Field tests provide the most reliable relationship between the lateral load applied to a deep foundation and the resulting lateral movement. Test results may also provide information used to assess the distribution of lateral resistance along the pile shaft and the long-term load-deflection behavior. A foundation designer may evaluate the test results to determine if, after applying an appropriate factor of safety, the pile or pile group has an ultimate lateral capacity and a deflection at service load satisfactory to satisfy specific foundation requirements. When performed as part of a multiple-pile test program, the designer may also use the results to assess the viability of different piling types and the variability of the test site.

Field tests provide the most reliable relationship between the axial load applied to a deep foundation and the resulting axial movement. Test results may also provide information used to assess the distribution of side shear resistance along the pile shaft and the long-term load-deflection behavior. A foundation designer may evaluate the test results to determine if, after applying an appropriate factor of safety, the pile or pile group has an ultimate static capacity and a deflection at service load satisfactory to support a specific foundation. When performed as part of a multiple-pile test program, the designer may also use the results to assess the viability of different piling types and the variability of the test site.

This test method covers procedures for testing vertical or batter piles individually or groups of vertical piles to determine response of the pile or pile group to a static compressive load applied axially to the pile or piles within the group. This test method is applicable to all deep foundation units that function in a manner similar to piles regardless of their method of installation.

Standard Test Method for High-Strain Dynamic Testing of Deep Foundations

This test method obtains the force and velocity induced in a pile during an axial impact event. Force and velocity are typically derived from measured strain and acceleration. The Engineer may analyze the acquired data using engineering principles and judgment to evaluate the integrity of the pile, the performance of the impact system, and the maximum compressive and tensile stresses occurring in the pile.

Low strain impact integrity testing provides acceleration or velocity and force (optional) data on slender structural elements (that is, structural columns, driven concrete piles, cast in place concrete piles, concrete filled steel pipe piles, timber piles, etc.). The method works best on solid concrete sections, and has limited application to unfilled steel pipe piles, H piles, or steel sheet piles. These data assist evaluation of the pile cross-sectional area and length, the pile integrity and continuity, as well as consistency of the pile material, although evaluation is approximate. This test method will not provide information regarding the pile bearing capacity. It is generally helpful to consider the soil profile, construction method and site records when evaluating data obtained by this method. Other useful information to consider and compare with results of this test includes low strain integrity test results of similar piles at the same site, concrete cylinder or core strength test results, automated monitoring data on equipment placing the concrete when augered piles are used, or information obtained from crosshole sonic logging (Test Method D6760) or thermal integrity profiling (Test Methods D7949) if available.

Standard Practices for Monitoring Earth or Structural Movement Using Inclinometers

 

An inclinometer is a deformation monitoring system, which uses a grooved pipe or casing with internal longitudinal grooves aligned with the anticipated direction of movement, installed in either a soil/rock mass or a geotechnical structural element. The inclinometer casing can be surveyed with a single traversing probe or with an array of in-place inclinometer (IPI) gauges connected to a data logger. The measurement and calculation of deformation normal to the axis of the inclinometer casing is done by passing a probe along the length of this pipe or placement of a sensor array, guided by the internal grooves. The probe or sensor array measures the inclination of the pipe, usually in two orthogonal directions 90° apart (X- and Y-direction) with respect to the axis of the casing (Z-direction, usually the line of gravity). Measurements are converted to distances using trigonometric functions. Successive surveys compared with an initial survey give differences in position and indicate deformation normal to the axis of the inclinometer casing. In most cases the inclinometer casing is installed in a near-vertical hole, and the measurements indicate subsurface horizontal deformation. In some cases, the inclinometer casing is installed horizontally, and the measurements indicate vertical deformation.

Inclinometers are also called slope inclinometers or slope indicators. Typical applications include measuring the rate and direction of landslide movement and locating the zone of shearing, monitoring the magnitude and rate of horizontal movements for embankments and excavations, monitoring the settlement and lateral spread beneath tanks and embankments, and monitoring the deflection of bulkheads, piles or structural walls.