, USA, had revealed 2 potential problems: dam overtopping due to inadequate spillway cap- aclty, and slope instability due to inadequate seepage control. As a result of this, an ex- tensive investigation (Fhase 2) of the dam w~s carried out: seepage analysis, slope stabi- lity analysis of the embankment, and spillway stability analysis. The investigation indicated that the embamkment had a satisfactory safety factor against slope failure and the concrete spillway a satisfactory safety factor against cwerturning. Construction of a new toe drain and an emergency spillway was also recomnended.

8321~? OLD NSW DAM IS STRENGTHENED Arbouw, J J Inst Engr Australia, V~4, hq7, 3 Sept 1982 ,

P18-19

A case stilly of the strengthening of the Chich- ester Dam, Australia, a concrete gravity dam structure which depends on its own weight for stability. This involves anchoring the dam to the bedrock using grouted steel tendons in a bid to combat uplift pressures.

832148 PORE PRESSURE MEASUREMENTS IN THE CORE OF CHYVOR DAM

Amay~, F; Cubillos, A; Sierra, J ~ Proc 10th International Conference on Soil

Mechanics and Foundation Engineering, Stockholm, 15-!9 June 1981, V1, P19-29. Publ Rotterdam: A. A. Balkema, 1981

Chivar (Esmeralda) dam, 237m high, located in Colombia, South America, is of the rockfill earth core type. Pne%mmtic piezometers were installed in the core of the dam to record pore pressure fluctuations within the core during the period of construction of the dam, the first filling of the reservoir and subsequent drawdowns and fillings of the reservoir. A description of the dam ard characteristics of the core material is presented as well as data registered in several of the plezometers. Pore pressures are evaluated and a comparison is made between actual pore pressures and those derived from a theoretical flow net. }I~,~mulic grad~er~ts thr*ut~ il.e core have been computed and their values are pre~e~t:6 amd discussed.