Anchor Orientation Research Articles

The Use and Implications of a Canine Companion in a Therapeutic Day Program for Nursing Home Residents with Dementia

This manuscript reports the use and implications of a Canine Companion within a rehabilitation model program for nursing home residents with dementia. Projected results included elimination of some restraints for wanderers, social interaction between the animal and individuals, between group members about the dog, and orientation of individuals to the present in the presence of the dog. Unexpected results included re-orientation of individuals who had withdrawn into themselves, and the use of the dog's presence to anchor orientation to the day of the week by residents. General and specific implications of these findings are discussed with recommendations for future research.

Stabilization of Coastal Slopes by Anchored Geosynthetic Systems

Coastal slopes are subjected to destabilizing forces from wave action, current scour, and exfiltrating ground water. As such, they are vulnerable to both surficial erosion and shallow sliding failure because of their low shear strength near the surface. One way of increasing the stability of these slopes is to increase the confining stress on the ground surface by means of an anchored geosynthetic system (AGS). This approach is less visually and physically intrusive than traditional “hard armor” methods, which in many instances are prohibited in environmentally sensitive areas such as coastal sand dunes. Theoretical relationships for determining required AGS loads and anchorage lengths are presented that can be used to evaluate stability for different soil conditions and seepage directions. Some important variables affecting AGS performance such as failure depth, surface configuration, anchor orientation, and seepage influence on near-surface stability are also described. The theoretical predictions were examined by conducting laboratory stability tests on saturated sand slopes, which were stabilized by an anchored geosynthetic netting and subjected to parallel seepage and tractive surface stresses. Good agreement was observed between predicted and actual anchor loads at failure.

The performance of drag anchor and chain systems in cohesive soil

The synthesis of anchor equilibrium equations with recently derived chain equilibrium expressions enables calculations for anchor system capacity which account for the anchor‐chain interaction. This forms the basis for a study into the effects of relative chain size on anchor performance, and extrapolation of scale‐model tests to prototype events. Applications of these expressions are particularly suited to clay soils, where the failure mechanism of the soil is local and hence the anchor capacity is essentially independent of anchor orientation. Expressions are derived for the ultimate holding capacity of anchors in terms of two fundamental anchor parameters. Analytical relationships for the development of embedment and capacity with drag distance are shown to compare favorably with numerical solutions and also with field test data.

Anchor Design for Slope Stabilization by Surface Loading

The increase in slope stability by application of discrete surface loads depends in part on the orientation of the load. For stabilization systems such as anchored geosynthetics, the load orientation corresponds to the angle of anchor installation. A theoretical study is performed to determine the optimum orientation of such anchors in purely cohesionless soils to maximize the increase in slope stability. Three cases are analyzed: a hypothetical surface load without anchorage, surface load with grouted end anchorage, and surface load with driven friction anchors. The last case involves the most interesting analytical solution since the optimum anchor orientation is a function of the slope geometry, the in situ stresses, and the desired increase in factor of safety. The required length and spacing of anchors depend, in addition to the aforementioned factors, on the anchor diameter, the internal friction angle of the soil, the soil-anchor interface friction, the strength of the geosynthetic, and the depth of the potential failure surface. A simplified equation is given for the anchor orientation, and a design chart is presented for determining spacing and length requirements. An example problem illustrates the importance of proper anchor orientation.

The performance of marine anchors with planar flukes in sand

The problem of determining the holding capacity of flat plates and marine anchors in cohesionless soils is briefly reviewed and the reasons for the difference in the performance of marine anchors and that of simple flat plates are identified. The role which each anchor component plays during the embedment process is discussed.An analytical procedure to estimate the holding capacity of anchors with planar flukes, such as the Danforth anchor, as a function of soil properties and the depth of penetration into the soil is presented and checked against data from laboratory and published field tests.Factors such as anchor stability and characteristics of the pulling cable which can affect both anchor orientation and the maximum depth to which a particular anchor can penetrate the soil have not been included in the analysis. Consequently, it is not yet possible to predict the ultimate holding capacity that a particular anchor may achieve if pulled through an adequate distance.