A New Soil Testing Apparatus

Green (1967) has effectively stated the case regarding certain serious deficiencies of the Authors' new soil test box. Ko and Scott mention that small volumes of the sample at the corners and along the edges of the box may not be in a homogeneous stress state but did not consider this to be important. This would appear to represent simply an error in judgement. The Writer agrees with Green (1967) that the soil cube was appreciably restrained by the relatively stiff stainless steel spacing frame. The Authors offer insufficient evidence to support the conclusion that the stress state generated in the sample contained within the new soil test box was found to be uniform or the opinion that the present equipment measures the true deformational behaviour of the soil tested. The opinions of Green (1967) and those of the Writer can easily be verified analytically or through the performance of simple experiments. The following brief and approximate analysis based on the theory of elasticity analytically demonstrates the possible importance of edge restraint for a particular stress path and a cylindrical specimen. Fig. 1 (a) represents a free cylinder with homogeneous triaxial compression while Fig. l (b) represents the same cylinder subjected to identical vertical loads but laterally fixed at four vertical edges

Deconvolution techniques for linear systems

Superposition for linear systems is the process in which the input is convolved with the transfer function of the system, whereby the output is obtained. Deconvolution is, therefore, the reverse process in which an unknown input (or the transfer function) is calculated from the measured output and a known transfer function (or input). Several methods of deconvolution are developed and the advantages and disadvantages of each are discussed. Examples are given to demonstrate the applicability of the methods

Model Parametric Studies of the Earthquake Response of the Embankment Dam

Several centrifuge model dams were tested with the conditions similar to those of O\u27Neill Forebay Dam, California to examine the structural behavior under seismic excitation. A few experiments were carried out to study the performance of the dam, whose geometry was still the same as O\u27Neill Dam, but the soil properties were altered by adding some gravel or increasing the compaction density. The results of either test clearly demonstrated a stiffer response to seismic excitation than the model with the original prototype material properties. Characteristics of O\u27Neil! Forebay Dam with different structural modifications were examined. These included construction of a berm at the downstream side of the model dam, which has been proposed and designed recently for the prototype dam by the Bureau of Reclamation personnel as a part of dam rehabilitation program to strengthen the structure, as well as addition of a rip-rap layer on downstream. The earthquake simulation tests conducted on these model dams with the various structural modifications suggested that the performance of the dam with any of above-mentioned reinforcement was somewhat stiffer than that of the current O\u27Neill Dam configuration. The response of the structure under various excitation intensities was also examined by increasing the magnitude of the input excitation but keeping the same frequency contents. Some models were tested with the embankment overlaying on a rigid base, while the others included an alluvium foundation underneath the dam

Lunar regolith densification

Core tube samples of the lunar regolith obtained during the Apollo missions showed a rapid increase in the density of the regolith with depth. Various hypotheses have been proposed for the possible cause of this phenomenon, including the densification of the loose regolith material by repeated shaking from the seismic tremors which have been found to occur at regular monthly intervals when the moon and earth are closest to one another. A test bed was designed to study regolith densification. This test bed uses Minnesota Lunar Simulant (MLS) to conduct shaking experiments in the geotechnical centrifuge with an inflight shake table system. By reproducing realistic in-situ regolith properties, the experiment also serves to test penetrator concepts. The shake table system was designed and used for simulation experiments to study effects of earthquakes on terrestrial soil structures. It is mounted on a 15 g-ton geotechnical centrifuge in which the self-weight induced stresses are replicated by testing an n-th scale model in a gravity field which is n times larger than Earth's gravity. A similar concept applies when dealing with lunar prototypes, where the gravity ratio required for proper simulation of lunar gravity effects is that between the centrifugal acceleration and the lunar gravity. Records of lunar seismic tremors, or moonquakes, were obtained. While these records are being prepared for use as the input data to drive the shake table system, records from the El Centro earthquake of 1940 are being used to perform preliminary tests, using a soil container which was previously used for earthquake studies. This container has a laminar construction, with the layers free to slide on each other, so that the soil motion during the simulated earthquake will not be constrained by the otherwise rigid boundaries. The soil model is prepared by pluviating the MLS from a hopper into the laminar container to a depth of 6 in. The container is mounted on the shake table and the centrifuge is operated to generate an acceleration of 10 times Earth's gravity or 60 times the lunar gravity, thus simulating a lunar regolith thickness of 30 ft. The shake table is then operated using the scaled 'moonquake' as the input motion. One or more model moonquakes are used in each experiment, after which the soil is analyzed for its density profile with depth. This is accomplished by removing from the soil bed a column of soil contained within a thin rubber sleeve which has been previously embedded vertically in the soil during pluviation. This column of soil is transferred to a gamma ray device, in which the gamma ray transmission transversely through the soil is measured and compared with standard calibration samples. In this manner, the density profile can be determined. Preliminary results to date are encouraging, and the Center plans to study the effects of duration of shaking, intensity of the shaking motion, and the frequency of the motion

Regolith-structure modeling

Early lunar missions have provided a basic understanding of the physical and strength properties of lunar regolith, which have been shown to differ from those of dry terrestrial granular soils. Lunar regolith is predominantly a fine sand of which nearly 40 percent can be characterized as silt with a particle size smaller than 100 micrometers. The top 10 to 20 cm of the regolith can be characterized as being in a loose to medium-loose state. The density of the regolith, however, rapidly increases below a depth of 20 cm. The highly irregular and angular shapes of the regolith particles tend to interlock and create relatively strong mechanical bonds that give the particulate mass substantial cohesive properties and smaller amounts of tensile strength properties. In addition, the friction angle of lunar regolith at medium to high densities is quite high and often exceeds 55 degrees. These known properties of lunar regolith have been matched in a terrestrially-manufactured analog known as Minnesota Lunar Simulant. A variety of experiments were conducted using this simulant to both verify existing information and generate new information on the physical and constitutive properties of lunar regolith. These experiments include maximum and minimum density determinations, specific mass of solids, grain-size distribution, conventional triaxial compression and extension, isotropic compression, one-dimensional compression, direct shear, and direct tension. Direct shear experiments were conducted under atmospheric and vacuum conditions. Results of the physical and strength experiments compare closely to results obtained from lunar missions. Results of simulant strength experiments performed in vacuum indicated no observable difference from results obtained in air. A test bed currently under study is one involving a regolith shield covering a first-generation human habitat module. It is understood that regolith in depths ranging from 3 to 5 meters is required for radiation shielding for habitation and workspace. The habitat module is treated as a rigid cylindrical tube with a smooth exterior. By making the cylinder rigid, a complex interaction problem is reduced to a situation where we can consider the support regolith and the shielding regolith as behaving independently of the structural properties of the cylindrical structure. Medium-dense lunar simulant was placed around a scaled model of the habitat module to provide a radiation shield. This embankment-type shield was constructed in relatively thin but fine layers by compacting, by mechanical vibratory means, layer upon layer of simulant placed adjacent to the horizontally-aligned cylinder. The slope angles were constructed at 55 degrees. The model described above was studied in a geotechnical centrifuge, which allows for the scaling of model dimensions to prototype dimensions by increasing the acceleration of gravity on the model. The deformation response can be scaled up to prototype dimensions to provide an assessment of the deformation patterns of the lunar structure. The actual process of local and/or global growth of instabilities or skip planes can also be observed

Static Stress-Deformation Characteristics of Sand

A soil test box, capable of applying any combination of principal stresses to a cubical soil sample, was developed for the experimental investigation of the behavior of granular soils under static loading. A stress control device was also developed, enabling a continuous and proportionate change to be made in the stresses along a stress path and considerably simplifying the calculation of the stress state in the sample. The apparatus was used to investigate (a) the hydrostatic compression of an Ottawa sand, and (b) the behavior of the same soil under various deviatoric stress paths in both loading and unloading conditions. A theoretical "holey" model was postulated for sand under hydrostatic stress and the results of the analysis of this model were found to correlate closely with the experimental data. The qualitative behavior of sand under shear stresses was examined from a particulate point of view. Specially designed tests were performed on the Ottawa sand with loading and unloading along stress paths which involved different combinations of hydrostatic and deviatoric stresses, with the purpose of examining the proportions of recoverable and irrecoverable deformations. A failure envelope was obtained for a medium dense and a medium loose sand by monotonically increasing τ_(OCT) while keeping σ_(OCT) constant under various conditions of stress distribution, and it was found that the value of equivalent Coulomb φ increased from 42° in triaxial compression to 48° in triaxial extension for the medium dense sand and from 36° in triaxial compression to 44° in triaxial extension for the medium loose sand

Proceedings of the ASAIHL Seminar on the Role of the ASAIHL in Combating Health Hazards of Environmental Pollution: June 17-20, 1992, University of Hong Kong

Includes bibliographical references.Sponsored by the ASAIHLpublished_or_final_versionLegal controls of environmental pollution in Asia: how effective are they? Allen, J. Allen, J. 256Hong Kong's water pollution controls: are we serious? Baillie, B.G. Baillie, B.G. 265Environmental law in Hong Kong - a legal practitioner's point of view Skrine, R. Skrine, R. 277Has the use of unleaded petrol provided a lead-free environment in Hong Kong? Au, C.T. Au, C.T. Chou, K.M. Chou, K.M. Wong, K.Y. Wong, K.Y. 282The influence of the health act on present environmental problems Prabawa Utama, S.H. Prabawa Utama, S.H. 288Characteristics of acid rain in mainland China Hong, Y.T. Hong, Y.T. 42Environmental impact assessment and the role of legislation in environmental control - the case of Malaysia Idris, A.B. Idris, A.B. Fuad, A. Fuad, A. 294Social responsbility awareness assessment of selected university respondents in combating environmental pollution Barcelona, A.C. Barcelona, A.C. 301Alternatives to legal controls on environmental pollution Kaine, G. Kaine, G. Reeve, I. Reeve, I. Musgrave, W. Musgrave, W. 306Introduction 315Towards low-waste technology Diaper, J. Diaper, J. 317Changing environmental values and institution building: the role of ASAIHL Hills, P. Hills, P. 325The nature and control of motor vehicle emissions - methanol as an alternative fuel Cheung, C.S. Cheung, C.S. Lui, Y.B. Lui, Y.B. Leung, T.P. Leung, T.P. 335Prevention and treatment of environmental pollution Mena, M.M. Mena, M.M. 332Treatment and disposal of heavy metal wastes using cementitious solidification Peralta, G.L. Peralta, G.L. Ballesteros, F.C. Ballesteros, F.C. Cepeda, M.L. Cepeda, M.L. 340A membrane anaerobic system for wastewater treatment Fakrul-Razi, A. Fakrul-Razi, A. 346Prevention and treatment of air pollution in Hong Kong Lam, J.C. Lam, J.C. 351Environmental education - a strategy for the treatment and prevention of environmental pollution Manalo, J.A. Manalo, J.A. Sergovia, V. Sergovia, V. Hocson, T.R. Hocson, T.R. 357Bacterial reduction during sewage treatment - the Hong Kong experience Hodgkiss, I.J. Hodgkiss, I.J. Chiu, S.H.C. Chiu, S.H.C. 360Treatment and prevention of environmental pollution in the Philippines De Jesus, E.M. De Jesus, E.M. 366Microbiological study of shellfish and water quality in Deep Bay, Hong Kong Kueh, C.S.W. Kueh, C.S.W. 369Environmental deterioration in greater Bangkok, Thailand Paraken, Y. Paraken, Y. 376The 'polluter pays' principle: the distribution of economic impacts Rahim, K.A. Rahim, K.A. 378The role of Philippine ASAIHL institutions in combating the hazards of environmental pollution in Manila Quirino, T.U. Quirino, T.U. 35Education programmes for training of agrichemical users in New Zealand Penman, D.R. Penman, D.R. 31The role of institutions of higher learning in combating health hazards of environmental pollution Rampal, K.G. Rampal, K.G. Ismail, N. Ismail, N. 26The contribution of health care departments in tertiary institutions in Hong Kong to combating the hazards of pollution King, A.R. King, A.R. 19Australian approaches to finger printing sources of environmental lead with isotopes Gulson, B.L. Gulson, B.L. 13D Treatment and prevention of environmental pollutionC Legal controls of environmental pollutionB Monitoring and instrumentation of environmental pollutionA Health hazards of environmental pollutionCountry reportsKeynote address Wang, Gungwu Wang, Gungwu 2Impact of industry on the health of surrounding communities: an analysis of epidemiological and public health challenges Bhopal, R.S. Bhopal, R.S. 65Epidemiology and environmental health: reliable risk measurement in well-populations Lam, T.H. Lam, T.H. Hedley, A.J. Hedley, A.J. Peters, J. Peters, J. 74An investigation into the presence of anaerobic bacteria in coastal waters of Hong Kong Boost, M.V. Boost, M.V. Wong, L.P. Wong, L.P. Wong, P.S. Wong, P.S. Ma, K.C. Ma, K.C. 82Pollutions within the built environment Burnett, J. Burnett, J. Chan, D.W.T. Chan, D.W.T. 87The effects of pesticides use on the health of on farmers in East Java, Indonesia Mukono, J. Mukono, J. 94Noise and human activities in Hong Kong: a review Tan, T.C. Tan, T.C. Wong, L.T.L. Wong, L.T.L. 98Analysis of organophosphorus insecticides in vegetables Tanner, P.A. Tanner, P.A. Leung, K.H. Leung, K.H. 105Health risk and environmental pollution: the hidden factors Peters, J. Peters, J. Lui, J. Lui, J. Wong, C.M. Wong, C.M. Hedley, A.J. Hedley, A.J. Lam, T.H. Lam, T.H. Ong, S.G. Ong, S.G. Tam, A.Y.C. Tam, A.Y.C. 109Risk assessment and management in the prevention of adverse effects on human health and the environment Spickett, J.T. Spickett, J.T. 117Indoor and outdoor pollution in shops and offices in Hong Kong and health effects Bacon-Shone, J. Bacon-Shone, J. Liao, S. Liao, S. 122Climatological assessment of potential heat stress in Hong Kong Kyle, W.J. Kyle, W.J. 126Asbestos dust: a silent enemy Lam, K.Y. Lam, K.Y. 131Integrating environmental health problems into urban planning: problems in the Asian-Pacific region and the challenges for universities Simpson, R.W. Simpson, R.W. 134Organic solvent exposure in some manufacturing industries in Malaysia Tan, G.L.E. Tan, G.L.E. 138Introduction 145Introductino 63Monitoring and instrumentation of environmental pollution Tebbutt, T.H.Y. Tebbutt, T.H.Y. 145The air quality monitoring programme of the Hong Kong environmental protection department Leung, R.T.M. Leung, R.T.M. 152Low technology sampling can show spatial and temporal patterns of airborne metal pollution Lloyd, O.L. Lloyd, O.L. Fay, Gailey Fay, Gailey 159Heavy metal contamination in coastal waters - a case study of the north coast of Central Java, Indonesia Supriharyono Supriharyono 165Determination of phosphorus in natural water at parts per trillion level by laser thermal lens effect Wu, L. Wu, L. Siu, G.G. Siu, G.G. Chiu, D.D.S. Chiu, D.D.S. Stokes, M.J. Stokes, M.J. 171A geographical approach to evaluating the human impact upon water quality Peart, M.R. Peart, M.R. 178Modular auto-enrichment subsystem for use in environmental high pressure liquid chromatography analysis Chen, S.C. Chen, S.C. Chang, J.Y. Chang, J.Y. Wang, R.K. Wang, R.K. 183Exposure to environmental pollutants in the work environment: a case study of a traffic toll booth in Malaysia Yaziz, M.I. Yaziz, M.I. 187A proposed air quality index in Hong Kong Ng, C.N. Ng, C.N. Tanner, P.A. Tanner, P.A. 191Background level of trace elements in soils of mainland China Chen, J.S. Chen, J.S. Tao, S. Tao, S. Deng, B.S. Deng, B.S. Wang, X.J. Wang, X.J. 196Indoor monitoring of nitrogen oxides Cheung, M.T. Cheung, M.T. 200The role of Thai universities in combating health hazards of environmental pollution Wangsuphachart, V.L. Wangsuphachart, V.L. 54Development of a piezoelectric crystal sorption detector for continuous monitoring of organic vapours at the workplace Fung, Y.S. Fung, Y.S. 205Effects of some standard fixatives on fish gill morphology Shepherd, M. Shepherd, M. Ivanstoff, W. Ivanstoff, W. 210Improving the total environmental of Singapore Tan, T.C. Tan, T.C. 46Simulation of urban traffic noise on the environment Pamanikabud, P. Pamanikabud, P. 215Investigation into the haze episodes in the Kelang Valley, Malaysia Samah, A.A. Samah, A.A. 221Photoacoustic determination of organic pollutant gases in Hong Kong air Shi, B. Shi, B. Siu, G.G. Siu, G.G. Chiu, D.D.S. Chiu, D.D.S. 228Application of the proton induced X-ray emission (PIXE) technique for the study of respirable suspended particulated (RSP) in Hong Kong Cai, Z.X. Cai, Z.X. Sze, P.Y.K. Sze, P.Y.K. Stokes, M.J. Stokes, M.J. Young, E.C.M. Young, E.C.M. 234Follow-up stream sediment geochemical reconnaissance surveys in the vicinity of Tai Mo Shan, New Territories, Hong Kong Yim, W.W.S. Yim, W.W.S. Ng, C.Y. Ng, C.Y. Thornton, I. Thornton, I. 240Introduction 249Environmental pollution, higher education, and the rule of law Axline, M. Axline, M. 25

Preliminary Investigation of a Buried Pipe Excited by an Earthquake

The consequence of a devastating earthquake is usually a result of fires, which are caused by breakage of gas pipelines and lack of water supply from damaged water pipelines. The seismic response of a buried pipe was studied using the geotechnical centrifuge facility at the University of Colorado, Boulder. Ottawa sand labeled F-75 was used to model the ground, which was contaminated in a rigid container with inside dimensions of 48 in. long, 12 in. wide and 9 in. deep. A 4-foot long micro PVC pipe having a 1/4-inch-inside diameter and a 5/16-inch-outsIde diameter was used to model a prototype pipe. When it is tested in a centrifuge at a 50 g acceleration, the model pipe represents a 1-foot-inside diameter prototype PVC pipe with a 1.5 in. wall thickness (200 ft. long). The model pipe was instrumented with 12 pairs of strain gages to measure axial strains at 12 locations along the pipe, and was buried in the soil, which was underlain by a bedrock. The bedrock formations were d1fferent from one test to another. Each model was excited with the N-S component of the 1940 Imperial Valley earthquake recorded at the El Centro Site, and the shaking direction was parallel to the long axis of the pipe. Axial strains of the pipe, accelerations of the ground, and settlements of the surface were measured during the earthquake. It appeared that the geologic feature of the bedrock played an important role on the pipe behavior

Addressing quality, access and equity in the school direct subsidy scheme in Hong Kong : a study of government strategies and tools

published_or_final_versionPolitics and Public AdministrationMasterMaster of Public Administratio