Drilled Displacement Research Articles

Measured end resistance of CFA and drilled displacement piles in San Francisco Area alluvial clay

Continuous Flight Auger (CFA) and drilled displacement (DD) piles in the San Francisco (California, USA) area are typically designed using a combination of side- and end resistances. For moderately...

Design and Construction Validation of Pile Performance through High Strain Pile Dynamic Tests for both Contiguous Flight Auger and Drilled Displacement Piles

Design and Construction Validation of Pile Performance through High Strain Pile Dynamic Tests for both Contiguous Flight Auger and Drilled Displacement Piles

Construction of Deep Foundation Ditch under a Reconstructed Multi-storey Building on the Main Avenue of St.Petersburg

The reconstruction of the former administrative building of the beginning of the 19th century in the center of St. Petersburg on the main avenue and adaptation it to the modern Hotel is considered. The new 6-storey building is done as a concrete frame with max height 27,7 m. The underground floor 66,9 x 20,09 m for parking and technical rooms is planned under the whole area of the building. The 4-5 storey brick block of flats and 3-5 storey administrative building, the historical memorial, adjoin to the building under the reconstruction. The adjacent buildings have cracks and defects due to general wear, rigidity decrease of the building and low deformation characteristics of the soil. The soft water saturated soil under the basement become thixotropic under insignificant dynamic effect (transport, seasonal freezing and etc). Prior to dissembling the building it was done the monitoring of the adjacent buildings and the reinforcement of their foundations using the method of injecting cement grout into foundation and erecting 75 tilted anchor piles 25 m long, 200mm diameter according to “Titan” Technology. The protection walls of the excavated pit for underground space in the reconstructed building was done by metal sheet pile “Arselor 37-700”13,5 m long, boring piles 27m long and diameter 410mm. Additionally jet-grouting piles were erected to the depth min 2 meters from the footing of the existed foundation along the break walls of the adjacent buildings. While excavating the pit in order to provide the sheet pile stability, the strut from metal pipes was done. In order to make pile base under the frame of the building 162 bore piles 27 m long and diameter 550mm were used. The piles were made according to the Drilling Displacement System (DDS) technology. Scheme of constructive decisions are given. The monitoring during the foundation construction and the beginning of the upper part construction showed that the additional settlement of the adjacent buildings did not exceed 20mm, the limited allowance for this type of the building.

Field Tests to Investigate the Installation Effects of Drilled Displacement Piles with Screw-Shaped Shaft in Clay

AbstractThis technical note presents a detailed field study to investigate the installation effects of drilled displacement (DD) piles with a screw-shaped shaft in Shanghai soft clay. Horizontal soil displacements and pore water pressures were measured in the vicinity of two DD piles with a screw-shaped shaft during their installation and subsequent soil consolidation periods. The results show that the horizontal soil displacements induced by the installation of a DD pile with a screw-shaped shaft are mainly concentrated within a circular region with a radius smaller than six times the pile external diameter and that the maximum horizontal soil displacements decrease by 10–20% one day after concreting and then tend to be stable. The excess pore water pressures reach their maximum when the drilling rod reaches the design depth or the concreting is completed and then start to decrease with time following approximately an exponential decay function.

Static load test interpretation using the t-z model and LRFD resistance factors for auger cast-in-place (AC IP) and drilled displacement (DD) piles

Static load test data for augered cast-in-place (ACIP) and drilled displacement (DD) piles were interpreted using the <i>t-z</i> model method. Eighteen load tests consisting of load-settlement and load transfer data were obtained from two different construction sites. A series of back-calculations were performed using the <i>t-z</i> model method to enhance the static load test data, which were then analyzed to obtain resistance bias factors for the currently used ACIP and DD pile design methods. The <i>t-z</i> model method enhanced load test data provides the ability to interpret field data for loading conditions beyond those measured during test. The resistance bias for the various design methods were then used to obtain the resistance factors based upon the traditional calibration approach. Furthermore, resistance factors were also obtained using probabilistic analysis based upon the <i>t-z</i> model method. The comparison of these two sets of resistance factor indicates that those obtained from the traditional calibration approach contain a wide range of magnitudes, while the resistance factors from the <i>t-z</i> model method design result in a consistent level of reliability.

Drilled Displacement Piles – Current Practice and Design

AbstractDrilled displacement piles are being increasingly used as foundation elements, particularly in projects requiring fast construction. Different types of drilled displacement (DD) piles are available in practice. DD piles are classified according to the drilling tool design and installation method. The capacity of a DD pile, depending on its type, is between the capacities of geometrically similar nondisplacement and full-displacement piles installed in the same soil profile. This paper provides an overview of the different types of DD piles and their installation techniques and describes three design methods used in practice. It also compares DD pile capacities obtained with these design methods for two different sites.