摘要:

AbstractA numerical model for wave scattering problems due to P and SV wave incidences is outlined in this paper. After verifying the present model, a general parametric study on the displacement patterns along the canyons of different shapes due to P and SV wave incidences is also performed. In order to investigate the effects of geologic conditions on ground motions, a weathered V‐shaped canyon, which has different elastic moduli in the weathered layer, is also considered herein. The numerical results from this investigation demonstrated that (1) the present model is very suitable to simulate the problem of P and SV wave scattering along a natural canyon; (2) the shape of a canyon may have important effects on the displacement patterns along the canyon, so that a rectangular canyon is not appropriate to be a dam site due to its high amplification effects on incident waves; (3) the weathered layer on the surface of a canyon will significantly amplify the free field motion, especially for the case of softer weathered layer. Therefore, the excavation or grouting on a dam or a bridge abutment is not only necessary for static stability under static loads, but also beneficial to earthquake resistance because less amplification can be expected for sound rock abutment

ISSN:0363-9061    

DOI:10.1002/nag.1610170202

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractIt is becoming increasingly important, from an environmental viewpoint, to minimize vibrations induced in urban dwellings by blasting. The present study illustrates how the delay interval between blastholes can be chosen to control and minimize the vibration energy within the structural response band of most houses. In particular, it is shown that the only possibility of reducing such energy is to employ a delay interval in the range 10–35 ms. However, the induced vibrations are also dependent upon the accuracy of the delay initiators as well as the level of random fluctuations between each blasthole signature. It is shown that only very accurate electronic delays give the possibility of utilizing fully the delay sequence in order to control structural vibrations. If the vibration emission from each blasthole is totally uncorrelated with that of any other blasthole then the resulting amplitude spectrum of the blast will be totally unpredictable. This situation occurs irrespective of the delay initiation sequence or its accuracy. Under these conditions it is impossible to predict the blast‐induced energy lying within the structural response b

ISSN:0363-9061    

DOI:10.1002/nag.1610170203

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe results of a numerical simulation of the observed field‐drying behaviour of an unsaturated clay are described. In particular, the simulation of soil drying during the summer of 1983 is addressed.Richards' pressure‐based unsaturated flow formulation is adopted. Transient numerical solutions are achieved by making use of the finite element method coupled with a finite difference timestepping scheme.The application of the algorithm to the simulation of the problem in hand is described. The initial moisture content distribution represents saturated conditions as indicated by field‐measured data. Boundary conditions are determined from an interpretation of meteorological data. A simple method of representing plant root extraction of soil moisture is proposed.Comparisons of numerical results with field‐measured data collected by British Gas are presented. Good correlation is obtained. The numerical simulation is shown to be capable of representing the observed field‐drying behaviour. The complexity of modelling soil drying, as opposed to infiltration, is clearly illustrated by the work

ISSN:0363-9061    

DOI:10.1002/nag.1610170204

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610170205

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610170206

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610170201

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY