Negative skin friction in piles due to fill surcharge | |
| Author | Ng, Hon-kwong |
| Call Number | AIT Diss. no.D15 |
| Subject(s) | Piling (Civil engineering) Friction |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering of the Asian Institute of Technology, Bangkok, Thailand |
| Publisher | Asian Institute of Technology |
| Abstract | The development of negative skin friction and settlement of a pile due to a fill surcharge is analysed in the form of a circular elastic rod embedded in a soil layer underlain by an ideal elastic substream of infinite depth. The soil layer is assumed to settle according to Terzaghi's one-dimensional consolidation theory. The problem is decomposed into three systems, manely, a consolidating top soil layer; an extended top elastic soil layer in the absence of the pile characterized by the elastic constants of the soil skeleton; and a fictitious pile represented by a Young's modulus equal to the difference of the Young's moduli of the real pile and the elastic soil skeleton. The unknow fictitious pile force is determined under the approximation that the axial strain in the fictitious pile is equal to the summation of the vertical normal strain in the consolidating soil layer and the average vertical normal strain in the clastic soil layer over a pile cross-section at the original pile location. The real pile force is then obtained by integrating and combining the axial stress in the fictitious pile, the effective vertical normal stresses is the consolidating soil layer and the vertical normal stresses in the elastic soil layer at the original pile location. Numerical solutions are obtained for various practical values of the parameters involved. Three types of drainage conditions are considered, namely, two-way drainage, one-way top drainage and one-way bottom drainage. Results are presented in graphs for the purposes of analysis and design of such structures. The pile force is found to increase with increasing pile radius-length radio, pile stiffness, compressibility of top soil layer and rigidity of the elastic substratum. When the top soil layer is incompressible, the pile force practically vanishes. The influence of Poisson's ratio of the substratum is not significant. When the substratum is compressible, positive skin friction is found in the lower part of the pile |
| Year | 1975 |
| Type | Dissertation |
| School | AIT Publication (Year <=1978) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Dissertation (D) (Year <=1978) |
| Chairperson(s) | Karasudhi, Pisidhi |
| Examination Committee(s) | Lee, Seng-Lip |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 1975 |