1995 Fiscal Year Final Research Report Summary
A Study on Methods for Judgment of Effectiveness of Grouting by Chemical Injections
| Project/Area Number |
06452265
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
Geotechnical engineering
|
|---|
| Research Institution | Tohoku University |
|---|
Principal Investigator |
YANAGISAWA Eiji Tohoku University, Faculty of Engineering, Professor, 工学部, 教授 (10005324)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
SUGANO Takahiro Port & Harbor Research Institute, Structural Division, Chief Researcher, 構造部, 主任研究官 (10187635)
KAZAMA Motoki Tohoku University, Faculty of Engineering, Professor, 工学部, 助教授 (20261597)
IKEDA Kiyohiro Tohoku University, Faculty of Engineering, Professor, 工学部, 教授 (50168126)
|
|---|
| Project Period (FY) |
1994 – 1995
|
| Keywords | Chemical Grouting / Consolidated Shapes / Injection Pressure / Gel Time / Permeation Grouting / Fracturing Grouting / Injection Rate / Overburden Pressure |
|---|
| Research Abstract |
In order to design chemical grouting process in sandy soil layrs, it is necessary to determine the most suitable grouting conditions depending on the characteristics of soils to be stabilized. For the purpose of finding ideal grouting conditions, one must know how soil conditions and injection conditions will affect the consolidation of soils quantitatively and qualitatively. This experiment focuses on the effect of four different variables, namely gel time, injection rate, overburden pressure and relative density of soils, on the growth of chemical grouts. The results presented in this study were drawn from 200 laboratory trials of cylindrical sand specimen whose height and diameter were held constant at 30cm respectively, which were prepared by Keisa No.6, No.7 and natural river sand. Two different types of chemical routs were used to get short get time (5 seconds) and long gel time (5 minutes) and injection rate was changed from 500cc/min to 2000cc/min. The overburden pressure was varied from 49kN/m^2 to 245.2kN/m^2 for the specimens of loose state (Dr=35%) an dense state (70% ).
The results of this experiment indicate that fracture grouting tends to occur when the gel time is short and injection rate is relatively slow. However permeation grouting tends to occur irrespective of other variables when the gel time is long and in this condition the grout results in nearly spherical form of consolidated sand which is said to be a desired condition of grouting. For the cases of short gel time grouts, hykraulic fracturing tended to occur when the injection rate low and in this case irregular form of consolidated sand was obtained. When the overburden pressure is high, it is possible to obtain a spherical shape similar to permeation grouting. However it should be noted that when the overburden pressure is high, the volume of the consolidated soil is decreased about 15% to 20% of the estimated volume.
|
Research Products
(14 results)
