応用水文 = Applied hydrology

Exploring and identifying structure is even more important for multivariate data than univariate data, given the difficulties in graphically presenting multivariate data and the comparative lack of parametric models to represent it. Unfortunately, such exploration is also inherently more difficult.

Multivariate Density Estimation

IAEG Commission No. 1—Engineering Geological Maps—is developing a guide to hazard maps. Scientists from 17 countries have participated. This paper is one of a series that presents the results of that work. It provides a general review of GIS landslide mapping techniques and basic concepts of landslide mapping. Three groups of maps are considered: maps of spatial incidence of landslides, maps of spatial–temporal incidence and forecasting of landslides and maps of assessment of the consequences of landslides. With the current era of powerful microcomputers and widespread use of GIS packages, large numbers of papers on the subject are becoming available, frequently founded on different basic concepts. In order to achieve a better understanding and comparison, the concepts proposed by Varnes (Landslide hazard zonation: a review of principles and practice, 1984) and Fell (Some landslide risk zoning schemes in use in Eastern Australua and their application 1992; Landslide risk assessment and acceptable risk. Can Geotech J 31:261–272, 1994) are taken as references. It is hoped this will also add to the international usefulness of these maps as tools for landslide prevention and mitigation. Six hundred and sixty one papers and books related to the topic are included in the references, many of which are reviewed in the text.

Engineering geology maps: landslides and geographical information systems

Why Big Fierce Animals are Rare: An Ecologist's Perspective. By Paul Colinvaux. Pp.236. (Princeton University Press: New Brunswick, New Jersey, 1978.) $9.50.

How Nature works

Experimental characterization of shrinkage and desiccation cracking in thin clay layer

Transition zones, such as bridge approaches, are discontinuities along a railway line that are highly prone to differential movement due to a rapid variation of support conditions along the track. The concrete approach slabs are often provided before and after the bridges to reduce this differential movement and provide a gradual variation in track stiffness. This paper provides insights into the dynamic behaviour of an integral abutment railway bridge (IARB) transition zone consisting of approach slab under moving train loads using finite element (FE) analyses. Firstly, the FE model is successfully validated against the published field data. Subsequently, the validated model is employed to investigate the influence of parameters such as approach slab geometry (length, thickness, inclination, and shape), backfill soil type, direction of train movement and train speed. Results show that the behaviour of IARB is sensitive to the length of the approach slab, backfill soil type and train speed. The findings of this study enhance the current understanding of the behaviour of IARBs subjected to moving train loading and identify the important parameters that influence their performance. 

Dynamic Behaviour of Integral Abutment Bridge Transition under Moving Train Loads

The objective of this study is to evaluate the spatial variability of depth to weathered rock in Chennai city using field test data. The database consists of nearly 400 borehole data covering the entire city with stratigraphic information and the same is used in the study. Ordinary kriging technique, which uses the spatial correlation of the data, is applied to estimate the depth at locations where the field measurements are not available. In addition, the variance of the estimated data is also computed. The developed map indicates that the depth to weathered rock in the study area varies from 3 to 30 m from the ground level. The estimated depths to weathered rock are compared and validated with a few selected borehole data and Multichannel Analysis of Surface Wave (MASW) test results. These maps can be used in the ground response analysis, foundation analysis, and design studies.

Spatial Variability of Depth to Weathered Rock for Chennai Using Geostatistical Kriging

Modelling of Early Age Concrete Temperature Distribution in Thick Rafts

Deep excavations and its impact on neighboring buildings is one of the most important issues when planning to construct new facility. In metropolitan city, it’s a challenging task for the execution of underground construction due to limited space and high cost of land. Hence, this implies that deep excavation has become necessary for the proper utilization of available space. Therefore, it’s important to make sure that adjacent structures are safe against deep excavation-induced deformation. In this study, a two-dimensional Finite Element Method in PLAXIS 2D has been chosen for the soil–structure analysis of deep excavation supported by contiguous pile wall located in Addis Ababa. For the numerical analysis two constitutive models Mohr–Coulomb and Hardening Soil have been applied in drained effective stress condition. The objective of this study is to investigate the effect of deep excavation on adjacent structures by considering support stiffness, ground water condition, neighboring building distance from face of excavation, and building load. The analysis of this study monitors parameters like maximum lateral wall deflection (δhm), maximum settlement (δvm), angular distortion of the neighboring structures, horizontal strain, and maximum bending moment of contiguous pile wall. Moreover, normalization of lateral wall deflection (δhm/He) and settlement (δvm/He) to the excavation depth (He) and neighboring building distance-excavation (D/He) has been presented. Parametric studies have been carried out by varying parameters of diameter of contiguous pile wall, horizontal anchor spacing, and pre-stress force of anchor. The analysis result has been recorded in terms of lateral wall deflection, ground settlement, and bending moment.

Assessment of Effect of Deep Excavation on Adjacent Structures Using Finite Element Analysis

Peninsular India is known for its complex intraplate seismicity and the southern part of it is characterized by diffused and distributed seismicity. In such cases the most com- monly adopted seismic source is the area source zone. The formation of seismic area source zone is subjective for regions such as south India and hence zonefree techniques to probabil- istic hazard analysis have been carried out in the past. The zonefree technique specifically the kernel technique is still new and has been applied to specific sites in south India such as Chennai and Kanchipuram. In this study the fixed and adaptive kernel techniques have been applied to the whole of south India to obtain the hazard value. The most influencing parame- ter affecting the kernel technique has been varied in two ways - the bandwidth parameters determined for the whole earthquake catalogue of south India and the other by determining the bandwidth parameters for the earthquakes lying in an influence area of 300 km radius around a particular site. It was observed that the adaptive kernel technique yielded slightly higher hazard values in regions of high seismic activity and lower values in regions of low seismic activity. However both the techniques yielded similar results in regions of spatial uni- form seismicity. A significant difference was observed in the uniform hazard spectra obtained for specific sites in south India when the bandwidth parameters were estimated considering whole of south India (regional) and an influence area of 300 km radius (local).

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G. R. Dodagoudar

Papers

Dynamic Behaviour of Integral Abutment Bridge Transition under Moving Train Loads

Spatial Variability of Depth to Weathered Rock for Chennai Using Geostatistical Kriging

Modelling of Early Age Concrete Temperature Distribution in Thick Rafts

Assessment of Effect of Deep Excavation on Adjacent Structures Using Finite Element Analysis

Kernel density estimation techniques for seismic hazard analysis of south india