A procedure is described for the analysis and interpretation of data from a seismic refraction survey of soil with a linear variation of wave propagation velocity with depth, with a deeply embedded shot point, and with refraction at the air interface, as well as at the lower boundary. The problem is solved analytically and a digital computer is employed to develop aseries of charts which give arrival times at various distances as a function of soil characteristics for media with wide ly varying velocity distributions. The interpretation procedure consists of using these charts to determine the soil characteristics which agree most closely with the recorded response. Three typical applications are illustrated by the use of field data from a hydraulic landfill composed of maintenance dredgings.

抄録全体を表示

Based on undrained cyclic shear experiments conducted on a saturated Ottawa sand in the Torsional Simple Shear Device, the writers propose Eqs. (8) and (10), which respectively pre dict pore-pressure rise in the above soil under uniform and non-uniform dynamic shear stresses. These equations take into consideration the stress loading history, number of stress cycles and stress intensity function. There is excellent agreement between the experimental pore-pressure values and the analytical predictions as shownin Fig. 7 (for uniform) and in Figs. 10, 11, 12, 13 and 14 (for non-uniform) dynamic loadings.

抄録全体を表示

Co-ordination number in the assemblies of glass balls was analyzed to make it clear the mechanism of random arrangement of constituent particles and its relation to their shear strength. The conclusions are summarized as follows : The frequency distribution of co-ordination number is generally represented by the Gaussian in the random-homogeneous assembly. The Gaussian is never found in the assembly mixed by particles having different diameters. Not only the mean value of co-ordination number but also its standard deviation are essential in order to understand the characteristic of random assembly of particles. The mean value of co-ordination number has a clear correlation to the void ratio of assembly which is independent of the characteristic of grain-size distribution. The standard deviation is an index to show the heterogeneity of fabric throughout an assembly and is determined by the minimum void ratio of assembly. Unstable particles whose co-ordination numbers are less than four are found to increase suddenly with the increase of void ratio of assembly over a critical value. The internal friction angle of particle assembly can be determined not only by the mean value of co-ordination number but by its standard deviation.

抄録全体を表示

An analytical solution is presented, making use of the Schwartz-Christoffel transformation, to determine the seepage characteristics for the problem of flow under a weir having an inclined stepping, with a sheet pile at the downstream side, embedded in an anisotropic porous medium of finite thickness. The effect of anisotropy is studied by analyzing the problem in an equivalent isotropic medium. Numerical results are presented for quantity of seepage and exit gradient distribution in the equivalent isotropic medium.

抄録全体を表示

The theoretical consolidation curve based on Terzaghi's theory has been successfully represented by a simple explicit algebraic equation. The use of this equation has been extended by obtaining an expression for consolidation-coefficient involving selected three oedometer test data. This method, unlike the existing one, does not require the use of graphs or charts and it can be effectively used on a digital computer.

抄録全体を表示

Model test results of a vertical square anchor plate in loose, medium and dense sand are presented. The ultimate anchor resistance has been expressed in terms of a nondimensional breakout factor, N_q=P_u/γAH. For shallow anchors, the breakout factor increases with embedment ratio. Beyond the critical embedment ratio, when the anchor behaves as a deep anchor, the breakout factor remains approximately constant. The critical embedment ratio is about 5 for loose sand and increases to about 8 for dense sand. The variation of the experimental breakout factor for deep anchor with the angle of friction of sand has been compared with that predicted by the existing theories.

抄録全体を表示