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Ground failure around buried tubes
lllA 883051 Ground failure aromd buried tubes Moore, I D; Booker, J R
Rock Mock Rack Fatgng V20, N4, Oct-Dec 1987, P243-260 The static response of circular tubes inserted into prestressed elastic-plastic ground is examined. A closed form solution determines the hoop forces in uniformly prestressed ground and finite element analysis is used to study biaxial field stress. Stress contours are constructed to estimate the influence of ground failure around tubes with biaxial prestress.
883052 Seimnic and strain studies on large laboratory rock samples being strmed to f a U m Spetzler, H; Sondergeld, C; Sobolev, G; Salov, B
Tectonophysics V144, N1-3, Dec 1987, P55-68 Large granite and basalt samples were cyclically loaded to failure. Strain and ultrasonic velocity measurements were made and acoustic emission recorded. Several zones of acoustic emission sources were identified. The Kaiser effect appears to hold to about one half of stress to failure. As failure approaches, individual acoustic emission events become more energetic and relatively more power is recorded at lower frequencies. Results indicate large variations in dilatancy in the samples. Results are consistent with those from smaller specimens.
Textures of sheared halite and their implications for the seimaoge~ -lip of deep faults Hiraga, H; Shimamoto, T
Tectomopkysics V144, N1-3, Dec 1987, P69-86 Unstable fault motion has been associated with strain localization within shear zones. Work to clarify the nature of this heterogeneous deformation is reported. Triaxial tests were carfled out on dry cylindrical sandstone specimens containing a 0.5ram layer of halite along a 35 deg precut, at rqom temperature, strain rate 3-300 microns/see, and confining pressures to 200MPa. Heterogeneous deformation was seen after a critical strain. Changes in deformation mechanisms are observed. Implications of observed microstructures to seismogenic fault mechanisms are discussed.
883O55 Constitutive relations betweea d ~ I~i near a tip of the propagaffq slip zone d u 4 ~ stick-dip skear fallEe Ohnaka, M; guwahara, Y; Yamamoto, K
Tectonopkysics V144, N1-3, Dec 1987, P109-125 Stick slip was generated along 40cm long precut faults in granite samples in a biaxial apparatus. Dynamic behaviour near the tip of the slipping zone was studied. Slip velocity and acceleration are given as a function of slip displacement, and breakdown shear stress as a function of slip velocity. A five phase process of breakdown and restrengthening is observed. Attempts are made to explain both small scale laboratory measurements and large scale failure as an earthquake source using this deformation model.
883056 Experiment and fndte elemem skmalaflon of X-type shear fractures from a crack in marble Wang, R; Zhao, Y; Chert, Y; Yan, H; Yin, Y; Yao, C; Zhang, H
Tectonoplwsics V144, N1-3, Dec 1987, P141-150 Laser holography was used to measure the out of plane displacement during uniaxial compression of a marble plate with an inclined crack. Tensile fractures propagate curvilinearly, bend towards the axial direction and become stabilised. If the crack is replaced by an open slot, X-type shear fractures appear near the slot tip, propagate in the opposite direction to tensile fractures and lead to specimen rupture. This can be explained by strain softening behaviour near the tip of the slot, • and modelled using finite element analysis with a strain softening elastoplastic material model.
883O57 Holographic testing method of earth material Park, D W
Proc Fourtk A M u l Workslwp Gemed¢ Mistral Teelmelogy Center, Mine Systems Desigm u d Grmmd Comtrol, Moscow, Idaho, 20-21 October 1986 P171-182. Publ Blacksburg: Virginia Polytechnic Institute and State University, 1986 New testing methods which employ laser holographic interferometry are described. Modulus of elasticity and quality variation of a rock core can be measured in a few minutes. Poisson's ratio can be measured with simple specimen preparation. The use of holography to measure the time dependent properties of soils is under development, and experiments have been carried out on artificial materials.
883O54 Frkflemd dependence of gouge mixtures of quartz and montmorilloalte on velocity, composition and fabric Logan, J M; Rauenzahn, K A
883O58 Calealation~xperimeatui method of evalMflag medmakal eharaeterindes of scale k e t e ~ reek nmmes Ukhov, S B; Semenov, V V; Scherbina, E V; Konviz, A V
Tectonophy$ics V144, N1-3, Dec 1987, P87-108
Proc 6tk Interutoul Coafertmee oR Rock Meeka~s, Momtreal, 30 Aq-lO Sept 1987 VI, P271.273. Publ Rotterdam: A A Balkema, 1987
The velocity of frictional sliding was studied using 35 deg precut cylinders of sandstone with a layer of quartzmontmorillonite gouge along the precut. Experiments were at room temperature, confining pressure 25, 50 and 70MPa, and strain rates 0.001-100 microns/see. Friction coefficients were measured. Pure quartz gouge showed stick-slip behaviour, but small montmorillonite additions stabilise sliding. Petrofabric analyses were carried out. Velocity history, gouge thickness, and initial grain size affect fabric and the ability to attain steady state sliding.
A new method to predict the mechanical characteristics of a rock-soil mass is presented. The heterogeneous mass is characterised into smaller bulks of different compositions as 'typical structures', and these bulks are laboratory tested. The larger mass is considered as being comprised of smaller of known properties, and its mechanical behaviour can be calculated. The method is experimentally verified by testing and calculation with a mixture of crushed marl and loam.
© 1988 Pergamon Press plc. Reproduction not permitted R.M.M.S. 25/3---G
Rock Mock Rack Fatgng V20, N4, Oct-Dec 1987, P243-260 The static response of circular tubes inserted into prestressed elastic-plastic ground is examined. A closed form solution determines the hoop forces in uniformly prestressed ground and finite element analysis is used to study biaxial field stress. Stress contours are constructed to estimate the influence of ground failure around tubes with biaxial prestress.
883052 Seimnic and strain studies on large laboratory rock samples being strmed to f a U m Spetzler, H; Sondergeld, C; Sobolev, G; Salov, B
Tectonophysics V144, N1-3, Dec 1987, P55-68 Large granite and basalt samples were cyclically loaded to failure. Strain and ultrasonic velocity measurements were made and acoustic emission recorded. Several zones of acoustic emission sources were identified. The Kaiser effect appears to hold to about one half of stress to failure. As failure approaches, individual acoustic emission events become more energetic and relatively more power is recorded at lower frequencies. Results indicate large variations in dilatancy in the samples. Results are consistent with those from smaller specimens.
Textures of sheared halite and their implications for the seimaoge~ -lip of deep faults Hiraga, H; Shimamoto, T
Tectomopkysics V144, N1-3, Dec 1987, P69-86 Unstable fault motion has been associated with strain localization within shear zones. Work to clarify the nature of this heterogeneous deformation is reported. Triaxial tests were carfled out on dry cylindrical sandstone specimens containing a 0.5ram layer of halite along a 35 deg precut, at rqom temperature, strain rate 3-300 microns/see, and confining pressures to 200MPa. Heterogeneous deformation was seen after a critical strain. Changes in deformation mechanisms are observed. Implications of observed microstructures to seismogenic fault mechanisms are discussed.
883O55 Constitutive relations betweea d ~ I~i near a tip of the propagaffq slip zone d u 4 ~ stick-dip skear fallEe Ohnaka, M; guwahara, Y; Yamamoto, K
Tectonopkysics V144, N1-3, Dec 1987, P109-125 Stick slip was generated along 40cm long precut faults in granite samples in a biaxial apparatus. Dynamic behaviour near the tip of the slipping zone was studied. Slip velocity and acceleration are given as a function of slip displacement, and breakdown shear stress as a function of slip velocity. A five phase process of breakdown and restrengthening is observed. Attempts are made to explain both small scale laboratory measurements and large scale failure as an earthquake source using this deformation model.
883056 Experiment and fndte elemem skmalaflon of X-type shear fractures from a crack in marble Wang, R; Zhao, Y; Chert, Y; Yan, H; Yin, Y; Yao, C; Zhang, H
Tectonoplwsics V144, N1-3, Dec 1987, P141-150 Laser holography was used to measure the out of plane displacement during uniaxial compression of a marble plate with an inclined crack. Tensile fractures propagate curvilinearly, bend towards the axial direction and become stabilised. If the crack is replaced by an open slot, X-type shear fractures appear near the slot tip, propagate in the opposite direction to tensile fractures and lead to specimen rupture. This can be explained by strain softening behaviour near the tip of the slot, • and modelled using finite element analysis with a strain softening elastoplastic material model.
883O57 Holographic testing method of earth material Park, D W
Proc Fourtk A M u l Workslwp Gemed¢ Mistral Teelmelogy Center, Mine Systems Desigm u d Grmmd Comtrol, Moscow, Idaho, 20-21 October 1986 P171-182. Publ Blacksburg: Virginia Polytechnic Institute and State University, 1986 New testing methods which employ laser holographic interferometry are described. Modulus of elasticity and quality variation of a rock core can be measured in a few minutes. Poisson's ratio can be measured with simple specimen preparation. The use of holography to measure the time dependent properties of soils is under development, and experiments have been carried out on artificial materials.
883O54 Frkflemd dependence of gouge mixtures of quartz and montmorilloalte on velocity, composition and fabric Logan, J M; Rauenzahn, K A
883O58 Calealation~xperimeatui method of evalMflag medmakal eharaeterindes of scale k e t e ~ reek nmmes Ukhov, S B; Semenov, V V; Scherbina, E V; Konviz, A V
Tectonophy$ics V144, N1-3, Dec 1987, P87-108
Proc 6tk Interutoul Coafertmee oR Rock Meeka~s, Momtreal, 30 Aq-lO Sept 1987 VI, P271.273. Publ Rotterdam: A A Balkema, 1987
The velocity of frictional sliding was studied using 35 deg precut cylinders of sandstone with a layer of quartzmontmorillonite gouge along the precut. Experiments were at room temperature, confining pressure 25, 50 and 70MPa, and strain rates 0.001-100 microns/see. Friction coefficients were measured. Pure quartz gouge showed stick-slip behaviour, but small montmorillonite additions stabilise sliding. Petrofabric analyses were carried out. Velocity history, gouge thickness, and initial grain size affect fabric and the ability to attain steady state sliding.
A new method to predict the mechanical characteristics of a rock-soil mass is presented. The heterogeneous mass is characterised into smaller bulks of different compositions as 'typical structures', and these bulks are laboratory tested. The larger mass is considered as being comprised of smaller of known properties, and its mechanical behaviour can be calculated. The method is experimentally verified by testing and calculation with a mixture of crushed marl and loam.
© 1988 Pergamon Press plc. Reproduction not permitted R.M.M.S. 25/3---G