Base grouting to improve the performance of wet process bored piles in Bangkok sub-soils | |
| Author | Anwar, Muhammad Ashfaq |
| Call Number | AIT Thesis no.GE-96-05 |
| Subject(s) | Piling (Civil engineering) Grouting |
| Note | A thesis study submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Civil Engineering |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. GE-96-05 |
| Abstract | Base grouting techniques are widely used to rectify the soft toe problem of large diameter wet process bored piles in Bangkok subsoils. In practice two different techniques, commonly known as flat jack and tube-a-manchette are used. This research study is mainly focused on the tube-a-manchette technique. Six prototype piles having pile tips in the well known second sand layer in Bangkok metropolitan area were constructed and tested to determine the mode of grout spreading under the pile tip. All these piles were grouted by varying the controlling parameters such as grout volumes, pressures and injection rates. Soil samples were collected from beneath the pile tip and some distance away from the pile tip and analyzed. It is observed that grout does not penetrate into the surrounding sand of the pile toe. It partially replace and/or precompress the sediments present under the pile tip and most of the grout just rises up the soil/pile interface by replacing the bentonite cake. Recommendation are made to eliminate the soft toe problem more effectively, hence to improve the performance of these piles. Additionally, pile load test data of some 26 piles with grouted and ungrouted bases, tested under similar ground conditions is analyzed to assess the improvements made by base grouting. It is observed that base grouting does not have much effect on the ultimate failure load of piles seated in the first sand layer but considerable improvement in stiffness is achieved and the settlements in the working stress range are definitely reduced by base grouting. Stiffness in the working stress range for piles seated in the second sand layer is not improved by base grouting but certainly once the skin friction is fully mobilized, based grouted piles behave in a more stiff manner in this range. Pile load test data of grouted base piles, grouted by two different techniques i. e) flat jack and tube-a-manchette, under similar ground conditions is also compared. |
| Year | 1997 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. GE-96-05 |
| Type | Thesis |
| School | School of Civil Engineering |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Geotechnical Engineering (GE) |
| Chairperson(s) | Balasubramaniam, A. S. ;Wanchai Teparaksa (Co-Chairperson); |
| Examination Committee(s) | Bergado, D. T. ;Noppadol, Phien-wej; |
| Scholarship Donor(s) | Government of Japan; |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology |