Mechanisms of large-scale landslides in China

Large-scale landslides in western China are famous for their size, complex formation mechanism and serious destruction. Data were collected from some typical large-scale landslides in mainland China in the 20th century. A number of geo-mechanical models have been identified: the “three sections” model (sliding; tension cracking; shearing), “retaining wall collapse”, “horizontal-pushing” in horizontal strata; large-scale toppling in counter-inclined strata; the creep-bending–shearing model etc. Large-scale rock landslides are generally accompanied by sudden brittle failure of the “locking section” along the potential sliding surface. The paper discusses the importance of this “locking section” which is key to assessing slope geohazard and to the development of control/mitigation measures.     

Catastrophic landslides associated with the M8.0 Wenchuan earthquake

Numerous earthquake-induced landslides occurred in the Longmenshan tectonic belt associated with the 12th May 2008 Wenchuan earthquake where the vertical acceleration was greater than the horizontal ground motion. Many of these landslides originated in the steep mountain terrain which amplified the effect of the ground shaking. Three typical landslides are discussed: the Niujuangou sturzstrom, the Chengxi rock slide and the 1,100 million m³ Daguangbao rock slide. Having discussed the individual slides and some previously published models, a mechanism to explain both the very fast velocity of the slides and their long run-out distance is proposed, taking into account aerodynamic principles. The model postulates that air trapped in the steep-sided valley by the collapsing rock mass forms a “cushion-effect” on which the debris moves.     

Experimental study on the motion behavior and mechanism of submarine landslides

Submarine landslide is a common marine geo-hazard that shows different motion behavior with subaerial landslide. In this study, a test apparatus is developed to reproduce the extremely long distance movement of submarine landslides at different sliding velocities. The frontal behavior of subaqueous landslide under the dynamic pressure and shear stress of ambient water is described and analyzed. The evolution of the sediment concentration during the submarine landslide propagation is investigated. With an increase of the sliding velocity, the state of soil-water mixture can be divided into three stages: 1) landslide stage, the mixture consists a water layer and a sand layer; 2) transforming stage, a turbidity current layer appears above the sand-water interface, and the sand mass decreases gradually; 3) turbidity current stage, all of the sand particles are eroded by water and the sand layer disappears. In addition, the critical velocities between each stage are defined and investigated.     

A simple model to study the influence of fluctuating airflow on the effective air exchange rate when using natural ventilation

Fluctuating airflow may strongly influence the real air exchange rate when using natural ventilation, resulting in a larger “effective” air exchange rate than the “mean” air exchange rate calculated by conventional methods (i.e., the network method). To study the effective air exchange rate during natural ventilation under conditions of actual use, this study proposes a simple model that accounts for fluctuating airflow. The model assumes that the airflow near a building opening fluctuates regularly and velocity is assumed to have either a square or sine wave pattern. Our analysis shows that the effective air exchange rate is larger when accounting for fluctuating airflow. This suggests that the mean air exchange rate should not be calculated without consideration of real airflow fluctuations.     

Use of gestalt in wayfinding design and analysis of wayfinding process

The authors brought forward the definition of “Gestalt space” and indicated this kind of space can be easily cognized. Three experiments showed that “classification” and “grouping” are the human strategies to solve wayfinding problems. “Similarity” and “Legibility” of the space are advantageous to help people to complete wayfinding tasks. The designer should provide the essential “Legibility” in Gestalt space, by using some techniques such as “break” and “accession” to settle the wayfinding problem. __________ Translated from Architectural Journal, 2007, (5): 89–91 [译自: 建筑学报]     

Stress determination in soils from variation in level of infrared radiation during unloading

A procedure for and results of model experiments conducted on insulated soil specimens in connection with the development of a method of measuring stresses in soil masses in accordance with an “unloading” scheme using infrared radiometry are discussed. The principal feasibility of the complete unloading of a volume of a slightly cohesive soil without its “instantaneous” failure with simultaneous thermoradiation measurements is indicated. A linear relationship is established between the change in the intensity of the radiation flux during unloading and the contact stress on the boundary of the specimen, which simulates the level of stresses in the mass. The value of the coefficient linking the indicated values can be used to interpret IR measurements conducted in other tests of the type of soil in question, including in-situ tests. The study was conducted with support from the Russian Fund for Fundamental Research (Project. No. 93-05-09246) Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 2–6 January–February, 1995.     

Comparative analysis of drinking water quality of different origin based on the results of integrated bioassay

The quality of water from public drinking water supply system, from artesian wells in Kiev and bottled non-carbonated drinking water produced by various companies was investigated using a set of animal and plant test organisms. The integral index—a total toxicity index which allowed researchers to classify water into different categories from “safe” to “highly hazardous” served as a water quality evaluation criterion.     

Investigating a safe ventilation rate for the prevention of indoor SARS transmission: An attempt based on a simulation approach

This paper identifies the “safe ventilation rate” for eliminating airborne viral infection and preventing cross-infection of severe acute respiratory syndrome (SARS) in a hospital-based setting. We used simulation approaches to reproduce three actual cases where groups of hospital occupants reported to be either infected or not infected when SARS patients were hospitalized in nearby rooms. Simulations using both computational fluid dynamics (CFD) and multi-zone models were carried out to understand the dilution level of SARS virus-laden aerosols during these scenarios. We also conducted a series of measurements to validate the simulations. The ventilation rates (dilution level) for infection and non-infection were determined based on these scenarios. The safe ventilation rate for eliminating airborne viral infection is to dilute the air emitted from a SARS patient by 10000 times with clean air. Dilution at lower volumes, specifically 1000 times, is insufficient for protecting non-infected people from SARS exposure and the risk of infection is very high. This study provides a methodology for investigating the necessary ventilation rate from an engineering viewpoint.     

"Composition" and regularisation of architectural production in contemporary China

The purpose of this paper is to explore how the “Beaux-Arts” “composition” sustained the constitution of design principles for architectural production in China in the last two decades of the twentieth century. “Composition”, a key technique of the “Beaux-Arts” system, is not a simple act of “putting elements together” into a unified whole, but also relates to an array of different “constructions” of architectural knowledge which regulate and sustain the act of design. Through analysing the structure of three “textbooks” published in the early 1980s, this paper examines three aspects of the “constructions”: the setting up of the principles for governing architectural forms, regularisation of design methods and approaches for architectural practice, and the construction of a “tradition” for the expression of “Chineseness”.     

Population,technological conversion,and optimal environmental policy

We consider an economy comprising two production sectors. A manufactured goods sector emits environmental pollutants during production. The other sector is an agricultural goods sector producing with constant returns to scale. It is used as numeraire. In our model, moreover, it is possible for the firms in the manufactured goods sector to select the production technology of intermediate goods out of two technologies: a “classical technology” with constant returns to scale or “modern technology” with increasing returns to scale. We explain the environmental Kuznets curve, which is described in many empirical studies of environmental economics, by using our theoretical model and show some relations between the technological conversion and the generating factor of the environmental Kuznets curve. Moreover, we consider a case in which a population can move freely between regions and in which this technological conversion affects the population distribution in the long run.     

Housing management matters: Citizenship and managerialism in the new welfare market

This paper addresses three neglected issues in the restructuring of housing policy and provision in the UK in the 1980s and 1990s: first, the relationship between welfare restructuring and management regimes; second, the nature of local variations in the impact of welfare restructuring; and third, the significance of human agency interpretations of change. The paper starts by summarizing the main features of welfare state restructuring and then considers recent manifestations of citizenship and managerialism in housing. Three competing conceptions of citizenship rights are used to examine changing notions of welfare: “market efficiency”, “institutionalized rights” and the “radical challenge” provided by social movements. A four-part typology of the main concepts and themes in the “new public management”—“efficiency”, “downsizing and decentralization”, “excellence” and “public service”—is used to present the main components of change in management regimes. The paper draws on literatures on housing management, citizenship and “the new public management” and on recent research into tenant participation, housing rights and housing advice services. Conclusions are drawn about how tensions between different conceptions of citizenship and public management are implicated with national and global influences at the local level to create particular welfare outcomes.     

Characterization of terrain surface and mechanisms of shallow landsliding in upper Kurokawa watershed,Mt Aso,western Japan

The paper describes the physical characteristics of the Mt Aso caldera (western Japan) where some 959 shallow landslides occurred between 1990 and 1998, denuding an area of 0.638 km². The variation in type and thickness of the recent pyroclastic deposits are described and linked to the spatial distribution of the landslides. The high monsoonal rainfall in July 1990 percolating into the recently deposited tephra overlying less permeable bedrock first saturated the soil mass and then effectively ‘floated’ the low density pyroclastic materials such that many slips occurred in the small, actively eroding, tributary valleys.      

Nonlinear elastic model for compacted clay concrete interface

In this paper, a nonlinear elastic model was developed to simulate the behavior of compacted clay concrete interface (CCCI) based on the principle of transition mechanism failure (TMF). A number of simple shear tests were conducted on CCCI to demonstrate different failure mechanisms; i.e., sliding failure and deformation failure. The clay soil used in the test was collected from the “Shuang Jang Kou” earth rockfill dam project. It was found that the behavior of the interface depends on the critical water contents by which two failure mechanisms can be recognized. Mathematical relations were proposed between the shear at failure and water content in addition to the transition mechanism indicator. The mathematical relations were then incorporated into the interface model. The performance of the model is verified with the experimental results. The verification shows that the proposed model is capable of predicting the interface shear stress versus the total shear displacement very well.     

Combined method of compaction of collapsible soils

The writer proposes a combined method of compaction of collapsible soils. He presents results of investigations carried out to study compacted zones of pads punched (tamped-out) by rammers 10 and 20 tons in mass, as well as a comparative analysis of the pads over against compacted zones obtained by means of plane rammers. The analysis results are illustrated by the “arch effect” on the stress conditions of the soaked soil mass. NIIOSP Institute. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 19–21, January–February, 1994.     

Experimental and theoretical investigation of deformation of water-saturated loess soils in the central asian region

According to the results of large-scale experiments with prolonged observations of vertical displacements, and also of total and pore pressures in the base, patterns of deformation of water-saturated loess soils were established. Practical methods are suggested for, calculating the final settlements of foundations and consolidation of their bases. Recommendations are given for correcting existing procedures for determining the modulus of deformation and the coefficient of consolidation of water-saturateed soils. Scientific Research Institute of Foundations and Underground Structures, Tashkent Coltruction Engineering Institute. “Uzstroimekhanizatsiya” enterprise, Taskent, USSR. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 3, pp. 27–31, May–June, 1994.     

Hazard potential of zones of weakness in gravity dams under impact loading conditions

Dam constructions worldwide are designed and constructed in view of the strictest safety aspects for all static and dynamic load cases. As experience shows, however, formation of cracks in the “homogeneos concrete” as well as unsatisfactory compound behavior of lift joints are not to be excluded. These zones of weakness especially on the upstream side of the dam—exposed to high water pressure (static and dynamic)—represent an increased risk of safety. The main investigation, apart from the computation of the dynamic effects on the dam as a global structure, focuses on the stability analysis of a pressure-water filled crack configuration subjected to “dynamic loading” in the form of seismic action on the dam-reservoir-system and alternatively by “impact spot-loading” within sectors of the reservoir. A fracture mechanics based analysis shows an excessive potential of damage for the afflicted structure.     

Simulation of a building and its HVAC system with an equation solver: Application to benchmarking

The today-availability of powerful engineering equation solvers is opening very new possibilities in technical component modelling and in system simulation. The simulation models, the “user guide” and the “reference guide” are all included in a same file. Reliable “reference” and “simplified” models are currently available for the building zone and for most (heating, ventilation and air-conditioning) HVAC components. Focus is given here on “simplified” models and on a simulation tool, called “Benchmark”. This tool should help an auditor to make the best use of the limited information usually available about actual fuel and electricity consumptions and to get a very first evaluation of the actual performances of a given HVAC system. An example of such use is presented. Another simulation tools and more information about the modelling of HVAC components will be presented in a further paper.     

Installation of underground structures by the method of underpinning with sectional tubing

Practical experience gained with work production on the installation of underground structures by the underpinning of previously installed structures with sectional tubing during reconstruction is discussed. Alternate schemes are cited for the mechanization of work involving the underpinning of a support structure constructed in the open by the “sunken shaft” and “wall-in-the-ground” methods. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 3, pp. 27–29, May–June, 1998.     

A critical comment on Oosterhaven–Stelder net multipliers

Recently, Oosterhaven and Stelder (OS; J Reg Sci 42(3):533–543, 2002; Trade, network and hierarchies: modeling regional and interregional economies, pp. 119–133, 2002) have introduced the operational idea of a “compensated net multiplier” (CNM) to take into account the double counting that occurs when output replaces final demand as an exogenous entry when the Leontief model is used to evaluate operationally the impact of large investments. Each output gross multiplier is compensated by multiplying it by the ratio of final demand to output. Oosterhaven (Research Report 04C01, 2004) has demonstrated that CNM fulfills an axiom of “total output preservation,” namely that the sum of effects equals the total output. It is shown in the present paper that the original CNM is only a homogenous formula with no causal link between the cause (the exogenous output) and the effect (the total output), so that it cannot be a multiplier. The paper explores all the other possibilities for deriving CNM by considering an exogenous output: (1) in absolute value; (2) in variation; and finally (3) at final equilibrium. Possibilities (1) and (2) do not work while only the variation from zero is option (3) working, although imperfectly. The derivations yield two results: (1) the final demand ratio, and so CNM, cannot be stable even if the technical coefficient matrix is fixed, except for very small perturbations; (2) even if total output preservation derives from the definition of a multiplier, CNM cannot fulfill total output preservation when an exogenous output is taken as the initial shock. De Mesnard (J Reg Sci 42(3):545–548, 200) has proposed another solution, “iterative net multiplier” (INM), derived by considering the successive rounds after an exogenous impact of output. INM is stable and makes a link between cause and effect. In contrast to the assertions by OS (J Reg Sci 42(3):533–543, 2002; Trade, network and hierarchies: modeling regional and interregional economies, pp. 119–133, 2002), INM fulfills output preservation when an exogenous output is taken as the initial shock. Neither CNM nor INM must be confused with the so-called “output-to-output multipliers.” The author thanks two anonymous referees, T. John Kim and Geoffrey Hewings, for their very helpful remarks.