摘要:

AbstractA hierarchical concept is proposed for the development of constitutive models to account for various factors that influence behaviour of (geologic) materials. It permits evolution of models of progressively higher grades from the basic model representing isotropic hardening with associative behaviour. Factors such as non‐associativeness and induced anisotropy due to friction and cyclic loading, and softening are introduced as corrections or perturbations to the basic model. The influence of these factors is captured through non‐associativeness manifested by deviation from normality of the plastic strain increments to the yield surface,F.Details of four models: isotropic hardening with associative behaviour, isotropic hardening with non‐associative behavioural anisotropic hardening and strain‐softening with a damage variable are presented. They are verified with respect to laboratory multiaxial test data under various paths of loading, unloading and reloading for typical soils, rock and concrete. The proposed concept is general, yet sufficiently simplified in terms of physical understanding, number of constants and their physical meanings, determination of the constants and impleme

ISSN:0363-9061    

DOI:10.1002/nag.1610100302

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThis paper attempts to present questions associated with the stability of advanced vault excavations which are driven according to the New Austrian Tunnelling Method (NATM) without lining of the temporary invert. The dimensions of the investigated cross‐section correspond to those of the tunnels driven on the new high‐speed tracks for the German Federal Railways. Two possible modes of failure are investigated with the aid of continuum mechanics analyses according to the finite element method. Reference is made to structural measures which may positively influence the stability of this construction stage. Furthermore, the manner in which the stress‐strain behaviour of a horizontal alternating sequence with open vertical discontinuities may be taken into consideration in a continuum mechanics analysis is also demonstrated. The analysis results presented clearly show that the load‐carrying action of the rock mass which characterizes the NATM may be better described by rock mechanics analyses according to the finite element method than by conventional pro

ISSN:0363-9061    

DOI:10.1002/nag.1610100303

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe paper considers the influence of a building wall system on the interaction between the soil and the foundation plate. A simplified semi‐analytical finite element method gives an economical solution for large three‐dimensional soil‐structure interaction problems. The simplified method appears to be sufficiently accurate for engineering purposes.Numerical results presented show significant influence of building walls on the foundation‐plate‐soil in

ISSN:0363-9061    

DOI:10.1002/nag.1610100304

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractAnalytic solutions to the problem of the time‐settlement behaviour of raft foundations have been limited in the past to flexible or rigid loadings, and have treated the foundation as being completely permeable. In this paper, solutions are presented for smooth circular rafts of any flexibility causing consolidation of a deep homogeneous clay layer, where the raft may be considered permeable or impermeable.Results for the time‐dependent behaviour of contact stresses, pore pressures, raft displacements and moment in the raft are presen

ISSN:0363-9061    

DOI:10.1002/nag.1610100305

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractExplicit time integration schemes provide an efficient solution to non‐linear dynamic finite element analyses of geotechnical problems especially when high frequency response is important. Such explicit time integration schemes require one of two distinct transmitting boundary formulations to overcome the problem of radiation damping. These are the superposition boundary approach, which involves the cancellation of the reflected waves by combining the solutions of two different boundary conditions and the viscous boundary approach, which involves the absorption of incident wave energy by frequency independent viscous dashpots. The theoretical justification of these two approaches and their means of implementation are reviewed. The solutions obtained using the two different boundary approaches to the problem of a rigid massless circular footing vibrating on an elastic half‐space are compared with an independent theoretical solution. The performance of the boundaries for problems involving step loading is also examined and the implications for any loading pattern with a non‐zero time average are disc

ISSN:0363-9061    

DOI:10.1002/nag.1610100306

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610100307

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610100308

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610100301

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY