Elastic Fields of a Nonhomogeneous Half-Space Subject to an Inclined Circular Load

The paper examines the elastic fields of displacements and stresses for a nonhomogeneous elastic half-space where the elastic parameters have a linear variation over a finite depth beyond which it is constant. The circular loading area is subjected to a uniform inclined load. The numerical method is developed by applying the fundamental solution of a layered elastic solid and integrating numerically it over the loading area. As a result, only the loading area needs to be discretized in using the proposed numerical method. Numerical examples of calculation of displacements are conducted, and excellent agreement with the existing closed-form solutions is obtained. The results obtained are used to understand the elastic fields induced by different types of loads in a nonhomogeneous medium.

Glacial lake deltas in New England record continuous, not delayed, postglacial rebound

Deltas formed in Lake Hitchcock, a glacial lake that developed in the Connecticut River Valley, New England, between ∼18.3 and 12.5 ka. The heights of topset/foreset contacts of these deltas presently increase northward, linearly, at rate of ∼0.9 m/km. Others have interpreted this as indicating that isostatic rebound did not begin until after the lake drained, several kiloyears after glacial retreat began. However, (non-elastic) adjustment of Earth's lithosphere to changing loads is known to occur on time scales of years. Late-glacial shoreline features elsewhere in New England also increase in elevation with distance from the LGM margin at ∼0.9 m/km, suggesting that this is a result of fundamental properties of the crust and mantle, and independent of the history of glacier retreat. On the basis of a numerical model of flexure of the lithosphere beneath a circular load, we suggest that deflection of the lithosphere is remarkably linear in a zone 50–200 km wide between the retreating ice margin and a forebulge, and that initial rebound of this zone is spatially quite uniform for some kiloyears before differential rebound starts. Thus, lake shorelines, formed over a period of some centuries during deglaciation would, today, rise linearly northward.

Analysis & Research on the Parameter Sensitivity to Bearing Capacity of Autocrane Operation Site

Autocrane has strict requirement for the bearing capacity of operation site during the process of lifting and transferring. To evaluate the intensity stability of operation site, the detailed analysis to ultimate bearing capacity of operation site must be carried out and find out the sensitivity factors which influencing the bearing capacity of operation site. In this paper, based on the analysis of computation pattern of ground bearing capacity, the ultimate bearing capacity is deduced through considering the shearing strength of superstratum under circular load ground. Simultaneously, based on single factor sensitivity analysis method, the sensitivity expression of cohesion force, internal friction angle and superstratum thickness to limiting bearing capacity is analyzed and calculated, and the influence regularities of the ultimate bearing capacity of operation site, due to the sensitive parameters, is discussed.

Load Model and F Coefficient on Asphalt Pavement Deflection

Deflection is the important index of asphalt pavement design and the final acceptance. Using double circular load of Design Specification and four circular load of Benkelman test vehicle, the deflection was analyzed with four kinds of common pavement structures, the results show that the deflection of theoretical calculation was the Benkelman beam test 55%-75%, but Design Specification uses the F coefficient which less than 1 to correct the difference, the two have had the contradiction. The deflection of two and three axles load mode were analyzed, and compared with the axle load conversion coefficient C1. The result could provide the reference of axle load conversion and the correction coefficient for the pavement design.

Target Loading from a Submerged Explosion

The pressure on a flat plate suspended over a submerged detonation is measured and simulated. Calculation and experiment are in relatively good agreement, although there is variation in experimental results and simulations are sensitive, near the centerline, to the computational details. This sensitivity is linked to the instability of the accelerating plume, typical of a Richtmyer-Meshkov instability. The plate loading features an initial force at plate center, followed by an expanding circular loading pattern. The initial load is due to plume impact, while the circular load arises from the impact of water transported up the edges of the explosion cavity.

THE ENGINEERING METHOD FOR DETERMINING THE SETTLEMENT OF POINT DUE ADJACENT CONSTANTLY DISTRIBUTED CIRCULAR LOAD

The article considers linear half space subjected to the circular load of constant intensity. Point settlement is determined by integrating relation to an infinitesimally small area, as per the Bussinesque solution, for concentrated load. The authors propose to replace an integration technique with a summation technique aiming to reduce computational efforts. The application of the summation techniques developed by the authors and their subsequent employment to develop an engineering method ensures sufficient accuracy for engineering purposes for point settlement evaluation. An attractive feature of the proposed engineering method is its implementation via nomograms ready for fast usage. It is especially convenient for a design process that requires obtaining relatively rapid results for multi-variant geotechnical design situations. A calculation algorithm and computational program have been developed to perform the summation techniques. Thanks to the extensive numerical simulations of settlement evaluations under the developed method, variation in the loading surface radius has also been limited. When applying the engineering method, relative error does not exceed 2% for cases when the ratio of radii from the settlement point being investigated to the centre point of circular loading varies within the interval of 1.5 to 7 times. This degree of accuracy is sufficient for engineering design needs. In practice, this engineering method can be applied in case it is assumed that the circular load of constant intensity is the load that acts on the base at the point of contact between the foundation and the base. The point the settlement of which is calculated is the point of the base or the point at the centre of the foundation. It is recommended to apply the engineering method presented in the article when the distance between adjacent foundations is 10 times less than the diameter of the foundation. When the distance is 10 times more than the diameter, foundations almost do not affect each other. The engineering method is especially useful when differential settlements are being calculated, e.g. the impact of deformation seams on the foundations or the effects of a projected building that will be attached to an existing one. This method can be used for calculating both shallow and deep foundations. When deep foundations are calculated, it is necessary to evaluate the enlargement of the pile base occurring due to friction between the ground and the pile material.