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A response surface methodology for determination of engineering properties of soil in situ
SITE INVESTIGATIONS:TESTING
951163 Study of 21 marine basins indicates wide prevalence of hydrates J. Krason, Offshore, 54(8), 1994, pp 34,35. A research project conducted by Geoexplorers International has assessed the gas resource potential associated with gas hydrates at 21 offshore sites. These are summarized with potential volumes of gas resources. Understanding the geological environments controlling hydrate occurrence and stability is fundamental in assessing potential resources and their exploitation. The study methodology and results are described. (LM.McLaughlin)
951164 Polycyclic aromatic hydrocarbons in old landf'dls D. C. Walsh, R. G. LaFleur & R. F. Bopp, Northeastern Geology, 16(2), 1994, pp 137-144. Available data for three New York City landfills constructed prior to 1925 are compiled to evaluate the presence and characteristics of seven non-alkylated polycyclic aromatic hydrocarbon (PAH) compounds in solid waste and pore waters. A characteristic pattern in the relative abundance of seven PAH compounds is observed for most waste samples. Peak abundances are seen for PAH compounds in the middle molecular weight range (mw = 178-226). Three compounds, phenanthrene, pyrene and chrysene, typically account for more than 35% of the total PAH in waste. The total PAH concentration is highly variable with depth and location and is probably dependent on random local variability of waste. The large percentage of ash observed in waste samples and the common occurrence of PAH in combustion products indicate that ash may be an important source of PAH in waste. (from Authors)
Suggested testing methods and standards 951165
An analysis of pressuremeter holding tests V. Fioravante, M. Jamiolkowski & R. Lancellotta, Geotechnique, 44(2), 1994, pp 227-238. The self-boring pressuremeter - Camkometer - was used to define the permeability characteristics of Fucino clay using strain-holding and stress-holding tests. The probe was expanded to a specific value of cavity strain; then the strain or stress was held constant while the dissipation of the excess pore pressure, induced by the initialexpansion of the probe, was monitored. The decrease of pore pressure obtained with time was used to derive the coefficient of consolidation for horizontal flow Ch. To account for the two-dimensional nature of the problem and the non-linear soil behaviour, numerical analyses were performed which simulated the tests by using the finite element program CRISP, which employs a coupled consolidation theory and the modified Cam clay soil model. (from Authors)
951166 Some aspects of pressuremeter test interpretation in clays S. Thevanayagam, J. L. Chameau & A. G. Altschaeffl, Geoteehnique, 44(2), 1994, pp 319-334. This paper addresses fundamental questions related to the interpretation of pressuremeter data, with emphasis on the self-boring pressuremeter. The state of stresses and mechanism of failure of clays during pressuremeter tests are identified. The generality of the plane-strain condition during expansion of a pressuremeter cavity is shown and conditions where it is far from plane strain are indicated. Experimental
23A
data substantiate the theoretical findings. A procedure is proposed to evaluate the error associated with initial disturbance due to unloading of the cavity wall caused during insertion of the probe, and corrections of the interpreted strength parameters are given for self.boring pressuremeter tests. (from Authors)
951167 Strain softening and state parameter for sand modcmng D. M. Wood, K. Belkheir & D. F. Liu, Geotechnique, 44(2), 1994, pp 335-339. Triaxial compression tests on sand typically show densitydependent and pressure-dependent response. Strain softening from a peak stress ratio is a familiar feature of the observed stress-strain relations, and it is important that this should be incorporated into constitutive models of sand behaviour. This Technical Note describes a method whereby this type of response can be reproduced by combining a simple monotonic hardening relationship with a link between current peak strength and a state parameter (a combination of volumetric and mean effective stress information). (from Authors) 951168
Piezometer performance at Wildlife liquefaction site, California T. L. Youd & T. L. Holzer, Journal of Geotechnical Engineering - ASCE, 120(6), 1994, pp 975-995. In response to an urgent need for field data from instrumented liquefaction sites, the US Geological Survey in 1982 selected and instrumented a site in southern California called the Wildlife site. The November 1987 Superstition Hills earthquake triggered sand boils and the desired instrumental response by generating excess pore-water pressure that approximately equaled the initial effective overburden pressure. These records are the first from a field site to trace ground motions and pore pressures through the entire liquefaction process. Because pore pressure continued to rise after most of the seismic energy had propagated through the site, questions about the fidelity of the pore-pressure records have been raised. This review concludes that no data or analyses have been developed that convincingly demonstrate that the pore-pressure piezometers responded incorrectly. (from Authors)
951169 Modelling soil distortion during compaction for cylindrical stress load paths C. T. Petersen, European Journal of Soil Science, 45(2), 1994, pp 117-126. A slightly modified critical-state model was formulated in order to account for the volume-change behaviour at yield and failure observed in triaxiai tests on unsaturated soils. Model parameters were specified for two soils (a sandy loam and a loam), each at three different soil-moisture contents. The agreement between predicted and observed maximum shear strain depended on type of load path and soil-moisture content. The model failed to predict maximum shear strain at stress states close to critical. The absolute different between observed and predicted strain was on average 0.05 for deviatoric stresses smaller than 90% of the critical-state values. The comparable maximum differences were 0.11 and 0.07 for load-path types I and II, respectively. (from Author)
951170 A response surface methodology for determination of engineering properties of soil/n situ D. Rubinstein, S. K. Upadhyaya & M. Sime, International Agrophysics, 8(1), 1994, pp 113-130.
24A
SITE INVESTIGATIONS:MONITORING
Since in situ soils seldom behave like remolded laboratory soils or disturbed field samples, it is important to 'identify' or 'calibrate' the engineering properties of field soil by means of in situ tests. A response surface methodology based on an orthogonal regression in the parameter space has been developed to 'identify' engineering properties of any material based on in situ tests. The proposed methodology was verified for the case of a two parameter hypo-elastic model for soil as well as a complex five parameter model for soil which includes nonlinear material behavior in elastic range, yield based on Drucker-Prager yield criteria and associated plastic flow upon yield. (Authors)
951171 Closed-loop random vibration control of n shaker table with a microcomputer M. L. Wang, Soil Dynamics & Earthquake Engineering, 13(4), 1994, pp 259-266. The objectives for this study is to design and renovate a shaker table into a state-of-the-art vibration testing station. The methods by which such an electromagnetic force generator is converted for utilization as a closed-loop materials testing station is described. This paper also discusses using a microcomputer as a viable, cost-effective alternative for short duration tests as opposed to more sophisticated and costly equipment. For certain applications, a microcomputer can be configured into a dynamic vibration system to control the desired random vibration imposed on a structure. In this case, the control signal (a digital signal from the microcomputer) can be generated for a given spectral density function. (Author)
951172 IMoxins in soils V. E. Sokolovich, Soil Mechanics & Foundation Engineering, 31(2), 1994, pp 74-76; translated from: Osnovaniya, Fundamenty i Mekhanika Grantor. This article reports on pollution of the environment with dioxins, which are lethal to the human organism. Dioxins are formed as a by-product at chemical plants with antiquated technologies. Entering into primitive slime pits with wastes, dioxin freely penetrates into surrounding soils and groundwater. Favorable conditions for formation of dioxins are created when soils containing chlorinated benzene and phenols are stabilized. The status of this problem abroad is described. Specific measures are suggested to eliminate dioxins in soils and in slime pits. (Journal summary)
951173 Natural chromatographic separation of benzene, toluene, ethylbenzene and xylenes (BTEX compounds) in a gasoline contaminated pound water aquifer J. R. Odermatt, Organic Geochemistry, 21(10-11), 1994, pp 1141-1150. The concentrations of aromatic volatile hydrocarbons (e.g. benzene, toluene, ethylbenzene and total xylenes, or BTEX) are commonly determined during the course of ground water investigations at gasoline contaminated sites. The physical and chemical properties of BTEX compounds are important characteristics which partially control the distribution of these compounds in the subsurface. Based upon these characteristics, the relative mobility of these compounds in ground water aquifers is predicted to be: xylene < ethylbenzene < toluene < benzene. The relative proportions of BTEX compounds and the concentration ratio of X/B may be useful parameters for mapping dissolved BTEX plumes during ground water investigation and remediation projects. (from Author)
951174 Extinguishing of Kuwalti oil fires - challenges, technology, and s u c c e s s T. Husain, Atmospheric Environment, 28(13), 1994, pp 21392147. In this paper, the challenges faced by the fire fighting companies in extinguishing fire in Kuwaiti oilfields are summarized. Various techniques adopted in extinguishing the fires and capping the wells are also discussed. The paper also summarizes the preparations made to extinguish the oil wells in a much shorter period than was initially anticipated. Statistics on the resources and manpower required and the economic losses are also compiled in this paper. Due to uncontrolled flow of the mixture of oil, gas, and water from high pressured oilfield, the damage caused to the reservoirs is also summarized. (Author)
Monitoring rock and soil mass performance 951175 Gravitational stresses in long symmetric ridges and valleys in anisutropic rock E. Pan, B. Amadei & W. Z. Savage, International Journal of Rock Mechanics & Mining Sciences, 31(4), 1994, pp 293-312. The effect of topography and rock mass anisotropy on gravitational stresses in long isolated symmetric ridges and valleys is modeled using an analytical method proposed previously. The rock mass deforms under a condition of plane strain. A parametric study is presented on the effect of: 1) topography, 2) orientation of auisotropy and 3) degree of anisotropy, on the magnitude and distribution of gravitational stresses in transversely isotropic rock masses with planes of anisotropy striking parallel to the ridge or valley axis. It is found that compressive stresses develop near ridge crests and that tensile stresses develop in valley bottoms and valley walls. The magnitude of the gravitational stresses is of the order of the characteristic stress pg\b\ where p is the rock density, g is the gravitational acceleration and \b\ is the height of the ridge or depth of the valley. (Authors)
951176 Rock mechanics investigations for rock slope stability assessment P. Lunardi, P. Froldi & E. Fornari, International Journal of Rock Mechanics & Mining Sciences, 31(4), 1994, pp 323-345. This paper describes investigations, geophysical and geomechanical studies of rock masses, carried out in order to analyse the stability of excavations for the Ravedis Dam and the slopes of the catchment basin upstream from the dam. A thorough geostructural survey revealed a network of discontinuities that characterizes the rock masses. Geomechanical sections of the slopes were constructed by integrating geostructural, geophysical and geomechanical data; the stability of the slopes was analysed by using a slices equilibrium limit method, generally used in soil mechanics (Bell method). Reinforc~nent of the rock mass with an artificial increment in cohesion was simulated using the concept of 'reinforced rock'. (from Authors) 951177 In situ evidence for fluid-induced aseismic slip events along
fault zones O. Scotti & F. H. Cornet, International Journal of Rock Mechanics & Mining Sciences, 31(4), 1994, pp 347-358. Stress measurements performod with the hydraulic test on preexisting fractures (HTPF) method, prior to and after
951163 Study of 21 marine basins indicates wide prevalence of hydrates J. Krason, Offshore, 54(8), 1994, pp 34,35. A research project conducted by Geoexplorers International has assessed the gas resource potential associated with gas hydrates at 21 offshore sites. These are summarized with potential volumes of gas resources. Understanding the geological environments controlling hydrate occurrence and stability is fundamental in assessing potential resources and their exploitation. The study methodology and results are described. (LM.McLaughlin)
951164 Polycyclic aromatic hydrocarbons in old landf'dls D. C. Walsh, R. G. LaFleur & R. F. Bopp, Northeastern Geology, 16(2), 1994, pp 137-144. Available data for three New York City landfills constructed prior to 1925 are compiled to evaluate the presence and characteristics of seven non-alkylated polycyclic aromatic hydrocarbon (PAH) compounds in solid waste and pore waters. A characteristic pattern in the relative abundance of seven PAH compounds is observed for most waste samples. Peak abundances are seen for PAH compounds in the middle molecular weight range (mw = 178-226). Three compounds, phenanthrene, pyrene and chrysene, typically account for more than 35% of the total PAH in waste. The total PAH concentration is highly variable with depth and location and is probably dependent on random local variability of waste. The large percentage of ash observed in waste samples and the common occurrence of PAH in combustion products indicate that ash may be an important source of PAH in waste. (from Authors)
Suggested testing methods and standards 951165
An analysis of pressuremeter holding tests V. Fioravante, M. Jamiolkowski & R. Lancellotta, Geotechnique, 44(2), 1994, pp 227-238. The self-boring pressuremeter - Camkometer - was used to define the permeability characteristics of Fucino clay using strain-holding and stress-holding tests. The probe was expanded to a specific value of cavity strain; then the strain or stress was held constant while the dissipation of the excess pore pressure, induced by the initialexpansion of the probe, was monitored. The decrease of pore pressure obtained with time was used to derive the coefficient of consolidation for horizontal flow Ch. To account for the two-dimensional nature of the problem and the non-linear soil behaviour, numerical analyses were performed which simulated the tests by using the finite element program CRISP, which employs a coupled consolidation theory and the modified Cam clay soil model. (from Authors)
951166 Some aspects of pressuremeter test interpretation in clays S. Thevanayagam, J. L. Chameau & A. G. Altschaeffl, Geoteehnique, 44(2), 1994, pp 319-334. This paper addresses fundamental questions related to the interpretation of pressuremeter data, with emphasis on the self-boring pressuremeter. The state of stresses and mechanism of failure of clays during pressuremeter tests are identified. The generality of the plane-strain condition during expansion of a pressuremeter cavity is shown and conditions where it is far from plane strain are indicated. Experimental
23A
data substantiate the theoretical findings. A procedure is proposed to evaluate the error associated with initial disturbance due to unloading of the cavity wall caused during insertion of the probe, and corrections of the interpreted strength parameters are given for self.boring pressuremeter tests. (from Authors)
951167 Strain softening and state parameter for sand modcmng D. M. Wood, K. Belkheir & D. F. Liu, Geotechnique, 44(2), 1994, pp 335-339. Triaxial compression tests on sand typically show densitydependent and pressure-dependent response. Strain softening from a peak stress ratio is a familiar feature of the observed stress-strain relations, and it is important that this should be incorporated into constitutive models of sand behaviour. This Technical Note describes a method whereby this type of response can be reproduced by combining a simple monotonic hardening relationship with a link between current peak strength and a state parameter (a combination of volumetric and mean effective stress information). (from Authors) 951168
Piezometer performance at Wildlife liquefaction site, California T. L. Youd & T. L. Holzer, Journal of Geotechnical Engineering - ASCE, 120(6), 1994, pp 975-995. In response to an urgent need for field data from instrumented liquefaction sites, the US Geological Survey in 1982 selected and instrumented a site in southern California called the Wildlife site. The November 1987 Superstition Hills earthquake triggered sand boils and the desired instrumental response by generating excess pore-water pressure that approximately equaled the initial effective overburden pressure. These records are the first from a field site to trace ground motions and pore pressures through the entire liquefaction process. Because pore pressure continued to rise after most of the seismic energy had propagated through the site, questions about the fidelity of the pore-pressure records have been raised. This review concludes that no data or analyses have been developed that convincingly demonstrate that the pore-pressure piezometers responded incorrectly. (from Authors)
951169 Modelling soil distortion during compaction for cylindrical stress load paths C. T. Petersen, European Journal of Soil Science, 45(2), 1994, pp 117-126. A slightly modified critical-state model was formulated in order to account for the volume-change behaviour at yield and failure observed in triaxiai tests on unsaturated soils. Model parameters were specified for two soils (a sandy loam and a loam), each at three different soil-moisture contents. The agreement between predicted and observed maximum shear strain depended on type of load path and soil-moisture content. The model failed to predict maximum shear strain at stress states close to critical. The absolute different between observed and predicted strain was on average 0.05 for deviatoric stresses smaller than 90% of the critical-state values. The comparable maximum differences were 0.11 and 0.07 for load-path types I and II, respectively. (from Author)
951170 A response surface methodology for determination of engineering properties of soil/n situ D. Rubinstein, S. K. Upadhyaya & M. Sime, International Agrophysics, 8(1), 1994, pp 113-130.
24A
SITE INVESTIGATIONS:MONITORING
Since in situ soils seldom behave like remolded laboratory soils or disturbed field samples, it is important to 'identify' or 'calibrate' the engineering properties of field soil by means of in situ tests. A response surface methodology based on an orthogonal regression in the parameter space has been developed to 'identify' engineering properties of any material based on in situ tests. The proposed methodology was verified for the case of a two parameter hypo-elastic model for soil as well as a complex five parameter model for soil which includes nonlinear material behavior in elastic range, yield based on Drucker-Prager yield criteria and associated plastic flow upon yield. (Authors)
951171 Closed-loop random vibration control of n shaker table with a microcomputer M. L. Wang, Soil Dynamics & Earthquake Engineering, 13(4), 1994, pp 259-266. The objectives for this study is to design and renovate a shaker table into a state-of-the-art vibration testing station. The methods by which such an electromagnetic force generator is converted for utilization as a closed-loop materials testing station is described. This paper also discusses using a microcomputer as a viable, cost-effective alternative for short duration tests as opposed to more sophisticated and costly equipment. For certain applications, a microcomputer can be configured into a dynamic vibration system to control the desired random vibration imposed on a structure. In this case, the control signal (a digital signal from the microcomputer) can be generated for a given spectral density function. (Author)
951172 IMoxins in soils V. E. Sokolovich, Soil Mechanics & Foundation Engineering, 31(2), 1994, pp 74-76; translated from: Osnovaniya, Fundamenty i Mekhanika Grantor. This article reports on pollution of the environment with dioxins, which are lethal to the human organism. Dioxins are formed as a by-product at chemical plants with antiquated technologies. Entering into primitive slime pits with wastes, dioxin freely penetrates into surrounding soils and groundwater. Favorable conditions for formation of dioxins are created when soils containing chlorinated benzene and phenols are stabilized. The status of this problem abroad is described. Specific measures are suggested to eliminate dioxins in soils and in slime pits. (Journal summary)
951173 Natural chromatographic separation of benzene, toluene, ethylbenzene and xylenes (BTEX compounds) in a gasoline contaminated pound water aquifer J. R. Odermatt, Organic Geochemistry, 21(10-11), 1994, pp 1141-1150. The concentrations of aromatic volatile hydrocarbons (e.g. benzene, toluene, ethylbenzene and total xylenes, or BTEX) are commonly determined during the course of ground water investigations at gasoline contaminated sites. The physical and chemical properties of BTEX compounds are important characteristics which partially control the distribution of these compounds in the subsurface. Based upon these characteristics, the relative mobility of these compounds in ground water aquifers is predicted to be: xylene < ethylbenzene < toluene < benzene. The relative proportions of BTEX compounds and the concentration ratio of X/B may be useful parameters for mapping dissolved BTEX plumes during ground water investigation and remediation projects. (from Author)
951174 Extinguishing of Kuwalti oil fires - challenges, technology, and s u c c e s s T. Husain, Atmospheric Environment, 28(13), 1994, pp 21392147. In this paper, the challenges faced by the fire fighting companies in extinguishing fire in Kuwaiti oilfields are summarized. Various techniques adopted in extinguishing the fires and capping the wells are also discussed. The paper also summarizes the preparations made to extinguish the oil wells in a much shorter period than was initially anticipated. Statistics on the resources and manpower required and the economic losses are also compiled in this paper. Due to uncontrolled flow of the mixture of oil, gas, and water from high pressured oilfield, the damage caused to the reservoirs is also summarized. (Author)
Monitoring rock and soil mass performance 951175 Gravitational stresses in long symmetric ridges and valleys in anisutropic rock E. Pan, B. Amadei & W. Z. Savage, International Journal of Rock Mechanics & Mining Sciences, 31(4), 1994, pp 293-312. The effect of topography and rock mass anisotropy on gravitational stresses in long isolated symmetric ridges and valleys is modeled using an analytical method proposed previously. The rock mass deforms under a condition of plane strain. A parametric study is presented on the effect of: 1) topography, 2) orientation of auisotropy and 3) degree of anisotropy, on the magnitude and distribution of gravitational stresses in transversely isotropic rock masses with planes of anisotropy striking parallel to the ridge or valley axis. It is found that compressive stresses develop near ridge crests and that tensile stresses develop in valley bottoms and valley walls. The magnitude of the gravitational stresses is of the order of the characteristic stress pg\b\ where p is the rock density, g is the gravitational acceleration and \b\ is the height of the ridge or depth of the valley. (Authors)
951176 Rock mechanics investigations for rock slope stability assessment P. Lunardi, P. Froldi & E. Fornari, International Journal of Rock Mechanics & Mining Sciences, 31(4), 1994, pp 323-345. This paper describes investigations, geophysical and geomechanical studies of rock masses, carried out in order to analyse the stability of excavations for the Ravedis Dam and the slopes of the catchment basin upstream from the dam. A thorough geostructural survey revealed a network of discontinuities that characterizes the rock masses. Geomechanical sections of the slopes were constructed by integrating geostructural, geophysical and geomechanical data; the stability of the slopes was analysed by using a slices equilibrium limit method, generally used in soil mechanics (Bell method). Reinforc~nent of the rock mass with an artificial increment in cohesion was simulated using the concept of 'reinforced rock'. (from Authors) 951177 In situ evidence for fluid-induced aseismic slip events along
fault zones O. Scotti & F. H. Cornet, International Journal of Rock Mechanics & Mining Sciences, 31(4), 1994, pp 347-358. Stress measurements performod with the hydraulic test on preexisting fractures (HTPF) method, prior to and after