Design of buried structures in squeezing rock in Toronto, Canada

1987 ◽  
Vol 24 (2) ◽  
pp. 232-241 ◽  
Author(s):  
K. Y. Lo ◽  
B. H. Cooke ◽  
D. D. Dunbar
Keyword(s):  
Laboratory Testing ◽  
Site Investigation ◽  
Horizontal Stress ◽  
Time Dependent ◽  
Buried Structures ◽  
Analysis And Design ◽  
Pumping Station ◽  
Time Interaction ◽  
Rock Structure ◽  
Squeezing Rock

The construction of the Domed Stadium in Toronto necessitated the relocation of the John Street Pumping Station and associated water supply tunnels for the downtown Toronto area. The proposed structures include tunnels, shafts, and a new pumping station built in or founded on rock. The shale rock of the Georgian Bay formation is known to possess high horizontal stresses and time-dependent deformation and at this site contains numerous horizontal fractures filled with clay seams. This paper presents the results of the site investigation, field and laboratory testing, analysis, and design for the buried structures. Special provisions for "rock squeeze" for different structures are also described. Key words: tunnels, shafts, shale, squeezing rock, horizontal stress, rock–structure–time interaction.

Design of tunnel lining in rock for long term time effects

1981 ◽  
Vol 18 (1) ◽  
pp. 24-39 ◽  
Author(s):  
K. Y. Lo ◽  
Clement M. K. Yuen
Keyword(s):  
Time Lapse ◽  
Time Dependent ◽  
Initial Stresses ◽  
Time Interaction ◽  
Underground Openings ◽  
Rock Structure ◽  
Rock Movement ◽  
Made In

Excavation of underground openings in rock relieves the in situ state of stresses, providing an initiating mechanism for time-dependent deformation in shaly rocks to occur. The construction of a permanent lining restrains the rock movement, resulting in an increase with time of pressure acting on the lining.Closed form solutions for this problem of rock structure – time interaction of circular tunnels have been developed, taking into account (a) the state of initial stresses, (b) the time-dependent properties of the lining as well as the rock, and (c) the time lapsed between excavation and lining. Expressions for lining pressures, stresses, thrusts, and moments are given for both "no slip" and "full slip" interface conditions.The effects of material parameters, lining flexibilities, and time lapse on quantities of engineering interest are studied and their implications on design illustrated.The results of analysis are compared with the field observations made in three tunnels. It is shown that the theoretical results are consistent with the observed extent and location of cracking in these tunnels.It is suggested that the methods proposed may be used for design considerations of permanent linings of tunnels in rock exhibiting significant time-dependent deformation.

Nonlinear Vibration Behaviors of Composite Laminated Plates with Time-Dependent Base Excitation and Boundary Conditions

2017 ◽  
Vol 18 (2) ◽  
Author(s):  
Yu-Yang Chai ◽  
Feng-Ming Li ◽  
Zhi-Guang Song
Keyword(s):  
Boundary Conditions ◽  
Theoretical Method ◽  
Laminated Plates ◽  
Time Dependent ◽  
Laminated Plate ◽  
Base Excitation ◽  
Analysis And Design ◽  
Composite Laminated Plate ◽  
Composite Laminated Plates ◽  
Frequency Relationship

AbstractThe nonlinear vibrations of composite laminated plates with time-dependent base excitation and boundary conditions are investigated. According to the von Kármán nonlinear plate theory, the dynamic equations of motion of the laminated plates are established. The nonlinear partial differential equations are transformed to the nonlinear ordinary differential ones using the Bubnov-Galerkin’s  method. The primary resonance and the primary parametric resonance of the laminated plate with time-dependent boundary conditions are investigated by means of the method of multiple scales. The validity of the present theoretical method is verified by comparing the amplitude–frequency relationship curves acquired from the present theoretical method with those calculated from the numerical simulation. The amplitude–frequency characteristic curves and the displacement time histories for different ply angles of the composite laminated plate are analyzed. The effects of the viscous damping factor and the transverse displacement excitation on the amplitude–frequency relationship curves are also studied. The present results are helpful for the nonlinear dynamical analysis and design of the composite laminated plate with time-dependent boundary conditions.

scholarly journals Probabilistic Space- and Time-Interaction Modeling of Mainshock Earthquake Rupture Occurrence

2020 ◽  
Author(s):  
Luis Ceferino ◽  
Anne Kiremidjian ◽  
Gregory Deierlein
Keyword(s):  
Seismic Hazard ◽  
Probabilistic Models ◽  
Spatial Interaction ◽  
Information Criterion ◽  
Passage Time ◽  
Time Dependent ◽  
Attractive Alternative ◽  
Earthquake Rupture ◽  
Time Interaction ◽  
Seismic Moment Release

ABSTRACT This article presents a probabilistic formulation for modeling earthquake rupture processes of mainshocks. A correlated multivariate Bernoulli distribution is used to model rupture occurrence. The model captures time interaction through the use of Brownian passage-time distributions to assess rupture interarrival in multiple sections of the fault, and it also considers spatial interaction through the use of spatial correlograms. The correlograms represents the effect of rupture nucleation and propagation. This model is proposed as an attractive alternative to existing probabilistic models because it (1) incorporates time and space interactions of mainshocks, (2) preserves the marginal distributions of interarrival times after including spatial rupture interactions, that is, model consistency, and (3) has an implicit physical interpretation aligned with rupture behavior observations. The proposed model is applied to assess the occurrence of large interface earthquakes in the subduction fault along the coast of Lima, Peru. The model matches well both the annual magnitude exceedance rates and the average seismic moment release in the tectonic region. The Akaike information criterion (AIC) test confirms that our model performs statistically better than models that do not capture earthquake space interactions. AIC also shows that the spherical correlogram outperforms the exponential correlogram at reproducing earthquake data. Finally, time-dependent seismic hazard in the region is calculated, and the results demonstrate that by accounting for recent earthquake occurrences, the inclusion of time-dependent effects can reduce the 30 yr seismic hazard by a factor of 4.

Measured and predicted time-dependent stress-strain behaviour of Hong Kong marine deposits

1999 ◽  
Vol 36 (4) ◽  
pp. 760-766 ◽  
Author(s):  
Jian-Hua Yin ◽  
Jun-Gao Zhu
Keyword(s):  
Hong Kong ◽  
Technical Note ◽  
Time Dependent ◽  
Practical Significance ◽  
Stress Strain ◽  
Analysis And Design ◽  
Marine Deposits ◽  
Modelling Framework ◽  
Strain Behaviour ◽  
Dependent Behaviour

Hong Kong marine deposits (HKMD) are considered to be difficult (or weak) soils for civil projects because of low shear strength and time-dependent high compressibility. Understanding and modelling the time-dependent stress-strain behaviour of HKMD are of practical significance in the analysis and design of civil structures on and in HKMD. In this technical note, test data on the time-dependent behaviour of a remoulded HKMD are presented and analysed. An existing elastic viscoplastic (EVP) modelling framework is used to describe the time-dependent stress-strain behaviour of HKMD. The modelling results are compared with the measured results.Key words: stress-strain, time dependent, creep, viscoplastic, triaxial, soil.

Alkali-aggregate reactivity in Newfoundland, Canada

2000 ◽  
Vol 27 (2) ◽  
pp. 192-203 ◽  
Author(s):  
D Bragg
Keyword(s):  
Laboratory Testing ◽  
Laboratory Tests ◽  
Construction Material ◽  
Concrete Structures ◽  
Site Investigation ◽  
Field Work ◽  
Concrete Core ◽  
Rock Types ◽  
Petrographic Examination ◽  
Alkali Aggregate Reactivity

Alkali-aggregate reactivity is a chemical reaction that occurs in some concrete structures. This reaction causes expansion and cracking of concrete. It may not be the main cause of premature deterioration; however, it is often the catalyst for other forms of deterioration. Since 1989, field work and laboratory testing for alkali-reactivity has been undertaken on selected aggregate, rock, and concrete core samples throughout Newfoundland. The field work and laboratory tests consisted of an assessment of the bedrock and aggregate sites to determine their quality and quantity for use as construction material; an examination of existing concrete structures to assess their durability with regard to alkali-aggregate reactivity. The site investigation of the concrete structures consisted of noting their date of construction, the rock and aggregate types used, the types of cracking, and the degree and type of deterioration of each structure. Results from laboratory testing, petrographic examination, and visual observation show that certain sedimentary, igneous, and metamorphic rock types may be potentially alkali-reactive, but the reaction may not always be deleterious to the concrete structure.Key words: alkali-aggregate reaction, concrete structures, laboratory tests, petrographic examination, rock types.

scholarly journals STRENGTH AND DEFORMABILITY OF SPECIFIC SEDIMENTARY AND OPHIOLITHIC ROCKS

2017 ◽  
Vol 43 (3) ◽  
pp. 1259 ◽  
Author(s):  
P. V Marinos ◽  
G. Tsiambaos
Keyword(s):  
Rock Mass ◽  
Laboratory Testing ◽  
Sedimentary Rocks ◽  
Site Investigation ◽  
Basic Component ◽  
Sufficient Data ◽  
Modulus Ratio ◽  
Characteristic Values ◽  
Rock Mass Deformability ◽  
Typical Range

The paper deals with the evaluation of strength and deformability of sedimentary rocks and ophiolites based on the processing of laboratory testing results. Characteristic values and their typical range for the parameters σci, Ei , as well as the Modulus Ratio (MR) are presented. These parameters are significant for the estimation of the strength and deformability of the rock mass since σci is basic component for the solution of Hoek-Brown failure criterion and Ei and MR are important components of the latest rock mass deformability expression (Hoek-Diedrichs, 2006). The recent site investigation and laboratory work undergone for the design of numerous tunnels in the Greek territory provided very good and sufficient data, derived from a specifically established database, for the estimation of strength and deformability of specific rocks. These rocks are sandstones and siltstones of flysch and molassic formations, as well as limestones and ophiolites.

Impact Mitigation for Buried Structures: Demolition of the New Haven Veterans Memorial Coliseum

2007 ◽  
Author(s):  
Pawel Woelke ◽  
Margaret Tang ◽  
Scott McClennan ◽  
Najib Abboud ◽  
Darren Tennant ◽  
...  
Keyword(s):  
Impact Loading ◽  
Field Testing ◽  
Hazard Evaluation ◽  
New Haven ◽  
Buried Structures ◽  
Analysis And Design ◽  
Numerical Investigations ◽  
Impact Mitigation ◽  
Underground Utilities

We present an overview of the analysis and design of mitigation schemes for buried structures subjected to impact loading, with a focus on the hazard evaluation to underground utilities from the demolition by implosion of the Veterans Memorial Coliseum in New Haven, CT, due to implosion. We discuss analytical and numerical investigations validated by field testing conducted prior to the implosion and leading to the design of the mitigation schemes aimed at protecting the utilities buried under the roadway. The mitigation schemes were successful during the January 2007 implosion of the Veterans Memorial Coliseum.

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