摘要:

AbstractPrecast concrete pavement units are used in areas with low subgrade CBR values and high static and dynamic loadings. Unlike flexible pavements and rigid pavements, there are no design charts from which pavement engineers can design precast concrete pavements. The author has investigated analytically the relative importance of the factors affecting the ultimate stress and subgrade bearing pressures in precast concrete pavements. Presenting the results in graphical form, the design charts are used toillustrate the new design method.

ISSN:0363-9061    

DOI:10.1002/nag.1610100202

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe subject of this work is the development of a code to study the behaviour of stratified and jointed rock masses around underground excavations. The rock mass is divided into two types of regions, one which is supposed to exhibit linear elastic behaviour and which may extend to infinity, and the other which will include discontinuities that behave inelastically. The former has been simulated by a symmetric direct, boundary integral, plane strain, quadratic, orthotropic module, and the latter by quadratic plane strain, membrane and inelastic joint elements. The two modules are coupled in one program. Sequences of loading include static point, pressure, body and residual loads, construction and excavation sequences, and quasi‐static earthquake load. The programe is interactive, with graphics. A numerical example is presented to illustrate the metho

ISSN:0363-9061    

DOI:10.1002/nag.1610100203

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractClosed‐form solutions are presented for the steady‐state distributions of displacement, pore pressure and stress around a point sink embedded in a homogeneous, isotropic elastic half space. These solutions have been evaluated for a typical case of a sink (pump) buried in sand and the magnitude of the settlement of the ground surface has been estima

ISSN:0363-9061    

DOI:10.1002/nag.1610100204

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractIn this paper it is shown that the Jaumann stress rate is not accurate for moderate deformations with deviatoric strains of more than 10 per cent; in such cases the objective stress rate is better calculated using the material rotation rate as calculated by polar decomposition. For very large deformations of granular materials this approach becomes invalid too because then the fabric tends to rotate together with principal stresses. Apparently in general the fabric rotation of a granular material cannot be described by continuum mechanics alone. For the numerical calculation of the material rotation for moderate deformations a numerical subroutine, based on polar decomposition, has been developed.

ISSN:0363-9061    

DOI:10.1002/nag.1610100205

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractDynamic stability of undrained, simple‐shear deformations on water‐saturated granular soil specimens is discussed. The soil is described by a 2D‐flow theory of plasticity for frictional and dilatant material. Contractant material becomes unstable (liquefies) at the state of maximum shear stress, whereas dilatant material becomes unstable after the state of maximum effective stress obliquity is reached in the softening regime of the background drained behaviour. In both cases the correct evolution equations for the growth coefficient of the instability are derived and compared with the results of the inertia‐free formulation of the

ISSN:0363-9061    

DOI:10.1002/nag.1610100206

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractHydraulic fracture propagation is predicted by a general numerical procedure which satisfies the transport equations in a global or integral sense over the entire fracture and over a small control volume near the leading edge. At each discrete time step the pressure distribution is selected from a four‐parameter family of profiles such that the stress intensity is equal to the critical value at the tip of the fracture and the integral equations are satisfied. Comparisons with previous analytical and, numerical solutions indicate accuracy within 10 per cent for a variety of test problems include wedge‐shaped and envelope‐shaped fractures, laminar and turbulent flows, incompressible liquids and ideal gases, permeable and impermeable media, prescribed inlet pressure and prescribed flow rates. CPU time is typically a few seconds for a tenfold increase in fracture length. The method has been applied to explosively driven and propellant‐driven gas fracturing problems as well as the traditional pump‐driven hydraulic fracturin

ISSN:0363-9061    

DOI:10.1002/nag.1610100207

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractSolutions are presented for the non‐linear load‐settlement behaviour of square‐configuration pile groups. The groups are represented by an equivalent axially symmetric model, and a non‐linear finite element is used to examine the mechanisms of group behaviour and their variation with pile spacing. It is shown that, at close spacings, the block failure mechanism occurs, with significant plastic zones being developed below the group and full pile‐soil slip only being developed along the outer piles. As the pile spacing increases, the failure mechanism gradually changes to the ‘single‐pile’ mode, whereby full pile‐soil slip occurs along all piles. Within the limitations of accuracy of the finite element solution, the values of group settlement ratio and efficiency are in reasonable agreement with values derived from

ISSN:0363-9061    

DOI:10.1002/nag.1610100208

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610100209

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610100201

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY