Behavior analysis of post-grouted micropiles in clay soils from tension load test results

Abstract

The design of micropiles is carried out through semi - empirical equations developed from field tests and previous<br> experiences. This design represents an approximation of the real soil - micropile behavior and generates uncertainty<br> since the design involves the ultimate micropile bond strength which is selected as a function of the type of micropile<br> and soil characteristics and presents a broad range of values leading to a wide range of micropile resistances for the<br> same conditions. Therefore, the standards recommend verifying and determining the field capacity of the micropile<br> designed by static load tests, which are real-scale tests that allow knowing the field behavior between the built<br> micropile and the ground. In the present paper, the analysis of the behavior of three different type D post-grouted<br> micropiles was carried out through the results of static tension load tests following the FHWA NHI-05-039 "Micropile<br> Design and Construction" standard, the geotechnical characteristics of the area were considered in the verification of<br> the design and with the results of the load tests an analysis of the acceptance criteria recommended in the<br> aforementioned standard was performed.