| Summary: | 碩士 === 國立雲林科技大學 === 營建工程系碩士班 === 100 === The bearing capacity of drilled shafts is probably affected by the drilling mud and losen zones around the pile tip, thus industries often use tip grouting to improve the pile tip resistance. In order to verify this improvement of tip grouting, the discrete element program PFC2D (Itasca, 2004) was used to simulate the tip grouting and the following pile load test in the bedrock depth of 34.6 m, according to the Sin-Yi district construction data. The field results were also compared with the numerical results, to better understand the variation of the pile tip displacement and the stress around pile tip and sleeve during the pile load test.
The numerical simulation of Brazilian test was used to obtain the reasonable parameters for later tip grouting simulation. During the tip grouting simulation, PFC2D fixed coarse-grid fluid was used to study the grouting with coupling computation of solid particles and the fluid under constant density and incompressible condition. Field injection rate was converted into the grouting rate between 5.6 and 1.4 m/sec and it was found that the grouted mass at high rate was around four times larger than the grouted mass at low rate. From numerical results of pile load test, the tip displacements of piles with low rate and high rate grouting were 10% and 19% respectively lower than the tip displacement of an un-grouted pile. The pile tip resistance was improved and the skin friction was relatively lower in the tip-grouted pile, compared to an un-grouted pile.
|
|---|
