Power Line Foundation Design Using the Pressuremeter

During the design phase of a 2000-towers electric power transmission line, a load test program was undertaken to evaluate the accuracy of new design methods for uplift and lateral capacity of drilled shafts. Seven uplift tests and six lateral load tests were performed in three different soil deposits: a medium clay, a very hard clay and a sand. The shafts were 2 ft in diameter and either 10 or 15 ft long. The pressuremeter test results are used together with existing methods to predict the behavior of the shafts

Numerical simulation of scour infilling in overset grid

In the present study, sediment transport models have been implemented in the CFD solver FANS3D to simulate scour infilling process around a circular pier. FANS3D uses the finite-analytic method, which incorporates the analytic solution of the differential equation in its linearized form in the respective small subdomain. The Reynolds-Averaged Navier-Stokes equations are solved in general curvilinear coordinate system. The Chimera overset grid technique is utilized to simulate flows in a multi-block domain. This paper presents the time development of the scour hole and the infilling process due to bed load transport of non-cohesive sediment under the three flow conditions: flood, normal, and flood-to-normal transitional. The effect of the size of the sediment particle is also discussed

The borehole erosion test

Soil erosion is a major problem in civil engineering. It is involved in bridge scour, meander migration, levee and dam overtopping, internal erosion of earth dams, surface erosion of embankments, and cliff erosion. The best way to predict the erodibility of a soil is to measure it directly on a site specific basis by testing samples in the laboratory or by in-situ testing in the field. The borehole erosion test or BET is a new in-situ soil erosion test proposed to measure the erosion of the walls of a borehole while wet rotary drilling takes place. The increase in diameter of the borehole as a function of time and for a given flow velocity in the borehole is measured with borehole calipers. The result is a profile of soil erodibility as a function of depth. Tests in clay and in sand conducted at the National Geotechnical Experimentation Sites at Texas A&M University are presented

Relationship between soil erodibility and engineering properties

Different soils exhibit different erodibility (sand, clay) therefore erodibility is tied to soil properties. On the other hand, many researchers have attempted to develop such equations without much success. One problem is that erodibility is not a single number but a relationship between the erosion rate and the water velocity or the hydraulic shear stress. This erosion function is a curve and it is difficult to correlate a curve to soil properties. The main purpose of this study is to develop correlations between the elements of the erosion function (critical velocity, critical shear stress, slope of the erosion function) with elementary soil properties (plasticity index, mean grain size, unit weight, shear strength, and others). There are many tests to evaluate the erodibility of the soil in laboratory and in situ and to identify the erosion function (i.e. Jet Erosion Test, Erosion Function Apparatus, Hole Erosion Tests, etc.). This study deals with developing correlating equations between erodibility parameters obtained from many years of testing experience with Erosion Function Apparatus (EFA) and geotechnical properties of the soil

Load-settlement modelling of axially loaded drilled shafts using CPT-based recurrent neural networks

The design of pile foundations requires good estimation of the pile load-carrying capacity and settlement. Design for bearing capacity and design for settlement have been traditionally carried out separately. However, soil resistance and settlement are influenced by each other, and the design of pile foundations should thus consider the bearing capacity and settlement inseparably. This requires the full load–settlement response of piles to be well predicted. However, it is well known that the actual load–settlement response of pile foundations can be obtained only by load tests carried out in situ, which are expensive and time-consuming. In this paper, recurrent neural networks (RNNs) were used to develop a prediction model that can resemble the full load–settlement response of drilled shafts (bored piles) subjected to axial loading. The developed RNN model was calibrated and validated using several in situ full-scale pile load tests, as well as cone penetration test (CPT) data. The results indicate that the developed RNN model has the ability to reliably predict the load–settlement response of axially loaded drilled shafts and can thus be used by geotechnical engineers for routine design practice